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Everything You Wanted to Know About NASA's Spec E46 Racing Series

Spec E46 is one of the newer series in NASA racing, but it’s catching on in a big way. Field sizes are increasing in many regions and Championships fields have soared from virtually nothing in 2015 to double digits in recent years. BMW sold a great deal of E46 cars, so finding a donor shouldn’t be too difficult.

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 known from the start. The series was devised to produce a good racecar, not necessarily a cheap one.

Once the initial build is done, the cars hold up well. Cars with as many as 200,000 miles on them still make viable racecars and run 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.

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.
The series is open to BMW E46 chassis 330 USDM models. This includes 2001-2005 sedans and 2001-2006 coupes. ZHP, 330xi, wagon, and convertible models are not permitted. A 323/325/328 chassis may be used, provided all components meet 330 specs.

$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.

M54, 2,979 cc, 182 cid inline six cylinder, 225 horsepower
2,850 pounds with driver
Fuel must be pump gas rated 93 octane or lower.
On the low end, with a lot of your own labor, less than $25,000. Typical cars cost from $25,000 to $35,000 for a solid build. For a top shelf home-built car, figure $40,000.
New builds run from $35,000 up to $55,000 for a first rate, turnkey car. Used cars are beginning to appear on the market, and they run usually from $25,000 to $35,000.
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.
Average cost to run a weekend — $1,500 to $2,000.

Tires, size, brand and prices

Toyo RR 255-40-R17 $249 from Phil’s Tire Service, Cragsmoor, N.Y.

Toyo RA1 235-40-R17 $234 from Phil’s Tire Service, Cragsmoor, N.Y.

Brakes, brands and prices

From Bimmerworld

  • Hawk HT10: $252 front; $160 rear
  • Hawk DTC-60 pads: $273 front; $186 rear
  • Hawk DTC-70: $295 front; $190 rear
  • PFC 08 pads: $332 front; $266 rear
  • PFC 11 pads: $323 front; $256 rear

Check the NASA Contingencies page for the latest programs.

Spec racing, all the cars are the same, one engine, one weight, one tune on a 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.
  • 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-inch diameter and maximum width 9 inches.


Questions and Answers to Feed Your Curiosity

The class includes 2001 through 2005 sedans and 2001 through 2006 coupes. However, later cars — starting in mid 2003 — have a different ECU (MS45) that has to be backdated to the earlier type (MS43) to run the spec tune. So, it’s generally best to stick with 2001 to 2003.5 cars.
Coupes are a bit lighter and have bigger doors, so tall and/or heavy drivers may find them easier to fit into. I personally prefer sedans because they provide better access and have framed doors, which makes travel glass easier to install, which is nice if you have an open trailer. Ultimately, it’s up to the racer. Both are fully capable of turning fast laps when built properly.
There are a ton of E46s out there, so new and used parts are cheap and readily available. And since the M54B30 motor was used in a lot of other BMW models, a blown engine can be replaced inexpensively, yet still be competitive.
It’s outstanding! As a spec class, one of the main priorities is focusing on vehicle parity, so you’re always racing other drivers, not their cars or checkbooks. We’ve had numerous races where the qualifying times of the top five or six drivers is separated by just a few tenths of a second. And with large fields, there is always someone to race, even if you’re a beginner.
Despite being one of the newer classes out there, Spec E46 often has one of the highest car counts in many regions, and we’re still growing. The east and west coasts have large, established fields. The midwestern regions aren’t quite as large, but are steadily gaining new cars and drivers every year.
The answer for Spec E46 is the same I’d give for almost any class: It’s really up to you. If you don’t know the answer, you should probably buy used. Spec E46 has been around long enough that used cars are out there, although you may need to travel a bit to find one that suits your needs. If you want a fresh build, you can do it yourself and pocket the labor savings, or there are a number of reputable shops that will build a car to your specifications.

In a spec class, it’s always tempting to call for “cheap” parts on the build sheet. After all, we’re all running the same parts so why spend a lot? With Spec E46, we wanted to make sure the cars performed well, were reliable and easy to maintain, and had enough adjustability so drivers could fine-tune them to match their preferences. So we attempted to strike a balance with the parts selection. Price wasn’t the only consideration.

Take the exhaust, for example. Engineered by Bimmerworld and produced by MagnaFlow, it’s a high-quality stainless item built in multiple sections, with beefy flanges, and strong V-clamps to make installation and removal easy. It includes a straight pipe and a resonator for tracks with stringent noise limits. The MCS adjustable shocks are another good example. Everyone who drives on them raves about their performance, and they have proven to be extremely durable and consistent even after several years and thousands of miles of racing. We’re not trying to be the cheapest series. We’re trying to be the most balanced. Ask almost any Spec E46 racer and he or she will tell you that the rules set is pretty spot-on.

The E46 platform has proven to be extremely durable, as evidenced by the number of street cars, and thus donors, with 200k-plus miles on the clock. The biggest E46 weak spot is the rear subframe mounting points, which should be reinforced, and there are a number of kits on the market to do just that. The plastic cooling system components can become brittle and crack after 7-10 years, and are generally replaced as part of the build. Beyond that, the rest of the car is pretty tough, Motors run basically forever as long as they aren’t overrevved or overheated, and suffer very little drop-off in power even with high mileage.
They are fast enough to be thrilling, but not so fast they’re always trying to kill you. They are generally easy to drive, but have enough adjustability to satisfy and reward experienced racers. Consumables are relatively inexpensive, and Toyo and Hawk have great contingency programs. They look good and sound great. They are easy to live with. All cars have headlights, glass windshields front and rear, and the lack of splitters/wings/etc. means you can just drive it on and off the trailer, throw a cover on if it rains, etc. You have a choice of coupe or sedan, and the overall cost is competitive with other classes. But the best reason of all is the racing itself. Large fields of closely matched cars is what spec racing is all about, and Spec E46 delivers that in spades. Come join the fun!


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Spec E46 Series Contacts

Spec E46
Danny Parkhurst
Region: Southeast
Title(s): Regional Series Leader
Series: Spec E30, Spec E46, Spec3
Eric Haagenson
Region: Mid Atlantic
Title(s): National Series Director
Series: Spec E46
Evan Levine
Region: Mid Atlantic
Title(s): National Series Director
Series: Spec E46
Jason Rikke
Region: Texas
Title(s): Regional Series Leader
Series: Spec E46
Jeremy Lucas
Region: Great Lakes
Title(s): Regional Series Leader
Series: Honda Challenge,Spec3,Spec E30,Spec E46
Katherine Agurkis
Region: Southeast
Title(s): Regional Series Leader
Series: Spec3, SpecE46, SpecE30
Peter Oneppo
Region: California-Southern
Title(s): Regional Series Leader
Series: Spec E46, Spec3
Steve Stepanian
Region: California-Southern
Title(s): Regional Series Leader
Series: Spec E46, Spec3
Steven Ferrario
Region: California-Northern
Title(s): Regional Series Leader
Series: Spec E46
Taylor Johnson
Region: Northeast
Title(s): Regional Series Leader
Series: Spec 3,Spec E46