Streets of Willow is a brutal track. Bumpy, lumpy and it’s bowled shape traps in heat like your girlfriend’s ceramics class oven. It’s hard on cars, with the lack of straight aways and open air causing running temperatures to be ever higher than other tracks. The bumpy ride means putting the power down is an exercise in patience.
Overheating, brake issues, power delivery issues, Streets has continually tested my patience.
It would be different this time. The car now had the CSF Radiator in place to help with cooling, and it was November, with the forecast expecting a high in the 60's, versus 100+ we usually see in the Spring and Summertime.
Upon arrival around 6:30AM it could actually be described as chilly. Unpacked everything, swap over to the track day wheel set up and generally fiddled with the car until the driver’s meeting. Meeting adjourned, it was time to hit the track.
This was a 1:27.7 lap time. A massive improvement from before, a miserable 1:30 set in 115* weather with the car constantly fighting limp mode and on the threshold of overheating.
Two laps later, out of the bowl, down the back straight, and over the crest. Downshift into 3rd and BOOOOOOM! Car loses all power, and will not accelerate. I coast through the next two corners, and off the track.
In the paddock, my sneaking suspicion was a big boost leak. No CEL, but no power. What makes a big boom and causes boost leaks? A blown chargepipe.
Peaking through the intake system, and down at the throttle body, I could tell what had happened, but didn’t want to admit it.
For those not privy to turbocharged engines, the chargepiping or “cold pipe” is the tubing that runs from the intercooler to the throttle body. On BMW N54 and N55 engines, this pipe is made of plastic. Over time the plastic becomes brittle, and when you run charged air through the pipe, it eventually blows up. This is such a common issue on this platform that a friend of mine actually carried a backup chargepipe in the toolbox in his trunk just in case.
The chargepipe is held to the throttle body with a C-clip, and when the pipe breaks it usually blows off the throttle body, shattering the plastic around the clip.
Lo and behold:
The chargepipe exploded around the throttle body. Lovely.
So, that was it, 8 laps and I was done for the day.
I swapped the OEM wheels with beater tires back on, loaded the car up san duct tape before venturing back to the engine bay.
One vigorous duct tape wrap job later, and I deemed the vessel safe enough to drive home.
No, those weren’t my tears of sadness, it actually rained in Southern California. All the better to match my mood, I suppose.
A turbo car that can’t even hit 0 psi is not a pleasant drive, but 150 miles later and we were home. An aftermarket metal charge pipe was ordered to remedy this. wounded warrior. I had been extremely lucky to make it this far, with 41,000 very hard, tuned miles on the car, I suppose I can’t complain that the stock unit held up so admirably.
Lesson learned: If you have an N54 or N55 powered BMW, consider this your warning, upgrade your charge pipe to a more durable, metal unit and spare yourself the heartache of going to a track day and getting 8 laps in before your day comes to an end.
Jake Stumph is a weekend warrior driver, and an occasionally smug asshole, that people seem to tolerate for some reason. If you find his antics entertaining then check him out on Facebook, where he posts things.