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Spec3 Constructor's guide


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NASA Spec3 Constructors’ Guide

Draft - Last Updated 11/16/2022

Written by: Taylor Johnson and Sean O’Hara


Welcome to the NASA Spec3 Constructors’ Guide. Please reference the official NASA Spec3 Rules for any part specific compliance issues. This guide serves to walk you through the “process” of building a NASA Spec3 race car. This does NOT replace the official rules of the series. Please double check the CCR and Spec3 rules before acting on anything in this guide.


This document’s purpose is to share useful information related to building a SPEC3 race car to compete in the racing class of the same name of the National Auto Sport Association. Auto racing is dangerous and this guide is not a definitive set of steps on how to be safe or how to drive or build in a responsible manner. Ultimately the final decisions are upon the builder and driver and due care should be taken at all steps.



Spec3 Forum: https://community.drivenasa.com/topic/58632-spec3-constructors-guide/

Official Website: https://drivenasa.com/road-racing/spec3/ 

Facebook Media Page: https://www.facebook.com/NASASpec3

Instagram: https://www.instagram.com/nasaspec3/

FB Discussion Group: https://www.facebook.com/groups/spec3

Sanctioning Body: https://drivenasa.com/ 

Parts List Spec3 Parts List

Table of Contents


What is Spec3?

Finding the Right Donor Car

Parts Required

Eligible Vehicle Table

Minimum Weight

Maximum Power


Engine Management










Building Tips

Heater Core Delete (not required)

Sunroof Cassette Delete

Fine tuning and car setup

Maintenance Procedures

Formal Rules



What is Spec3?

The NASA Spec3 (S3) racing class is devoted to BMW E36 325 models. The goal for Spec3 is to create high levels of competition between similarly prepared cars at a reasonable cost. Purchase and preparation of a car for these series should be less than $15,000. A Spec3 is great for HPDE and Time Trial duty while being built.


Spec3 is similar to Spec E30 but for the newer chassis. With limited engine and suspension modifications allowed, Spec3 ensures close racing, while not breaking the bank due to a plentiful supply of low cost street vehicles to convert. A spec Toyo tire and Koni/Swift suspension package take the guesswork out of building a competitive car and the series platform has proven to be as reliable on track as any existing class. 

How do I get started?

Come visit a NASA event! Find the registration table and ask for a map. Ask for the places to park and watch the racing action. Find the Spec3 paddock area and introduce yourself and ask questions! 


Read the rules! Read the NASA CCR, Spec3 rules, and your region’s supplemental CCR.


Set your budget! Make a plan for how fast or slow you want to go. Ready to dive head first? Great! Make a plan and start sourcing parts! Want to stretch it out over a few years, no worries! Spec3 cars are great in HPDE and will be perfect for you while you build and work towards racing. 


Make some friends! The best part of racing are the friends you make along the way.


Most importantly, have fun! Very few of us are racing for anything more than a trophy to put on a shelf. If you aren’t having fun, take a step back and reevaluate. 

Finding the Right Donor Car

A 1992-1995 BMW E36 chassis is required for the NASA class.  Sedans or Coupes are legal, but convertibles, compacts, and wagons are not. There is great debate on coupe vs sedan, but ultimately it’s down to personal preference and what clean chassis you can find. The coupe provides larger doors which aid egress, however the sedan’s rear doors aid in access to the rear seat area.  The most important thing to consider when sourcing a car is the quality of the shell.  Cars that have been in significant collisions should be avoided because the unibody may be out of alignment.  Cars with significant rust should be avoided because rust may compromise structural components, rust repairs can be expensive, and the rust may reappear in the future.  High mileage drivetrains are often still competitive and high miles should not discourage a potential buyer.


Areas to inspect when looking at a potential shell/car:

  • Shock towers front and rear. If not reinforced, they can blow out or “mushroom”

  • Rear trailing arm pockets - This can rust out and pose a potentially build-ending safety risk 

Parts Required

Eligible Vehicle Table 





325i / E36



325is / E36



The Spec3 class is designed around the 1993 – 1995 BMW 325i sedans and 325is coupes.  See Rule 6.3.1 and Appendix A.   In addition, any 1992 – 1998 BMW E36 chassis may be used provided that all relevant components (motor, engine wiring harness, transmission, brakes, etc.) are used from a 1993 – 1995 production vehicle. See Rule

Minimum Weight 

2825lbs including driver, fluids, etc.  See Rule 9.2.1 and Appendix A. 

Maximum Power

195.9 horsepower and 179.9 foot pounds of torque as measured by a dynamometer at the rear wheels.  See Rule and Appendix C.


2.5 Liter single-vanos inline six cylinder motor known as the BMW M50b25TU. See Rule 6.3.1. and Appendix A.

Engine Management

Stock Bosch DME, part numbers 0-261-200-413 or 0-261-203-506, with Bimmerworld performance chip, part number #Chip_BWS3.  See Rules Section

Stock DMEs are commonly known as Red Label (no EWS) and Silver Label (with EWS)



 Stock Getrag 250 five-speed transmission

Automatic to manual swaps are fairly straight forward.

Here is a great guide http://shatteredk.blogspot.com/p/e36-1993-325is-bmw.html


Stock flywheel and clutch or an approved single mass flywheel kit of the same weight as stock.


The Valeo Single Mass Flywheel conversion kit is the most popular

BMW Flywheel Conversion Kit - Valeo 52281208




Stock air intake with K&N or Green Filter air filter and optional “S3 Air Duct” sold by Bimmerparts.com and available via the Ebay store of seller “cmuzyy.”  See Rules Section 9.3.1



If the Ebay link ceases working, you can order directly from Bimmerparts:

Chris Muzylowski

Zygmunt Motors


215 348 3121

215 688 1350

[email protected]


Stock exhaust manifold and collector pipes followed by the Spec3 exhaust sold by Mitchum Enterprises Richmond, VA (804) 402 1239; [email protected]  See Rule

Installation of this exhaust requires you cut the exhaust on your car right after where the two pipes join in a “Y” after the header, before the catalytic converter. This exhaust will then clamp on using exhaust clamps. You may weld any of these portions together. 



The Spec3 suspension setup is Swift springs and koni yellow strut inserts on an M3 (1996-1999) strut housing modified to take a strut insert. These are paired with Vorshlag camber plates and 96-99 front lower control arms.

There is a spec eibach anit roll bar kit that must be used as well. This kit is NLA as of 2021. The replacement for this part are similar sized H&R bars. See the anti roll bar section later in this document. 

The rear suspension is just a koni yellow shock and a swift spring.

Basically they make aftermarket shock inserts that allow you to cut your stock m3 struts and pull the factory shock tube out. Then you slide the aftermarket one in and attach it with a bolt through the bottom.

Camber Plates

Vorshlag Motorsport part number VM-CP-SPEC3 and spring perches part number VM-SP-96S-14. See Rule 



Front Control Arms

BMW part numbers 31-12-2-228-461, 31-12-2-228-462, and 31-12-9-069- 035 from the 1996-99 BMW M3.  See Rule 3.8.2.

These are sometimes hard to find. Note that the 96-99 M3 arms are DIFFERENT than the 95 M and 92-99 NON M arms. The M3 arms use a centered bushing while the other arms must use an offset bushing to have the same geometry and they are NOT ALLOWED. Pick up a used set of 96-99 M3 arms and press in new ball joints.


Outer BMW Ball Joint - Lemforder 31121126254




Inner BMW Ball Joint - Lemforder 31121126253



Front Struts

BMW part numbers 31-31-2-228-007 and 31-31-2-228-008 from the 1996 – 99 BMW M3 modified with Koni front strut inserts, part number 8641-1342S3.  See Rules and

Strut Housing Modification Video: https://www.youtube.com/watch?v=qzNZCnUYtzo

Modification steps

  1. Remove spring from strut

  2. Drill a hole in the bottom of the strut housing and drain the oil from it

  3. Cut the strut housing at the top, below the lip where the strut piston extends out of the strut body. 

  4. Slide the strut tube out of the top of the strut housing

  5. Clean the now empty strut housing and enlarge the hole in the bottom of the housing to accept the bolt supplied with the strut insert

  6. Slide the strut insert into the strut housing and attach it with the supplied bolt through the bottom of the housing

  7. Install any dust caps included and reassemble the strut with the spring and top hat


Rear Suspension

Stock M3 upper and lower ball joints, part number 33-32-1-140-345, and stock   rear trailing arm bushings, part number 33-32-6-770-817.  RTAB shims (limiters) are highly recommended. See Rule One thing to note is that the NON M cars have a bushing for the rear lower outer control arm connection to the trailing arm. It is legal and recommended to upgrade this to the M3 ball joint, which is used on the rear upper outer trailing arm connection. 33326775551



33-32-1-140-345 has been superseded by 33-30-6-852-895 and is also legal


It is highly recommended you weld in the rtab pocket reinforcement plates. Here is an example of RTAB Pocket failure https://www.youtube.com/watch?v=J4zPECASIrs...


Subframe bushings can be poly, delrin, or any other non-metallic material but you must also weld in the reinforcement plates if you do that.The inner bushings on the upper and lower control arms are usually fine to leave alone but not a bad idea to replace if everything is dropped. It is recommended to replace your diff bushings while you are in there and upgrade to the LARGER front diff bolt.



Part Number


Useful Link







Rear Shocks

Koni part number 8240-1115S3. See Rule  Stock rear shock mounts, part number 33-52-6-754-096. See Rule



Part Number


Useful Link








Swift Race Springs, front and rear, part “NASA Spec3.”  See Rule

Contact RRT Racing in Sterling VA as they carry these. 






Anti Roll Bar (erroneously referred to as “sway bars” colloquially)

Eibach front and rear, part number 2033.32.  See Rule


As the Eibach kits are harder to find, new for 2021, you can run this H&R kit in its place





Wheels shall be either 15 inches by 7 inches, with a minimum weight of fifteen and one half half (15.5) pounds OR 17 inches by not more than 8.5 inches with a minimum weight of sixteen and one half (16.5) pounds, and can be any brand, unless otherwise specified in these regulations. All wheels on the vehicle must be of the equivalent size

The recommended “optimal” size is 17x8.5 ET40 with 15mm front spacer and either 15 or 12 in the rear.

Wheel spacer guide: https://www.facebook.com/groups/spec3/permalink/2712605542173903


Toyo Proxes RR in size 235/40/17 (dry conditions),  or 225/50/15 Toyo RA-1 (wet conditions).  See Rule


Stock non-M calipers and rotors with Hawk DTC-60 front pads, part number NBS3F or HB136G.690, and Hawk DTC-60 rear pads, part number NBS3R or HB227G.630.  See Rule

These can be found at Andrew-Racing as well



The stock caliper brackets can be upgraded using the same part from a Z3. https://www.facebook.com/groups/spec3/posts/3654181118016336/


Brake pad part number explanation

Hawk brake pad part numbers consist of:


The part number “HB136

The pad material “G” for DTC-60
The pad thickness including backing plate “.690



Motor Mounts

Any non-solid motor mounts of the stock height. See Rule

Transmission Mounts 

Any non-solid transmission mounts of the stock height.  See Rule


3:15 ratio limited slip differential.  See Rules,, and Appendix A.

These differentials were standard on OBD1 cold weather package cars.

Differential Bushings

May be upgraded with aftermarket bushings, including metallic. See Rule


It is a common mod to drill the front diff bushing and install a larger bolt. E36s are known for snapping the stock size bolt under hard acceleration.

Rear Subframe Bushings

May be upgraded with non-metallic aftermarket bushings. See Rule


Reinforcement of the following components is highly recommended but not required:


Rear sway bar pick-up points, front subframe motor mounts, rear lower control arms, rear trailing arm pockets, and rear subframe attachment points, BMW part numbers 41-00-2-256-495, 41-00-2-256-496, 41-11-2-256-497, and 41-11-2-256-498. See Rule

Shock Towers

Front shock tower, part number 31-31-2-489-795, and rear shock tower, part number 51-71-8-413-359.  See Rule


Front X-brace, part number 51-71-8-410-212, and any bolt-in front and rear shock tower braces.  See Rules and


Building Tips

Heater Core Delete (not required)

To get down to the class weight, most Spec3 drivers delete their heater core. This has the added benefit of removing hot coolant from the passenger compartment, simplifying the cooling system greatly, and clearing up space under the dash. See the image below for a basic visual of what hoses to delete and which ones to connect.


A block off plate must be installed on the rear of the head http://www.hardmotorsport.com/hard-motorsport-heater-core-coolant-block-off-plate-bmw-e36-m3/


Then, a heater core firewall block off panel MUST be added



Water temp sensor install

In the diagram above, there are three ports on the intake side of the head. The farthest to the rear of the engine is a coolant passage that gets blocked off when doing a heater core delete. This nipple can be removed and replaced with a water temp probe. Most likely, you will need an adapter such as this: Extended 12x1.5 to 1/8" NPT Adapter https://www.bimmerworld.com/Gauges-Data-Acquisition/Data_Gauge_Sensors/Extended-12x1-5-to-1-8-NPT-Adapter.html?gclid=CjwKCAjwx8iIBhBwEiwA2quaq71wS-gWFhSysWSp0VhRg-hrU2ZEkc1Z6SVpuZsVKUX-lT6-Ssf4AhoC3MEQAvD_BwE to thread into the head, which will then accept the water temp probe.


Alternative: Part number A2C59517248S threads right into the extra port on the head without any adapter



Brake caliper rebuild

The piston for the front brake calipers may be listed incorrectly. This is the correct part https://www.rockauto.com/en/moreinfo.php?pk=13228349&cc=1433882&pt=1724&jsn=10


Killl switch wiring

Per the CCR, every race car must have a kill switch. This switch must not only disconnect power from the battery when turned off, but it must also disable the car and turn the engine off. The only exception here are items like electric fire suppression, radios, cool suits, etc. This switch should be placed in a place easily reached while you are strapped in your seat, and also by emergency workers from outside the vehicle. Purchase a quality switch as you don’t want this part failing in the middle of a race, or 5 minutes before the flag drops! See below for a common way to hook up a 6 pole switch on an E36. A 2 or 4 pole switch will not work.


Source: https://www.hardmotorsport.com/hard-motorsport-bmw-e36-battery-disconnect-kill-switch-kit/

Reaching minimum weight

The following most likely need to be done to a prepped car to reach race weight

  1. Wire harness thinning

  2. Polycarbonate rear side windows (windscreen and rear glass must remain stock)

  3. Wire harness thinning

  4. Heater core removal

  5. Door gutting

  6. Lightweight battery

  7. AC/Cruise Control delete

  8. Interior stripping/Sound deadening removal


Sound deadening removal

There are two popular options for removing sound deadening, heat or cold

  1. Heat the sound deadening with a heat gun and scrape it up, then use a solvent to scrub up the adhesive 

  2. Use dry ice to freeze the sound deadening, then chisel it up. This method is much cleaner


It is suggested that you install something like the bimmerworld defrost kit, or install a blower motor to blow air from the transmission tunnel to the windshield to use as a defroster. At any rate, you should invest in some RAIN-X Defogger spray or dish soap to coat the windshield with.


96+ M3 control arms vs Non-M control arms

The 95 M3 used the same control arm geometry as a regular E36 but with an offset bushing to give extra caster.

  • 1995 M3 control arm part no: 31 12 2 227 249/250 (L/R)

  • 1995 non-M3 control part no: 31 12 6 758 513/514 (L/R)

  • 1995 M3 offset LCA bushing part no: 31 12 9 064 875

  • 1995 non-M3 LCA bushing part no: 31 12 9 059 288*

From September 95 onwards BMW did away with the offset bushing and fitted all M3s with concentric/non-offset bushings, with the additional caster coming from a new control arm design.

  • 1996+ M3 control arm part no: 31 12 2 228 461/462 (L/R)

  • 1996+ non-M3 control arm part no: 31 12 6 758 513/514 (L/R)

  • 1996+ M3 concentric LCA solid rubber bushing part no: 31 12 9 069 035

  • 1996+ non-m3 LCA bushing part no: 31 12 9 059 288*

A lot of online vendors will list the NON M part as fitting the M3 and pair it with an offset bushing. This is NOT the arm you should use for Spec3. The easiest way to tell the arms apart is that the M3 arm has the outer ball joint centered in line with the control arm where the non-m (and 95 M3) arm has the ball joint offset and this creates a little “dog leg” bend.

Pictured below (the non M arm on top (black), the M3 arm on the bottom (silver)). Note that the color and number of holes in the arm are not indicators.


Source: Vorshlag


Roll cage Design

Some important things to remember when designing your roll cage. Please read section 15.6 of the NASA CCR thoroughly 

  1. This class only allows a 6 point cage, meaning the cage can contact the body at the base of the A, B, and C pillars only. Foot protection bars are allowed. No gusseting of the cage allowed along the pillars.

  2. You should see that the bars of the cage as close to the roof sides of the chassis as possible to aid in egress 

  3. Make sure provisions for a window net, center net, kill switch, and fire suppression system pulls are considered in the design

  4. 15.6.4 Padding All roll cage surfaces that may come in contact with the driver’s head, knees, and elbows must be padded with high-density padding such as Ethafoam or Ensolite or other material labeled “high density padding” and manufactured for road racing use. 

  5. Optimal tube sizing for our cars is as follows

    1. 2501 - 3000 lbs 1.500” x 0.120” Seamless Alloy (4130), Seamless mild steel (CDS Mechanical), DOM, or Docol R8 (only) 1.750” x 0.095” Seamless Alloy (4130), Seamless mild steel (CDS Mechanical), DOM, or Docol R8 (only) 1.750” x 0.120” ERW* (No issuance of logbooks for cars with ERW cages) *Note- Specifications listed only for reference for inspection of grandfathered vehicles


A transponder is a box that transmits a unique number to the timing system as you drive over the start/finish line. Most organizations use what NASA uses, which is an AMB/MyLaps system. Your transponder should be placed as low and as far forward on the car as possible. Any obstruction between the transponder and the ground can negatively affect the signal to the timing loop. A transponder being farther forward on the car can mean the difference between 1st and 2nd place on a photo finish. 


A popular place is on the frame rail.


Cooling system

The achilles heel of most BMW engines is the cooling system. Early M5/X engines came with a plastic composite water pump impeller that would come apart and let the engine over heat. These engines do not tolerate high water temps (260+) and will quickly warp or crack the head. 


It is suggested to upgrade to a performance water pump with a metal impeller such as a Stewart unit, along with a metal thermostat housing (replacing the stock plastic part) and an aluminum radiator such as a CSF or Mishimoto. Some racers elect to run a lower temperature thermostat as well.


It is IMPERATIVE that you have at least the factory radiator ducting (top, sides, and undertray) to ensure adequate air flow through the radiator. The next step to upgrade beyond that is an undertray with an integrated radiator baffle (such as the Motion Motorsport unit) or a dedicated radiator duct such as the Kinematic Speed Radiator Duct kit. 



Euro Coolant Tank 

The late model E30 tank / E36 Euro tank is self bleeding and allows you to delete your fan shroud. It is a major upgrade over the stock unit.


E30 late-model 6 cyl. tank (17111712641)

Front Plastic Clip: (17111719190)

Rear Euro Mount (41122256492)

First, relocate the battery terminal by notching the metal:


Drill a couple holes and mount the battery terminal:



Make a bracket out of aluminum stock for the front plastic clip:


Rivet the rear euro mount/bracket to the firewall:


Wedge the rear of the tank into the euro mount and snap the front clip into place:



Brake cooling

This topic is up for debate, but the general consensus is that running at least the factory brake ducting is recommended if you are a front runner in the class. The Hawk DTC-60s operate fine and do not fade or drop off unless you are pushing the car 10/10s in a hot summer event. Expect to replace your rotors every 3-5 events as they will crack. Some racers elect to run dedicated brake ducting systems and results are unclear. Brake pad temperatures will be kept lower and basically eliminates brake fade, but at the potential cost of cracking rotors more often. Your mileage may vary.

Wheel studs

It is highly recommended that you convert the wheel lug bolts to wheel studs. Only use a high quality kit such as the race studs from Bimmerworld and replace them every 1-2 seasons.

Dual fuel pumps/fuel starvation fix

With the 25+ year old fuel pump in your car, you may experience fuel starve in long right hand turns when below ⅓ tank. There are a few legal options to remedy this.

  1. Some people have found that simply replacing their pump with a new one allows them to run down below ¼ tank without issue. Your mileage may vary 

  2. Most people install a second fuel pump in the driver side of the tank, replacing the sending unit. There are multiple ways to do this

    1. You can run the 95+ model year blue top pumps and just plumb the feed lines together going to the fuel rail, this is not suggested

    2. The better option is to run two white top pumps and plumb the return from the rail into the return on the the driver side pump, then send the feed from the driver side pump to the passenger side return, then have the passenger side feed the fuel rail like normal. The Bimmerworld kit does exactly this. https://www.bimmerworld.com/Intake-Fuel/Fuel-Filters/E36-Fuel-Starvation-Kit.html?gclid=CjwKCAjwx8iIBhBwEiwA2quaqzD52jLP1VvCK1vPxBKv9AhBbFOb7P-3Mjk4Xu9K2q6tnSTmr1qM4BoC98MQAvD_BwE

Oil pump nutJUnlysAzf8oqgqsCEsqOpt4gKXYEC9AgwF4-NwJzF5Xbur4vl5QaZEfR2eKOMhGCqPnn-Ojs1QAmxFlCFgn-I-uD3mzwTP-F8O2enBnlOnN3raKeDnT1JMtnY45iQ0kD5VfWTajBLpleyOl2XFUGdNlBZeEud2BoSodCmAamKrHyQVpJID46TRxO6HCX

The oil pump nut on these engines can get loose when the engine is turned backwards due to a spin on track. This problem is made worse by the lack of a tensioner on the oil pump chain. The slack creates an impacting motion on the sprocket which can work the nut loose. The fix for this is to safety wire the oil pump nut to the sprocket.




Source: https://shop.bimmerbum.com/products/3-00091-safety-wire-oil-pump-nut-for-m5x-s5x-engines

Oil Pan Baffle

It is suggested to run a baffled oil pan and also overfill by 1-2 quarts to avoid oil starvation during sustained later Gs. 

Engine Harness Diagram

The following is not 100% accurate, but should assist in figuring out what goes where if you did not label them during disassembly


Source: https://www.r3vlimited.com/board/forum/e30-technical-forums/24v-engine-swaps/m50-52-s50-52/265351-m50-52-s50-52-harness-diagram-simplified


DME Chip install

  1. Locate the DME cover on the passenger side firewall

  2. Unscrew the screws holding the cover in place

  3. Slide the DME out and unplug the connector

  4. Use a screwdriver to pry back the metal tabs on the bottom of the DME

  5. Lift the cover off of the DME

  6. Locate the chip on the board and pry up gently with even pressure all around

  7. Install the new chip with decoder board in place of the old chip. Press gently and evenly to secure it

  8. On later cars, you will need to cut the green wire on the main DME loom on the driver side of the car to disable EWS


Sound deadening removal

There are two ways to remove the sticker tar-like sound deadening material. Heat or dry ice. Most cars respond well to the dry ice method where you freeze the sound deadening and then hit it with a hammer to break it away from the chassis, but these cars do not respond will to that and the clean up can get nasty. Most find success with a heat gun, a scraper, and mineral spirits or some other adhesive remover. 


Before: After: CoP1B4nhgj5p4w3QPDSVk9W7VMl9wUpoeoouZJ2-phbvr5HVVl7m3aCt0c4CxILXDwSNHatueyT30O4FoipYP2rBCf4fO__Y8xAQpRLSDd649oA2SppTr-vftmTHPvbjt6TOa7ZkfVJMgVPKRxZHqW7UX5mJJqrsEYTjGY0z-iwCg_4s3tMVMtRKJWWaUnmW4qs5E8Vino_BMV4UUK_VCYEfaro44s8npwywwr32-XhfVAdXRPwYitqfZKUy7_6VaTWUFDFc5ASImXtnvYeCRtf0aDGsnEXusnX4zgXSobDVg6MzhIbdtrCQlpEj9kFCqmFTVR-eWAZikgIz3BOUq5GsUxl9N3VjUT0retCQx1fmGFGSig-pN8BX

Mounting an E36 on a rotisserie



Subframe reinforcement welding photos



Rear control arm reinforcements

It is recommended that the rear control arms have a reinforcement plate welded on. 



EWS disable

On OBD1 cars, if the chassis was equipped with EWS, you need to remove that link between the EWS computer and the DME as well as use an EWS delete chip. The wiring can be disconnected at the DME side (pin 66) or at the X20 side (pin 7). The X20 is the easiest to access and cleanly modify.


We recommend pushing the pin out of the X20. (big round plug by the fuse box.) If you unscrew that connector, pull back the boot, find pin 7 (green wire), twist the lock mechanism on the connector, push the pin (pin 7, green wire) out of the connector, re-lock the connector, fold the pin/wire back into the boot, put the boot back on, and reconnect the connector.

For EWSII equipped cars, there is also a starter lockout. We recommend bypassing that as well. On the EWSII module itself, there are only two large wires. Those are the wires for the starter solenoid. Cut them near the plug and butt connector them together and your car will start even when the key transmitter or antenna fails. (https://www.trmtuning.com/2013/10/11/ews-e36-chassis/)



Car setup and maintenance

Alignment Specs



Camber: -3.5 to -4.0 deg per side

Toe: 0


How to achieve that much camber in the front. 

  1. Cut a section out of the lip of the strut tower reinforcement plate if you have one installed to allow the camber plate to be adjusted to max camber. DO NOT CUT THE SHOCK TOWER ITSELF. THIS IS ILLEGAL

  2. Add washers or shims to the bottom of the strut where it meets the hub/knuckle



Camber: -1.8 to -2.2 deg per side

Toe: 0 to 0.10 total toe in (IIRC this is 1/8" total toe in)



Suspension Setup

A good baseline is to set the front anti-roll bars to full stiff and the rear to full soft. Also set the front shocks to full stiff (then turn it back a turn) and the rear to full soft (and turn it back a turn)

Brake pedal feel

The E36 is known for sub par pedal feel at times. The easiest fix for this is to bleed your brakes at least every other event and try to keep fresh brake pads on the car. If your pedal feels vague and squishy, it’s likely your pads are worn. Replacing the brake pads will bring back a surprising amount of pedal feel.


A lot of racers also install solid brass caliper bushings to normalize pad wear and reduce the taper of the pad material. These must be cleaned and lubricated every event.


Body Panels

Coupes and Convertibles share body panels except for the trunk. Sedans do not share body parts with the coupe or convertible except for the front and rear bumpers. Body panels from 92-99 models will all fit, however, the nose panel and bumper are different on 92-95 and 96-99 models. The E36 compact (318ti) is a sedan from the a pillar forward, so hood and fenders will swap to a sedan. 


Cylinder Head rebuild

It is the general consensus that a healthy, strong, front running motor can be had with a simple head rebuild and leaving the bottom end alone. You can mill the head .03mm before needing a thicker head gasket. If you mill beyond .03mm, there is a thicker head gasket made by victor reinz that will make up the milled material and restore your compression ratio to factory spec. The more you mill without making up the space, the higher your compression ratio will be and your cam timing may eventually be slightly off. Hot tanking the head, lapping and grinding the valves, and refreshing the Vanos will net a strong motor, assuming the bottom end is fine. E36 engines have been known before to have valve retainers crack and cause a valve to drop due to age or high revs. It is wise to replace all the retainers and springs, but most do not. If you have a noisy engine when hot, it may be worthwhile to replace the lifters as well when you rebuild the head. Note: It is rumored that BMW upgraded the spring retainers after 1995 to a hardened steel part, so any engine with the original spring retainers will have the weaker pieces and any retainers purchased new will be the stronger versions.


Head rebuild parts:

24 x BMW 11341724991 (Valve spring plate “retainer”)




48 x BMW 11341461405 (Valve keeper)



ELRING Head Gasket Keep (includes valve seals) BMW 11129064467






Tire Pressures

Toyo RR

  • Operating Temperature: 160°F to 220°F

  • Hot Inflation Pressures: High 30s to Low 40s (psi)

  • Camber: -2.5° to -5.0°

  • Caster: As much positive as possible

Toyo RA1 

  • Operating Temperature: 160°F to 220°F

  • Hot Inflation Pressures: High 30s to Low 40s (psi)

  • Camber: -2.5° to -5.0°

  • Caster: As much positive as possible

Tire Mounting and Rotation




Fluid Capacities and weights





Engine Oil

5w-30, 10w-30, 5w-40, 10w-40, 5w-50, 10w-50

6.5-7.5 qts

Gear Box

D4 ATF (most common factory fill, but not most common refill) Most use Redline MTL (70W80) or Redline MTL-90 (75W90) or equivlalent

1.5 qts


75w-140 GL5

1.8 qts


Distilled water + water wetter

11 qts


Oil Filter Housing Welch Plug o ring

The oil filter housing went through various revisions. Some units having press fit plugs while others have threaded plugs. If your housing was threading plugs, they use an o ring to seal and this can start to leak. This is the part number that can be used to replace it.



Build Threads

Taylor’s 325 



Sean’ 325



Tom Neely 



Edward Higginbothom



How to get started? Order of Operations on a fresh build.

This section will walk you through a potential order of operations when building a car and working your way through HPDE. Expected time to start in HPDE1 and make it to competition school is 2 years. 


Year 1: HPDE 1 -> HPDE 2

Year 2: HPDE 2 -> HPDE 3

Year 3: Competition School in first event and rookie season of Spec3


This can be done faster or slower all depending on skill level, experience, and of course, luck. 


  1. Join the Spec3 Facebook group! 

  2. Read the rules and this manual! 

  3. Find a donor car

  4. Do basic maintenance such as change all of the fluids, flush the brakes, and replace any worn suspension and brake components

  5. Install good brake pads (Something like a Hawk HT10) and do you first event! Get your feet wet and participate in an HPDE1 weekend.

  6. Search for safety gear. If you’re ready to take the plunge, it’s never too soon to get a full cage welded in and secure the relevant safety gear, but for now we will assume you aren’t ready for all of that. So source a quality roll bar, 2 race seats, brackets, harnesses, a helmet, and a HANs device

  7. After basic safety components are taken care of, you can continue driving HPDE1 weekends and we can assume you’ve moved up to HPDE2 at this point. The next logical step is to assemble your suspension and start removing interior pieces. Pull the carpet, AC components, radio, window regulators, and any other stuff you don’t need. 

  8. Cooling system refresh! Pick up an aluminum radiator and a performance water pump with a metal impeller. Now is a good time to replace hoses and install a quality thermostat. Make sure all of your ducting around the radiator is intact!

  9. Install a fire extinguisher or fire suppression system!

  10. Start shopping for M3 control arms, m3 strut housings, the koni shock inserts, swift springs, sway bars, camber plates, chassis reinforcement pieces(rear subframe, trailing arm pockets, engine mount/subframe, sway bar), and buy some new poly/solid bushings (engine mounts, transmission mounts, stock front control arm bushings, stock rear trailing arm bushings with limiters, poly subframe and diff bushings, upgraded diff bolt, and new ball joints for the rear control arms)

  11. Pick up an oil pan baffle and drilled oil pump nut

  12. Install yourself, or take to a shop. Most of the chassis reinforcements need to be welded in. It makes sense to do all of your suspension work and bushing replacement at the same time since both the rear and front subframe must be dropped to complete the reinforcements. The front subframe must be dropped to do the oil pan and oil pump nut, so now is the time to do those as well

  13. Winter after first season. Congrats! You’re probably in HPDE2 or HPDE3 now. Time to get serious! 

  14. Time to pick up a Spec3 exhaust and DME chip

  15. Now is the time to start contacting shops to see about getting a full cage welded in. You’ll probably need to book a few months out. See if they are willing to use your roll bar as a starting point for the main hoop and plan accordingly with what they say

  16. Additional weight loss. Now is the time to consider thinning your wire harness some more and gutting your doors in preparation for a full cage

  17. Get a fire suit if you haven’t already. This is your last season before racing, so get used to being in the fire suit with the shoes, socks, balaclava, and other fire safety gear. Ideally you already did this before you stepped on track!

  18. Now is the time to also go trailer shopping. You may have been driving to the track before, but with a full roll cage, this is no longer a good idea. 

  19. Install the head light intake duct

  20. If you haven’t already, consider installing water temp, oil temp, and oil pressure gauges. The factory gauges are not very useful 

  21. Strip your interior and get your cage welded in. Ask them to weld in your sunroof as well! 

  22. Final prep. Rain light, install your stickers, rookie designation, kill switch, fire surpression system, window net, center net, a steering wheel with a quick release, etc. 

  23. Complete competition school and go racing! 



Preparing for your first track event

It’s very intimidating going to your first event, but it doesn’t need to be! Don’t be afraid to ask questions. Every single person there has been in your shoes before and can relate.


First things first, be prepared! Ask off of work for the event well in advance. Figure out your lodging (tent camping? Sleeping in your trailer or car? Getting a hotel? Hotels fill up fast so book early!). Find out where the restrooms are at the track. Do they have showers? Do they have food vendors or will you have to pack in everything. Does the track have a gas pump or must you bring fuel?


What to pack! Basic things like sunscreen, wallet, phone charger, your helmet are easy to remember, but there are some things you may not consider.

  • Way more bottled water than you’d expect

  • Paper towels and hand washing water jug

  • Spare parts for your car. Extra set of brake pads? (Not just for the track, but for the drive home!)

  • Towel for the shower

  • Snacks

  • Mode of transportation in the paddock? Bicycle? Scooter? No skateboards! 

  • Chairs and canopy 

  • Air compressor

  • Torque wrench and sockets

  • Small tool set

  • Jack/Jack stands, but also wood to place under the jack and stands! Most tracks require this

  • AAA or insurance? You may need a tow home

  • Tire Pressure Gauge

  • Zip ties

  • Tape (painters and duct)


Now, here are some basic E36 parts to bring as spares

  • Brake light switch (cheapest part that will ruin your weekend. You can’t go on track without working brake lights)

  • Brake light bulbs

  • One front brake line and one rear brake line

  • Throttle pedal (these are plastic, and you’ve probably never looked at yours to see if it isn’t already broken!) 


Okay, you’re all signed up, you’ve arrived at the track. Now where do you paddock? Drive around the paddock until you find someone in a similar car (in your case, an E36) and ask them if you can paddock near them. Even if they say no (very unlikely) they will probably have a good idea for where you can paddock and set up camp. Find the Spec3 racers near you and tell them you’re interested in the class and they’ll surely take you in. Having knowledgeable folks with the same car as you is invaluable.


You’re paddocked and ready to drive. What’s next? 

  1. Take stock of your surroundings. Where is the medical area, where is registration, where is the tech station? Where is the entrance to grid, where are the restrooms, where can you get food, where can you get warm/cool/dry in case of inclement weather. Where is the closest spill clean up station, fuel station, or fire extinguisher?

  2. Prep your car. Clean out your car, no floor mats, no loose items, take out your spare tire, etc. Tape your numbers on, cover your battery terminals with tape, make sure your belts and everything are tight. Torque your lug nuts and check your tire pressure.

  3. Get your car tech’d. Go to the tech station (consult your schedule to see when they are open) and get your car approved by the tech inspector.

  4. Check in at registration. This varies region to region, so check your pre-event emails to see what they want you to do. Some don’t require check in and just call attendance at the driver’s meeting. 

  5. Check the schedule and see where you need to be first thing in the morning. Usually there is an all hands driver meeting early, then your first class room session or run group meeting will be right after. Figure out where these will be and don’t be late! 

  6. REST! Get a good night’s sleep. Wake up early and give yourself time to prepare and double check everything before going to the classroom. You may not have a lot of time after class to prepare for your first session.

  7. Have fun and ask lots of questions! HPDE is about learning, so soak it all in. 


To-Do List 

  1. Roll cage bends/measurements

  2. Oil Pressure Gauge

  3. Water Pressure Gauge

  4. Oil Pressure switch

  5. Rain Light Install

  6. Harness Mounting points

  7. Control arm bushing install (90 degree clock for stiffness) 

  8. Anti Roll Bar setup

  9. Suspension setup

Edited by TaylorGoesFast
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  • TaylorGoesFast changed the title to Spec3 Constructor's guide

Updated NASA National URLs, updated information about sway bars and flywheels. 

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