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Just got back from a great CHIN weekend at VIR. Here are a few laps from Sunday. Unfortunately, my camera wasn't working for my best session later in the afternoon. I included some AIM data on those laps to give an indication of where the improvement happened, mostly due to higher confidence on my part. I was roughly 1.5 seconds faster in the afternoon session, and could have broken 2:01 if I didn't run into a slow moving Vette. I think a sub 2:00 is possible with a little bit deeper braking on the back straight and a bit more pucker factor through the esses. This was my first time on 19" wheels, running 265/325 Trofeo Rs. Couldn't be happier with the setup. Even tire wear and no understeer (at least at VIR). Kudos to Goldcrest Motorsports in Atlanta for setting up the car so perfectly.
Thanks guys. I'm wedded to the arrive and drive model for now. Not sure track support for the Cup is in my budget. I may try Hoosiers at Road Atlanta, where I'm local, but that's probably as far as I'll take it in the next year.
What kind of negative camber do you have dialed in there Rich?
I've tried camber settings from 2.75 to 2.5 in front and 2.5 to 2.25 in back, plus a few weekends at stock when I first got the car. The Trofeos like more camber - the Cup 2s seem to like less. The key with the Trofeos, as has been mentioned many times, is keeping the pressures around 30/31.
I don't think the magic in my setup is in the camber - everyone should adjust as they see fiit for a combination of tire wear and the tracks they run. For me, the big changes have come from aero, ride height and rake. My friend has the identical car setup and mods except for a minor difference in rear ride height (and hence rake) and we could both easily tell the difference when we traded cars at Road Atlanta. I think those variables were the main reason I didn't like the stock RS setup as much at Road Atlanta. Not an issue at all on slower speed tracks, but at VIR and Road Atlanta, which have several very high speed turns and braking zones, it is very noticeable. Another point worth noting is that I couldn't run my setup without the caster pucks and solid bushings in front given the lower ride height unless I wanted to shred my front wheel liners every few days, which I did a few times before making that change!
Thanks for sharing. That is an awesome set of laps. Going into the esses at 155 - wow! He really used the FIA curbs to the max. Lots of opportunity left in a stock GT3. Can't wait to go back.
Thanks for sharing. That is an awesome set of laps. Going into the esses at 155 - wow! He really used the FIA curbs to the max.
His car presumably has slicks and serious aero, so we can't really compare with his speeds, but there's much to be learned from his use of the pedals.
Note the deceleration into apexes by trailbraking (eg, T1, T3, T4, and T10), lifting (eg, lower esses), and brake modulation (eg, all of oak tree, top of the hill after the back straight, and hog pen). He even taps the brakes while the car is momentarily just about straight right before the T9 apex, which enables the higher entry speed into the climbing esses. Of course, this all requires subtlety with the pedals, and a setup which isn't loose.
He also typically rolls on the throttle fairly quickly starting at apexes, and once he's flat, he stays flat.
I've tried camber settings from 2.75 to 2.5 in front and 2.5 to 2.25 in back, plus a few weekends at stock when I first got the car. The Trofeos like more camber - the Cup 2s seem to like less. The key with the Trofeos, as has been mentioned many times, is keeping the pressures around 30/31.
I don't think the magic in my setup is in the camber - everyone should adjust as they see fiit for a combination of tire wear and the tracks they run. For me, the big changes have come from aero, ride height and rake. My friend has the identical car setup and mods except for a minor difference in rear ride height (and hence rake) and we could both easily tell the difference when we traded cars at Road Atlanta. I think those variables were the main reason I didn't like the stock RS setup as much at Road Atlanta. Not an issue at all on slower speed tracks, but at VIR and Road Atlanta, which have several very high speed turns and braking zones, it is very noticeable. Another point worth noting is that I couldn't run my setup without the caster pucks and solid bushings in front given the lower ride height unless I wanted to shred my front wheel liners every few days, which I did a few times before making that change!
Thanks Rich. I find this all very interesting. As you know Im not a believer that there is any performance benefit in camber on increased these cars - all it helps with is managing tyre wear as yoi day, and I find on the GT3 at least the tyres are usually cycled before worn out using -2.00-2.200 F+R so I see no need to go further - at least with MPSC2.
What is really interesting if the height and rake. I assume this matters more to your chassis as you have probably double the rear downforce at speed with the Crawford wing compared to standard (I believe the RS has 3x the GT3 downforce at the rear at 300kmph so Im guessing you are closer to the RS than the GT3), I guess front downforce becomes even more important here to offset the rear and ensure you dont have huge understeer. It almost certainly also improved the frontal CD resistance.
How much lower have you taken the car front and rear?
Are you aware there are some Cup front wheel undertrays that do not have the hump that gets constantly damaged. They are $40 a pair and bolt pretty much straight up. No more damaging that part and they can be bought just the front part you need :-). If you want the part number ill post it. I bought these and had them fitted and they are great - havent tried them on the track to see if they cause any issues etc...
Rich. Do you have your smartycam calibrated correctly for G? Id be interested to see your AIM trace for G with the new tyre combo (perhaps correlated against prior running at the same track on other tire/wheel) combo if you have it? This is a good way of telling teh extra grip you are getting - I even see a difference between new tyres vs say tyres with 20+ heat cycles on them...
Rich. Do you have your smartycam calibrated correctly for G? Id be interested to see your AIM trace for G with the new tyre combo (perhaps correlated against prior running at the same track on other tire/wheel) combo if you have it? This is a good way of telling teh extra grip you are getting - I even see a difference between new tyres vs say tyres with 20+ heat cycles on them...
VIR was repaved before this event, and indications are that the grip is a bit better, so that would be a confounding variable as far as comparison with that last time Rich was at VIR. But if Rich has before/after comparison at other tracks, that may be useful.
I'm game for improving the grip of my GT3 if that doesn't void the warranty or necessitate trailering. But even as-is, I think the car is amazing and plenty fast.
10-25-2016, 02:00 PM
