Piston Slap: Two Turbos And One Lead Foot

Fast Driver writes:

I used to be a major hooligan, taking cloverleaf offramps every morning at speed in my E46 3 Series with tires squealing and occasional stability control intervention. I also enjoyed revving the German machinery to about 3500 rpms and dropping the clutch for a warp speed launch. After 20 or so launches like that with the car, nothing broke, fell off, or otherwise malfunctioned. It’s like the car was made for that kind of abuse.

My latest question related to my 2009 335i sedan with auto trans. When I give it full throttle from a dead stop, the stability light goes crazy and the car seems to be moving slowly. Is this because if it were to unleash 300 ft.. lbs. to the tires the car would be sitting there spinning its wheels mercilessly and for an eternity? Theoretically, what would happen if I activated the DTC (first level) and tried this?

Would it allow the tires to spin freely before launch or would it give me a nice “chirp” and faster launch compared to when all stability/traction controls are active as described above? I know the simple answer is “try it” but these runflats are something like $1,200 a set and my wife would not approve.

Another question is what would likely happen if I turned off all stability/traction controls (second level; everything off) and floored it from a dead stop. Would the tires spin until RPMs reached 3500 and then the tires would hook up (in a cloud of very expensive tire smoke)? Maybe the answer again is “try it” but with no kind of safety net and the risk of getting arrested along with serious mechanical abuse, I am not inclined to.

My final question relates to the real power of the twin turbo motor. Automobile magazine and others have dynoed this engine and surmise that it is making more than the rated 300 hp and 300 ft lbs given that it can get to 60 mph in 4.8 (3560 lbs. curb weight) and do the quarter mile in 13.5. I know that the engine is tremendously powerful. I can spin the tires (as indicated by the blinking stability control light on the dash) in first, second, and sometimes when downshifting into third, which makes me assume that there’s more than the rated horsepower or torque there.

What do you think? Thanks!

Sajeev Replies:

Just in case it isn’t common knowledge, we’re talking about holeshot techniques this time ‘round on Piston Slap. Question is, do you want to make a scene and hear the noise Hollywood style, or beat the clock by pushing your skills to the limit? Because launching is a technique best served with 20+ practice runs in a race setting where you can monitor your 60-foot elapsed times.

Which is a real nice way of saying that you need to get your car on a drag strip. So do it already!

You won’t waste your tires once you learn that spinning wheels equals slow elapsed times. Get the lead out of your shoes and start practicing your launch technique without traction control assists. You are better than the electronic nannies, unless you own a SL65 Black Series with insane torque on a tight suspension. With practice, it will come.

To your second question, yes the 335i’s are underrated from the factory. And they respond quite well to ECU modifications, just like any other modern vehicle with hairdryers in the exhaust (i.e. Turbocharger). If you go the tuning route, the stock runflat tires will be even more of a joke: you’ll need summer tires with normal sidewalls. Not only are they faster and quieter, I suspect you and your wife will appreciate the price advantage too.

(Send your queries to mehta@ttac.com)