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Discussion Starter · #1 ·
Hello E46Fanatics,
I thought I'd give back to the forum and share my in-progress track car build.

About me (if anyone cares):
I'm an engineer who loves cars. Shocker! I work as a design engineer making all sorts of nifty products for the commercial marketplace. I also have a small side gig doing custom vehicle projects like motorcycle customization, race car fab and prep, and other random metal working projects. I have been "improving" cars and racing them for as long as I can remember- Slot cars, R/C, karts, FSAE, Lemons/Chump/WRL, HPDE, Autocross. I've done it all as they say; growing into bigger and faster toys as my age and budget allowed.

On to the car:
After ten years of doing team driving events like Lemons, Champcar, and WRL I decided I wanted to build a car just for me. The plan is to buy a decent daily driver that I can slowly transform to a dedicated track car and have some fun with along the way. Around the time this plan started I read an article in Grassroots Motorsports comparing the various BMW spec series. After reading about the formulating Spec E46 class I was hooked on the idea of building my own SE46 racer. Good looks, decent power, capable chassis, and lots of aftermarket and enthusiast support. I had found my new obsession.

I began looking in the local Denver market for a car and found few good options. All the cars were automatics, overpriced and beat to hell and back. The few 5-speed 2-door cars I did find were just too far gone to consider. Then one day while looking in reasonable fly-and-drive distances I came across a pristine 2002 sedan in Minneapolis. I hadn’t considered a four door car, but seeing as I had a baby on the way it was starting to make sense. A few phone calls, one flight and a long drive later I have a car in my garage. Her name is Heidi.
 

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Discussion Starter · #2 ·
I had Heidi about 1 week before I started with the mods. (That’s how long it took for the parts to show up) I did a few cosmetic mods like a front plate delete and blacked out the trim. I also did some maintenance work like bushings, control arms, and shifter rebuild. The first “race car” mods I did were wheel studs, M3 fuel baffle, and Hotchkis swaybars. I neglected to take photos of most of this work, so just refer to all the great DIY posts and you’ll get the idea.

Digging further into the car necessitated some jack stand modification so I did a quick mill job on my 6 ton HF stands to fit the lift points better. [pic below]

I also built an engine support so I could hang the engine from above while I replaced the engine mounts, installed an upgraded oil pump shaft, and welded in an oil pan baffle. [pics below]
 

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Discussion Starter · #3 ·
I managed to pick up another pair of Style 68 17x8.5” wheels while on vacation in Tucson for Christmas. I found a guy selling them for $100 and I walked away with them for only $60. I just had to box them up as one of my free bags on Southwest to get them home to CO. Now with four same size rims I could mount up a square set of 245/40-17 Yokohama AD08R tires that I also got for a song. [pic]

Craigslist came to the rescue again with a lightly used Sparco Pro 2000 racing seat and side brackets. It took me a while to sort out my seat mounting plan but I came up with something similar to Vorshlag’s design using a double locking slider and the factory 3-point belts. [pics below] A racing seat in a street car really sucks to get in and out of, but it is easily the best mod you can do to any track driven car. Without proper support you are fighting g-forces just to stay in place. It’s very difficult to control the steering and pedals precisely when your body isn’t working from the same “reference” point.

I also picked up a tow strap to mount to the front bumper. This is a requirement for all track days in case you end up needing a tow back to the pits. The factory screw-in tow point is adequate for casual trackday users but this is a hardcore casual trackday car (for now). So I built some mounts to hang the Sparco strap from the factory bumper bracket. It pokes out the factory screw-in hole so I didn’t have to cut through the bumper. Conveniently I can still use the screw in mount for a security tie down on my trailer. [pic]
 

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Discussion Starter · #4 ·
This leads to my first track outing with Heidi in late March 2018 at High Plains Raceway in Deer Trail, CO. I have hundreds of laps around this track in all sorts of machinery. However, it had been over a year since I drove there and my last stint was in a 24 hour WRL race at 4am in the pitch black dark of night. Rusty best describes my first few laps. Heidi, however, was on point. She ran perfectly all day and really gave me an opportunity to appreciate the good and bad attributes of her track prowess.

The grip produced by the Yoke’s was impressive but overall the chassis was held back by the stock springs and Previous Owner installed Koni FSD dampers. I had the big Hotchkis bars set to full soft but I was struggling with a strange “heaving roll” feeling in the car. The roll stiffness was just mismatched to the rest of the suspension. I knew this was a possibility before I installed a more track oriented setup.

I also couldn’t help but feel underwhelmed by the power of the M54B30. I usually try to address all chassis related items first when building a car but I might have to put power higher up on the priority list. Headers and a full exhaust should make a noticeable bump in power. I am also going to put in a higher diff ratio to shorten up the gears.

I had previously upgraded to new rotors and a set of Hawk HT-10 track pads along with racing DOT4 fluid. The brakes were awesome with only a faint hint of fade after 20 minutes of abuse. I decided to pursue some brake cooling as one of my next mods regardless.

Overall I was really happy with her performance. I really liked how easily I could run consistent laps and play with my lines in search of lap time. The steering feedback and seat of the pants feel really boosted my confidence throughout the day. Dare I say, she felt like a bigger faster Miata out there? I clicked off a 2:12.3 as my best lap which was a record for me around this track in any car. Unfortunately that puts me about 10 seconds away from my goal lap time in order to be competitive in NASA TTD. [pic at track]
 

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Upgraded oil pump shaft and baffled oil pan as your first couple of mods? you definitely have your priority's in the right place haha, i like it. The cars are definitely under powered as you said, but thats easily fixed with a rainy trackday where your HP is easily tripled with lack of traction :). Keep it up man looks like a good start.
 

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Discussion Starter · #8 ·
The only casualty of my first track day was the front swaybar mounts. They began to tear and make some awful clacking noises. Fortunately they didn’t pull through like I had seen on other cars so I was able to massage the metal back in shape and then put a beefy reinforcing plate on top. Somehow in this process I managed to make the prettiest MIG welds of my life whilst on my back under a car getting white hot weld BB’s showered all over me. No one other than the readers here will ever see them… typical. [pic]
 

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Discussion Starter · #9 ·
I hate when brakes are the limit to my fun at the track. I was getting just a hint of fade on a 65-70 degree day so I know I might really start having problems when the temperatures rise closer to triple digits. After reading Vorshlag’s epic E46 track car build like five times I came away with a plan to replicate their forced air brake cooling setup (thanks Vorshlag!). Like them, I used the OEM ducts and cut them down to fit a 3” round aluminum tube that I riveted in place and sealed the gaps with RTV silicone. Then I made a couple 3” aluminum tube adapters that bolt to the OEM backing plates over the factory cooling inlet. Last, a piece of 3” diameter wire reinforced tubing connects the two ends. This gives me pressurized forced air cooling directly into the center of the rotor hat and makes a significant improvement over the OEM cooling setup. The ducting has just enough room to clear my tires at full lock using a 15mm spacer.
 

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Discussion Starter · #11 ·
My next track day came in early May. A group of friends and I took the day off work to beat on a few of our track toys. There was my car, a track prepped Focus RS, a 991 GT3RS (!!!), and an Ariel Atom SRA (!!!!!). We went to a track in southern CO that none of us had driven before, Pueblo Motorsports Park in Pueblo, CO.

Heidi ran perfectly again all day without any problems. The new brake cooling system kept rotor and pad temps in check. I also got to test out my new lap timer and video overlay setup. I’m using an Android phone with Harry’s Lap Timer and external OBD2 and GPS modules. I even 3D printed a little mount to hold the GPS module to the side of my phone mount. The GPS module wasn’t working for some reason so I was stuck with the 1Hz internal GPS. Good enough for posting cool videos but not helpful in finding tenths of a second on track. See the video: https://youtu.be/pj-In0x5ykA

As good as the E46 is, or can be, it will never be as sublime as a GT3 or visceral as an Atom around the track. Both are incredible machines. Track fun per dollar is squarely in Heidi’s favor here though. For all I have into it, my lowly 330i still makes me smile. I would do naughty things for a GT3RS though…
 

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I came away with a plan to replicate
any chance you would want to make another set, and sell them to me? just the aluminum bits, i can source the hose.
i don't have the fab skills, time, or place to make them. i could design them easy enough, but that's as far as i could get.
 

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any chance you would want to make another set, and sell them to me? just the aluminum bits, i can source the hose.
i don't have the fab skills, time, or place to make them. i could design them easy enough, but that's as far as i could get.
I would also be interested, if this was possible!
 

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Discussion Starter · #15 ·
My next project was to pull the rear subframe and tackle the subframe mount reinforcement and replace the old worn bushings. I started by dropping the differential since I was going to replace it with a different ratio (LSD someday…). I just followed all the DIY’s out there and had the diff and subframe lowered down and slid out without any drama. [Pic 024] The worst part in all of this process was dropping the gas tank down and out of the way. Even with it nearly empty it is just an awkward job. Some say you can install the front plates without dropping the tank. You can, but you can’t do the job right.

I chose the Turner subframe reinforcement plates and followed their directions for the four bottom plates and two top plates. This is not a trivial amount of work! I spent lots of time on my back grinding paint, welding, and grinding down welds. [Pic 025, 026] Luckily my OEM subframe mounts were not cracked at all. Once the reinforcements were complete I sprayed on some Rustoleum and reinstalled the gas tank and EVAP parts I had to remove for access. While I was in the trunk finishing up the top plates I started to experiment with removing the tar sound insulation in the spare tire well. A heat gun and scraper do a pretty good job then follow up with mineral spirits and a rag to clean up the adhesive residue. Tedious but effective.

To remove the subframe bushings I made a beefy bushing press out of some scrap steel. [Pic 027] This pushed out the old bushings with ease. I tried a rented ball joint press from Autozone first with limited success. The right tools make all the difference. Rent, borrow, build or buy the right tool before attempting this job, trust me.

I had to make an aluminum rear diff bushing to replace my old sloppy OEM bushing. [Pic 028] I had intended to buy a urethane bushing but forgot to add it to my order. Luckily I had a chunk of 3” bar stock and the tools I needed to pop this out in a couple hours. The four subframe bushings were replaced with urethane bushings from SuperPro. With everything reinforced, cleaned, and replaced I bolted the whole mess back together. [Pic 029] Overall it’s a lot of work with little to no performance benefit, but huge piece of mind.
 

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That diff carrier bushing is kind of gorgeous. I wish I had the facilities to do such work myself (I have the knowledge, minus welding skills)
 

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Discussion Starter · #17 ·
I know the M54B30 doesn’t respond well to “cold” air intakes so I couldn’t justify spending hundreds of dollars on an aftermarket system that might gain 2-3 horsepower. I actually had no plans to do anything with the intake. As silly as the factory air box looks it actually performs really well. Of course one day I stumbled on to a picture of the Dinan long tube system and I thought I might be able to make my own version. Why buy when you can spend more time and money building one, right? Even if it makes no more power, at least it would be unique and I might learn something.

My design, like the Dinan, puts a conical filter down below the frame spar behind the fog lamp. In order to fit a 3.5” tube through this space I needed to relocate the HID headlight ballast first. I built a simple bracket from .050” aluminum [Pic 030] and remounted the ballast between the frame and the radiator bracket, turning it up on its side [Pic 031, 032]. For the intake itself I used my 3D printer to produce a custom MAF elbow that utilizes the factory o-ring and retaining clips. [Pic 033, 034, 035] The elbow seamlessly transitions from a 3.5” polished aluminum tube to the MAF. At the other end of the aluminum tube is another 3D printed piece that transitions to a 4” K&N cone filter. [Pic 036, below] Both printed parts have a mounting bracket provision that attach to the frame with a small piece of aluminum strip.
CONTINUED below
 

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Discussion Starter · #18 ·
CONTINUED from above
The finished custom long tube intake fits neatly into the available space and really de-clutters the engine bay. [Pic 037, 038] The best part about the whole installation comes from a small block off panel that is installed on the OEM lower grill. With this panel removed the air filter has a direct feed from the front bumper cover. [Pic 039, 040] Hard to get much colder air than that! There is even the plastic mesh covering the resultant opening to prevent large debris from entering. Thank you BMW!

Using my Torque Pro app I was able to do some “scientific” testing with the new intake. On an 85 degree day I was able to get 90 degree Intake Air Temp readings at WOT through third gear. Of course I didn’t get a ‘before’ measurement from the OEM intake so I have no idea if this is an improvement. Heat soak at idle speeds was around 120 and it would drop immediately to ambient temperature when the throttle was opened up. Everything seems to be working as well as one could hope.

What about power? I’m not going to dyno the car for a while so I have no idea if there was any performance gained. It doesn’t feel any slower, that’s all I know. It does sound damn nice when the RPM’s climb past the DISA actuation point, so that counts for something. Hopefully I’ll be able to hear the car better while on track. If a louder intake saves me from one bad shift then maybe it’s worth the effort?
 

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That'a a quality setup! What did you use to draw it up? SolidWorks? I'm trying to decide what I am going to do with an intake, there is so much divided opinion. Even just getting that part of the engine bay cleared up seems pretty convenient!
 

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Discussion Starter · #20 ·
That'a a quality setup! What did you use to draw it up? SolidWorks? I'm trying to decide what I am going to do with an intake, there is so much divided opinion. Even just getting that part of the engine bay cleared up seems pretty convenient!
Yeah, I drive SolidWorks for a living so I drew this up in some free time.

Intakes are tricky buggers. Everyone knows they hardly do anything, but we all feel compelled to put one on anyways.
 
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