# A few more Auto X questions



## maxcat (Feb 11, 2005)

Are there any Florida Festers (is that what Bimmerfest members are referred to as?) going to be in Gainesville on April 2?

I feel almost like I've done too much research and am mixing and matching ideas so 2 easy questions.

As to tire pressure I've told to show up with my tires inflated to the max listed on the sidewall which would be 50PSI. Is this a good idea. I know its easier to get air out than put air in. I also read about putting the chalk lines on the sidewall but I am just concerned with the starting point. I am running Goodyear F1's.

Second, do I run the car with the DSC off or on?

Thanks for any replies. I am very excited to attend my first autocross.


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## ///M3lissa (Jun 23, 2005)

I ran my first autocross last weekend..so consider that when you read what I write  

I increase my tire pressure to 40 psi.

I was given advice by an instructor to leave DSC on for Auto-X. I wonder if they are told to say that when asked by the legal entities involved :dunno: 

Anyway, I did for the first 3 runs with it on, then turned it off. For me, turning it off will be the way to go for every future Auto-X, provided I remember to turn it off  . 

You need to decide if you are comfortable with it off and if that is the right thing for you. I have some personal friends that if they asked me if they should turn DSC off, I would empatically say "NO", but I know others who are entirely capable of driving with it off, no exceptions.


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## cenotaph (Dec 19, 2001)

For your 330, I'd say start with 40-41 psi front and 36-37 psi rear and adjust from there. You might want to get a compressor/pump for the future, but you might be able to borrow one at the event if you need to add air. Also remember that the pressure changes ~1 psi for each 10 F of air temp. So if it's cool in the morning and then heats up, you'll probably need to bleed off some air. Don't worry too much about pressures at first, just don't run what you're probably running on the street.

Everyone I know runs with DSC off. When you first start, it probably won't matter too much but you should eventually move toward running without it. The one exception to this is when it rains. Autocrosses are run almost regardless of weather. IME, thunderstorms will cancel one, but near torrential rain without lightning probably won't. Some guys like to leave DSC on in the rain because it does a better job than you could. Especially with an open diff in the back.


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## EdCT (Mar 14, 2002)

maxcat said:


> Are there any Florida Festers (is that what Bimmerfest members are referred to as?) going to be in Gainesville on April 2?
> 
> I feel almost like I've done too much research and am mixing and matching ideas so 2 easy questions.
> 
> ...


I'd second cenotaph's advice and further recommend you get a cheap, cigarette lighter-powerd compressor and a decent tire guage.

I think 50 psi is too high, low 40's is good, you're just trying to keep the tire from rolling over under hard cornering.

DSC can bring the car to an almost complete stop, that's not what you want, turn it off, but as Ceno says, leave it on in the rain. If your car has DSC/DTC, try turning off the first level but leaving the second on. See what's best.

Have fun!!!

Ed


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## cenotaph (Dec 19, 2001)

EdCT said:


> If your car has DSC/DTC, try turning off the first level but leaving the second on.


Your car does have two "levels" of stability/traction control. To turn off one level, hit the DSC button. This will cause the DSC light (the warning triangle in a circle in the middle of the gage cluster) to stay on. To turn off both levels, hold the DSC button for 3-5 seconds. In addition to the DSC light, this will cause the BRAKE light (the one for the parking brake) to turn yellow/orange. I've accidentally done a dry run with only one level turned off before and it was ~2 seconds slower. :yikes: To give you an idea of how bad that is, the top places are usually decided by a few tenths. Not that I'm usually contesting the top places. 

For your first few events, I wouldn't worry about your times. As long as you're getting faster.


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## maxcat (Feb 11, 2005)

Thanks for the replies. I will run with stability and traction control turned off. One reason I was considering the advice to max out the tire pressure is that the sticker on the car calls for high pressures to begin with, 39 front and 46 rear. I don't know if the factory recommended pressures would change much since the Potenzas have been replaced with F1's. I guess I'll start with 45 PSI cold and go from there. Thanks again for the help. :thumbup:


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## Sands (Apr 7, 2004)

As for the tires, using tire black or the tire shine stuff also works - and looks better too. You will see a small triangle on the sidewall. Probably about 0.5 or a little smaller on a side. If you are scrubbing that off, your tire pressures are too low.

The white marks you may see is actually white shoe polish - also used to put your number on the rear quarter windows.

I'd do your first one with DSC on. If it's flashing at you, you are probably not smooth enough and turning it off will not help much. If you are smooth you should be able to get the car to drift a little bit and NOT have DSC intervene.

BTW - drive with your window open, both sides, so that you can hear your tires.

When you get to where you understand car dynamics, weight transfer, the real purpose of brakes, etc. then you can start to turn it off.

Too many rookies either don't drive hard enough to bother DSC at all, or WAY to hard and just eat up tires - in that case DSC will probably give you a faster time.

But then, this is just my $0.02

What matters the most is that you have fun!!!

BTW, don't forget to check your wheel bolt torque prior to the event!!!!


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