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What is the difference between Spec3 and Spec E36?


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Hello all! I get asked this question a lot, so I'll go ahead and write it down. These views are not those of NASA or of BMW Club, but are my own personal findings and opinions on the matter. 

TL;DR: Spec3 is more popular than Spec E36 and has a more "spec" ruleset similar to Spec E46 and Spec E30. Build a Spec3 if you want to run both classes. You will need to swap the shocks and springs on your car and that's just about it. More info below. 

While the true history and context of this action predates me by a lot, from my research, I can see that a couple of years after Spec E30 took off with NASA, BMW Club appears to have filed a trademark for Spec E36. Due to this, it seems Spec3 was unable to use that name. 

Where are these classes popular?

Spec3 currently has ~30 active racers and an additional ~40 cars being built with the potential to join the racing field with NASA in the next 2-3 years. Spec3 is averaging a new build starting once every 2-3 weeks or so across the USA. 

In 2023, Spec3 had 17 or so race weekends across 4 different NASA regions at 12 different tracks. Spec3 will have 20+ race weekends this year.

Spec3 has cars being built in 9 different NASA regions across the United States including California 

Spec E36

I cannot speak to the true metrics of this class, but it is less popular than Spec3. In 2023, from my research, I see results at VIR, CMP and Roebling with a total of possibly 4 race weekends for the entire year. 

What is different about the two classes?

Sanctioning Body

Spec3 is sanctioned by the National Auto Sport Association at the regional and national championship level

Spec E36 is a registered trademark of the BMW Club of America

The main difference is that Spec E36, unlike most Spec classes, allows multiple engines (2.5 or 2.8) and open DME (ecu) tunes. Spec3, like most spec classes, is limited to one engine. 

Spec E30 only allows the M20b25, Spec3 only allows the M50B25TU, Spec E46 only allows the M54B30. 

Spec Miata is one of the only exceptions where it allows multiple engines, and the balance of power (Which changes regularly) is constantly debated. Currently, the NB2 is the most dominant chassis and engine in Spec Miata and the 1.6 liter engine is no longer competitive beyond a regional level. 

Spec3 also requires a spec engine tune which cannot be altered and is easy to compliance check, similar to Spec E46.


Spec E36 
Three suspension package options with various shock and spring combinations. 
Any anti roll bar
Any Camber Plate
Any brake pad
Stock Control Arms or m3 arms

one legal suspension - E36 M3 strut housings, Koni yellow shocks, Swift Spring (made for Spec3) 
Spec H&R or Eibach(NLA) Anti Roll Bar
Vorshlag Spec3 camber plates 
Hawk Brake DTC 60  pads 
96-99 M3 control arms only

Spec3 allows either the stock sunroof to be secured into place or a piece of sheet metal of the same type as the stock panel to be secure in place. The Spec E36 rules specifically call out the stock sunroof panel being needed.


Is a Spec3 legal in Spec E36? Is a Spec E36 legal in Spec3?

Neither class is technically legal for the other. A Spec E36 running in Spec3 is very illegal. There are exceptions made for special events where Spec E36s come to run with NASA, but it has not happened in quite a while. Since the Spec E36 rules are much more "open", including major changes Spec E36 has appeared to make for the 2023 rule set, a Spec3 is almost legal to run in Spec E36. The only thing that makes a Spec3 illegal in Spec E36 is the shock/spring combination. If you swap on the Spec E36 ground control coilovers, for example, your car is likely to be legal for Spec E36. It makes the most sense to build a Spec3 if you wish to race in both classes. 


Why don't the two classes just merge their rule sets?

Spec3, at this point, has little reason to change its rules. If it did so, it would force ~70 cars to replace parts or change their builds as of writing this in February 2024, and at best, might gain ~5 cars from BMW club that may run 1-2 races a year with NASA. A lot of the 325i cars in Spec E36 are using Spec3 parts, so they are already Spec3 legal except for the suspension and could swap their shocks/spring to run Spec3 at any time they wanted. The other few cars are 328i models which will likely never be legal in Spec3 due to balance of power/parity concerns. Spec3 is hyper focused on staying low cost and utlra-competitive, so the class will likely never allow any of the "open" rules of Spec E36 and is very unlikely to allow 2 engine options. The M50b25tu is one of BMW's most produced engines and are easily found for $300. 

Spec3 is one of the fastest growing classes in the nation across any club/amateur racing organization, which confirms the rules are good and attractive to perspective racers. 

If Spec E36 allowed the Spec3 suspension, or if Spec3 ever changed their suspension to match Spec E36, then that would open up Spec3 cars to compete in Spec E36, but presently, there is little incentive to do that as at most, it would add 4 races a year to the calendar for people in the Carolinas and Virginia where they already have ~20 to weekends to choose from. 


Parts Compatibility Matrix as of February 2024. 


Key Same/Legal in both Spec3 parts legal in SE36, but SE36 parts may not be legal for S3
  Showstopper/Not compatibe SE36 legal in Spec3, but Spec3 may not be legal in SpecE36
Item Spec3 Spec E36
Sanctioning Body NASA BMW CCA
Chassis 92-99 E36 Sedan/Coupe 92-99 E36 Sedan/Coupe
Engine M50B25tu M50b25, M50b25tu, M52b28, M52b25 w/M50b25tu head
Shocks/Springs M3 strut with Koni Yellow, customer Swift Springs H&R E36 RSS ClubSport CoiloverKit OR Ground Control/Eibach/Koni Front
suspension with H&R Rear Suspension
Camber Plates Spec3 Vorshlag Camber plates Open
Anti Roll Bars Spec Eibach or H&R (see rules) Open
DME Spec chip by Epic Motorsports Open
Center Net Optional. Required without containment seat Required
Head Light Duct Stock headlight, RaceGerman Duct, Spec Ebay Duct Open
Exhast Spec exhaust (see rules) Open
Max Piston Overbore .025 inch .025 inch
Suspension bushings OEM M3 FCAB, OEM M3 RTAB w/limiters, Poly everywhere else Open (no spherical)
Front Control Arms 96-99 OE M3 Stock non M or M3
FCAB Set Screw? NO YES
Brakes Stock w/ Hawk DTC-60 Open
Ball Joint reinformcent on subframe Yes No
FCAB reinforcement No Yes
"Steering Box reinforcement" [sic] We assume this means the steering rack mounting tabs No, E36s don't even have steering boxes? Yes
Rear Shock Mounts OEM Open (spherical)
Wheels 17x8.5 OR 17x8 over 16 lbs 17x8.5 over 16 lbs
Dry Tires Toyo RR 235/40/17 Toyo RR 235/40/17 OR 245/40/17
Wet Tries Toyo RA1 225/50/15 Toyo RA1 235/40/17
Transmission Getrag 250 Getrag 250 OR ZF320d
Sunroof Stock panel or "similar material" riveted to the roof Stock Panel
Fuel filler neck Cannot be modified Can be modified
Min Weight 2825 w driver ???
Max HP/TQ 195.9/179.9 ???


Edited by TaylorGoesFast
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