991 Turbo track car
10-08-2018, 11:56 PM
#151
Burning Brakes
How do you like the IPD Y plenum? I saw this on Suncoast and was thinking it could be a nice off season upgrade.
https://www.suncoastparts.com/product/91274.html
https://www.suncoastparts.com/product/91274.html
10-22-2018, 04:35 AM
#152
Just some feedback on Cup2 vs Trofeo R
Cup2
Fronts 265/35/20 N2 compound from Gt2rs/Gt3rs
Rears 325/30.20 M0 compound from AMG GTR
TrofeoR
Fronts 245/35/20 XL
Rears 305/30/20 XL
I have raced these tires on two different tracks, the best times were
TRACK1
Cup2 - 1.47.85, before doing ICs and 30C temps, Cup2 were consistent low1:49, guess on cooler weather should have been faster
TrofeoR - 1.48.35 AMS IC and 22C temps, Trofeo were consistent 1:48s
TRACK2 - same track mods and track temp
Cup2(already used!) - 1:25.89
TrofeoR - 1:25.85
I have checked my vbox and discovered that the turn-in was way better on Cups, better speed till the apex, but with Trofeos I was able to accelerate a bit earlier, a bit faster on straights too. Braking wasn't too much different
From my point of view, Trofeo have better grip if we compare size for size, but having wider and taller Cup2 gives the car just the right balance, I felt Trofeo 245s weren't wide enough and my car was understeering badly and that wasnt a proper behaviour for a fun car at the track. Till Pirelli will provide a good combo for our cars, I would skip the Trofeo and go only for Cup2. Still seems 255/315 combo might work, but I would be interested more into something like 265/325 as seems the fronts are the most sensible part.
Also the tires are overheating faster than cup2, maybe due to smaller size too, and the performance drops a lot after only 2 laps.
I have bought a set of SuperForgiattas and just put on 265/305 R7s, feedback soon here
Cup2
Fronts 265/35/20 N2 compound from Gt2rs/Gt3rs
Rears 325/30.20 M0 compound from AMG GTR
TrofeoR
Fronts 245/35/20 XL
Rears 305/30/20 XL
I have raced these tires on two different tracks, the best times were
TRACK1
Cup2 - 1.47.85, before doing ICs and 30C temps, Cup2 were consistent low1:49, guess on cooler weather should have been faster
TrofeoR - 1.48.35 AMS IC and 22C temps, Trofeo were consistent 1:48s
TRACK2 - same track mods and track temp
Cup2(already used!) - 1:25.89
TrofeoR - 1:25.85
I have checked my vbox and discovered that the turn-in was way better on Cups, better speed till the apex, but with Trofeos I was able to accelerate a bit earlier, a bit faster on straights too. Braking wasn't too much different
From my point of view, Trofeo have better grip if we compare size for size, but having wider and taller Cup2 gives the car just the right balance, I felt Trofeo 245s weren't wide enough and my car was understeering badly and that wasnt a proper behaviour for a fun car at the track. Till Pirelli will provide a good combo for our cars, I would skip the Trofeo and go only for Cup2. Still seems 255/315 combo might work, but I would be interested more into something like 265/325 as seems the fronts are the most sensible part.
Also the tires are overheating faster than cup2, maybe due to smaller size too, and the performance drops a lot after only 2 laps.
I have bought a set of SuperForgiattas and just put on 265/305 R7s, feedback soon here
11-03-2018, 10:44 PM
#153
Racer
Thanks for a great thread Randy, and to all the track rats who have contributed so much! This, and the "tracking the turbo" thread, has convinced me to order a 991.2 Turbo S. I've been tracking a '14 Viper TA for the last 4 seasons, mostly at Mosport and Mont Tremblant, and where I bought that car with a priority for tracking 1st and touring 2nd, the 991 TS will be the reverse. As such I'd like to do only minimal track mods initially, but expect to sell the TA after a season or two with the 991 and will likely be tempted to get into more track mods then. I have a few questions regarding optioning the car's build for eventual tracking priority.
I was tempted to go non-S as I'd prefer iron rotors for heavier track use in another year or two, and not sure about dealing with hassles with the center lock wheels. But I figure I can use the PCCB's (with GT3 pads if quiet for street use) until I start tracking it more. At that point I could swap Girodisc irons and track pads with the PCCB street combo. I have a few questions based on what I've read here...
1. Are OEM GT3/RS pads quiet for street use with PCCB's, and would doing maybe 8 track days with 7 - 20 min sessions each on tracks that are not too hard on brakes cause a lot of wear on the rotors, with advanced driver at 7/10ths? If answer is yes then I'll need Girodiscs sooner.
2. I'd like to order front axle lift as I have a fairly steep driveway entrance where the Viper scrapes regardless of approach. Is there any downside to FAL for tracking other than maybe fewer lowering spring options that I know I would want later?
3. I was going to spec the standard 18 way seat. Is it compatible with a 5 or 6 pt harness and harness bar later, or is there a better optional seat choice?
4. Up-sizing tires to 265/325 seems to make sense to address entry under-steer and to minimize rear brake wear from resulting PTV intervention. I think I might do that right away and save the OEM tires. Will those sizes on stock wheels rub without lowering or camber plates?
5. I've found the stock Pirelli Corsa tires on the Viper TA to last extremely well on higher speed tracks including Road America, VIR, and Mosport, I get 5-6 track days (7 - 20 min sessions running roughly GT3/GT3RS times at 9/10ths) and a lot of street miles. They don't heat cycle out like friends on MPSC2's and I've tracked them on many damp and wet days. They'd be my 1st choice but don't see reviews on them here on a 911. No good or has nobody really tracked them yet? Not sure if stock suspension would provide enough front camber though as TA is -2.5 and front outside edges wear on that car, with - 1.5 on rear that yields even wear. Thoughts?
6. I think I'm going to have to order the glass sunroof for the wife but are there any other options that I should order or avoid for track focused use later?
Thanks in advance, and I'm looking forward to learning and sharing as I experience my first Porsche! I always figured it was inevitable that I would one day buy a Porsche, although I always thought it would be a GT. It's been an adventure getting here via some other great street/track cars like the Viper and Supra TT before it. Can't wait to get my order in!
Cheers,
Bruce
I was tempted to go non-S as I'd prefer iron rotors for heavier track use in another year or two, and not sure about dealing with hassles with the center lock wheels. But I figure I can use the PCCB's (with GT3 pads if quiet for street use) until I start tracking it more. At that point I could swap Girodisc irons and track pads with the PCCB street combo. I have a few questions based on what I've read here...
1. Are OEM GT3/RS pads quiet for street use with PCCB's, and would doing maybe 8 track days with 7 - 20 min sessions each on tracks that are not too hard on brakes cause a lot of wear on the rotors, with advanced driver at 7/10ths? If answer is yes then I'll need Girodiscs sooner.
2. I'd like to order front axle lift as I have a fairly steep driveway entrance where the Viper scrapes regardless of approach. Is there any downside to FAL for tracking other than maybe fewer lowering spring options that I know I would want later?
3. I was going to spec the standard 18 way seat. Is it compatible with a 5 or 6 pt harness and harness bar later, or is there a better optional seat choice?
4. Up-sizing tires to 265/325 seems to make sense to address entry under-steer and to minimize rear brake wear from resulting PTV intervention. I think I might do that right away and save the OEM tires. Will those sizes on stock wheels rub without lowering or camber plates?
5. I've found the stock Pirelli Corsa tires on the Viper TA to last extremely well on higher speed tracks including Road America, VIR, and Mosport, I get 5-6 track days (7 - 20 min sessions running roughly GT3/GT3RS times at 9/10ths) and a lot of street miles. They don't heat cycle out like friends on MPSC2's and I've tracked them on many damp and wet days. They'd be my 1st choice but don't see reviews on them here on a 911. No good or has nobody really tracked them yet? Not sure if stock suspension would provide enough front camber though as TA is -2.5 and front outside edges wear on that car, with - 1.5 on rear that yields even wear. Thoughts?
6. I think I'm going to have to order the glass sunroof for the wife but are there any other options that I should order or avoid for track focused use later?
Thanks in advance, and I'm looking forward to learning and sharing as I experience my first Porsche! I always figured it was inevitable that I would one day buy a Porsche, although I always thought it would be a GT. It's been an adventure getting here via some other great street/track cars like the Viper and Supra TT before it. Can't wait to get my order in!
Cheers,
Bruce
Last edited by Bruce H.; 11-06-2018 at 08:58 AM.
11-04-2018, 08:55 PM
#156
Race Director
Bruce H
You can not nor should not run a harness in standard type of seats. Very dangerous. The Porsche lightweight buckets like other track racing style seats have cut out sections of the seat for the shoulder straps . This keeps the straps aligned on your shoulders and on the HANS device.
FAL weights 40lbs...your call if you want it.
I believe with pccb you’ll need to run the stock pads to insure you don’t destroy the expense rotors too quickly. I’d rather wear pads than rotors. Some on the gt3 forum have better input on this and Auto Quest in Naples FL has been running pccb for years and Gavin there knows a lot about carbon ceramic brakes.
You can not nor should not run a harness in standard type of seats. Very dangerous. The Porsche lightweight buckets like other track racing style seats have cut out sections of the seat for the shoulder straps . This keeps the straps aligned on your shoulders and on the HANS device.
FAL weights 40lbs...your call if you want it.
I believe with pccb you’ll need to run the stock pads to insure you don’t destroy the expense rotors too quickly. I’d rather wear pads than rotors. Some on the gt3 forum have better input on this and Auto Quest in Naples FL has been running pccb for years and Gavin there knows a lot about carbon ceramic brakes.
11-05-2018, 09:25 AM
#157
Rennlist Member
Thread Starter
1. Are OEM GT3/RS pads quiet for street use with PCCB's, and would doing maybe 8 track days with 7 - 20 min sessions each on tracks not too hard on brakes cause a lot of where on the rotors, with advanced driver at 7/10ths? If answer is yes then I'll need Girodiscs sooner.
2. I'd like to order front axle lift as I have a fairly steep driveway entrance where the Viper scrapes regardless of approach. Is there any downside to FAL for tracking other than maybe fewer lowering spring options that I know I would want later?
3. I was going to spec the standard 18 way seat. Is it compatible with a 5 or 6 pt harness and harness bar later, or is there a better optional seat choice?
4. Up-sizing tires to 265/325 seems to make sense to address entry under-steer and to minimize rear brake wear from resulting PTV intervention. I think I might do that right away and save the OEM tires. Will those sizes on stock wheels rub without lowering or camber plates?
5. I've found the stock Pirelli Corsa tires on the Viper TA to last extremely well on higher speed tracks including Road America, VIR, and Mosport, I get 5-6 track days (7 - 20 min sessions running roughly GT3/GT3RS times at 9/10ths) and a lot of street miles. They don't heat cycle out like friends on MPSC2's and I've tracked them on many damp and wet days. They'd be my 1st choice but don't see reviews on them here on a 911. No good or has nobody really tracked them yet? Not sure if stock suspension would provide enough front camber though as TA is -2.5 and front outside edges wear on that car, with - 1.5 on rear that yields even wear. Thoughts?
6. I think I'm going to have to order the glass sunroof for the wife but are there any other options that I should order or avoid for track focused use later?Bruce
2. I'd like to order front axle lift as I have a fairly steep driveway entrance where the Viper scrapes regardless of approach. Is there any downside to FAL for tracking other than maybe fewer lowering spring options that I know I would want later?
3. I was going to spec the standard 18 way seat. Is it compatible with a 5 or 6 pt harness and harness bar later, or is there a better optional seat choice?
4. Up-sizing tires to 265/325 seems to make sense to address entry under-steer and to minimize rear brake wear from resulting PTV intervention. I think I might do that right away and save the OEM tires. Will those sizes on stock wheels rub without lowering or camber plates?
5. I've found the stock Pirelli Corsa tires on the Viper TA to last extremely well on higher speed tracks including Road America, VIR, and Mosport, I get 5-6 track days (7 - 20 min sessions running roughly GT3/GT3RS times at 9/10ths) and a lot of street miles. They don't heat cycle out like friends on MPSC2's and I've tracked them on many damp and wet days. They'd be my 1st choice but don't see reviews on them here on a 911. No good or has nobody really tracked them yet? Not sure if stock suspension would provide enough front camber though as TA is -2.5 and front outside edges wear on that car, with - 1.5 on rear that yields even wear. Thoughts?
6. I think I'm going to have to order the glass sunroof for the wife but are there any other options that I should order or avoid for track focused use later?Bruce
1. I tracked my first 991.1 TTS with the PCCB rotors and OEM pads for about 30 events. The rotors showed no sign or symptoms of wear, but I'm sure the nearly fraudulent Carboteq measurement tool would say they were shot. My car passed CPU testing with those rotors!! For pads, the OEM TTS pads offer exceptional bite and feel on the track, but I sometimes used the GT3RS pads occasionally for lower cost and experimentation. Girodiscs and aftermarket pads are simply a no-brainer when you are ready.
2. No, FAL is OK, but you will have issues finding lowering options later. KW offers a coil-over kit with optional FAL, but it's pricy. For the first few years, you won't need it probably.
3. Go with the 18-way seats. They are super comfy for the street. When you track more and want a harness (highly recommended), you are absolutely changing out the seat for something with pass-thus and sub-stap openings anyway, so it won't matter which seats you order with. I'm happy with my custom Cobra Misano setup after tracking with it for a couple of years.
4. Absolutely go with the 265/325 setup on the OEM wheels, yes. It will fill the wheel wells much better and you may not want to lower the car after that. They fit fine on the new 991.2 wheels, which are 9x20 and 12x20, just like many aftermarket options. (Verify when you order, but the 325 need at least 11.5" wheels, which is what I unfortunately have)
5. I have not tried the Corsa tires, so no help there, but they come standard on some pretty fast cars so go ahead and start there. As for camber, it's harder to put in front camber to -2.5 without hurting the axle life, but I get even wear at the factory max -2.0. You will have to check that out more.
6. I'd only say don't get any sunroof, but that does not seem to be an option for you, so at least lobby for the steel roof?? Also avoid the auto-retracting side mirrors, and I am not a fan of auto-braking cars for track use (but love it on street)
Good luck!! You won't be disappointed at all with this setup.
Last edited by Randyc151; 07-16-2019 at 02:39 PM.
11-05-2018, 10:38 AM
#158
Racer
Thank you gentlemen for the detailed replies. If I can rule out lowering the car then I'll see if I can maybe do without the FAL for my driveway entrance, but you can't really predict when you're going to need it on road trips and underground garages and such. I hear the front active spoiler is worth a few bucks to replace! Understood on the seats. I have to say the center lock wheels sound like nothing but trouble for a track rat, but not fond of the look of the optional Classic Sport 5 lug wheels that maintain the wider rim on the car to enable the wider tires. I'm frequently pulling wheels on my lift when tracking the Viper.
Randy, did you find that pad life shortened much as you racked up a lot of track days on the rotors? CC rotor surface wear on an ACR for instance causes pads to wear out more and more quickly where it becomes cheaper to replace the expensive rotors rather than frequent pad changes, and well before 30 days. Is the auto braking not defeatable in any way on track? And you have awesome powers of persuasion because my wife now says she can do without the sunroof!
Bruce
Randy, did you find that pad life shortened much as you racked up a lot of track days on the rotors? CC rotor surface wear on an ACR for instance causes pads to wear out more and more quickly where it becomes cheaper to replace the expensive rotors rather than frequent pad changes, and well before 30 days. Is the auto braking not defeatable in any way on track? And you have awesome powers of persuasion because my wife now says she can do without the sunroof!
Bruce
11-05-2018, 11:04 AM
#159
Rennlist Member
Thread Starter
Thank you gentlemen for the detailed replies. If I can rule out lowering the car then I'll see if I can maybe do without the FAL for my driveway entrance, but you can't really predict when you're going to need it on road trips and underground garages and such. I hear the front active spoiler is worth a few bucks to replace! Understood on the seats. I have to say the center lock wheels sound like nothing but trouble for a track rat, but not fond of the look of the optional Classic Sport 5 lug wheels that maintain the wider rim on the car to enable the wider tires. I'm frequently pulling wheels on my lift when tracking the Viper.
Randy, did you find that pad life shortened much as you racked up a lot of track days on the rotors? CC rotor surface wear on an ACR for instance causes pads to wear out more and more quickly where it becomes cheaper to replace the expensive rotors rather than frequent pad changes, and well before 30 days. Is the auto braking not defeatable in any way on track? And you have awesome powers of persuasion because my wife now says she can do without the sunroof!
Bruce
Randy, did you find that pad life shortened much as you racked up a lot of track days on the rotors? CC rotor surface wear on an ACR for instance causes pads to wear out more and more quickly where it becomes cheaper to replace the expensive rotors rather than frequent pad changes, and well before 30 days. Is the auto braking not defeatable in any way on track? And you have awesome powers of persuasion because my wife now says she can do without the sunroof!
Bruce
11-05-2018, 12:02 PM
#160
Racer
Good to hear the rotors stand up so well, Randy. I was referring to ease of wheel removal on my 2 post lift at home, and never remove at the track either. Thanks again!
Bruce
Bruce
11-05-2018, 01:01 PM
#161
Rennlist Member
Thread Starter
Oh, if you have a lift at home, then the CL wheels add 3 minutes to the job, max. Don't give them a second thought. The most time consuming part for me is lifting the car off the ground before I remove the wheels - a lift eliminates that problem entirely.
11-07-2018, 12:12 AM
#162
Burning Brakes
FWIW, the 991.1 turbo has good front clearance, as the overhang is not nearly as great as that of the GT3. My car does not have the FAL, and yes, it's at stock height, but I can't think of a situation where I've needed it. Even in hilly Northern California.
11-07-2018, 01:19 AM
#163
Racer
Sorry Randy, back to track related discussions.
11-08-2018, 09:45 PM
#164
Rennlist Member
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5. I've found the stock Pirelli Corsa tires on the Viper TA to last extremely well on higher speed tracks including Road America, VIR, and Mosport, I get 5-6 track days (7 - 20 min sessions running roughly GT3/GT3RS times at 9/10ths) and a lot of street miles. They don't heat cycle out like friends on MPSC2's and I've tracked them on many damp and wet days. They'd be my 1st choice but don't see reviews on them here on a 911. No good or has nobody really tracked them yet? Not sure if stock suspension would provide enough front camber though as TA is -2.5 and front outside edges wear on that car, with - 1.5 on rear that yields even wear. Thoughts?
11-08-2018, 10:55 PM
#165
Rennlist Member
2015 991.1 TTS recent config changes
Goals have always been to maintain street ride in regular suspension mode, but firm up and tighten responsiveness for Sport+ mode and track.
Short version current state of car: OEM shocks, springs, sways, PCCB brakes/GT3 pads, no power mods (so much more potential), GT3 control arms, some OEM rubber bushings and some non OEM steel, front axel spacers, Tarett camber plates, front lower control arms & longer steering toe links, DSC controller custom calibration evolved. OEM ride height, no lowering except for impact from camber/caster settings which is significant. Car weight near 3800 lbs, full 92 oct fuel, no driver, Sharkworks, Hoosier/Forgelines. Centerlocks.
Comments below based on Sport+ mode on track, with DSC now progressively even firmer. Street comments and that DSC config portion are same as in prev posts. This update is since last main posts #42 and 161 in this thread:
https://rennlist.com/forums/991-turbo/941896-tracking-the-turbo.html
Updates -
Recently added above longer front steering toe links to provide final pieces needed to get lot’s of camber and caster to run new 20” Hoosier R7s with proper wear and tread temps. Comments below:
Various Wheels & Tires
1). OEM wheels & tires
Pirelli P Zero
I use these for all around street and winter, they came w/car, get something better like the Michelin PS4S when you can.
2). OEM wheels
Pirelli TrofeoR
Fronts 245/35/20
Rears 305/30/20
First trackish tires I used on this car. Hot pressures 30 rear/34 front, camber at 2.5 & 2.9, very good grip and responsiveness, consistent. Wear out quick but performance didn’t seem to diminish or degrade through heat cycles like some other tires. Typically got up to (25) 20 min cycles out of these at best, last set was more like (20) or fewer cycles total.
3). OEM wheels
Michelin Cup2 – larger than OEM
Fronts 265/35/20 N2 new RS compound
Rears 325/30/20 M0 Mercedes compound
Hot pressures 32 rear/35 front, camber at 2.9 & 3.4. Caster 9.2. With the larger than OEM sizes, grip, turn-in, transient response, braking, all were excellent. Lap times were quicker than OEM Trofeo sizes above. Apples to apples sizes though, C2s would have been slower than the Trofeos. Durability/heat cycles much better compared to Trofeo or R7. These are going to be my main tire til R7 issues get improved or new Trofeo 265/315 combo is ready to test.
4). Forgeline GS1Rs
Front 20x9 ET 52
Rear 20x12 ET 47 Hoosier R7s 265/335 (a wider 335 version is coming, these measured like 305 or 315s)
These Forgelines are great for track, no flex felt and take reasonable curbs well. R7 hot pressures 40 rear/45 front, camber at 3.0 & 3.5. Caster 9.8, grip, turn in, transient response, braking, all outstanding. Lots of camber and caster works well and additive in corners. Caster is great for hi speed stability. Handling very neutral except for usual braking/tight slow turn understeer that many cars have. Pushing that friction circle asking for more brake and turn grip than available. Durability/heat cycles poor IMO, even for this type of R comp tire. Got about (10) 20 min cycles from these. Due to hi caster and hi compression track dip/turn rubbing, had to do some clearance work behind front of front fender liners and back off alignment to # 3) config specs above. This alignment in # 4) had looked good static and on street, clearance fine now after going back to 3. Firmed up DSC more too. As expected lots of wheel/suspension deflection due to increased grip and some OEM rubber bushings remaining. The new R7s seem to have issues related to shoulder construction or seams there. Others mention cold peel, cracking, showing what appears to be a seam blend line, and not being able to run with as wide a tire pressure range as the R6s could, being down around 30-35lbs where grip and times seemed to be best. I experienced some of this too. Hoosier says the R7 must be run at their required higher specified pressures. See this R7 thread I had read before if interested in more:
https://rennlist.com/forums/racing-and-drivers-education-forum/1097514-have-r7-s-changed-disturbing-grooving.html
Overall this config w/C2s and especially R7s has been exceptional on track, and still comfortable in street mode. A great track or street ride on demand, console suspension mode switched as needed, no compromise except inside wear for road trips when leaving alignment same, but then when the P Zeros are on, not a concern to me. This combo has left RS’s and Cup cars behind easily on track, yet could be toured across the country in comfort. My experiences above only, and too many years to admit. Definitely enjoying, turbo rules! Hope this is of benefit.
Short version current state of car: OEM shocks, springs, sways, PCCB brakes/GT3 pads, no power mods (so much more potential), GT3 control arms, some OEM rubber bushings and some non OEM steel, front axel spacers, Tarett camber plates, front lower control arms & longer steering toe links, DSC controller custom calibration evolved. OEM ride height, no lowering except for impact from camber/caster settings which is significant. Car weight near 3800 lbs, full 92 oct fuel, no driver, Sharkworks, Hoosier/Forgelines. Centerlocks.
Comments below based on Sport+ mode on track, with DSC now progressively even firmer. Street comments and that DSC config portion are same as in prev posts. This update is since last main posts #42 and 161 in this thread:
https://rennlist.com/forums/991-turbo/941896-tracking-the-turbo.html
Updates -
Recently added above longer front steering toe links to provide final pieces needed to get lot’s of camber and caster to run new 20” Hoosier R7s with proper wear and tread temps. Comments below:
Various Wheels & Tires
1). OEM wheels & tires
Pirelli P Zero
I use these for all around street and winter, they came w/car, get something better like the Michelin PS4S when you can.
2). OEM wheels
Pirelli TrofeoR
Fronts 245/35/20
Rears 305/30/20
First trackish tires I used on this car. Hot pressures 30 rear/34 front, camber at 2.5 & 2.9, very good grip and responsiveness, consistent. Wear out quick but performance didn’t seem to diminish or degrade through heat cycles like some other tires. Typically got up to (25) 20 min cycles out of these at best, last set was more like (20) or fewer cycles total.
3). OEM wheels
Michelin Cup2 – larger than OEM
Fronts 265/35/20 N2 new RS compound
Rears 325/30/20 M0 Mercedes compound
Hot pressures 32 rear/35 front, camber at 2.9 & 3.4. Caster 9.2. With the larger than OEM sizes, grip, turn-in, transient response, braking, all were excellent. Lap times were quicker than OEM Trofeo sizes above. Apples to apples sizes though, C2s would have been slower than the Trofeos. Durability/heat cycles much better compared to Trofeo or R7. These are going to be my main tire til R7 issues get improved or new Trofeo 265/315 combo is ready to test.
4). Forgeline GS1Rs
Front 20x9 ET 52
Rear 20x12 ET 47 Hoosier R7s 265/335 (a wider 335 version is coming, these measured like 305 or 315s)
These Forgelines are great for track, no flex felt and take reasonable curbs well. R7 hot pressures 40 rear/45 front, camber at 3.0 & 3.5. Caster 9.8, grip, turn in, transient response, braking, all outstanding. Lots of camber and caster works well and additive in corners. Caster is great for hi speed stability. Handling very neutral except for usual braking/tight slow turn understeer that many cars have. Pushing that friction circle asking for more brake and turn grip than available. Durability/heat cycles poor IMO, even for this type of R comp tire. Got about (10) 20 min cycles from these. Due to hi caster and hi compression track dip/turn rubbing, had to do some clearance work behind front of front fender liners and back off alignment to # 3) config specs above. This alignment in # 4) had looked good static and on street, clearance fine now after going back to 3. Firmed up DSC more too. As expected lots of wheel/suspension deflection due to increased grip and some OEM rubber bushings remaining. The new R7s seem to have issues related to shoulder construction or seams there. Others mention cold peel, cracking, showing what appears to be a seam blend line, and not being able to run with as wide a tire pressure range as the R6s could, being down around 30-35lbs where grip and times seemed to be best. I experienced some of this too. Hoosier says the R7 must be run at their required higher specified pressures. See this R7 thread I had read before if interested in more:
https://rennlist.com/forums/racing-and-drivers-education-forum/1097514-have-r7-s-changed-disturbing-grooving.html
Overall this config w/C2s and especially R7s has been exceptional on track, and still comfortable in street mode. A great track or street ride on demand, console suspension mode switched as needed, no compromise except inside wear for road trips when leaving alignment same, but then when the P Zeros are on, not a concern to me. This combo has left RS’s and Cup cars behind easily on track, yet could be toured across the country in comfort. My experiences above only, and too many years to admit. Definitely enjoying, turbo rules! Hope this is of benefit.
Last edited by nolimits; 11-09-2018 at 05:24 AM.