Went to Texas World Speedway for the first time this past weekend with the NARRA group which used to be called Viper Days. Had to leave my SRT-10 Vert home bc it does not have a roll bar and I was told instructors might not want to get in car with me in blue group.

So I took my 996tt Proto650 car which has pss10's and was running 19 inch hre p40's with ps2's. Had it aligned to -.9 camber front and -1.2 rear which I think is just a tad further out than the X73 setting. My rears got scrubbed pretty good all the way down past the shoulders and up to the line. Does that sound right?

I started on full hard all around and ended up going one click softer in rears bc someone said I might get better grip. I think Porsche suggests 36 front and 44 rear cold tire pressure, but I would start at 32 front and 40 rear to end up at 37 front,45 rear hot. I tried to keep it around there but at one point I came in and the rears had gone to 50.5 hot and the tire says 50 is max so I dropped down again.

What is the right hot pressure for max performance in everyones opinion?

I think next time I go with my stock wheels with a toyo r888 would that help?

A C4S 996 owner I met there suggested gt3 swaybars in front and rear as well as lower arms in front and shims etc...in front to be able to add more neg camber in front.

What is everyones opinion on camber settings that would work for say 50/50 street/track or maybe 60% track?

Odly enough, I won first place in my class which was the gt6 class with 6 cylinder motors and there was 10 in my class. I started at 2.13 and ended with my best lap at 2.06.

I ran in low boost mode the whole time, I felt high boost would get me in trouble at my skill level.

Thoughts?

 

PS2's should be 36f-38r psi hot. Start them at 26f-28r psi cold. 40 and over hot, and they get greasy.

Larger sway bars definitely improve the car's handling, helping to control the rear weight bias of the turbo, and body roll in general. Lowering the car helps too. Adjustable lower control arms allow more camber than stock. I have -2.25f, -2.1r. Check out the suspension thread by Mikelly.

 

Run 32 hot front 34 hot rear. You may have to go as low as 30's hot all around.

Get more negative camber. You also need some toe in, in the rear and toe out in the front...

 

You should check out Mikelly's thread on suspensions as Landjet suggested.

Sway bars will help to reduce roll, and you can tune out some understeer. You will see excessive outside shoulder wear especially in front until you get at least -2.5 deg camber. You cannot get that without replacing the lower control arms with the 2-piece GT3 control arms. You'll want about -2 deg in the rear, for which you will also need to get either adjustable dog-bones for the upper control arms, or the GT3 control arms. There is no good street-track compromise for alignment. These settings will give excessive wear on the insides on the street. I change mine from street to track whenever I go. I use the toe settings given above.

Whoever told you to make the rear softer for improved grip was wrong. These cars understeer badly, especially in stock trim. You have to soften the front and stiffen the rear to help that situation. I run the rears at 2 or 3 and fronts at +1 from the rear. Depends a little on the track - I like it a little softer on the high speed tracks, stiffer on the tighter ones. I run the rear sway bars at full stiff, fronts at full soft or +1 from that.

I've instructed for Viper Days a few times. Very classy group. Did they go under?

Jon

 

Aim for about 36/40 hot pressures on street tires, so you will have to start a bit lower on the ambient setting. If running sport cups start even lower as they don't do well at high pressures, becoming very greasy. For sways, if you are running stock now, consider a rear GT2 sway bar only as the stock front is fine. You will want to dial out understeer, to do this adjust the rear sway stiffer as a start. It also sounds like you may need a little more neg camber at the rear, try -1.9 or so ( stock range is something like -1.4 to -1.9).
These are all just general suggestions, consult your local race shop for the exact numbers.
2:06 is a great time!

 

Thanks for the input from all. Looks like I have some more mods to do in future.

The higher 45+ hot temp on rears based on what everyone said explains why in some of the slower tighter turns, I really had to take them slow or my rear would slide out pretty good.

As for Viper Days, I think the owner sold to NARRA but was still quite involved in the event and presented me my trophy.

I will look into the susp thread that was suggested.

Thanks Again!