AT THE TRACK: Need more front grip

[boothkc]

I tend to agree with Brian that springs over 550# in the front seem too much especially for the low powered school cars....but what do I know. Now you've got me wondering and maybe will try some swaps at our next test day. To get good data would require alot of testing time and several good drivers etc.

Maybe just an issue of feel and preferance, but I personally dont think the GTS cars are undersprung. We are also limited to spec springs in the GT2 class.

Our best GRIP investment so far has been to upgrade to 18x11 and 18x10 CCW wheels with the new Hoosier slicks this changed our average lap times at Thunderhill (Northern CA) from 2:02s (17" Hoosier R6s)to 1:59s with lots more room to gain courage and seconds. TBL for the slicks at this track should be 1:57s....big improvement. Hoosier indicates that they may come out with these in 17" tires this summer so good cost effective grip solution for school cars when available. Just make sure the frames are reinforced.

Kevin
GTS (SCCA GT2) & GTRA (fun for friends)

[P_Mac]

Originally Posted by boothkc

Hoosier indicates that they may come out with these in 17" tires this summer so good cost effective grip solution for school cars when available. Just make sure the frames are reinforced.

Is the difference in grip between these tires and, say, an R-compound really so great that the chassis is threatened by one, but totally fine with the other? It just seems like the frame of the car shouldn't be the weak link, as far as breaking stuff from cornering loads.

[panozracing]

Originally Posted by boothkc

I tend to agree with Brian that springs over 550# in the front seem too much especially for the low powered school cars....but what do I know. Now you've got me wondering and maybe will try some swaps at our next test day. To get good data would require alot of testing time and several good drivers etc.

Maybe just an issue of feel and preferance, but I personally dont think the GTS cars are undersprung. We are also limited to spec springs in the GT2 class.

Our best GRIP investment so far has been to upgrade to 18x11 and 18x10 CCW wheels with the new Hoosier slicks this changed our average lap times at Thunderhill (Northern CA) from 2:02s (17" Hoosier R6s)to 1:59s with lots more room to gain courage and seconds. TBL for the slicks at this track should be 1:57s....big improvement. Hoosier indicates that they may come out with these in 17" tires this summer so good cost effective grip solution for school cars when available. Just make sure the frames are reinforced.

Kevin
GTS (SCCA GT2) & GTRA (fun for friends)

What do you think of the new hoosiers compared to the pirellis slicks? I have not tried the new hoosier slicks but the R6 compound is night and day compared to a slick. But again, when you change a tire it requires EXTENSIVE testing to get a setup for that tire. IT REALLY matters. We tried a bunch of tires and didnt have the time or money to setup for each so we stuck with the one that worked with the setup we know.

[eric1h]

All good points, car setup is very subjective, especially at most of our levels of driving. No doubt we have some very skilled and none(or I am guessing at least most)of us have the time, money, and maybe even skill to notice or try every minute change that gain or lose a few tenths or hundreds.

I found a setup that worked for my car and IMHO it is night and day better than the way the car came. Brian or someone may drive my car and hate it, but for me it works.

I'm not one to make minor tweaks at each track or from session to session. I find a happy medium and change the driver to suit the changing track conditions.

I drove my previous best laptime at VIR - N in my old BMW M3 racecar with completely blown rear shocks. The car would bounce so hard coming out of hogpen it was scary, but fun! Drive the car you brought and enjoy!

[DrBro]

Drew - I kinda know your car and I think it is the tires. I put a new (old) set of P3's on my car (same as you have on your car) and it was scary. Until the tires got really hot, they were just plain slick. I let another drive my car and got the WTF*** comment. The left over WC tires look good, but really are past their prime.

Your dad said they were fine, but maybe he is just driving too slow!

[boothkc]

Brian,
we never tried the Pirelli slicks. I run GT2 in Northern California SCCA and it's my 2nd season. There are 2 other Panozs, mostly RX7s, and some other basic GT2 cars...no Porsches or really high end stuff in our group. We've run the R6s in the past, but the grip limited our lap times a lot.

Read about the Hoosier slicks and success in Texas (- 2sec over Pirellis I think) and decided to bite the bullet. The wheels from CCW are about $800 each and the tires are about $1700/set so no small investment.....drives like different car. Would be interesting to compare with other slicks.

Regarding the frame reinforcement there is a comprehensive discussion on this site. The school cars are designed for street tires and low HP engines (low forces) and most had the gusseting and bracing of the GTS cars left off....so if you run slicks and/or up HP you WILL break parts of the frame. We've had failures on reinforced GTS frames so no doubt the school cars will fail too.

Kevin

[Soflow1]

Originally Posted by |Drew|

Pretty steady understeer all the way in, through, and out of the turns. I'm thinking about lowering the rear just a tad, I'm not sure if this car is weighted or not.

Suggestions?

Also, what's a good hot pressure range for the Pirelli D3s?

Drew,

I'm sure you've already received lots of helpful hints and suggestions. However, do not under any circumstances lower the rear of the car. This will cause the car to understeer even more!

In fact, I'd recommend you check your ride heights to verify you have rake (front should be lower than the rear) in the car. The Panoz is sensitive to rake adjustments and needs the front at least 3/4" lower than the rear to handle well.

Also, if you have the Penkse adjustable shocks be sure you have them set properly. Poorly set shocks will limit the cars ability to transfer its weight to the front at corner entry. You can adjust your shocks all square (6 sweeps from firm to start), then go firmer with your rebound settings in the front to dial out understeer at corner entry.

From what you describe it doesn't sound like you're transferring weight forward at corner entry. Hope the this helps!

Rod

[panozracing]

we run about 1/2" lower on the front then the rear....hmmmm

what lead you to the at least 3/4"?

[eric1h]

Originally Posted by panozracing

we run about 1/2" lower on the front then the rear....hmmmm

what lead you to the at least 3/4"?

I think that was in the GTS alignment guide, I run 1" lower front, before I corner weight the car. Which of course screws everything up! lol

[Dawgfan]

I have tried a set of the new Hoosier Slicks and they were great. They have a lot of grip. We lowered my car to the Panoz specs. I am not sure my mechanic ckecked everything and if I remember correctly the front is either 3/4" or 1" lower than the rear. Soflow1, I meet you ar R A and you told me about getting some used tires. Would you share the place with me so I could possibly buy some tires too?

[eric1h]

I'm currently running the new Michelin slicks and obsolutely love them!

[Soflow1]

Panozracing - It's the published baseline setup PAD documented for the GTS. That baseline was developed over a couple years worth of input from early GTS drivers, and the Panoz Racing School instructors and mechanics. We realized over time (and was able to confirm with Joel Grewitt) that the car is rather sensitive to this rake adjustment. The lower the front gets relative to the rear the more loose the car will handle.

Dawgfan - Sorry, there must have been a misunderstanding. The only source for used tires I'm aware of is myself. I never run on used rubber. I'm at the point, where I'm looking for tenths of a second and NEED fresh rubber to do that. When I'm racing, I usually use at least 2-3 sets per weekend. When done, I have no more than 6 to 8 heat cycles on them at a maximum.

Erich1h - Yes, I agree. The Michelin slicks work great. Lots of grip and they're very consistent.

[eric1h]

Soflow, got any used rubber currently?

[Panoz26]

On the springs comment, I had changed mine out to 900/750 and experienced all sorts of push issues - changed down to 750/550 and removed the rear sway bar and the car handles better than it did with the 550/350 setup. (Eric's advice for this change)...

A slightly heavier spring rate than what the series cars came with, new slicks, rear sway disconnect and it's a brand new handling adventure.

just my 2 cents.

[Dawgfan]

Soflow I meet the guy that I was thinking about today and he is from Cumming. I would be interested in some good used tires if you have them. I'm still working on seconds. Doing R A around 1:45. I will start working on tenths when I get to 1:42. Are you going to be at R A next weekend for the N A S A event?