Spec E46 Test Day Ends Early @ CMP

Note: This event originally occurred on 12 July 2015, I’m a bit behind in my posts.

Following my first full race weekend, which was a mad dash to ready the car, I knew I had a few bugs to work out.  Chief among those issues was a persistently warm running engine.  Of course this was in the heat of the South Carolina summertime, but I wanted to get my temps a little lower.

To that end; I installed a larger CSF all aluminum radiator specifically for the E46 non-M chassis.  Unfortunately the mounting points weren’t ideally designed to interface with the factory plastic mounts.  I did my best to modify the mounts to work, installed it, and off I went to Carolina Motorsports Park for a day of testing.

Spec E46 Testing at CMP

I went out on my first lap and found that the temps were much lower.  Prior to the new radiator I was averaging ~212-215F in the heat of the day.  Now I was sitting at around 202F, much more reasonable.  I pushed on harder for the next couple laps, besting my previous times by more that 2 seconds.  Then on the third or so lap I got a warning light briefly for engine temps.  It went away as I looked down at the dash to decipher what the problem was.  Then a few seconds later it reappeared.  By now I was paying closer attention to the numbers, and I watched as the water temp spiked to over 250F then back down.

I immediately let off the throttle, short shifted, and brought it in to the paddock as quickly as possible using as little engine as possible, coasting the last hundred feet or so with the engine off.  Hopping out I could see steam rising from the engine compartment.  A peek under the car showed hot water dripping to the ground.  This certainly wasn’t any good.  Popping the hood confirmed my concerns about the mounting of the CSF radiator.  It had slipped from its mounts and shifted rearward where the expansion tank made contact with the serpentine belt.   The belt made quick work of the plastic tank, sawing right through it.

My day had come to an early end with a destroyed expansion tank, a radiator that wouldn’t sit securely, and possible engine damage.  Later on, after everything had cooled, I also discovered that high temps had destroyed the expansion tank cap.  The lower portion that retains the sealing o-ring was completely missing.

Damaged Expansion Tank Belt Cutting Expansion Tank

The good news: CSF was quick to help rectify the situation.  They sent me one of their OEM+ radiators, covered the cost of the expansion tank, and promised to redesign their all-aluminum radiator.  Hopefully they get it corrected soon, because other than the mounting problems, it’s a solid piece.

And finally a short video of my one hot lap before the radiator mounting failed:

httpvh://www.youtube.com/watch?v=-DuvY_UuF9I

Spec E46 First Shakedown

Before a race car turns a wheel in anger, it really should be put through its paces in a test or shakedown drive.  Since this car isn’t street legal and you could never truly test in on public roads, you need to schedule some track time.  Fortunately I’m only an hour away from Carolina Motorsports Park (CMP) in Kershaw, SC.  They even have their own track day organizer, Turn One, that has multiple events a month, making it fairly easy to get track time.

Spec E46 Alignment

After alignment, I loaded up the car on the trailer and headed for CMP to see how all my work handled.  It was a weekday event, so the track was fairly empty, great for some testing and tuning.  Just like any track day event, the car went through a short tech inspection.  Normally this wouldn’t be necessary on a race car, but I hadn’t received an annual tech inspection yet.

Spec E46 Loaded for Testing

The first session was just a an exploratory lap, since I had never driven this track before.  The tires were also fresh sticker and we were receiving some light rain, so it was a bit slippery but grip gradually came in.  That said, CMP is a very slick track, nowhere near as grippy as NOLA, COTA, or Road Atlanta.  It reminded me a lot of Motorsports Ranch Cresson, which is very old pavement and very slick in light rain.

Towards the end of my first session I was black flagged, which was odd because I had no off track excursions and there were only 2 other cars on track.  I pulled into the pit lane and up to the pit exit marshal who told me several corner stations were hearing a loud metallic screeching sound from my car.  He did a quick walk around of the car and noticed a lot of aluminum shavings on the rear left wheel…. great.

Cut Apex Wheel Wheel Shavings

I pulled off the pit lane, headed back to the garage to see what had happened.  Turns out I picked up a rock, which became jammed between the caliper and wheel.  It then worked just like a lathe, cutting a 1mm deep groove around the inside of the wheel.  My guess is that I picked it up during the tech inspection, as the tech shed and weigh station is off a gravel road (terrible layout.)

I pulled the wheel and gave it a good inspection, even called the friendly folks at Phil’s Tire Service to see what they had to say.  I forwarded them some photos, which they in turn sent on to Apex Wheels.  After a close inspection, I determined it was reasonably safe to continue on for the day.  I took it a little more carefully, avoiding the curbing as much as I could.

Spec E46 Testing

The car continued to run well throughout the remaining sessions.  Temps were within safe margins and the engine felt decently strong.  I knew the alignment could use a bit more dialing in, and a corner balance was definitely in order.  It was certainly nice to finally be in a true race car with a proper race seat and harness, making it much less physically demanding to drive the car while also easier to feel what the chassis was doing under me.

Then towards the end of the fourth and final session I suddenly lost power steering.  It was a sudden stoppage, like I had experience in my E36 when it popped a line at Road Atlanta.  I pulled back into the paddock to check what happened.  A quick glance under the power steering reservoir cap revealed the telltale signs of a ruined pump, as it was sparkling with a metallic sheen.  And so ended my test day.

Steering Pump Shaft Ruined LF20 Pump

Once back home I pulled the power steering pump to discover the pulley shaft was completely disconnected from the pump and free spinning.  No doubt this was a design function, a break-away shaft much like those found on the air turbine starters on jet engines.  I further disassembled the pump to discover the vanes which slide in and out of slots where dislodged and had jammed up the pump.  My guess is that this was the original pump and at 220k miles it had just had enough.

All in all, not a terrible first run of the car.  It showed its weak points, and that is the point of testing after all.