After a Crash, Part 4: Building a New Race Car From Scratch

By christinaylam
Apr 30, 2020 | Safety, Crashing | Posted in Safety , Features | Never miss an article

Read Part 3

Read Part 5

After deciding to start a fresh race car build, I began my search for a new E46 BMW M3 shell. Friends were quick to send links for ones for sale. 

A few people offered up their already-built race cars for sale. Ultimately, I decided to build another Hi-Speed Motorsports car from scratch with shop owner Hugh Stewart.

There are a few things to consider when purchasing an E46 donor, and they are applicable to both E46 M3s and E46 non-M models.

The most notorious issue on the E46 chassis is the subframe. The subframe itself is very strong—the problem lies where the subframe meets the chassis. The floor in this area often develops cracks that can spread. It is critical to catch this early. Otherwise, it can become an extremely expensive fix.

Here’s the truth about E46 subframes: Many people post that they have “inspected” the floor and that it shows no signs of cracking. But to truly be able to examine the condition of the rear subframe, the subframe needs to be removed from the chassis. That is the only way to get a full view of the floor. 

Ninety-nine percent of the time, E46s have minor cracking underneath the subframe that is not visible when the car is just sitting on a lift. When you’re purchasing an E46, these minor cracks are acceptable since you should plan on reinforcing the subframe anyway. Minor cracks can be repaired while the subframe reinforcements are being installed.

There is a myth that gently driven SMG street cars won’t be cracked while spiritedly driven track cars will have the worst damage. We have not found this to be true, as the use of the car often has little correlation to the subframe condition. Both my E46 M3s donors came with very minor cracking, while we’ve seen some garage queens with the floors falling out. 

If you plan on keeping your E46 long-term or tracking it, reinforcements are a must. We use AKG Motorsport E46 subframe reinforcements for all of our cars. AKG Motorsport manufactures the thickest plates on the market, and all of their parts are designed and manufactured in the U.S. 

I’ve used their parts for years. My previous E36 M3 race car and my wrecked E46 M3 race car were fully outfitted with everything they make, from reinforcements to bushings to their well-known Stage 3 shifter.

Another aspect that we look at when considering an E46 shell is prior accident history. A pristine, accident-free chassis is always preferred, but as these cars get older, they become harder to find. 

Run a Carfax for an initial overview, but also do a thorough inspection since not all accident repairs show up on the history report. A repaired chassis is not a deal-breaker as long as it has been repaired correctly.

There are a few differences outside of the drivetrain between the E46 M3 and non-M (323i, 325i, 328i, 330i) to consider when buying a donor. An M3 chassis will come at a cost premium over a non-M model, but there are a few benefits that come with it as well: The M3 has stronger rear subframe, differential, axles and front control arms plus wider fender arches.

The subframe on the M3 differs from the non-M models to accommodate the larger differential. The larger differential in the M3 measures 210mm across versus the 188mm diameter in the non-Ms. The gear set is larger, along with the clutches in the center, and the added fluid capacity ensures that the bigger differential stays cool. The non-M diff provides weight savings over the M3 versions, and axles are cheaper to replace.

M3 fender arches are larger than those found on non-M cars. They were designed to fit a wider tire from the factory. The M3 fenders will fit a 275mm Hoosier with ease, but we take it one step further to race in Touring 1: The front fenders are rolled through an English wheel and the rears are flared to fit a 295mm square Hoosier setup. Fitting the bigger tire is much easier when starting with the bigger arches. 

For our purposes, it made sense to find another M3 chassis. A non-M chassis can work, but sourcing all the M3 parts to recreate an M3 costs more time and money in the end.

The first two cars we looked at did not work out. The first had a damaged floor, and while it could be repaired it was not a first pick. The second chassis, which came with a full drivetrain, looked promising, but the seller went back on an agreed-upon price as he sensed the urgency in the situation.

Third time’s the charm. My friend Scott Heckert reached out on Instagram

A shop in Charlotte had a clean E46 M3 shell that had been sitting for a few years. The car was used as a parts car and not much remained other than the clean chassis. 

EuroMpire, where the car sat, was quick to put the car on a lift and send detailed photos. This was the one. I immediately sent payment and began working on transport.

Al Taylor from the SpecE30 community helped me arrange transport up to Virginia International Raceway. Hugh then fetched the chassis during a 20-hour round trip from his shop in Connecticut. 

We were 57 days out from the SCCA Runoffs with a big task ahead. The first E46 M3 took over a year to build from the conception of the idea to turning a wheel on track. 

While I learned how to do much of the work the first time around, condensing a full build into less than two months was a tall order. We were going into the biggest race of the year with a fresh build. 

The clock was ticking. Time to get to work. 


Read the rest of the series:

Part 1: Three Types of Wrecks

Part 2: The Day After the Wreck

Part 3: Seeking Racing Justice

Part 5: A New Roll Cage for the New Race Car

Part 6: The Thrash to Meet a Firm Deadline, the SCCA Runoffs

Part 7: Before Returning to the Track, Time to Make It Look Like a Real Race Car

Part 8: 60 Days After Destroying the Race Car and Building a New One, It's Time to Take the Green at the Runoffs

Part 9: Pondering Future Racing Plans


How Christina got her start in motorsports.


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christinaylam (Forum Supporter)
christinaylam (Forum Supporter) New Reader
4/27/20 8:41 a.m.

Huge thanks to AKG Motorsport for their support in this new build. AKG Motorsport has been a sponsor of my racing since the very beginning. I'm a big believer of their products having outfitted most of their catalog on my E36 prior to them becoming a sponsor. They are a great family owned business that make some of the best BMW parts in the business right here in the USA. 

kevlarcorolla Dork
4/27/20 8:59 a.m.

We're doing to same after writing off our K20 crx endurance car the last race of the yr.


 Replaced it with a free EG civic hatch,yes we're very budget limited

RyanGreener (Forum Supporter)
RyanGreener (Forum Supporter) Reader
4/27/20 9:24 a.m.

Watching this whole process was seriously impressive. I've never been good at sourcing good/non-overpriced shells which makes this almost seem like a miracle!

roger_waltman None
4/27/20 10:30 a.m.

In reply to christinaylam (Forum Supporter) :

Folks over at AKG are awesome. I stumbled upon them a few years ago while I was building my street E36, made a mistake on ordering parts, they were super helpful in helping me find the right parts and took the time to explain why's. Really different tone as opposed to other stores that just try to sell you the most expensive bits.

Racerjiggs New Reader
4/27/20 11:25 a.m.

My son, Mark, and I have been racing our 70 Ford Cortina since 1971, so 49 years for me and 32 years for Mark. The Cortina has been through 2 series accidents. The 1st in the Moosehead GP in Halifax, NS in 1991. Very Hard wall hit which did quite the number on the front subframe- made up our own guide rack taken from the factory Ford manual, reinforced the frame with 3/16" plate. It was now strong enough to mount our engines direct to the frame. Since 1993 have been using a full race 2.3 Pinto motor- Esslinger/Race Engineering. But that's another story.

The 2nd incident was in 2003, a broken rear brake caliper jambed up the rotor and put the Cortina left rear 1/4 panel into the wall, she then switched around to the left front fender. Quite the mess. The Cortina arrived back on the back of a two truck before my son was released from his medical checkup and when he got out of the ambulance , looked at the damage. Quote" Sorry Dad, but I think I wrote her off this time" . By then I had a good look at all the carnage and replied" I don't think so. I can rebuild her. A year later she was back on the track with all new fiberglass 1/4 panels, rear valance, and roll cage extended all the way back.

After destroying a newly built 2.3 SOHC Pinto motor last May, we came to the decision to switch to a new Mustang 2.3 EcoBoost and everything it entails. The T5 transmission will need mods for moly or G- Force gears to meet the HP/Torque of the EcoBoost . Have already purchased a QuickTime bell housing and the differential already meets the new requirements. It's a Winters Mini Quick Change.

One of our local Ford dealerships was throwing out a Fusion 2.3 EcoBoost as scrap, but fortunately as my crew chief  works in their shop and convinced them to give it to us as a mock-up . As a result all the engine and transmission work is completed  and the next step will be to by an EcoBoost motor. Once our suppliers open  back up , then we will get busy ordering the engine , provided our funding is all in place.

See our Website.

Congratulations on getting back up on that horse.
Gerald Elliott.     Enfield,    Nova Scotia

bentwrench SuperDork
4/27/20 11:31 a.m.

A bonus to building a new chassis is you get to update and/or fix any little issues. Tune up any ergonomics and make it easier to work on. That bar you bang your knee or elbow on, that knob you can't quite reach, that gauge that is hard to see.

Especially the electrical, don't hide stuff and make the cluster removable or hinged so you can easily get to it. Nothing worse than having to stand on your head to service something. Between rounds this becomes even more important time wise and reduces stress levels when there are problems.

I've learned a lot living with stuff others have put together and having to work on it at the track. Especially something that is long in the tooth and has been reworked a time or two. Starting over can be such a blessing.

Tom1200 Dork
4/27/20 11:49 a.m.

People ask me how long does it take to build a race car; I usually tell them plan on 18-24 months for a regular guy doing it in their garage. Professional shop or not  doing it in 57 days is damn impressive.  

Jerry From LA
Jerry From LA SuperDork
4/27/20 5:04 p.m.

Christina, what will you save from the wreck?

christinaylam (Forum Supporter)
christinaylam (Forum Supporter) New Reader
4/27/20 7:02 p.m.

In reply to bentwrench :

We did make some updates to the new car mostly to make it faster. This one that got wrecked was a mere 10 weeks old so not much of a blessing there. The work we did on the first one was very diligently planned out from the start and based on Hugh's T1 car at the shop. 

Strike_Zero UltraDork
4/27/20 7:07 p.m.

I love AKG Motorsport! I have a few of their bits on my E36.

I plan to hit up their catalog later this year for upgrades.

In reply to christinaylam (Forum Supporter) :

Thanks for doing this series/blog!

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