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Autocross and PSS9

 
Old 08-11-2010, 01:01 PM
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levtron
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Default Autocross and PSS9

I bought a 993 with pss9 suspension and 18" PZero Rosso all around. I have taken it to autocross, but am having an issue with plowing of the front end.

First few times that I went to autocross, I did not touch the PSS9, and left them at 9 (Softest) all around. Last time I went, I decided to start playing around, and after reading a few posts, set them all to 1. Ended up spinning out 3 times on the course. I do have to add that my air pressure was not well adjusted for a few of the runs, but the spins did happen even after I re-adjusted the pressure. I was running 34/38 hot.

So the question is. Are there any recommendations on how to set the PSS9? should all 4 be the same, or is there a better combo for front/back?

I am new to this, and this is my first Porsche (And now that the ADDICTION has set in, wont be my last )
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Old 08-11-2010, 01:48 PM
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Mussl Kar
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Sounds like you ran with us last Saturday. I think you had Charles as an instructor for most of the day? Was that you?
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Old 08-11-2010, 02:31 PM
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Originally Posted by levtron View Post
I bought a 993 with pss9 suspension and 18" PZero Rosso all around. I have taken it to autocross, but am having an issue with plowing of the front end.

First few times that I went to autocross, I did not touch the PSS9, and left them at 9 (Softest) all around. Last time I went, I decided to start playing around, and after reading a few posts, set them all to 1. Ended up spinning out 3 times on the course. I do have to add that my air pressure was not well adjusted for a few of the runs, but the spins did happen even after I re-adjusted the pressure. I was running 34/38 hot.

So the question is. Are there any recommendations on how to set the PSS9? should all 4 be the same, or is there a better combo for front/back?

I am new to this, and this is my first Porsche (And now that the ADDICTION has set in, wont be my last )
that is exactly why 'i-know-everything' instructing types on forums respond to such questions 'you do not need that'.
do not feel discouraged though. you have adjustable shocks, so, it will take some time to learn them. one thing about PSS9 bilsteins - do not run them ever at their softest settings - keep it at least one click from it - they will serve longer this way.

here is an excerpt from Penske shocks manual regarding adjustment. it sounds a bit cryptic but actually is quite correct.
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Old 08-11-2010, 02:50 PM
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Yeah, forgot to say that. LMAO.
If you don't spin you are not trying hard enough.
Make sure you ask for rides in other *** engine cars, see how they cope with it. I like to trail brake to get the car to rotate. Car turns quick with the weight transfer. 911 will push like crazy if you try to turn under acceleration.
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Old 08-11-2010, 03:11 PM
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Originally Posted by Mussl Kar View Post
Yeah, forgot to say that. LMAO.
If you don't spin you are not trying hard enough.
Make sure you ask for rides in other *** engine cars, see how they cope with it. I like to trail brake to get the car to rotate. Car turns quick with the weight transfer. 911 will push like crazy if you try to turn under acceleration.
Scrufy,

i can say from my own experience - it is damn confusing for a student to get used to a feel in instructor`s overtuned stiff car. taking a regular stock car as a sample than comparing it to your car than comparing it to, say, ron mann`s track rig with 1300lbs springs or what he has there, i do not know, it is very confusing indeed.

overall rule is - as stiffer your car gets - that faster it can get via corners but that threshold of feedback you get when it starts to slide gets shorter and shorter, and corrections must be done essentially same faster to keep it on track, so, essentially, that is why all instructors repeat that same mantra - keep driving on street tires and stock setup, etc. downside of mantra is - you never learn any new things until you try them and fail on them repeatedly.

Lev,
i can only say, with my overall lack of knowledge in mind, i had my JRZs at click '3' for compression all around and ended up still quite soft at click 4 front and 5 in rear after going as high as '8'. i would think that 'middle area' would work best for pss9 as well in the beginning. But my JRZs and your PSS9 have completely different valving and springs rates so our settings are not nearly same, keep that in mind too.
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Old 08-11-2010, 04:29 PM
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Two corrections Paul
There are 2 Fs in Scruffy.
And I learned something at one of my very first events by riding in Rons car. Dropped 5 seconds in the afternoon that day after the ride.
I still learn things by riding with other drivers.
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Old 08-11-2010, 04:49 PM
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Originally Posted by Mussl Kar View Post
Two corrections Paul
There are 2 Fs in Scruffy.
sorry, otal shame, it is my stupid keybrd.

i even did no correct what i typed above. i just need to throw away this pc of junk.

PS. what i wanted to say - car setup 'hints' may be confusing, not driving 'hints'. put me in ron`s car now - it will result in nothing but constant spins and total lack of control. despite all this crap i did to my poor car so far it is setup fairly mild. almost as soft like stock.
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Old 08-11-2010, 04:52 PM
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First read everything on this website 3 times.

http://farnorthracing.com/autocross_secrets.html

...Then come back and lets talk setup. Goes far beyond shock settings and tire pressures. You have to look at entire suspension, sprung and unsprun weights, wheels, tire compounds, alignment settings, wheel offsets, etc to optimise your car for AX.
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Old 08-12-2010, 09:46 AM
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OK, by now your head is spinning. Start here. Full hard in the rear, half hard in front. Keep tire pressure under control, bleed after every run. Pump up to starting pressure before afternoon runs.
Your engine is hanging on the backside of the rear axle. Good for massive acceleration and also good for massive stopping because the weight back there makes the rear brakes stop almost like front brakes. It also acts like a pendulum if you swing the car to violently, making it spin. Pick a wider line at corners and start the turn much earlier than you think you should. Slower too and accelerate through the corner. Slower in and faster out.
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Old 08-13-2010, 10:59 AM
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Thanks... This is Lev, I am in the Blue 993 (#31) and I have was running last time with you guys..

There is just so much to keep track of, and being a NOOB, its 'difficult' to not loose your mind.

I will play around on Oct 24 at our last Autocross...

"this is ridiculously addictive"

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Old 08-13-2010, 11:28 AM
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Originally Posted by Mussl Kar View Post
Yeah, forgot to say that. LMAO.
If you don't spin you are not trying hard enough.
Make sure you ask for rides in other *** engine cars, see how they cope with it. I like to trail brake to get the car to rotate. Car turns quick with the weight transfer. 911 will push like crazy if you try to turn under acceleration.
Great point... I think that i need to learn trail-breaking. I have been trying to slam the breaks, and then excel out of the turns, and that where I was spinning.

From Auto#4, I spun coming out of the two clam shells on the back stretch, just prior to the increasing slalom. I also spun coming in the final 'forced slalom' just prior to finish line, at the second cone in the series.
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Old 08-13-2010, 03:56 PM
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Originally Posted by levtron View Post
Thanks... This is Lev, I am in the Blue 993 (#31) and I have was running last time with you guys..

There is just so much to keep track of, and being a NOOB, its 'difficult' to not loose your mind.

I will play around on Oct 24 at our last Autocross...

"this is ridiculously addictive"
It is? Really? I cut back to maybe 30 events this year. NNNnnnnnot hhhhhaving a ppppproblem with it.
Did you know you can come to our event Sept 19, NCR Region? And also Zone 1 the last Sat and Sun this month?
We were all NOOBs when we started. It really does get easier.
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Old 08-16-2010, 02:15 PM
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Originally Posted by levtron View Post
I bought a 993 with pss9 suspension and 18" PZero Rosso all around. I have taken it to autocross, but am having an issue with plowing of the front end.

First few times that I went to autocross, I did not touch the PSS9, and left them at 9 (Softest) all around. Last time I went, I decided to start playing around, and after reading a few posts, set them all to 1. Ended up spinning out 3 times on the course. I do have to add that my air pressure was not well adjusted for a few of the runs, but the spins did happen even after I re-adjusted the pressure. I was running 34/38 hot.

So the question is. Are there any recommendations on how to set the PSS9? should all 4 be the same, or is there a better combo for front/back?

I am new to this, and this is my first Porsche (And now that the ADDICTION has set in, wont be my last )
I run PSS9's couple suggestions:

- I set to full hard, I dont play with tire pressures or suspension settings much, I find I do better just correcting the mistakes and driving better than messing with car settings.
- Take out the spare and anything up front, run with less than 1/2 tank. I ran this weekend with full tank and I noticed much more understeer than normal.
- a $100 front strut tower brace helped more than I thought it would.
- I generally run lower pressures in the rear to help the rear get grip.
- A couple events I noticed having big problems spinning I found 2 things that probably helped it spin along with my lack of skill - rear sway bar link broken (common on 993's with PSS9's) and that I had one rear shock on hard and one on soft (not paying attention when I changed them duh!)
- Alignment helps a good amount, I have full camber dialed in etc.. it will eat tires but, it helps
- Acclerate harder and brake harder before turns, get braking done as much as you can before the turns, use the rear weight and throttle to help you get through turns rather than just turning the wheel (my theory I guess its against what others say)
- best mod (already had Pss9's too) racing seats. These helped my times more than r-comps or hoosiers, you feel the car starting to step out so much sooner, so you can use it vs. just try to save it. completely changed the feel of the car. You would be shocked at how much you are bracing yourself with normal seats. Before the seats a spin would start to happen before I noticed and by that time it was a heroic effort just to save it. Now I know soon enough to make minor inputs to keep it from going around.
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Old 08-17-2010, 06:41 PM
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I would advise that, as HOT, you would want all pressures the same. If your tires work best at 38hot, then make sure ALL 4 get to that pressure, hot. Now, that could mean, given the penchant for a 911 to heat REARS quickly, that you would want to start Higher in front, say 35f/32-33r cold and check them as they heat up.. Devens is a BIG place so getting heat in tires shouldn't be hard.

Despite the myriad of adjustability, if you aren't comfortable with it, KISS (Keep It Simple Stupid). Find a setting you like (full soft, full hard) and adjust to it.

One thing nice about a "stock" car is their is only driver skill or Tire Pressure to adjust.
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Old 08-18-2010, 08:02 AM
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People are always worried about too much understeer. But keep in mind that if you can't trust the car to stay under you then you will not be fast. Also the faster the course the looser the car. A friend who is a 3 time National autocross champ sets his car up with a fair amount of understeer and says that he and his co-driver are much faster that way. Loose may feel fast but the stopwatch does not lie.
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