Getting electrical signals from point A to point B is pretty standard
thing...Put a piece of copper wire between A and B and the job is done.
A century of development has left us with increased specialization in
wiring, connection devices, and everything in between point A and B.
"Mil-Spec" or military specification, has become the buzz-word in
motorsport electrical harness construction. Actually motorsport wiring
has developed it's own specialized connectors but it's still largely
constructed from aerospace components.
Perhaps "Race-Spec" will become the new buzz-word....Probably not with
the trillions of dollars spent on drones, F22's, and commercial
This is not a definitive guide on building wiring harnesses as this
could encompass two wheels, four wheels or no wheels. It does give you
a perspective on motorsports ecu wiring and provides access to further
literature for you to study and make your own decisions. We build ecu
wiring harnesses for our production items and for our own racing
On one end of the scale there is OEM automotive wiring, like on your
new passenger vehicle or truck, wherein costs are paramount and
warranties are offered, in some cases, bumper to bumper for 100,000
miles. Pictured above is a production passenger car harness in GXL and
These vehicles and their myriad of up to sixty microprocessors,
connectors, sensors, relays, and switches are tested for years on end
in extremes of temperature, humidity, vibration, and electrical
interference. There are no mil-spec metal shell connectors, no airframe
tie wrapping or concentric twisting, and no epoxied or glue-shrunk
connections...Only plastic connectors and crosslinked polyethylene GXL
and TXL multi-strand copper wiring without any silver, tin or nickel
plating. Guess what, they work just fine...amid increasing complexity,
for years on end. A typical mid-sized car will have about 45-70 lbs of
One time we scrapped out a 20 year old Honda Civic and were amazed at
how all the wiring was still in perfect shape...Connector seals were
still sealed and clean inside and all the grime, water and heat had not
caused any failures. Wiring was still flexible and not cracked. OEM
specifications and engineering are pretty damn good.
In short, automotive grade wiring and connectors have a pretty good
track record. Not glamorous, but in business, economics and bean
counters seldom are.
Airbus 380: With 530Km of wires, cables and wiring harnesses
weave their way throughout the airframe. With more than 100,000
wires and 40,300 connectors performing 1,150 separate functions, the
Airbus A380 has the most complex electrical system Airbus had ever
designed. They got to do it twice i.e. rip it all out and do it over
due to incompatibility in various software programs spread across a
myriad of suppliers. No concentic twising, no DR-25, no RT-125 epoxy.
20,000 flight hours life. Go figure.
You Tube Video
This has evolved from aircraft and military specifications wherein
light weight and reliability are paramount. As motorsports evolved into
an increasingly more sophisticated and expensive professional endeavor,
specific motorsport connectors have evolved which are even lighter and
smaller than their aerospace counterparts. These products don't have to
meet oem production testing requirements...They just have to be
reliable in a racing environment which is not the same as freezing in
Siberia or bouncing down rural roads in your F150 pickup for decades.
Sort of serious in a Darth Vader, rubber-fetish way. Bondage and latex
in the hell of an engine bay. Above are heat shrink boots sealing
circular connectors and the DR-25 heat shrink wire protection.
Everything than can slow you down is the enemy....weight of the wires,
weight of the connectors and any kind of outright failure, or worse,
intermittent failure, which is harder to isolate. This is why F1 might
be using tiny 30 gauge wire or why the new McLaren MP4-12C went to
extremes in specifying hexagonal aluminum wire to save both space and
In motorsport electronics Mil-spec circular connectors are the norm,
full of all sorts of trickery like strain reducing service loops and
concentric twisting for flexibility and more compact wiring harnesses.
Reliability at 30,000 feet or going airborne at the Nurburgring...it's
all the same thing...well, sort of the same thing.
"Service Loops" are used on Mil-Spec / Deutsch Autosport circular
connectors for wire sizes 16 AWG to 30 AWG. The purpose is to provide
strain relief to the wire termination and to provide a surplus length
for repair purposes. It is not an aircraft procedure per se and is only
used in military and motorsport applications.
Depending on your planning these can go in first or last. The wires
have to be loose so doing them as they are installed in the connectors
easier with a large number of terminals.
In any case
extra wire length has to be planned for with concentric twisting,
service loops, and bends in the installed wiring harness (longer radius
on the outside of the bend). On the average plan for 15% additional
length. PDF on
Looping Tool and
The process is to crimp and insert the wires into the connector
singularly or two at a time. Use an 1/8" or 3 mm round-nosed tool to
form a loop in the wires. You can grind down and modify a machinist's
scribe or small screw driver to make a looping tool.
On circular connectors it is recommended to start at the center and
work outwards if the numbering system runs clockwise or
counterclockwise. For rectangular or circular connectors identified in
rows, it is recommended to work row by row. Loops should face inwards.
Loops must be staggered to minimize any increase in the cable diameter.
When looping is complete all loops should face inwards to give a neat
appearance and to insure that the wires are not trapped or damaged if
an adapter or back fitting is present.
If your connector is already terminated and the wires are shrunk with
DR-25 it gets a little more difficult as you will have to press back
the connector to bow the wires. You may have to cut back on the harness
DR-25 to free up the wires.
All of this is a bit stiff to wrestle with so holding the wiring
harness, the connector, and the looping tool at the same time is a bit
interesting. Think ahead. A specialized connector fixture (best) or a
vise with aluminum jaws can be used to hold the connector.
The connector above features concentric (twist) wiring, service (strain
relief) loops at the connector, lacing cord and Kynar clear shrink to
hold the wires tightly together near the connector. Kapton tape will
cover the wires at the connector to protect them from the special
adhesive-lined shapes or RBK Adhesive Lined Shrink. With the wires
covered by DR-25 and the Connector sealed by the Raychem Boot, the
harness will be protected from the environment and from abrasion.
Here flat braided lacing tape is counter-wound to hold the concentric
twisted wires in place. Something to think about: Were the service
loops put in first or last? Generally first. Guideline for
Here a Deutsch Autosport connector has its Spec 55 wires wrapped in
Kapton tape to prevent the adhesive shrink or harness epoxy from
grabbing the wires. The
tape allows repairs to be made at a later date. Once the adhesive or
it really grabs the connector, the DR-25 wire covering, and anything
underneath it. Raychem boots are heat shrunk at about 480F (280C).
Low Static Kapton adhesive tape is commonly available in 1/4, 3/8" and
1/2" rolls. The silicone adhesive does not leave any residue. It is
amber in color.
Circular connectors, glue shrunk boots, Raychem DR-25 shrunk over
concentric wound silver-plated Raychem Spec 55 XLETFE wiring and, of
course, the requisite yellow shrink tube labels covered in Raychem
RT-375 clear shrink tubing. Cosworth Pectel
. Mil-Spec evolved into Race-Spec.
In case you doubt the need for epoxy or adhesive-lined terminations,
the above picture gives graphic evidence of corrosion traveling down
the voids between the strands of copper wires. Since we go to the
Bonneville Salt Flats two to three times a year for up to a month, and
everything gets bathed in salt, properly sealing the electrical
connections is a major concern. Year one OK...year two fix one or two
things...year three redo everything. Using adhesive-lined or
epoxy-based sealing schemes we can keep corrosion out of our wiring
OEM harnesses employ silicone seals on thermoplastic connectors to
address these issues. Any gap in the harness can provide a path to
Sealing boots and shapes that do not have adhesive melt can be done
with specialized two part epoxies. Abrading the inner surface and
applying the epoxy to the connector and cable before the heat shrinking
operation. Epoxy is not applied to the inside of the heat shrink. Here
the connector is sealed to the cable using V25 Deray thin wall shrink
tube (2:1) and sealed with epoxy.
Resintech RT125 Epoxy
The preferred epoxy for sealing wiring harnesses is Resintech RT125
is a two part semi-flexible epoxy that is mixed 50/50. You can purchase
RT125 and a 3M applicator mixing gun from Prowire. These are standard
50ml cartridges. Note they have a shelf life. If you are using this in
concert with non-adhesive lined boots do not fill the boot up with
or you will have a real mess. Only seal the ends one at a time. Be
prepared to do some clean up wiping with a clean cloth and alcohol as
hardens much later than the adhesive lined boots.
If the entries and exits of the boot are single round diameters then
either adhesive lined or non-adhesive lined boots can be used. If
non-adhesive then seal the exits with RT125, one exit at a time, wiping
the excess off. Syringes are used for more delicate sealing of smaller
Here we have sealed the multiple branches under the Raychem boot with
Resintech RT125 and shrunk the boot over the epoxy. It's a good idea to
use an additional tie wrap strain relief at the multiple branch point.
Resintech RT125 3M
3M EX-PLUS-II-APPLICATOR for the Resintech RT125. This makes the
application of the epoxy a lot less messy. About $50.00 from
... well spent. You throw away the mixing nozzles after each
application as the RT125 starts setting rather quickly. You should let
the applied boot and RT125 harden as it can get a bit messy before you
go off to the next sealing point. Hanging the harness up so the RT-125
doesn't flow "down" away from the joint is a good idea.
We buy the mixing nozzles in packs of 12 as we use RT125 for other
projects in addition to sealing wiring harnesses.
Epoxy Syringes 3cc and Epoxy Needles 15 ga
Sold it kits with supporting materials S1125 adhesive
is used to
DR-25 and Raychem Boots in the same manner as Resintech RT125. This
shows the proper procedure for sealing and testing the bond
DR-25 and molded boots. S1125 is more expensive than RT125. The
are the same for both. Here a non-adhesive lined boot is sealed on both
With Ideal 46-204 Elite Plus Heat Gun use 46-955 Ovelap Adaptor to
shrink the boot.
Chemtronics Coventry Sealed Foam
are perfect for dealing with harness epoxy as you don't
have to mess with the fuzzies in common cotton swabs. Available
in packs of 500
for about $0.12 each. We
use all sorts of potting compounds beyond the harness specific RT125
and have found these to be the best way to clean and manipulate the
The comprehensive guide is Raychem
Heat Shrink Products
. However, it
can get a bit confusing and, in general, you will be using System 25
Specifications for your wiring and connector sealing. For example on a
Pectel SQ6M with three Autosport connectors we might use a 90 Degree
Boot with adhesive. 222K152-25/225-0. The /225 refers to the factory
applied adhesive, and the "25" is the boot material used in System 25
Whether you use adhesive lined boots or seal them on their ends
with RT125 Epoxy you use about 480F or 280C with your heat gun with a
flat bladed tip.
There is a newer "25L" designation for a lighter boot, not listed in
With Ideal 46-204 Elite Plus Heat Gun use 46-955 Overlap Adaptor to
shrink the boots.
We have found the best Cable ties are Thomas &
stainless steel locking mechanism. Metal locking tabs are a NASA
requirement (NASA-STD-8739.4 [7.3.4])
An alternative is the Panduit
Contour-Ty (right picture). Normally you use Black Nylon cable
they are UV Stabilized and only purchase Brand Names like Panduit,
Thomas & Betts Ty-Rap, or Hellerman Tyton. Once at Bonneville we
bought some cable ties from local auto parts store and they broke when
you tightened them
Peek Cable Ties
PEEK Cable ties
are rated up to about 500 Deg F... way, way, beyond
normal Nylon cable ties (185 Deg F). There are priced in the $1.80
each price range
for 100 6" ties. Available from Panduit in 4.0"
(PLT1M-C71); 5.9" (PLT1.5M-C71); and 7.4" (PLT2S-C71) lengths.
and MIL-W-22759/41-46 or Raychem "Spec 55"Primary Wire (Race-Spec)
Raychem Spec 55 wire has become the defacto standard for motorsports
wiring. "Spec 55" is a trademark of Tyco Electronics. The actual
designation is MIL-W-22759/32-35 and 41-44. MIL-W-22759/44 is the
normal wire of choice with silver plated copper stands. Silver plated
copper (SPC) strands have a higher temperature rating than does Tinned
copper (TC) strands.
Spec 55 Single Wall or "interconnect" wire carries the designation
55A011-xx-xx. Spec 55 Dual Wall or "airframe" wire carries the
"XLETFE" insulation refers to Cross Linked ETFE Polymer (Tefzel) which
provides increases abrasion resistance over Tefzel insulation. Dual
wall construction is commonly used in aircraft. ETFE is described as a
"modified radiation cross-linked polymer”.
Dual wall (normal weight) "Spec 55" will have an inner layer of a
contrasting color (blue) to indicate when the wire has been nicked,
abraded or cut.
TC refers to Tin Plated Copper. SPHSCA refers to Silver Plated High
Strength Copper Alloy. NPC refers to Nickel Plated Copper. NPHSCA
refers to Nickel Plated High Strength Copper Alloy. Note: 24-30 AWG
should use SPHSCA conductor
Nickel has a higher melting point than does silver but this is of
little consequence in motorsports ecu wiring.
MIL-W-22759/44 "Spec 55" Race- Spec Primary Wire
A less expensive and more commonly available wiring is the single wall
Tin Plated (TC) Copper strand wiring MIL-W-22759/16 or the thinner wall
22759/32. It could be argued that silver has a better conductivity and
higher temperature rating than tin plating...but, both offer increased
protection against corrosion over bare copper wires.
The main benefit of Spec 55, MIL-W-22759/44 and MIL-W-22759/32, over
the alternative MIL-W-22759/16 is that it is "tougher" i.e. it has
better abrasion properties due to its irradiated jacket. This is less
of a concern if the harness is sheathed in DR-25 heat shrink, which is
a common motorsports practice. In short it is an acceptable alternative
to the more expensive 22759/44 silver plated wire.
In 20 AWG it weighs 5.18 lbs/1000 feet as opposed to Spec 55 20 AWG
which weighs 4.3 lbs/1000 feet. It is also larger in diameter in 20 AWG
.060" versus .050" for the Spec 55 wire.
A thinner and bit tougher insulation alternative to the /44 wire is the
MIL-W-22759/32 and saves a few thousandths in diameter and
weight...It's the same price as the /16 wire. Both are tin plated
copper ("TC"). Available
. A thinner tougher wire in the 22759/44 and
Wire is really the cheapest part of the equation. It's the labor
stupid. We use the /32wire for our harnesses.
Note: Tefzel is Ethylene-Tetrafluoroethylene (ETFE)
Protection From EMI Interference
How do you strip shielded cable for a solder sleeve?...Well there's
always a tool. The Ideal 45-402 Ringer Cable Stripper.
Crankshaft sensors, camshaft sensors, RS 232 and other communications
should use twisted pair, shielded, wiring. 20 or 22 AWG is typical for
twisted pair sensor and communications. We use 22 gauge Shielded
wires for our two wire crank position sensors.
Twisting the wires reduces magnetically induced interference. Forcing
the wires together reduces the loop area and therefore the induced
voltage. Since the currents are flowing in minimum loop areas, magnetic
field generation is reduced. Good idea to avoid signal problems due to
noisy ignitions, coils etc.
Note that the commonly used model 45-402 comes with a blade and is used on 20-24AWG M27500 SB cable.
Grounding of the shielded cable is accomplished by using
dedicated solder splices. Section 8-3 of Tyco Electronics
(te.com) main Wire
and Cable 27.9Mb Catalog
lists these solder splices.
They are available with or without leads. We ground our shielded wire
jackets directly at the SQ6M ecu.
Procedures are defined for grounding the of the shielded wires.
to Buy Supplies
An excellent source for your wiring supplies for you go it alone types
as they stock
about everything you need and sell in small
quantities. It a good place to pick up your MIL-W-22759/32 and
MIL-W-22759/16 wire and supplies. They have 140 Mil-Spec wire color
combinations in stock. ProwireUSA has extensive experience building
harnesses and only stocks the best and competition proven parts. Quick
service and excellent prices.
9260 Isaac St Suite B
Santee Ca 92071
Specifically designed for motorsport. Lightweight.
Expensive. Requires Mil-Spec crimping and stripping tools. This is
Cosworth Pectel SQ6M
that we use on our
ORCA motor turbocharged
. The color bands denote the connector shell keyway. The
and right connectors are 26 Pin 20 gauge of different keyway locations
so you cannot mix them up. The center connector is a 55 pin 22 gauge
connector. Figure on spending about $400.00 for the associated
connectors, sockets, and insertion tools for the SQ6M. 107 pins total.
Metal shells don't melt like plastic ones do. Higher end motorsport
applications all use Autosport ECU connectors...Pectel, McLaren,
Magnetti-Marelli, and Bosch.
Pectel MQ12 controller. Same as used by Aston Martin, Lotus, Nissan
Nismo GTR and in World Superbike. Full Autosport Connectors. In
case you are wondering how fast this controller can process things it
has a MPC5200 processor that delivers 760 Million MIPS (Instructions
per second) to keep track of all your inputs. Four Autosport
Where to Buy Deutsch
Deutsch DT, DTM and DTP Sealed
thermoplastic connectors are the cost effective motorsport standard...A
step above the ubiquitous Weatherpack connectors.Used by all motorsport
wiring professionals in Mil-Spec and Race-Spec Motorsport wiring.
The best place to buy these is the Deutsch Connector Store
With 100 rated mating cycles and precise pins and sockets these are the
next step below the all metal Autosport Connectors which are way, way,
more expensive. Its best to buy these from someone who can provide a
complete solution in both parts and tooling. Fast shipment and
If you get confused by all the Deutsch Suffixes in the part numbering
scheme check out
this page done by LADD
Deutsch DTM Series
: Sealed thermoplastic connectors designed for
environments like engine compartments. Reasonably priced. Available
from many sources, they offer watertight silicone seals that also act
as a strain relief. Available in 2, 3, 4, 6, 8 and 12 pin contacts with
size 20 contacts for AWG 16 to 24 gage wire. Either solid pins and
sockets or crimped pins and sockets can be used. Solid pins are crimped
and are easiest to work with. In no case should the pins and sockets be
soldered. Multiple wire size #20 contacts with 7.5A rating.
Pictured above are 2, 3,and 4 pin DTM connectors with the optional
shrink boot adapter (Option E007). There are all sorts of suffixes for
the DTM connectors and whereas you might spec out a particular option
i.e. like the shrink boot...It may not be available in plug and
receptacles. We suggest you check out this interactive
All of the pins and sockets are made from 98% pure copper and then
plated. Standard plating is Nickel. For critical circuits, pins and
sockets are plated with Nickel and then Gold. For lighting, power and
control circuits choose Nickel. For critical and very low voltage and
amperage circuits such as oxygen sensors that operate at 0-1 volt or
0-5V (wideband) and for data transmission circuits that operate at 5
volts, choose Gold. Type K Thermocouple wire should use Chromel or
Alumel terminals (see below) in the DTM two or three wire connectors.
Note: rear silicone seal will seal on smooth insulation from .053" to
.120" O.D. Of importance is the fact they are rated at 100 cycles of
engagement and disengagement. These are your affordable step below the
very expensive Deutsch Autosport line. They will melt if they touch
something like an exhaust so be careful about securing things before
you start an engine.
Deutsch DTM Connectors with Alumel
and Chromel Thermocouple Terminals
a BIN (Basic Identification Number) code consisting of three color
bands around the crimp barrel. There are 10 colors which designate a
number. The BIN codes are read from the wire barrel end of the contact
towards the mating end. The first band is wider than the other two to
further facilitate identification. Bin-code can also be stamped on the
contact. Example: Red/Yellow/Black above would be -240 suffix.
Deutsch DTM #20 terminals in Alumel and Chromel are available. The
sequence of the color bands defines the terminals material and type.
0 = Black
1 = Brown
2 = Red
3 = Orange
4 = Yellow
5 = Green
6 = Blue
7 = Violet
8 = Gray
9 = White
Thermocouples, either EGT probes or Cylinder head
temperature, have to be wired with special thermocouple wire all
the way to the ECU input pins. You must use Alumel or Chromel wires and
terminals i.e. pins or sockets, or you will have cold-junction errors.
The all-metal Deutsch Autosport Connectors have specialized size #22
Alumel and Chromel terminals as well as #23 for the MicroLite Series.
There are also size #20 Chromel and Alumel
available for the less expensive DTM series of connectors.
Pectel SQ6M ECUs
have two dedicated EGT Chromel (+) pins: (TC1 POS [YEL Wire], TC2 POS [YEL Wire]); and one common EGT Alumel (-) pin (TC
NEG [RED Wire]) in the AS216-35PN connector.
Chromel Pins Size #20: MIL-C-39029/9-135; Brown Orange Green
Alumel Pins Size #20: MIL-C-39029/9-134; Brown Orange Yellow
Chromel Sockets Size #20: MIL-C-39029/10-141; Brown Yellow Brown
Alumel Sockets Size #20: MIL-C-39029/10-140; Brown Yellow Black
You should always use twisted
24ga stranded (7x32), typically shielded, with a integral drain wire.
If shielded with a drain wire, use 3 position connector with gold
terminals on the drain wire Cover leads with Raychem DR-25 and heat
shrink the DTM connectors for strain relief. Typically this is type K Thermocouples.
Fast acting (150ms) Thermocouples can be purchased from HGSI Industries
"Cat-Spec" Detusch DT
Deutsch DT Series have #16 contacts with a 13A rating. Often
called "Cat-spec as they are used by Caterpillar and have improved seal
retention on the plug and a cap on the rear of the housing to retain
the silicone wire seal.
for SAE J1939/15 2-wire CAN systems. DTM04-2P-P007 Receptacle "Y"
Connector above left. Right: DTM06-2S-EP10 Plug with molded-in 120 Ohm
rubber push to connect seals. Like any specific
connector they require specific and expensive tooling. These connectors
are rated at
50 cycles of engagement and disengagement.
Weatherpack: Ubiquitous automotive silicone sealed thermoplastic
connectors designed for harsh automotive environments. These connectors
are validated to perform to specification for 10 cycles of engagement
and disengagement, but up to 50 cycles probably will not see any signal
degradation. In short they are excellent for oem use but a bit wanting
in a motorsports environment where >10 engagement/disengagement
cycles are normal.
Weatherpack GM MAP Sensors can be further sealed with a shrink
available from ProwireUSA. If you use GM 1, 2, or 3 Bar Map Sensors
with 22 Gauge 22759/16 or /32 wire use the 15324983 DARK RED Silicone
Cavity Seals and Pins 12089307 (22ga). Appropriate pins, sockets and
seals for the different wire sizes are available from ProwireUSA.
GM 2 and 3 Bar Connector 12015384 Black; GM 1 Bar Connector 12020403
Although the Weatherpack connector is "sealed" by the cavity seals it
is a good idea to provide additional strain relief. Alternatively seal
the ends of the DR-25 with 1.2" of ES2000-1.
Injectors and Connectors
The trend in injectors is to use the Bosch EV14 injectors
high impedance, typically 12 Ohms, instead of the older style Low
Impedance (2-3 Ohms) as the EV14's are very fast opening and very
accurate. To use these you will need to use USCAR EV6 Type B Red style
connectors (Green Cavity Seal 22ga). The exception to this are the
ID2000 Injectors which use a Sumitomo
6189-039 Injector Connector (Black Cavity Seal 22ga)
People tend to yank on the injector wires which are typically 22 ga.
Make sure you have the proper crimping tool. Do not solder the
wires...ever. We use 22759/32-22 gauge wires for our injectors and we
crimp them with our Delphi GT150 Connector crimping tool (15359996)
after we remove spring loaded plastic GT150 terminal stop, using the
22-20 position. If you are using 20 gauge wires you can use the general
12014254 Crimping Tool
These days there is a lot of BS floating around about injector matching
etc...Take our advice and use Injector
as they work directly with Bosch Motorsport.
Check out the lengths they go to in this video
We use their 750cc, 850cc, 1000cc, 1050cc, 1300cc, 1700cc and 2000cc
injectors. Pictured above
are the new ID1700X injectors developed in conjunction with Bosch
Motorsport. Tony Palo drives a 2400hp GTR so he's crazy like the rest
us...only he has more horsepower.
Breakers not Fuses
Passenger cars use fuses everywhere whereas, in motorsports,
re-settable aviation-style circuit breakers are preferred. Circuit
breakers have the advantage of being re-settable which allows you to
perhaps just "push it in" and get going until you diagnose the problem.
You also don't need to replace a fuse. Harley uses truck style
thermal breakers...your bike would sign off due to some short and a few
minutes later it would run again...but you didn't melt your wires.
Tyco W23, ETA 483, and Klixon 2TC14 series push to set circuit breakers
are a standard aviation item and are available in many amperages. They
"pop up" when they trip and you push them down to reset them. If you
are using the popular sealed WeatherPack silicone sealed fuse holders
you can use Bussmann 227 series circuit breakers that are a drop in
replacement, albeit pricey, for the cheaper one time fuses.
(green breaker) are available from ProwireUSA in
varying amperages from
1A to 25A for about $20.00. Higher end ETA 483 series are about four
times more expensive.
Breakers like the Tyco W23 are usually installed in panels that a race
car driver can reach and reset. "Reach and reset" doesn't work on
motorcycles. Space is also a premium on motorcycles and there is the
issue of being exposed to the elements like pressure washers. If you go
to the Bonneville Salt Flats like we do then corrosion is a major issue.
Cooper Bussman 227
Low Profile ATC Blade Type Manual Reset
Circuit Breakers fit in Delphi Metri-Pack Sealed Fuse Holders
(12033731 Cap Cover and 12033769 Female Connector). Waterproof and no
screw terminals or panel nuts to get loose.
Panel Mount Circuit Breakers
High Amp Series 17 Waterproof Panel Manual Reset Circuit Breakers from
Mechanical Products are available from Waytek
Amperage Ratings from 25 to 300 Amps
Industry standard terminations available in panel and surface mount
New "Easy Access" Panel Mount and "Side by Side" Surface Mount
Surface Mount available with 1/4" and New 3/8" stainless steel terminal
studs and sems nuts
Panel Mount available with 1/4" brass, nickel plated terminal studs and
stainless steel sems nuts
Auto, manual, or manual push-to-trip options
Dustproof and waterproof
Visible trip indication
Sealing Backs of
Raychem SCL heat shrink can be used to seal circuit breakers and other
types of switches from the environment. Much niftier than trying to
heat shrink a couple of screw terminals. It is a dual-wall adhesive
lined shrink tube with a 2.5:1 shrink ratio.
A greater shrink ratio (4:1) can be accomplished by using Raychem
, or DSG-Canusa CDR adhesive-lined semi-rigid shrink tubing.
Raychem ES2000 is available in small quantities (4' sticks) from
various electronic suppliers like Mouser.
Sealed K4 Toggle
K4 Triple Sealed Switches are used in off road racing and other
motorsports where moisture and dust are your enemy. Complete K4
. Available from ProwireUSA
Sealed Toggle Switches
Instead of having to deal with exposed blade contacts or tiny
brass screws with eylets, get a sealed toggle switch with lead wires
and install a Deutsch DTM Connector. Grote
82-2111 SPST Toggle
pictured above left. Similar
switches, above right, are also available from Littelfuse
Several less things to worry about...no loosening of
screws or issues of sealing blade contacts from corrosion. Here with a
DTM connector, Raychem DR-25, RT125 sealing and ATM 16/4. Alternatively
you can hardwire the switch with two step-down butt connectors (offset
them) and seal the connections with 1.2" ES2000-1 and cover with 1/4"
DR-25 sealing both ends of the DR-25.
Sealed Mil-Spec OTTO pushbutton switches
are available from ProwireUSA
They come in different color buttons but you really need to label them
where they are installed.
K4 Battery Disconnect
Battery Disconnect Switch
. If you run expensive Lithium Racing
batteries you need to remove any parasitic draw to prevent the battery
voltage from dropping when the vehicle sits for awhile. If the voltage
drops too low due to long term milliamp draws it will permanently kill
the battery. The switch also serves as a safety kill switch where
regulations require and manual disconnect.
Rotary Map Selection
Rotary position switches are a fact of life in Formula 1...Fuel,
suspension, traction control, braking bias and whatever the rules allow
these days with the spec ecus from McLaren Electronics are all
switchable on the carbon fiber steering wheel.
We make up our own Rotary Map Switches that have to survive on a
Harley-Davidson. We set these up for four map positions. Traction
control maps, fuel and spark maps...all changeable on the fly. Four
position switch pictured uses three resistors to set voltages from 5
VDC to 0 VDC in equal steps.
Here is the final assembled switch with the laser cut stainless steel
mounting bracket and faceplate. Laser cut slots allow the faceplate and
the mounting bracket to index to each other. We stamp the switch
positions into the faceplate. The entire assembly is sealed for
reliability. We label the color of the signal wire so it can marry up
with the appropriate DTM connector on the wiring harness.
We machine the switch enclosure from Delrin plastic and encapsulate the
rotary switch in epoxy to waterproof it and use DR-25 heat shrink and
formed boots to protect the wiring and install a three position Deutsch
DTM connector. 5 VDc, Analog Ground and Signal wires (color coded). We
pot the Delrin enclosure / switch with Resintech RT125 on both ends. It
takes a few days to cure.
Eight Position Traction Control Rotary Switch. Seven resistors set
voltages from 0 VDC to 5 VDC in equal steps. Pectel SQ6M controllers
have 7 traction control settings. Position #1 will be traction control
Ideal Ergo Elite, pictured on the left, is an excellent wire
stripper...Be sure you order the model 55-1987 for MIL-W-22759 wire
plus the LB-1904 Clear Plastic Wire Stop. About $250.00. The clear
plastic Wire stop cuts accurately but can trap the insulation between
the stop and the blades. Often we leave the stop off.
The Ideal 45-177 Stripmaster Lite (16-26 AWG, Type E Teflon), on
the right, is also an excellent choice. Keep the screws in the jaw
tightened as they tend to loosen with use. You should also order the
L5720 Wire Stop Assembly. About $150.00
We suggest you get the Ideal Ergo Elite for the most precise work.
Wire Stripping Thermal
The claim is that thermal wire strippers do not nick or cut or scrape
the wiring. There
are several manufacturers like Teledyne and Hakko. The Teledyne
Strippal® Plus pictured to the left above is a self-contained hand-held
stripper that either comes with a fixed or variable temperature
control. The insulation melts and is stripped cleanly and quickly,
readying the wire for crimping or soldering. To the right is the Hakko
FT-801 thermal wire stripper.
We don't like getting burned by hot objects. We tried but it was back
to mechanical and automatic blade strippers.
Ideal 950 Stripmaster
This is the pricey pneumatic stripper we use at RB Racing. It
simplifies doing production work and the stripped insulation collects
in the tray. Of course we still use hand strippers because the 950 is a
stationary unit, not suited for lugging around the shop doing
prototypes in place. Bench item.
If you are doing production work and don't want to spend the day
squeezing manual crimpers then you need spend about 25 times more money
for an electric stripper like this one. Video of it in
Daniels crimping tools are the defacto standard for motorsports
connector pins and sockets. We also use specialized tools to crimp
Weatherpack connectors and Deutsch connectors.
Daniels AFM8 Turrets
M22520/2-07 Autosport 22 gauge sockets
M22520/2-09 Autosport 22 gauge pins
M22520/2-10 Autosport 20 gauge sockets
M225034 Autosport micro sockets
M225035 Autosport micro pins
M22520/2-02 Turret for DTM and Mil Spec
This is a selection of the crimping tools that we use to make our
motorcycle harnesses. Daniels, Delphi, AMP, Rennsteig, and Deutsch
crimpers. We don't do custom wiring harnesses except for our own
products and racing.
There are different types of crimps used for different purposes i.e.
insulated or non-insulated connectors. The Rennsteig PEW-9
here with a hexagonal crimp die for non-insulated splice connectors.
These are moderately expensive, around $120.00. No
interchangeable dies as it is calibrated at the factory. The hexagonal
crimp is a superior crimping method for splice connectors. For single
splices 18/16/14 ga and for multiple of smaller wires.
Rennsteig also has a MultiCrimp tool with interchangeable dies. About
$250.00. Fives dies are available. It normally ships with with:
- 1x (P/N 629 050 3 0 1) Die Set for Non-Insulated Plug Connectors (0.5
- 6.0 mm² | 20 - 10 AWG)
- 1x (P/N 629 060 3 0 1) Die Set for Insulated Terminals (0.5 - 6.0 mm²
| 20 - 10 AWG)
- 1x (P/N 629 090 3 0 1) Die Set for End-Sleeves/Ferrules with and
without Collar (0.25 - 6.0 | 24 - 10 AWG)
- 1x Tool magazine for up to 5 Die Sets
Less expensive ratcheting crimpers are available from Del City. Some
aerospace items can be up in the thousands of dollars.
A good guide to crimping is in the Molex Industrial Crimp
. Page 18 of the Molex PDF describes the types of crimp
These are the best battery cables for your racing application. Don't go
looking for welding cables, get the correct motorsport ones. ProwireUSA
also has the correct lugs. In order to crimp the lugs you can spend
anywhere from $35.00 to $3,000.00 for specialized hexagonal crimp tools.
If you are only going to do this occasionally a cheap Hydraulic Crimper
(read China) with insertable hex dies can be had for under $40.00.
Pictured is an 8 ton crimper with 4, 6, 10, 16, 25, 35, 50, and 70mm
die sets. Definitely not Aircraft Milspec but cheap.
Metric to AWG Conversions: 10mm (6AWG); 16mm (4AWG); 25mm (3AWG); 35mm
(2AWG); 50mm (0AWG); 70mm (2/0AWG).
to Wire Splices
Wire to wire splices can be accomplished with Tyco Raychem D-406, or
Sumitube W79 adhesive lined shrink tube. Do not solder the wires
together. Proper crimping is the preferred method .Raychem part #
D-406-0001, Red in color, marked "Duraseal 18-22" pictured.
Alternatively, un-insulated butt connectors can be used and sealed with
adhesive-lined Raychem ES2000 heat shrink. Often wires will branch i.e.
1-2, 1-3 etc. and splices are necessary.
Here we have two multi-wire splices via step-down un-insulated butt
connectors: (below) five 22 gauge 22759/16 black wires going into one
black 22 gauge wire; and (above) four 18 gauge 22759/16 red wires going
into one 16 gauge 22759/16 wire. The connections are glue shrunk. In
the case of multi-wire butt splice connections we use 1/8"
adhesive lined shrink tube on the single wire and a larger size (3/16"
or 1/4") over the entire splice.We make sample splices, in this case
stripping the wires 3/8" and crimping them in the butt connector. Do
not twist or solder the multiple wires together. All connections must
be adhesive sealed.
For a comprehensive guide to Un-Insulated butt connectors see the TE
Un-Insulated Terminals and Splices PDF
These go down to 26AWG-20AWG (#321198) pictured above. Uses AMP Crimper
Crimp Tool 69363 26-24 22-20.
We don't have pull testing equipment so we simply take the test
pieces and yank on the wires as hard as we can. Be careful to insure
all wires are fully seated into the butt connector. Refine your crimper
choice and crimp techniques until you can be assured your splices will
not come apart. Not sophisticated but it works.
FYI: NASA-STD 8739.4: Minimum Tensile Strengths: 22ga 13 lb; 20ga
21 lb; 18 ga 32 lb; 16 ga 41 lb.
SAE AS7928: Minimum Tensile
Strengths: 22ga 15 lb; 20 ga 19 lb; 18 ga 38 lb; 16ga 50 lb.
Raychem Stub (Parallel)
When you are terminating multiple wires in a splice in your harness,
and not a wire-to-wire butt splice, use MiniSeal Stub Spices
and crimp with a Rennsteig Hexagonal crimp tool or a DMC GMT232
Crimping Tool and then seal the stub splice with a Raychem ES Cap.
Stub (Parallel Splice) Red Tin Plated;
Stub (Parallel Splice) Blue Tin Plated;
Stub (Parallel Splice) Yellow Tin Plated; Raychem D-609-05
Raychem ES Caps for
Parallel Stub Splicing
Alternatively you can use 1.2" Raychem SCL Encapsulating Tubing, typically SCL-3/16-0 or SCL-1/4-0.
Wire to Wire Solder
Joining wires without crimping in a sealed manner requires the use of
specialized solder sleeves that both solder the wires together and
adhesive seal them at the same time. Pricey devils. Figure upwards of
$3.00+ each. Pictured is Raychem / Tyco D-1744 Series
. Designed to provide an environment resistant in-line splice
wires having tin (22759/16 or 22759/32) or silver-plated conductors
(22759/44) and insulation rated for at least 125C. Example pricing via
We stagger our splices in each harness. Here we have staggered the
splice joints for a Pectel SQ6M ECU. This avoids overlapping the splice
points, which are sealed in adhesive shrink tubing.
Pin and Socket
Daniels makes a relatively
to test retention of pins
and sockets...Simply push until flush and the socket/pin is tested to
about 30% of it's yield i.e. if it is actually seated.
If you are a big buck operation and you need to test your crimp
connection strengths you buy one of these from Alphatron
Heat Shrink and Molded Parts
DR-25 heat shrink and transitions are joined with Raychem or
molded parts, To seal the ends of the transitions or boots there are
two options: Use adhesive lined boots (expensive) or use
syringe-applied Resintech RT125 black epoxy on the connector or the
DR-25 wire cover. The shrink ratio is 2-1.
This environmentally seals the wires and connectors and provides a
protective layer against abrasion.
is simply the best wire covering. The suffix determines the
color of the printing on the tubing
; while DR-25-1/8-UK
is White lettering
Color of the lettering is simply customer preference as the DR25 is
exactly the same. We use DR-25 in
the standard thickness with the yellow print as it seems a bit sexier
and is visually diffrent than other suppliers being instantly
recognizeable as genuine Raychem. The special
lightweight motorsport version with white lettering DR-25-TW
To choose a size of DR-25 for your harness sections choose the largest
size that will shrink firmly to your wiring cross-section diameter. In
other words if your wiring bundle is 3/8" in diameter you don't use
3/8" DR-25 as it has a shrink ratio of 2:1 (.375 start to .1875 final).
The above dimensions are for several diameters of 20 gauge Spec55
wires, .058" in diameter.
An alternative to DR-25 is Raceline 150 from Whitmor
Basically the same specifications you just don't get "DR-25" printed in
yellow. We all know how important labels are these days.
A second source for a less expensive alternative to Raychem DR-25 is
.which also has
the same 2:1 shrink ratio as
Pull don't Push
Trying to push some 22 gauge wires through 1/8"or 3/16" DR-25 is an
exercise in frustration. Crimp the wires to something like a length of
welding rod and pull them through.
Sealing DR-25 with
Semi-rigid 4-1 shrink ratio adhesive lined Raychem ES2000
to wires as well as serving as a strain relief for wire splices,
terminals and other components.
Shrink tubing typically comes in four foot long sticks. We cut these to
fit McMaster Carr clear boxes 4629T. For the most part this is rigid or
semi-rigid adhesive-lined tubing, typically, for harnesses, cut in
lengths less than 2.5" for connectors and sealing DR-25. It easy to
keep track of the various types and wall thicknesses as well as 2-1,
3-1 and 4-1 shrink ratios. You're always cutting parts and have lengths
left over. It's easier to keep track of these in some form of
Heat Guns and Heat
Heat Guns and Heat Blowers are different animals. The Steinel and the
Snap-On to the left are Heat Guns whereas the Master Appliance pedestal
mount is a Heat Blower. They all apply hot air but the Heat Guns are
easier to work with, especially when dealing with Raychem Shrink Shapes
and Boots as you must quickly rotate about the part to cause the
controlled shrinkage. The larger Heat Blower is too unwieldy for this
fine controlled shrinkage. Being able to regulate the temperature is
DR-25 and various boots are rated at about 150C to 175C (350F) and will
shrink at these temperatures. Heat guns and blowers can go to
1000F...that is too hot and can damage the DR-25.
Probably the best value in a heat gun is the Ideal 46-204. Lots of
bells and whistles. You can regulate the temperature and the blower.
About $200.00 as pictured above. We use both this "gun" and the Master
Appliance pedestal blower.
Installing a 202K132 Raychem Boot on this Autosport Connector has to be
done with a Heat Gun, not a Heat Blower. A Heat Blower will cause a too
quick and uncontrolled shrinkage and ruin the Boot.
Twist Layers... Race-Spec
The stiffness of the harness will depend largely on how the underlying
wires are arranged. The correct method is concentric twisting where
successive layers are twisted in opposite directions...One wire
surrounded by six wires, with each successive layer adding six
additional wires i.e. 1-6-12-18. The twisting of the wires gives the
harness additional flexibility and reduces strain on the wires. The
above table provides some insight into the methodology. TE Connectivity
offers a PDF
Guideline for Concentric Twisting
The 1-6-12 etc is not inviolate i.e. you may have a central bundle of
say, twisted pairs, that may approximate the diameter of six
wires...Then the other layers 12 etc may follow.
This is a motorsports Race-Spec technique and is not an aerospace
standard where weight is critical. Concentric twisting adds flexibilty
to the harness were routing and possible removal are involved. 22759
Mil-Spec wires are twisted internally for the same reason.
CW and CCW Twisting
Here we have the connectors on a Cosworth Pectel SQ6M
, pins facing out
from the ECU, two 26 Pin Autosport and one 55 pin Autosport. Below is
the sequence of twisting for the mating Autosport connectors. If you
are planning on pretty Instagram pictures it will be time to plan your
(2) 26 Pin Connectors C1 and C3: Center
b; Layer 2 CCW:
T, S, a, Z, Y,c; Layer 3 CW:
U,V,W, X, K, L, M, N, P, R A, B; Layer 4 CCW:
J, H, G, F, E, D,
(1) 55 Pin Connecttor C2: Center
28; Layer 2 CW:
27, 35, 36, 29, 21, 20; Layer 3
26, 19, 12, 13, 14, 22, 30, 37, 44, 43, 42, 34; Layer 4 CW:
33, 41, 48, 49, 50, 51, 45, 38, 31, 23, 15, 8, 7, 6, 5, 11, 18; Layer 5
17, 10, 4, 1, 2, 3, 9, 16, 24, 39, 46, 52, 55, 54, 53, 47,
Things get a bit more complicated where there are internal splice
points in the harness i.e 1 into 2 wires or 1 into 4 wires such as in
5V supply or digital / analog grounds.
Note: Unused positions in the harness must have the contacts installed
and use either plugs or filler wires to maintain sealing integrity.
Perkins...Concentric Harness Construction
Concentric twisting of a motorsports harness requires a lot of planning
when you have different gauge wires, multiple connectors, filler wires,
splices, service loops etc. Here Zac Perkins
(firstname.lastname@example.org) of Motorsportselectronics
how it should be done. Kevlar braided lacing cord secures the bundle.
Zach is a master fabricator and motorsports electronics specialist.
Check here to see his portfolio
Zac can be reached via his website (or
email) to schedule your project. BMW and Porsche 911 projects.
Zac doing M1 Series Motec integration in a Porsche 911
. A complete rewire of a Porsche 911T
Zac. Zac is currently working as a Senior Engineering Technician -
Special Programs & Motorsport at Faraday Futures and holding
a second hat at motorsportselectronics
with Tim Whitteridge.
Center above, Tim Whitteridge, one of
the good guys in Motorsports Electronics, working on the late
Nissan LMP1 car. Tim did some top notch work for us at his previous
employer before he joined the Nissan LMP1 effort and went to LeMans. Tim's
resume is lengthy
and we can vouch for his expertise. Besides his
duties as an Electrical/Data Engineer at Magnus Racing he wears a dual
hat at Motorsportselectronics.com
doing wiring and systems integration with Motec, Pectel and other
systems. He has worked at the highest levels in motorsports. Tim can be
contacted at email@example.com for your special projects.
In Tank Looms
Zach Perkins: "Building an in tank fuel cell loom. It's important to
use the correct supplies, especially when dealing with ethanol or
alcohol fuels. Pictured here: Deutsch hermetic fuel safe flange mount
connectors, Raychem -12 chemical resistant boots, Raychem RW-200 viton
shrink and Resinlab EP1385 epoxy- specially formulated for E85 and
alcohol fuels. It's always better to test chemical resistance of what
you're putting in you're fuel tank BEFORE you gum up all your fuel
pumps, luckily with these products I know they're up for it! Motorsportselectronics
Tying or Lacing Wire
Braided Lacing Cord is commonly used, bound to the twisted cables in
the opposite direction of the cable twist, secured at each end by tape.
There are a wide variety of these in nylon yarn, polyester yarn, Teflon
yarn, glass yarn, and aramid (Kevlar/nomex) yarn.
MIL-T-43435B Lacing Cord (Left Above): Braided nylon lacing cord
meeting specification MIL-T43435B, Type I, Size 3, Finish B:
Micro-crystalline wax with melting point above 55/ C ° 130° F and
non flaking characteristics it is compounded to develop excellent knot
retention, yet not giving a waxy feel to the user. Used to tie wiring
bundles together. Less bulky than plastic tie wraps which can actually
cut into wires and, when cut, leave a sharp edge that can cut your
MIL-T-43435B Lacing Cord size 4, Dacron, 2nd from Left, Finish C
MIL-T-43435B Lacing Cord size 3, Nylon, 3rd from Left, Finish C
MIL-T-43435B Lacing Cord (Far Right Above): Flat Braided Glass Yarn,
Type IV, Size 1, Finish D: TFE-fluorocarbon coating, Black Color.
(size 1) .180" to .220". Stable to 427C (800 Deg F). Gudebrod
Continuous loops with the waxed MIL-T-43435B Lacing Cord (Left Above)
should tied in the above manner with continual lock stitches. Normally
you just put a wrap and a square knot every 6-12".
and Nomex (Aromatic Polyamide) Flat Braided Lacing Tapes
A-A-52084 Lacing Cord available in 250 or 500 yard rolls from suppliers
, or Atkins
Formerly known as MIL-T-43435 Type V it is available in four different
sizes in natural or black finishes. Lacing tapes are wrapped in an
opposite spiral direction from the last upper layer left-hand
concentric twist. Lacing techniques are described in this TE Connectivity
Specification Nomex Lacing Tapes...Continuous Filament
These are the gold standard in Nomex lacing
tapes. Manufactured from continuous filament yarns in accordance to CID
AA52080-AA52084 (formerly MIL-T-43435B). Keyword is "yarns".
BMS 13-54 Boeing Specification Nomex® Lacing Tape. Western Filament
Flat braided Nomex lacing tape. Type III, Grade D, Finish C, Class
I with cross-tracer.
Available colors: White, Black, Blue, Brown, Green, Gray, Magenta,
Orange, Pink, Purple, Red, Yellow.
Western Filament Inc.Part Number Width
Inches Thickness Inches PutUp
Western Filament Part
Inches Thickness Inches
HOF70RTR 0.110 "
After you've laced your wire harness together with neat little square
knots, how do you insert extra wires? The answer is a Wire
Note that all the wires are white which is a normal practice in many
applications. Spec 55 wire is available in up to 10 color and or color
stripe combinations which makes keeping track of things much easier.
Without laser-marking of each wire it can be a real chore to track down
issues when all the wires are white. You can also label each wire (we
do) as we have so many interruptions it's easy to lose track after
numerous phone calls.
For your information a typical late model Harley-Davidson Touring bike
uses about 77 different wire colors (color and stripes) in its wiring
harness. 100 color and color/stripe combinations are delineated in this
. In aerospace applications wires are white and
Ultra Vilolet (UV) laser marked.
Portable Shrink Tube Thermal Printers
You can, however, label each wire with 1/8" 3:1 heat shrink labels near
the terminations to keep track of things and use one color mil-spec
wire. Low end heat shrink printers can be purchased way under $100.00
or you can spend many thousands of dollars on commercial units. We
label all our wires anyway, even with different colors.
BEE3+ unit from K-SUN pictured above is about as cheap as it gets.
Lists for about $250.00 but sells for about $150.00 or less. It prints
on 1/8" (single MIL-SPEC wire), 3/16", 1/4", 3/8", 1/2" and up to 3/4"
wire shrink tubing. It also prints labels in widths of 1/6"(4mm),
1/4"(6mm), 3/8"(9mm) 1/2"(12mm) and 3/4"(18mm) widths. The catch is the
cartridges are expensive. There is always a catch. Expendables. Oddly
the 3/8" shrink tubing is only available in white.
The lower priced BEE3 unit will only print up to 3/16" shrink tubing.
Best get the BEE3+.
Use either KYNAR or Tyco Raychem RT-375 clear 2:1 heat shrink over your
The Rhino 6000 will print wire shrink tubing up to 1" I.D. and flat
labels up to 1" in width. These are in the mid to low $200.00 range.
For labeling individual wires they do not go down to the 1/8" size
shrink tubing that the BEE3+ does.
Production Shrink Tube Printer Kroy K4350
If you plan on doing production work the Kroy K4350 is a good bet...in
the $500.00 range. You use 100 foot reels of shrink tubing.
High End Design: TE Connectivity HarnWare/HarnVis & Catia V6
offers 2D and 3D modeling of harnesses. Complete
libraries of all Raychem TE components. License must be purchased
(dongle). Based on 32 bit Microsoft VISIO. HarnWare (2D)
are developed and maintaned by ADE Analysis & Design
is the high end OEM tool. Aircraft and OEM manufacturers.
Visio Professional 2013
Race-Spec Harness Design and Initial Layout
The above is a typical Microsoft Visio diagram for motorsports wiring
and harness design.
We can make an initial Visio drawing of the wiring diagram but this
will only aid
in planning purposes. The actual harness has to be measured on the
application with all the hardware in place. It is critical that there
be no strain or interference issues and that serviceability is planned
for. This is often done in Microsoft Visio
. Template included on the Visio link.
Basic Visio Tutorial
We also construct a detailed harness description in a CAD Program which
lists every component in the system which can be printed out on a large
format printer. This puts everything on one sheet to avoid looking
through various documents. Lots and lots of details.
Wires in the above harness are MIL-22759/32 in 16/18/20 and 22 gauge.
Deutsch DTM Plugs and Receptacles use a mix or gold and nickel plated
pins and sockets. Deutsch Autosport Connectors are used for the SQ6M
on this harness. Different wire colors prevent confusion and we
also label each wire. This particular harness has 49 outboard
connectors. The SQ6M itself has 107 pins. In the case we are using 76
of them. Filler wires, also labeled, fill out the 107 pins.
We also do complete documentation in Excel and Pages (Mac) and Word
listing every component, pin, socket, splice points, Raychem boots,
wire lengths etc.
We use 4' x 8' whiteboard to layout the wiring harness. We use 3/4"
adhesive tie wrap pads, plastic tie wraps, Velcro, and white gaffers
tape to hold the main harness and connector leads in place. The
adhesive pads can be removed or relocated without damaging the boards
surface. No need to replace the surface.
For planning purposes we determine which and how many wires exit the
harness at each break point and also the diameter of the runs between
the break points. Wire bundle diameter is important in choosing the
correct diameter of DR-25 shrink tubing. 88 wires exit towards the SQ6M
in this case with three separate leads going to each of the Deutsch
We twist the wires CW and CCW the best we can by the above format, but
we always run into issues with 2-1 and 3-1 splices so we don't go the
extra mile to put in dummy filler wires to get the 1-6-12-18 etc
layers. We do the concentric twisting and secure the runs with
Mil-T-43435B Lacing Cord. We label each wire with 1/8" yellow shrink
tube covered by clear Raychem RT-375 clear shrink tubing.
We leave the exit branches about 4" longer than necessary and then trim
the wires to length for the connector. You can slide the labels up and
down the wire with a bit of force. Labels are necessary for us as we
are constantly interrupted and brain fade sets in.
DR-25 1", 3/4", 1/2", 3/8". 1/4" and 1/8" is being used in this
harness. Raychem 202A153, 202A142, 202A132 and 202A111 straight boots
are being used with Resintech RT125 epoxy sealing the branches exiting
the boots. Raychem ES2000-1, -2 and -3 tubing seals wires exiting the
DR-25 on branch legs to sensors, circuit breakers, relays etc. Raychem
ATUM is used to seal the back of connectors
Raychem DR-25 covers the main harness and the branches. Connectors are
installed and sealed. Each branch is labeled with the connector number
as well as the function. Kapton tape covers exposed wires before they
have Raychem boots heat shrunk. In this application we have 49 outboard
connectors to keep track of. Without documentation future issues as
well as current assembly would be very difficult.
Labels on all connectors help keep track of things. Documentation is
maintained on both the internal and external structure of the harness. Pectel SQ6M ECU
Hi-Pot testing is used in aerospace and high-end motorsports wiring
houses to verify wiring harness integrity. Any poor connection, nick in
wiring insulation, or short can be isolated and fixed. Simple
continuity checks are OK but are not foolproof. CH2 pictured
A PDF lising
for various cable testers.
The hipot test is a nondestructive test that determines the adequacy of
electrical insulation for the normally occurring over voltage
transient. This is a high-voltage test that is applied to all devices
for a specific time in order to ensure that the insulation is not
explanation of Hi-Pot testing is offered by Cirris
Hi-Pot CableEye testers from CAMI Research. PC based i.e. software
driven Hi-Pot testing makes isolating things a lot easier.
Wideband Sensor Wiring
The Bosch LSU-4.2 (left) or the NTK (right) wideband sensors are
typically married with six position Deutsch DTM connectors. In that
they are five wire sensors the sixth position uses a seal plug. LSU 4.9
is the newest version and is not compatible with 4.2 electronics.
Wiring colors for the different sensors is as follows:
Bosch LSU-4.2 Typical DTM positions: DTM Terminal 1, Red Wire, WB_Pump;
DTM Terminal 2, Black Wire, WB_Cell; DTM Terminal 3, Yellow Wire,
WB_Com; DTM Terminal 4, White wire, WB_Htr-; DTM Terminal 5, Gray wire,
WB Htr+; DTM Terminal 6, seal plug.
Bosch LSU-4.9 Typical DTM positions:DTM Terminal 1, Red Wire, Pumping
Current; DTM Terminal 2, Yellow Wire, Virtual Ground; DTM Terminal 3,
White, Heater Minus (H-); DTM Terminal 4, Grey wire, Heater VBat (H+);
DTM Terminal 5, Green wire, Trim Current; DTM Terminal 6, Black Wire,
Nernst Voltage. LSU-4.9 Data.
NTK L1H1 Wire Colors: Yellow Wire: Heater -; Blue: Heater Wire +;
Black: Signal Ground; Grey: Nernst Cell Voltage; White: Ion Pump
NTK L2H2 Wire Colors (8 pin Sumitomo H90 Connector): Pin1: Yellow
Heater Wire -; Pin 2: Blue: Heater Wire +; Pin 3: Rc (cal resistor);
Pin 4: Rc 0V; Pin 5: NC; Pin 6: Grey Wire Vs; Pin 7: White Wire Ion
Pump; Pin 8: Black Wire Sensor 0V.
L2H2 Cal Resistor shown above between pins 3-4 which is read by oem
application or devices like Motec PLM. These are individual to each
sensor. High end ecus like the Pectel SQ6M do not use a Cal Resistor.
NTK sensors are extremely accurate at Lambda 1.0 (14.57 AFR) but should
be custom calibrated between Lambda 0.75 (10.92 AFR) and Lambda 1.25
(18.21:1 AFR). Nitrogen gas can be used to test for Lambda 1.0
(14.57:1). Calibration data can be entered into your ecu. Free Air has
20.95% Oxygen with a Lambda 1.43 (20.80AFR).
In general NTK sensors are higher temperature rated. We use them
pre-turbo with pressure compensation tables as under rich conditions
they show richer under boost pressure and leaner in lean conditions
under boost pressure. Pectel SQ6 / SQ6M controllers are designed for
NTK sensors. NTK sensors are tolerant of leaded fuels whereas Bosch
LSU-4.9 are not. Connectors for the L2H2 LZA-09-E1 sensors are
available from Ballenger Motorsports.
Another consideration is that the NTK sensors are about twice as fast
as the Bosch 4.2 / 4.9 Sensors. No matter what anyone tells you the
response times to correct injector output have a latency of 500Ms up to
980Ms which is why you do steady state step testing on a dyno. A fast
dyno "sweep" can point out deficiencies but not exactly pinpoint them.
The base mapping has to be correct.
NTK L2H2 LZA-09-E1
Cut and remove connector with calibration resistor. Leave longer
silicone heat sheath.
Cover wires with 1/4" DR-25 overlapping the long NTK silicone
heat sheath. Heat shrink the DR-25 and seal both ends with 1" ES2000-1.
Heat shrink 11mm label and seal with RT375 clear. Slip over 1.5"ATUM
12-3. Strip wires, crimp pins or sockets and insert these in the
connector. Filler wire with pin or socket for the unused pin 6. Heat
shrink the ATUM 12-3. Slip 2" ATUM 24-6 over the sensor and heat shrink
to the DTM six position connector.
When mounting the NGK/NTK wideband lambda sensor pre-turbo you need to
create pressure compensation tables in your ECU. We made a Back pressure
that shows how lambda reading are skewed under
exhaust back pressure....Or simply change your aim.
New Bosch LSU ADV...
Lambda ADV Sensor
for pre-turbo installation. Previous LSU 4.2 and
4.9 sensors could not be placed pre-turbo.
NTK L2H2 Lambda Test
NTK L2H2 Test Stand for sensor linearization: Propane with a variable
air bleed and three 18mm x 1.5 ports. Used for calibrating two NTK L2H2
Lambda meters against a known calibrated meter. Flowing Nitrogen gives
Lambda 1.0 (14.57:1 AFR). Free Air at one end of the scale 100% propane
on the other and propane/varying air mixtures for in-between. We
burn the propane as so as not to vent unburned propane.
Pectel SQ6M engine controllers have 33 points to linearize or calibrate
for each of the two NTK sensors. The SQ6M has internal NTK amplifier
and heater circuits, so no external devices are required. Alternatively
you can purchase a $1,200.00 drum of test gasoline and a $1,200.00
bottle of Lambda calibration gas to do your testing.
Keep in mind although NTK sensors are fas responding, around 1.3Ms,
fuel map must be correct as sensor latency in fast closed loop sweeps
is an issue. Step tests on Dynamometers is recommended.
Pectel offers specifically calibrated five wire NTK "Band 10"
sensors for their engine control systems that come with Deutsch
Viper Specialty Performance designed a nifty fuel
incorporates differential pressure and temperature sensing which are
then inputted to your engine controller...This simplifies things in
terms of wiring, sensor placement and data acquisition.
We use Hella or Bosch 30 Amp relays in our wiring harnesses. This is a
pictorial reference as to how they work.
At the Bonneville Salt Flats the salt air and salt eats everything.
Internal cavities in relays turn into green gardens. Starter relays and
switches die sooner or later. Cadmium plated hardware corrodes quickly.
Battery terminals and any metal exposed that isn't stainless or chrome
plated begins its ugly descent to mother earth from whence it
came. Boeshield T-9
best thing we've found to protect
metal surfaces. WD-40 seems to disappear after a time. This stuff stays.
Saltproofing USA Fluid
bit like snake oil but it really works.
Protects about everything including alternators, relays, switches, and
Raychem Spec 55 Wire
(XLETFE Polymer) The standard for high end motorsports wiring.
For Mil-Spec Wiring. 100 possible combinations. 10 colors are
Master Catalog Raychem Heatshrink
Raychem Heatshrink Products
Covers everything including tubing, all
molded shapes (with dimensions), tools, and materials
DR-25 Heat Shrink
Used to cover XLETFE wires in wiring harnesses. Has a 2-1 shrink ratio.
Single Wall. Motorsports std. Yellow or White Lettering. Available
from Prowire USA
a less expensive alternative to DR-25
Clear heat shrink tubing. Use to cover your yellow/black wire heat
shrink labels. Available
by the foot from Prowire USA.
Shrink Tubing to cover wire and cable heat shrink labels.
Adhesive-Lined Shrink Tubing:
heat shrink. Semi Rigid 4-1 shrink ratio. Sealing wire transitions.
Adhesive heat shrink. Used to seal wire transitions and
connectors. Less flexible than ATUM. Strain relief.
Raychem SCL Heat Shrink
Used to seal shapes like switches and relays in
lieu of specific "boot". Adhesive lined. 2.5:1 shrink ratio. Available in
4 foot lengths from Prowire USA.
ATUM_semi-flexible Adhesive-lined heat shrink
. Sealing Boots and
transitions and shapes. 3-1 and 4-1 shrink ratio available. Here a
three wire Cherry Hall Sensor has 1/4"DR-25, Resintech RT125 epoxy
sealing the DR-25 ends, and 16mm ATUM semi-flexible adhesive shrunk to
the assembly. Available in
4 foot lengths from Prowire USA
. Last digit is Color Code.
Black is "0" (Zero).
|3-1 Shrink Ratio
|4-1 Shrink Ratio
Adhesive lined shrink tube. 4:1 shrink ratio. Semi-rigid. More
rigid than Tyco ATUM. Splice covering.
Adhesive lined shrink tube. 3:1 shrink ratio. Connector sealing.
Covers everything including tubing, all molded
shapes (with dimensions), tools, and materials
Heat Shrinkable, adhesive or non-adhesive lined, for
wiring harness transitions and connectors.
, Heat shrinkable up to 5-1 ratio shapes for
transition and connector sealing.
Wiring Harness Epoxy.
Parts (Boots) Cross Reference
Raychem, Hellermann-Tyton etc.
Wire Stripping Guide
Processing (Stripper) Catalog
Autosport (connectors) Catalog
Series Connectors (thermoplastic)
Sureseal Rubber Connector
parts to Deutsch Autosport
Metri-Pack GT150 Connectors
used for various sensors like Cherry
Hall etc. (See Page 22: Pull to seat)
ETA 483 Circuit Breaker
Tyco W23 Circuit
Klixon 2TC14 Circuit Breaker
Bussman 227 Manual Reset ATC
Electrical and Electronic Wiring
(Over 1000 pages) 12.8
Mb. Lots of mil-spec reference #'s, data and techniques.
Wire Harness Lacing
NASA wiring and Harness Standards
Protection Ratings Chart
Explains "IP" or Ingress Protection
of connectors from water, dust, etc..Not a military specification.
In WWII we were cranking out bombers and fighter aircraft faster than
they could be shot down. Extremely high crew losses were backed up by a
system of production and training not seen since. Women were a major
part of the work force and kicked butt. After the war their jobs were
taken away from them. There went 50% of the talent.
Production and aerospace wiring harness construction is still largely
done by women whether in the USA or elsewhere. Seems to be an ego deal
in motorsports for males to twist and glue motorsport
harnesses....probably Instragram wiring photos aren't part of the
Defense contractor routines. Would you have the patience?
(Formerly Tony James
Wiring) in the United Kingdom is a
specialist in high end motorsports wiring. This is a video
work for the now defunct USA F1 Team. Let's hope they got paid. HAAS is
up and running these days.
Motorsports Pectel SQ6
Here we have an 88-way Cosworth Pectel SQ6 connector with service loops
twisted just before the connector sockets. Follow the construction of a
Cosworth Pectel SQ6 Wiring Harness
It requires a lot of money, time and supplies. In this case all the
wires are all white in color...This makes servicing things down the
road as well as construction much more difficult. If you label each
wire and use colors codes it's easier.
An excellent source for your wiring supplies for you go it alone types
as they stock
about everything you need and sell in small
quantities. It a good place to pick up your MIL-W-22759/32 wire and
supplies. They have 140 Mil-Spec wire color combinations in stock.
Quick service and excellent prices.
A Reality Check
The simple fact is that a professional motorsports wiring harness costs
a lot of money. Unless it is some kind of production item, which it
never is, these are going to be expensive whether you like it or not
and a rule of thumb is that it is going to cost as much as your engine
controller of choice and almost certainly likely more. One of the
people we know typically spends about 200 man hours designing and
fabricating a custom wiring harness. If you were a lawyer that would be
about $70,000.00 billable hours...If you were only charging a minimum
burger slinging wage of $10.00 per hour, the labor costs alone would be
$2000.00. That's a wide spread.
Even at a proposed minimum wage of $15.00 per hour the labor alone for
a 200 hour plan and build would be $3,000.00 not including parts. Sort
of depends on what you think your ass is worth after years and years of
experience. Do you work for minimum wage? Do you expect your harness
supplier to? Instagram photos and glory does not pay the bills, nor
a pat on the back. Hobby versus business, the eternal struggle.
Another person we know used to wire high end off the road racing
vehicles where the total wiring bill was often North of $25,000.00 for
parts and labor and he did not want to do it anymore as it was tough
getting paid for the work, not to mention all the travel and fighting
clients. He cut back on that work and just sells parts these days and
deals with clients who he can bill and get paid.
It's the old adage "Time is Money". Add up all the hours in planning,
ordering and stocking parts, buying tooling, plus the actual
fabrication and write yourself a fat check...Or let someone else do it.
Letting someone else do it implies there is a solid design template or
that person is going to have access to the project where it can be
planned and executed in place. Travel expenses may be involved as
remote designing is a bit of a risk. Sometimes it's best to pay
and get on
with your life.
We do our own harnesses and have for over 25 years as we have our
projects in-house and don't like running around...and these days life is a lot more complicated. Time is money as they say.
making Mil-Spec Motorsports wiring harnesses
on a contract basis for a long time. There are many others but you can
research these out. Professional Motec Tuners like Shane Tecklenburg
, Electron Speed
East/West), and Pectel
Specialists like Dan
have solid reputations and are well versed
in harness construction. UK/USA based dce
builds the highest quality
harnesses. The new firm of Zac Perkins and Tim Whitteridge
does excellent wiring, ecu calibration and systems integration work.
Jeremy Gibson at Indy Wiring Services LLC does the highest level of
motorsport wiring and provides full documentation and Cirris Hi-Pot
testing of every harness. Jeremy can be reached by phone at 1 (317)
371-7044 and by e-mail at firstname.lastname@example.org. Jeremy provides
Formula 1 level quality and adheres to all current Mil-Spec testing
standards and specifcations. He is familiar with the wiring
requirements for the Cosworth Pectel SQ6, SQ6M and MQ12 series of
engine controllers as well as Bosch Motorsport controllers. Jeremy does
Indy Car, NASCAR as well as complete harness construction for club
racing. Jeremy did harness design, construction, and repair
for Cosworth/Pi Research/Pectel for 9+ years. He has more than 15 years
experience in motorsports wiring. Nissan LMP1 above work by Indy Wiring