boxsternewbie

Video is done by EVO magazine in a 958 Turbo S with no launch control.

Basically this is what they said:
1) turn on sport mode
2) turn off traction control
3) floor brakes
4) floor gas. PCM will limit you to 5,000 rpm
5) release brakes



it's at 2 minutes and 24 seconds into the video if the link doesn't take you directly there

TomF

Interesting. I was wondering what the ECU would limit the revs to in such a start on the 958. I haven't tried it in my 2009 CTTS, but I suspect that the revs will be limited to around 2k. Thanks for sharing.

Cheers,
TomF

deilenberger

#2 and the limiting of RPM to 5,000 by the PCM seem rather contrary don't they?

"Traction control" - is PSM. Not PCM - what's PCM?

I'd also have to ask why one might want to do this sort of abusive thing to a Cayenne? They are not dragsters. I can imagine how much damage this is causing to the entire driveline.

deilenberger

BTW - out of curiosity one time on my '06 955, I tried increasing rev's while standing on the brake. No dice. System doesn't allow it. I believe that has a bit to do with avoiding "unintended acceleration" - which almost killed Audi in the '70's and didn't do Toyota a lot of good in the last decade. Easy to disable the electronic throttle-body. Does turning off PSM defeat this safety feature?

19psi

^^^^
I really wish this forum had a like button feature.

wkearney99

I had a chance to use the factory launch control with a Turbo S 958 and it managed things quite well. No real sense of over-working the drivetrain at all. Granted, that's the factory launch control, which is working through software to manage all of the systems together. It was fantastic how well-planted it stayed, didn't seem to lurch/squat at all.

So I wouldn't imagine hooning it without factory launch control would do any appreciable 'harm' to it. I wouldn't bother doing it regularly, but then I wouldn't do that with factory launch either. I'm guessing the real thing you want to be careful about is jamming a lot of power through the drivetrain if you're on anything other than very good, straight pavement. Start trying that with tight turns or really bad pavement and you're asking for transfer case problems...

Still, from what I gather, having the Sport Chrono option is little more than a software change and the addition of the clock and console button panel. The latter probably requiring the most labor to install. I'm considering it, not for launch but because I'd really like to have a digital clock up there instead of just the analog hands.

cdog533

That's just powerbraking the car, the same way you would with a '77 Trans-Am.

Your revs (RPMs) while power braking are limited by the stall speed of the torque converter. I think it's around 3k or so. It's not like a PDK or dual clutch setup where it will launch the car at 6 grand in a big puff of clutch dust.

All that being said, when I launch my GTS by powerbraking it, it actually does launch pretty hard and take right off.

Powerbraking on an occasional basis isn't going to hurt anything and is probably the preferred method of launching the car if you are really trying to set a low ET or beat a Corvette to the next light.

Now, back in high school, we used another technique known as 'neutral dropping' to get good launches in cars that didn't have the horsepower to even squeal a tire when plain ole powerbraking.... A neutral drop is where you rev the car in neutral to the redline then cram it into drive... That probably IS harmful to any car. I wouldn't try that in a Cayenne; maybe try it on the wife's Camry though!

Or try the PRO version of the neutral drop - the 'reverse drop'! Get the wife's Camry going like 10-15 mph in reverse, shift to neutral, mat the gas til it redlines, then cram it into drive. I guarantee it will smoke the tires for 10-15 seconds.

deilenberger

@cdog533 - I'd be interesting to see if it actually works. I assume by "traction control" he means PSM. I don't believe PSM can ever be entirely shut off - but it would be interesting if you can rev the engine while in gear holding the brake on a 958. Certainly couldn't on my 955 (but I didn't try it with PSM off.)

prosled8

The occasional power brake shouldn't hurt it. There is no way the trans in gear is allowing 5000 rpm though. It will hit the convertors stall speed probably around 2000 rpm. On a turbo this a huge advantage because you can spool up the turbos some and avoid the lag. You never want to hold the brake and gas down for very long as it will create dangerous amounts of heat quickly in the torque convertor. I doubt it would harm any of the driveline designed to tow 7700 lbs either. These are Porsche hot rods and will tolerate quite a bit of hard use. Common sense and experience should be applied

I have had my CTT for a few months now and have not tried this. My wifes new Golf R with the DSG has a factory launch control that has been un-tried over the same period of time. We may have to take them to the strip this summer and see how they run.