Sebring Time Trials 03/31 and 04/01 with NASA Florida
#31
That's most guys everywhere. What's worse is hearing them blame everything but themselves as to why the car isn't going fast. Love watching Corvette's and Vipers, GT3's (and especially Porsche Turbos) on slicks or semi slicks getting mauled by boxsters and spec miatas.
I think I have a video of Andrew Davis driving my car and us stuck behind two miatas that are stuck behind a Viper (on slicks). Was pretty funny.
I think I have a video of Andrew Davis driving my car and us stuck behind two miatas that are stuck behind a Viper (on slicks). Was pretty funny.
And agreed.
And I remember that--I was there. Pitiful.
#32
I just took a quick look, and my top speeds before T17 this weekend were in the 149-151 mph range. Back in Winterfest (a little over 2 months ago) my speeds were in the 155-157 mph range. No idea how much power I lost this past weekend, but 6mph at those high speeds is a good loss, and the car is 60 lbs lighter than at Winterfest.
I ran my street tires Saturday (2 years old RE11 245/285), except the last session on Saturday that I put Pirelli DH slicks (the hardest of 4 compounds available) to set my time for the TTU class, on Sunday I ran 3 more sessions. I'm testing these tires, as I was told they are cheaper to run than A6 (which is what I run for fast times in the Fiat).
The Bridgestone gained 16 psi from cold pressure to hot pressure, I haven't seen these tires gain that much pressure.
There was a nice group of cars on Hoosier R6 and slicks just burning through heat cycles, I timed a F458 Challenge in the 2:30s range, a car that is currently faster than the latest GT3 Cup, and the 2012 GT3 Cup is lapping in 2:07s (driven by Pros).
I ran my street tires Saturday (2 years old RE11 245/285), except the last session on Saturday that I put Pirelli DH slicks (the hardest of 4 compounds available) to set my time for the TTU class, on Sunday I ran 3 more sessions. I'm testing these tires, as I was told they are cheaper to run than A6 (which is what I run for fast times in the Fiat).
The Bridgestone gained 16 psi from cold pressure to hot pressure, I haven't seen these tires gain that much pressure.
There was a nice group of cars on Hoosier R6 and slicks just burning through heat cycles, I timed a F458 Challenge in the 2:30s range, a car that is currently faster than the latest GT3 Cup, and the 2012 GT3 Cup is lapping in 2:07s (driven by Pros).
I passed a 458 challenge at Road Atlanta at a Chin event, was probably the same guy as I don't think many people driving those at regular events, and I'm pretty sure I remember this one having Florida plates on the regular old enclosed trailer he pulled the car off of.
#33
That's most guys everywhere. What's worse is hearing them blame everything but themselves as to why the car isn't going fast. Love watching Corvette's and Vipers, GT3's (and especially Porsche Turbos) on slicks or semi slicks getting mauled by boxsters and spec miatas.
I think I have a video of Andrew Davis driving my car and us stuck behind two miatas that are stuck behind a Viper (on slicks). Was pretty funny.
I think I have a video of Andrew Davis driving my car and us stuck behind two miatas that are stuck behind a Viper (on slicks). Was pretty funny.
#34
+1....I ran Homestead for the 1st time back in February...and the Freedom Autosport Grand Am team was testing during our Chin event. That Mazda MX5 was all over me in the corners. I'd point them by for a series of tight fast corners, catch them in the straights or sweeper maybe get pointed by only to point them by immediatly after that. Of course I believe they had pro drivers testing and one of them I was told was Guy Cosmo....not way I can out drive those guys....lots of fun being on track with better drivers though.
That's a little different. Jack Baldwin ran a Cayman Interseries car in a DE last year at Road Atlanta, whatever group they put him in, he punished everyone in it.
#35
Nick, I'm trying out MPSC in stock 235/305 sizes for the 1st time. I'm not getting the front grip I use to get when I ran Rennlist's Offical Most Hated Tire...Toyo R888....especially in 18" 245/305 or 255/315. I'm going to try out some used 245's MPSC front's and see if that helps. I swear the R888 even in stock 235/305 19" has more grip than N-Spec MPSC in the same sizes.
Am I wrong? What am I missing?
Am I wrong? What am I missing?
#36
You are not wrong. I have reams of data supporting your observation. I've tried 235 19" MPSC, 255 18" R888, 245 18" RA1 and the MPSC produces consistently less braking G's. The only place the MPSC is better is in lateral responsiveness (S curves), but not enough to make up for the loss under braking and overall cornering speed.
#37
Nick, I'm trying out MPSC in stock 235/305 sizes for the 1st time. I'm not getting the front grip I use to get when I ran Rennlist's Offical Most Hated Tire...Toyo R888....especially in 18" 245/305 or 255/315. I'm going to try out some used 245's MPSC front's and see if that helps. I swear the R888 even in stock 235/305 19" has more grip than N-Spec MPSC in the same sizes.
Am I wrong? What am I missing?
Am I wrong? What am I missing?
I found front grip vastly improved with rake adjustment. Play around with ride height and rake.
Tires are always a compromise. What's good for the track isn't necessarily good for the street. Most R compounds really like a lot of camber on the track, and believe it or not, most street tires like EVEN MORE camber on the track because of the softer sidewalls. My car does not have an aggressive alignment- it is more than OEM but not off the charts like a race setup- it is a street car that happens to go pretty quick on the track.
We've discovered (keeping in mind this Porsche is my first so I'm by no means learned on them) that the stiffer the rear, the better the front (up to a point of course). You need front bump compliance but no porpoising- so ideally you would want 4 way shocks up front, or at least very, very well tuned two ways. With 4 way shocks you can chase the shock degradation as it wears, but with a 2 way you'll need to rebuild more often.
Another thing we did is increase the front tire patch. With the Guard GT2 diff we were severely pushing into turns and no matter what we did we would encounter push at some point. A bigger front tire alleviates that to some degree.
The third thing you should be aware of is wider tires are not necessarily better. Scrub radius is completely ignored on forums because most weekend warriors don't even know they are affected by that. Reducing scrub radius is super, super important if you want to allow your car to roll through the turn with minimum drag- drag which most people think of as turn in understeer.
I don't know if I helped you on this issue. PM me if you have any questions!
edit-
The other thing I can think of right off the bat is to swap to a non-N spec Cup. There should be more contact patch. I found the N spec rears to be almost too sticky relative to the fronts, balance is out of whack.
#38
Thanks Nick...well my GTS is no where near this adjustable. I am running -2.5 camber front with .5mm toe out and -2 camber with 2mm toe in. Also my caster is adjusted as much as possible with out rubbing the fender liner.
What I noticed is I have to wait longer to get on the power at or after the apex with MPSC compared to the R888. Rear end grip on both tires seems closer to the same but the 235 MPSC front push/understeer if I get on power at Sebring where I'm use to. Also I've had to adjust my brake zones because the MPSC will skid at activate ABS much easier than R888's.
What I noticed is I have to wait longer to get on the power at or after the apex with MPSC compared to the R888. Rear end grip on both tires seems closer to the same but the 235 MPSC front push/understeer if I get on power at Sebring where I'm use to. Also I've had to adjust my brake zones because the MPSC will skid at activate ABS much easier than R888's.
#41
Thanks Nick...well my GTS is no where near this adjustable. I am running -2.5 camber front with .5mm toe out and -2 camber with 2mm toe in. Also my caster is adjusted as much as possible with out rubbing the fender liner.
What I noticed is I have to wait longer to get on the power at or after the apex with MPSC compared to the R888. Rear end grip on both tires seems closer to the same but the 235 MPSC front push/understeer if I get on power at Sebring where I'm use to. Also I've had to adjust my brake zones because the MPSC will skid at activate ABS much easier than R888's.
What I noticed is I have to wait longer to get on the power at or after the apex with MPSC compared to the R888. Rear end grip on both tires seems closer to the same but the 235 MPSC front push/understeer if I get on power at Sebring where I'm use to. Also I've had to adjust my brake zones because the MPSC will skid at activate ABS much easier than R888's.
Your alignment is fine, don't change it.
On MPSC, my data showed me laps in the 1:59-2:00 at Daytona, I can live with that. I ran 265x19 and 345x19 both of them race spec MPSC. The 345 is too fat for your Carrera GTS, but the 325 n-spec is fine.
#42
I timed Nick's GT2 at 2:29 at best with my iPhone from my garage, but no idea what the best laps were, as they had traffic, and conditions were really bad (low grip, high humidity, and very hot).
Gavin was there this weekend, with the 997.1 GT3 RS, a car where he ran 2:14s in February on slicks. He was doing 2:22s and up the few times I timed him this weekend, the car was on Michelin slicks .
Gavin was there this weekend, with the 997.1 GT3 RS, a car where he ran 2:14s in February on slicks. He was doing 2:22s and up the few times I timed him this weekend, the car was on Michelin slicks .
#43
Rad has us pretty close, but we never got a clean lap. If you saw the "fast" guys and how much we were tailgating them, you would understand. I would think a fast lap would be significantly quicker, like knock 15 seconds off, and a lap with lower ambient temps on Cups, look out!
A DE is only for education, and we weren't going to try to beat anyone into submission... since the traffic was bad we ended up testing sectors, like track out, brake zones, etc. A high speed wiggle before apex on throttle application at 120mph is an eye opener!
A DE is only for education, and we weren't going to try to beat anyone into submission... since the traffic was bad we ended up testing sectors, like track out, brake zones, etc. A high speed wiggle before apex on throttle application at 120mph is an eye opener!
#44
Peter
#45
Put a 265/30R19 MPSC on your front wheels, and run the 325/30R19 n-Spec from the GT3 RS 3.8/4.0 and GT2 RS. You need adjustable sway bars to keep the car balanced.
Your alignment is fine, don't change it.
On MPSC, my data showed me laps in the 1:59-2:00 at Daytona, I can live with that. I ran 265x19 and 345x19 both of them race spec MPSC. The 345 is too fat for your Carrera GTS, but the 325 n-spec is fine.
Your alignment is fine, don't change it.
On MPSC, my data showed me laps in the 1:59-2:00 at Daytona, I can live with that. I ran 265x19 and 345x19 both of them race spec MPSC. The 345 is too fat for your Carrera GTS, but the 325 n-spec is fine.
Those Cup tire sizes are what I want to use up here for Road America. Should be quite a good ride!