Spec E46 is one of the newer classes in NASA racing, but it’s catching on in a big way. Field sizes are increasing in certain regions and Championships fields have soared from virtually nothing in 2015 to double digits in 2016. BMW sold a great deal of E46’s, so finding a donor shouldn’t be too difficult, according to Spec E46 National Director and series founder Jason Tower.

Initial build costs will be greater than some other spec classes, such as Spec Miata, Spec E30 or 944 Spec, and the required parts aren’t inexpensive, but that was intentional, Tower said.

“It is a bit more expensive than other spec series. We knew that going in, and that was part of the goal,” he said. “It’s not the cheapest way to enter racing, but it’s far from the most expensive, and you get a genuinely good car out of the deal.”

Once the initial build is done, the cars hold up well. Tower said cars with as many as 200,000 miles on them still make viable racecars and are strong enough to set lap records and win races. What’s more, because of an aggressive weight target, just 2,850 pounds, the cars are easy on tires and brakes. Running a Spec E46 registers in the bottom half of a NASA race field in terms of cost, but in the top half in terms of fast laps. That’s where the value lies.

“They’re surprisingly easy to own and operate,” Tower said. “The running costs, they’re not going to be quite as low as a Spec E30, for example, but they’re really not that much higher, and much lower than, say, GTS, ST or American Iron. Any of those cars are going to chew up consumables two or three times faster.”


Class Description

“Spec E46 is a spec racing series combining vehicle equality with a high level of chassis performance and adjustability to maximize driver involvement. Engine development above a stock power level is not included in the intent of Spec E46. Future additions to this rulebook, potentially including, but not limited to, maximum power definitions, mandatory teardowns, and engine claim rules, can and will be made to eliminate engine development if needed to maintain car parity within the originally intended budget.”



Eligible Makes and Models

The series is open to BMW E46 chassis 330 USDM models. This includes 2001-05 sedans and 2001-06 coupes. ZHP, 330xi, wagon, and convertible models are not permitted.”


Donor Prices and Availability

$1,000 to $4,000

The key is finding the combination of a 330i or 330ci with a manual transmission. You can substitute a manual in an automatic car, but that requires additional work and parts, such as pedals, slave cylinder bits and a driveshaft.


Engine Specs

M54, 2,979 cc, 182 cid inline six cylinder, 225 horsepower



2,850 pounds with driver


Fuel Required

Fuel must be pump gas rated 93 octane or lower.


Average Cost to Build Car

On the low end, with a lot of your own labor, less than $20,000. Typical car cost from $20,000 to $25,000 for a solid build. For a top shelf home-built car, figure $30,000.


Average Cost to Buy Built Car

New builds run from $35,000 up to $50,000 for a first rate, turn-key car. Used cars are beginning to appear on the market, and they run usually from $25,000 to $30,000.


Typical Modifications

  • Must-do items include an up-to-date cooling system, which means a new radiator, thermostat and water pump and hoses.
  • You also must reinforce the unibody attachment points for the subframes and suspension bits. Full weld-on kits are available.
  • You must replace subframe bushings, preferably with delrin or metal pieces.
  • To be competitive, you’ll need the spec suspension kit, which runs $4,400 and a 3.46:1 limited slip differential for $3,000.


Cost Analysis

Average cost to run a weekend — $1,500 to $2,000.


Consumables Prices

Tires, size, brand and prices

Toyo RR 255-40-R17    $231.29 from Phil’s Tire Service, Cragsmoor, N.Y.

Toyo RA1 255-40-R17  $226.88 from Phil’s Tire Service, Cragsmoor, N.Y.


Brakes, brands and prices

From Bimmerworld

Hawk HT10: $192 front; $161 rear

Hawk DTC-60 pads: $273 front; $181 rear

Hawk DTC-70: $295 front; $191 rear

PFC 08 pads: $332 front; $266 rear

PFC 11 pads: $323 front; $256 rear


Available contingencies

Toyo Tires, Hawk Performance, Bimmerworld, Epic Motorsports, Winding Road Racing, Neo Motorsport, Redline Oils, Spec Clutches, Sampson Racing Communications, Frozen Rotors, Tilton.


Factory Participation





  • Spec racing, all the cars are the same, one engine, one weight, one tune on sealed ECU.
  • There is some freedom within the rules to set up the car to suit you.
  • Late-model cars at good donor prices, competent chassis and vehicle dynamics, long-lasting engines, vast knowledge base.
  • Growing class, fields increasing throughout the country and at Championships events.



  • As spec classes go, this isn’t the cheapest route, but Spec E46 was designed to create good cars, not necessarily the lowest cost racing class.
  • The cars never came with a factory limited slip, so you have to buy one from Bimmerworld or Diffsonline.com.


Rulebook Highlights

  • If a part may be removed any related brackets, fasteners, electrical components, etc may also be removed.
  • Compression ratio may be changed only within the tolerances affected by resurfacing for trueness and within factory tolerances, and shall not exceed 10.5:1 [exact value TBD] as measured by a whistler device.
  • Oil pan baffle may be added.
  • Either the 5 or 6-speed E46 330 manual transmission may be used.
  • Flywheel and clutch assembly may be replaced provided they use the stock hydraulic actuating mechanism. Clutch must be a single disc type.
  • Finned and/or larger capacity differential cover may be used.
  • Swaybars may be replaced provided they use stock mounting locations with non-metallic bushings and either individual hole or sliding collar adjustment. Remote-adjustable or pivoting blade bars are not permitted.
  • Adjustable camber/caster plates are permitted. The three front strut mounting holes and center hole may be notched/trimmed to provide clearance for fitment or achieving full range of adjustment.
  • Wheels may be replaced, 17″ diameter and maximum width 9″.


What Racers Say

Mason Meredith, NASA Great Lakes

“I was racing in Spec E30 and I wanted a faster car with more chassis adjustment capability. I was looking at other classes when the rules for Spec E46 came out, and it was almost exactly what I was looking for.

I think the class is great, the cars are fun to drive and competition is close. Participation is low in our region right now, but looks to be picking up. Also, the rules have been stable and the only changes to the rules have been logically thought out and presented to the competitors for comment before being implemented.”


Ali Salih, NASA Great Lakes

“I always wanted to race in a Spec class, however available options (Spec E30 and Spec 3) were not all that “fun” due to a focus on using economical performance parts. When I heard the series leaders —Jason and Evan — were consulting with professionals and addressing these concerns, and came up with a real racecar recipe, I jumped on-board. The class is in a good shape, growing in a steady pace yearly. There’s great camaraderie between racers, and event rivalries building. We hope to have more racers in the following seasons, because these cars are uber fun to race with, and it is very economical run cost wise. Come join us!”


Jason Tower, Spec E46 National Director

What drew you to create Spec E46?

“I started racing in Spec E30 and while I thoroughly enjoyed the racing and the people, I was always somewhat frustrated by the car. I also raced a Honda Integra in ChumpCar, which was all the things the SE30 was not — lightweight and adjustable in particular. That got me thinking about what my dream car would look like from a racing perspective. Inexpensive and abundant donors, durable motor and driveline, strong factory brakes, aggressively low weight, fully adjustable suspension and chassis, rear-wheel drive, light flywheel and clutch, optimized gearing, proper LSD, all combined in a spec class where vehicle parity is paramount and racing is first and foremost about the drivers. Spec E46 was created to meet those goals and has done so beyond my expectations.”


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