CMP Test Day

Posted on 2015/09/21 by Chad

Note: This event took place on 30 July 2015, just getting caught back up with posts.

My last test day at Carolina Motorsports Park ended prematurely when my radiator popped off its mount and the belt cut into the coolant expansion tank. With the car back home I pulled the plugs to check the compression since it saw temperature spikes over 250F. Fortunately the numbers came back good, actually matching the numbers I had taken when I first installed the engine.

I put the car back together, this time with a new CSF OEM+ radiator and a cooler 80C thermostat while ditching the stock fan, and headed back to CMP to get some testing in. I knew the car needed some chassis tuning after its first race post-crash.

It was a low turn out at the track, so we were able to double up on track time. That’s 8 full 30 minute sessions. That’s a lot of driving in a single day, so I cut a few sessions short and skipped the last one. What I did discover was that I needed a little more rear end grip. The week prior I had done some ride height adjustments and corner balanced the car at a friend’s house. The first couple sessions were a mess, I either spun or got into some serious tail out action.

I brought the car in and decided to stiffen the front bar one notch. This had an immediate positive impact, the car was much more neutral, at least as much as I could get it on CMP’s slick surface. Either way it felt much better and gave me more confidence going into my upcoming NASA race at Road Atlanta.

As for the engine temps; the car ran much cooler. I was seeing a high temp of around 202F, albeit in completely clean air. Looks like removing the stock fan and shroud allowed for better flow through the radiator. I also had done a little work with foam rubber insulation to force air through the radiator rather than around it.

Spec E46 Race @ Carolina Motorsports Park

Posted on 2015/09/21 by Chad

Note: This Event originally took place on 27-28 June 2015, sorry for the delay in posting.

Having finished the requirements for my provisional racing license, I was looking forward to the next opportunity to race my Spec E46. The upcoming NASA-SE event at Carolina Motorsports Park (CMP) looked very promising, with a possibility of five other SE46’s in attendance. One slight hiccup; my car was still in pieces. Several delays in parts shipping meant I was way behind my anticipated competition date.

I had already committed to this race, having already cancelled the previous Road Atlanta event due to the crash, and I really didn’t want to miss another opportunity to get some much needed track time. The week leading up to the event became a mad thrash. I was working until the wee hours of the morning right up to the day before the race. The good news: CMP is only an hour away from home, so at least the few hours of sleep I did get were in my own bed.

I also needed an annual tech inspection the morning of the event, so everything had to be just right. I escaped with a few minor discrepancies which were easily corrected and was able to make the race. I had barely got the car off the alignment rack the night before, so there was zero time to shake down the car, much less tune the chassis. I’d run what I brung as the saying goes.

I missed the first practice, fiddling with a few last minute things, but was able to go out in one of the HPDE sessions to get a feel. I knew the track was slick from my previous test day, but having an untested car made it much more of a challenge. My goal was to just keep the car on track and avoid any contact, speed was way down my list of things I was worrying with.

I qualified at the back of the SE46s, as expected given the all-star veteran competition I was up against. No big deal, I was here to learn. We, as a class, decided to start at the back of the Thunder run group in our own separate start rather than gridding on pure time. The first race started off cleanly, but I was out of it both mentally and physically. The lack of sleep had caught up with me big time, and I couldn’t maintain my concentration and felt like garbage, my times were reflecting my condition.

I continued to press on, just looking to finish when a red warning light illuminated on my AiM MXL digital dash, water temps. I was at 230F and it looked as though it would keep climbing. I had pressed my luck enough already, so I pulled off that lap and putted back to the paddock area. I couldn’t find any obvious issues with the cooling system, all signs pointed to trapped air bubbles. This is the price you pay when rushing to get a car ready at the last minute.

I decided to pack up for the day, let the car sit and cool overnight and get some rest. Another SE46 driver had already had worse luck when one of his rear shock mounts failed, resulting in a destroyed MCS shock. I left early to get caught back up on sleep and hopefully have better luck on Sunday.

The next day I jacked up the front of the car and bled the cooling system thoroughly. It looked like my suspicions were correct and the engine had some significant amount of air trapped in it. Feeling recharged from a long night of sleep I headed back on track, this time in a much better frame of mind. The car still wasn’t working as well as I had hoped, oversteering terribly on exit and pushing on entry, but it would have to do.

(Note how I was still missing the trim under the headlights and decals from the new fender)

Again I started at the back of the SE46 pack, where we started as group behind the rest of the Thunder field. This time I felt a little more confident making passes and tried my best to hang on to the back of the SE46 in front of me. I certainly wasn’t pushing for overtakes, rather waiting for the safest opportunity to get by slower traffic. Towards the end of the race I could see I was closing back up to the next SE46 up the road, but every time I tried to push, the car would just lose traction on exit. I was at opposite lock over and over, watching the Mustang and other SE46 in front grow the gap.

Despite the headaches and lack of a good setup, I still had a blast driving with other SE46s and finally getting a chance to mix it up in traffic in an actual race. This was, after all, the first race where I got beyond the first lap. It was great to meet and hangout with other racers in the paddock, gleaning knowledge wherever I could.

Finally a little video from the weekend. Due to my zombie-like state on Saturday, I neglected to bring the memory card for the camera. I made sure to get it for the Sunday race. Here’s the race in its entirety:

httpvh://www.youtube.com/watch?v=GFrz5KTHV20

SpecE46 Wreck Repair

Posted on 2015/09/08 by Chad

After the Spec E46’s debut at Barber Motorsports Park, I was left with a crumpled and undriveable car. The initial visual inspection at the track showed that I’d be in need of the following:

Hood
Left Fender
Bumper
Left and Right headlights
Left control arm
left tie rod
Airbox
Left aluminum engine mount
Apex Wheel
Radiator core support

Once I had the car home, I immediately unloaded it directly from the trailer into the shop and up on jack stands. From there I started to dismantle the front end. With the hood, fender, and bumper off, I got a much better look at what lay ahead. I then found the following would need replaced:

Front left wheel housing
Front subframe
Left and right engine mounts
Steering rack
Power steering pump pulley
Radiator
Front bumper crash bar

The whole left front had been pushed to the right and rear, forcing the wheel well up into where the DME box and brake master cylinder/ABS/booster are located. Several welds had pulled apart, and I don’t think a simple frame pull would get it back to where it needed to be. So I opted to order brand new OEM sheet metal. BMW offers the entire wheel housing and frame horn as a replacement part, though it’s certainly a special order item.

The engine came out, which was in surprisingly good order, other than the torn Bimmerworld engine mounts and cracked aluminum mounts. I got lucky in that none of the bolts pulled from the block. The crash did manage to put a ding in the Y-pipe, but I decided to leave it alone.

The engine subframe was twisted at the engine mounts, so it went in the trash. I sourced one from a junk yard, as well as a used core support and crash bar. The subframe was cleaned up and a set of Turner reinforcements were welded on.

I completely cut away the original wheel well by drilling out all the factory spot welds, leaving the front left firewall completely bare. The new housing was squeezed into place, and leveled using tape measures and a plumb bob. I welded it back on using the factory spot weld locations. The interior of the transmission tunnel needed a patch plate where some original metal tore during removal.

The left control arm bushing had stripped the threads from the frame, so I ended up drilling it up a size and inserting a helicoil.

With the new metal final welded into place, I gave everything a good scuff with a 3M pad, followed by cleaning, then a coat of automotive primer. I then sealed up the gaps with some plain seam sealer before painting everything a matched 300 Alpine White and a coat of catalyzed clear.

Everything went back together as it did the first time. I did find that both frame horns slightly shifted (~1/8″) to the right when checking the frame for squareness. A little extra effort on panel gaps brought everything within factory spec and the car aligned properly as well. I’ll let the photos do the rest of the talking.

Note: While everything was apart, I took the opportunity to replace the brake master cylinder and booster. These weren’t damaged in the wreck but were original to the car (~220k miles).

[foogallery id=”7886″]

First SpecE46 Race: Barber Motorsports Park

Posted on 2015/08/17 by Chad

The time had finally come to put the Spec E46 race car to the test in wheel to wheel competition. I signed up for the May 2015 BMW CCA Club Racing event at Barber Motorsports Park in Leeds, AL. I had never driven the track, so there would certainly be a lot to take in.

If you haven’t been to Barber, you should really make a trip to visit it. It has to be the nicest race tracks in North America, with finely landscaped grounds, excellent facilities, and perhaps the greatest motorsports museums for the motorcycle and Lotus car enthusiast.

This event was put on by the BMW Car Club of America, so there were multiple run groups of DE in addition to the race sessions. The schedule called for three races, two on Saturday and one on Sunday. Two other SE46s were in attendance, so at least I would have some company in the class. The majority of the cars were I-prepared, with a smaller mix of Modified, SE36, and KP cars.

The car ran well during practice and qualifying, though I really didn’t have a good grasp of the track or the handling of the car. I had a few mental mistakes at various points, just not remembering where the track was going. Though it’s only 2.38 miles, the course has 15 turns, with a great variety to make things interesting.

Saturday Qualifying
httpvh://www.youtube.com/watch?v=oaxRQwBPFL4

I only ran three laps in qualifying. I had no idea what a good time was, or even really how to operate the lap timer on my MXL, so I figured no point in running more time off the tires. My time was a good bit off Damion Moses’, but enough to qualify second in class and 14/24 overall. BMWCCA club events don’t group cars by class, but by outright qualifying time. So I was sandwiched between a Super Modified and I-Prepared car.

The first race started well enough, the first few turns were without drama and I didn’t lose any positions. Then coming onto the front straight the cars pretty much went single file and relatively slow to make it through the hairpin-like turn 5. Right as I was about to hit the apex I caught a glimpse of something moving very quickly out of my left peripheral. I had nothing but grass and curbing to my left, so I knew something was wrong. It happened too fast to avoid, and I got hit hard in the front left.

The impact spun me off into the outside adjacent gravel trap. The car was still running, so I shut it down. After sitting for a bit, I cranked it again and attempted to get moving, but I was sunk up to the frame in gravel. I also had steam coming out of the engine, so better to just wait. The rest of the pack continued around for about three more laps under a full course caution (turns out another car crashed on the first lap.) They eventually black flagged the race and I was stuck waiting on the roll-back, who was tending to the other wreck. The car that hit me was able to be towed out and continued back to the pits under its own power.

Saturday Race Crash

(note: first perspective is from a car behind me, followed by my in-car)

httpvh://www.youtube.com/watch?v=w7vyRInVU5o

With the EMS personnel on scene, I got out to check over the damage. The hood was buckled, the fender crushed, the bumper knocked off, both headlights destroyed, the wheel cracked in several places, and after trying to turn the steering wheel I discovered that the left tie rod was also sheered.

Eventually we got the car loaded on the roll back and back to the paddock. There I discovered the damage was a bit worse than I initially thought. The engine mount arms were both cracked and separated, the lower control arm was twisted, the steering rack was shattered, the airbox was cracked, the power steering pump pulley cracked, and the core support was twisted. It was certainly nothing that could be repaired in the paddock, even if I had all the parts on hand.

Thankfully I had recently installed a winch on the trailer, so getting the damaged car loaded wasn’t too difficult. I stayed the night rather than driving back home in a bad mood and sore from the impact. The group of racers were all very considerate and sympathetic to my situation. And eventually the driver who hit me came over to apologize. I have to say he was very humble and sincere, and I know that this could have happened to any of us. I was lucky that he hit me where he did, rather then in the door, which could have been much more dangerous and damaging. Unfortunately his car didn’t fare so well. The whole right side was crushed in, pushing the door bars, main hoop, and rocker panel inward.

It was an unfortunate experience, made worse that it was my very first race in a recently completed car, but everyone walked away without any injuries, so I can be thankful for that.

Spec E46 Build Part XI: Data Acquisition

Posted on 2015/07/15 by Chad

Up until this true race car build I have been using my Android smart phone as my source for data acquisition. The Race Chrono app, paired with an external Bluetooth GPS, has been a great tool, especially for the price. However, with a dedicated race car, I wanted a dedicated system.

I had picked up a lightly used AiM MXL Pista dash logger from eBay back when I was gathering parts for the E36 GTS build. At the time I was debating between the AiM and Racepack loggers, ultimately settling on the AiM due to their widespread use at the club racing level of competition. Having a highly adopted system means it’s easier to get data from other drivers for comparison as well as troubleshooting the system.

The MXL is the previous generation of dash loggers, so the prices were reasonable with the new MXL2/MXS/MXG now on the market. It still does nearly everything I could ask of it. It provides a LCD display of all the critical information I choose (temps, pressures, speed, revs, shift lights) and alarms for when user set thresholds are exceeded. It also provides lapping info, including forecasted (or predicted) lap times.

The other nice thing about the MXL paired with a modern CANbus car is that it can pull almost any available information that the car is already reading. So RPM, fuel level, temps, steering angle, TPS, etc are already ready to record. Additional analog inputs allowed me to add standalone sensors for brake pressure, oil temperature, oil pressure, fuel pressure, and differential temperature.

The MXL essentially replaces the stock dash in the Spec E46, so I mounted in directly to the steering column, just behind the steering wheel. I used some scrap carbon fiber sheet to fabricate a simple mount that is secured using the two screws that hold the wiper and lighting stalks. The wiring harness run from the back of the MXL to behind the dash where it splits to the analog sensors, power/ground, and the CANbus. I added a 4-port CAN expansion so that the GPS, Smarty Cam, and a Memory Key could be added.

The other aspect of data acquisition is getting video of your laps. I’ve been using GoPros for this, but it’s a constant hassle. The batteries don’t last long, their WiFi remote is very temperamental, and you don’t have any ability for automatic start and stop. While the video is high quality in resolution and color terms, it’s not very good for the race environment. The rolling shutter sensor means you get a wavy jello effect of objects in the distance (clouds are the most obvious.) The other, perhaps most frustrating, negative of using the GoPro is that to truly use the video for driver improvement means hours of post production editing to actually produce a helpful video.

The solution to this is the AiM SmartyCam HD, a truly purpose built motorsports camera. The price is certainly way above the GoPro, but time and frustrations saved has made it worth it. The camera interfaces with the AiM MXL dash for both additional data (including GPS) but also means its internal battery is charged by the car and it starts and stops automatically. It’s pretty much a set it and forget it driver tool. The raw video is 720p, so not as high def as the GoPros, but the CMOS sensor eliminates the wavy effect and it has light metering functions and stabilization tailored to use in a car. The end result is actually better video than you can get from any GoPro (for the purpose of in car video.)

The other nice thing about the SmartyCam is that it overlays data on the video in real time. Speed, lap times, revs, brake pressure, throttle position, temps and pressures are all automatically displayed on the video. The gauges and graphics are fairly canned when compared to what is possible with RaceRender or Dashware, but it is also much easier to use and saves hours of time. Because everything is automated means you can simply pull the SD card at the end of a session and have instant feedback from viewing on a laptop.

Another form of data acquisition is the on-board transponder that is required by most racing organizers for timing and scoring. MyLaps (formerly AMB) has a solid monopoly on this market, so that’s what I ended up purchasing. It’s a fairly simple system and install. The physical transponder device is mounted near the front of the car and must be less than 2 feet above the road surface. I made a simple aluminum mount out of some scrap sheet, which was then riveted to the right frame horn. Four small rivet nuts then allowed me to bolt the transponder to this mount. The cable from the transponder runs up through an existing hole in the passenger footwell to the center stack of the dash. That’s where the “key” resides and power and ground functions are split off. I integrated the power into the switch panel so the transponder could be switched on and off.

Eat, Sleep, Tinker.

No, it's not done yet…

Tag Archives: Spec E46

CMP Test Day

Spec E46 Race @ Carolina Motorsports Park

SpecE46 Wreck Repair

First SpecE46 Race: Barber Motorsports Park

Saturday Qualifying
httpvh://www.youtube.com/watch?v=oaxRQwBPFL4

Saturday Race Crash

(note: first perspective is from a car behind me, followed by my in-car)

Spec E46 Build Part XI: Data Acquisition

Saturday Qualifying httpvh://www.youtube.com/watch?v=oaxRQwBPFL4

Saturday Race Crash

(note: first perspective is from a car behind me, followed by my in-car)

Saturday Qualifying
httpvh://www.youtube.com/watch?v=oaxRQwBPFL4