outer edge of hoosiers eaten too much
06-03-2010, 01:02 PM
#16
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06-04-2010, 06:18 AM
#17
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1) The standard 997 and 997S need more static camber than a 997 GT3/GT2/GT3 RS. On the RS I ran -2.5 rear and -3.5 front. On a 997S or 997 I would run -3.0 rear and -4.0 front (not possible with stock 997 parts).
The control arm bushings in the 997 and 997S (and Cayman and Boxster) are very soft, so the car changes dynamic camber and toe a lot. In GrandAm, the Porsche teams requested the allowance of non-stock bushings due to these dynamic alignment problems, they were experiencing 5mm to 7mm deflection on the rear control arms bushings, 7mm shorter lower arms = 1 degree of camber, so a loaded corner setup at a static -1.9 degrees can get down to -0.9 degrees when the tire is at its critical load. On A6 (more grip than GrandAm spec tires) and with older stock bushings, you could get even more deflection, something close or above 10mm and equivalent to 1.4 degrees.
2) The Cayman/Boxster are 200+ lbs lighter than a 997S, and they carry less weight in the rear so less load on the tires. Rear tires in a 911 generally last 1/2 the life of the front ones.
On A6 I got 40-50 laps out of the rear tires on a GT3 RS, 4 events with 12 laps per day, and somewhere around 12 heat cycles, they had tread left but very low grip. On the Cayman I'm projecting to get around 12 HC as well, and as many runs on those heat cycles, with plenty of tread but low grip after that. Each autocross session counts as one HC, so if your club has two sessions per day, you should get 6 autocross days from A6.
A6 die from heat cycles in cars with proper alignment and suspension settings, or the die from tread wear on camber challenged cars (this is rare). Some guys with Mini Cooper S were getting less than 20 runs from the front tires.
3) You could try a little more toe-in in the rear (0.25 degrees per corner), and compensate with toe-out in the front (0.15 degrees per corner). I ran these toe settings in my 996 GT3 and 997 GT3 RS. If the bushings are that flexible, they are not flexible in just one axis, but in 3 axis causing toe, camber and caster unexpected changes.
4) M030 is not an option for any 997, M030 shocks from the 996 don't fit the 997 in front or rear. Cross-JIC are garbage, I would rather keep the stock shocks, but cannot use stiff enough springs with the stock shocks. I would sell the Cross-JIC on eBay, buy PSS10 and replace the springs with 600# front and 800# rear with zero rate tenders, if I'm on a budget. Otherwise, I would go with Moton 2-way and same 600#/800# spring rates.
4) Check the rules, choose your class (PCA, SCCA, whatever), and modify accordingly. PCA has unique rules per region, and few regions run the Parade rules. It is always fun to pick up a class with plenty of competitors, and even more fun to pick up a class with top talented drivers.
SCCA is considering to move all the non-Turbo and not-GT 911 to BSP (FastTrack June 2010). The 997 runs in SS where it is not competitive, but it could be competitive in BSP. In BSP you can replace the bushings with Delrin (they are already made for the GrandAm cars), use any springs, shocks, sway bars, exhaust, ECU tuning, intake and lightening (seats, battery), any size wheels/tires.
More often than not I see modified cars that are slower than stock, especially with Porsches made since the switch to water cooled engines.
5) Get a very experienced National level autocrosser to co-drive with you for one event. If you're over 2 seconds behind on a typical 60 secs course, does it make sense to modify the car and run expensive tires? I would rather try to improve my driving and stick to shaved Toyo RA1, or Dunlop Z1, or RE11.
6) I ran the A6 at 28/32 hot on the RS and 04GT3. I run them at a maximum of 32 psi hot and a minimum of 26 psi hot per axle depending on the car balance at a given course/day/tire conditions/weather.
The control arm bushings in the 997 and 997S (and Cayman and Boxster) are very soft, so the car changes dynamic camber and toe a lot. In GrandAm, the Porsche teams requested the allowance of non-stock bushings due to these dynamic alignment problems, they were experiencing 5mm to 7mm deflection on the rear control arms bushings, 7mm shorter lower arms = 1 degree of camber, so a loaded corner setup at a static -1.9 degrees can get down to -0.9 degrees when the tire is at its critical load. On A6 (more grip than GrandAm spec tires) and with older stock bushings, you could get even more deflection, something close or above 10mm and equivalent to 1.4 degrees.
2) The Cayman/Boxster are 200+ lbs lighter than a 997S, and they carry less weight in the rear so less load on the tires. Rear tires in a 911 generally last 1/2 the life of the front ones.
On A6 I got 40-50 laps out of the rear tires on a GT3 RS, 4 events with 12 laps per day, and somewhere around 12 heat cycles, they had tread left but very low grip. On the Cayman I'm projecting to get around 12 HC as well, and as many runs on those heat cycles, with plenty of tread but low grip after that. Each autocross session counts as one HC, so if your club has two sessions per day, you should get 6 autocross days from A6.
A6 die from heat cycles in cars with proper alignment and suspension settings, or the die from tread wear on camber challenged cars (this is rare). Some guys with Mini Cooper S were getting less than 20 runs from the front tires.
3) You could try a little more toe-in in the rear (0.25 degrees per corner), and compensate with toe-out in the front (0.15 degrees per corner). I ran these toe settings in my 996 GT3 and 997 GT3 RS. If the bushings are that flexible, they are not flexible in just one axis, but in 3 axis causing toe, camber and caster unexpected changes.
4) M030 is not an option for any 997, M030 shocks from the 996 don't fit the 997 in front or rear. Cross-JIC are garbage, I would rather keep the stock shocks, but cannot use stiff enough springs with the stock shocks. I would sell the Cross-JIC on eBay, buy PSS10 and replace the springs with 600# front and 800# rear with zero rate tenders, if I'm on a budget. Otherwise, I would go with Moton 2-way and same 600#/800# spring rates.
4) Check the rules, choose your class (PCA, SCCA, whatever), and modify accordingly. PCA has unique rules per region, and few regions run the Parade rules. It is always fun to pick up a class with plenty of competitors, and even more fun to pick up a class with top talented drivers.
SCCA is considering to move all the non-Turbo and not-GT 911 to BSP (FastTrack June 2010). The 997 runs in SS where it is not competitive, but it could be competitive in BSP. In BSP you can replace the bushings with Delrin (they are already made for the GrandAm cars), use any springs, shocks, sway bars, exhaust, ECU tuning, intake and lightening (seats, battery), any size wheels/tires.
More often than not I see modified cars that are slower than stock, especially with Porsches made since the switch to water cooled engines.
5) Get a very experienced National level autocrosser to co-drive with you for one event. If you're over 2 seconds behind on a typical 60 secs course, does it make sense to modify the car and run expensive tires? I would rather try to improve my driving and stick to shaved Toyo RA1, or Dunlop Z1, or RE11.
6) I ran the A6 at 28/32 hot on the RS and 04GT3. I run them at a maximum of 32 psi hot and a minimum of 26 psi hot per axle depending on the car balance at a given course/day/tire conditions/weather.
06-04-2010, 10:21 AM
#18
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I used to run my A6s at 34F 36R, hot. This year I bumped them up to 38/40 and it seemed to help my time. True that the tire did not feel as confident, but it was faster.
Paul
Let me hop in the car with you at the NCR autocross next Saturday. I'll be setting up the course so will be available in either run group.
06-04-2010, 02:10 PM
#19
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1) The standard 997 and 997S need more static camber than a 997 GT3/GT2/GT3 RS. On the RS I ran -2.5 rear and -3.5 front. On a 997S or 997 I would run -3.0 rear and -4.0 front (not possible with stock 997 parts).
The control arm bushings in the 997 and 997S (and Cayman and Boxster) are very soft, so the car changes dynamic camber and toe a lot.
3) You could try a little more toe-in in the rear (0.25 degrees per corner), and compensate with toe-out in the front (0.15 degrees per corner). I ran these toe settings in my 996 GT3 and 997 GT3 RS. If the bushings are that flexible, they are not flexible in just one axis, but in 3 axis causing toe, camber and caster unexpected changes.
4) M030 is not an option for any 997, M030 shocks from the 996 don't fit the 997 in front or rear. Cross-JIC are garbage, I would rather keep the stock shocks, but cannot use stiff enough springs with the stock shocks. I would sell the Cross-JIC on eBay, buy PSS10 and replace the springs with 600# front and 800# rear with zero rate tenders, if I'm on a budget. Otherwise, I would go with Moton 2-way and same 600#/800# spring rates.
4) Check the rules, choose your class (PCA, SCCA, whatever), and modify accordingly. PCA has unique rules per region, and few regions run the Parade rules. It is always fun to pick up a class with plenty of competitors, and even more fun to pick up a class with top talented drivers.
SCCA is considering to move all the non-Turbo and not-GT 911 to BSP (FastTrack June 2010). The 997 runs in SS where it is not competitive, but it could be competitive in BSP. In BSP you can replace the bushings with Delrin (they are already made for the GrandAm cars), use any springs, shocks, sway bars, exhaust, ECU tuning, intake and lightening (seats, battery), any size wheels/tires.
More often than not I see modified cars that are slower than stock, especially with Porsches made since the switch to water cooled engines.
5) Get a very experienced National level autocrosser to co-drive with you for one event. If you're over 2 seconds behind on a typical 60 secs course, does it make sense to modify the car and run expensive tires? I would rather try to improve my driving and stick to shaved Toyo RA1, or Dunlop Z1, or RE11.
6) I ran the A6 at 28/32 hot on the RS and 04GT3. I run them at a maximum of 32 psi hot and a minimum of 26 psi hot per axle depending on the car balance at a given course/day/tire conditions/weather.
The control arm bushings in the 997 and 997S (and Cayman and Boxster) are very soft, so the car changes dynamic camber and toe a lot.
3) You could try a little more toe-in in the rear (0.25 degrees per corner), and compensate with toe-out in the front (0.15 degrees per corner). I ran these toe settings in my 996 GT3 and 997 GT3 RS. If the bushings are that flexible, they are not flexible in just one axis, but in 3 axis causing toe, camber and caster unexpected changes.
4) M030 is not an option for any 997, M030 shocks from the 996 don't fit the 997 in front or rear. Cross-JIC are garbage, I would rather keep the stock shocks, but cannot use stiff enough springs with the stock shocks. I would sell the Cross-JIC on eBay, buy PSS10 and replace the springs with 600# front and 800# rear with zero rate tenders, if I'm on a budget. Otherwise, I would go with Moton 2-way and same 600#/800# spring rates.
4) Check the rules, choose your class (PCA, SCCA, whatever), and modify accordingly. PCA has unique rules per region, and few regions run the Parade rules. It is always fun to pick up a class with plenty of competitors, and even more fun to pick up a class with top talented drivers.
SCCA is considering to move all the non-Turbo and not-GT 911 to BSP (FastTrack June 2010). The 997 runs in SS where it is not competitive, but it could be competitive in BSP. In BSP you can replace the bushings with Delrin (they are already made for the GrandAm cars), use any springs, shocks, sway bars, exhaust, ECU tuning, intake and lightening (seats, battery), any size wheels/tires.
More often than not I see modified cars that are slower than stock, especially with Porsches made since the switch to water cooled engines.
5) Get a very experienced National level autocrosser to co-drive with you for one event. If you're over 2 seconds behind on a typical 60 secs course, does it make sense to modify the car and run expensive tires? I would rather try to improve my driving and stick to shaved Toyo RA1, or Dunlop Z1, or RE11.
6) I ran the A6 at 28/32 hot on the RS and 04GT3. I run them at a maximum of 32 psi hot and a minimum of 26 psi hot per axle depending on the car balance at a given course/day/tire conditions/weather.
I have GT3 front LCAs with default bushings, not steel inserts, I believe. Are GT3 LCA bushings also problematic in the same way as C2 stock?
I did put JICs on ebay but got no interest at all.
Will post them there again. You are not a first person who advices on re-valved PSS10 with stiffer springs, perhaps it is the best possible budget way.
06-04-2010, 02:11 PM
#20
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06-04-2010, 03:50 PM
#21
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Thanks for very detailed post. I will definitely take all that to consideration, I was not aware of bushings issue at all.
I have GT3 front LCAs with default bushings, not steel inserts, I believe. Are GT3 LCA bushings also problematic in the same way as C2 stock?
I did put JICs on ebay but got no interest at all. Will post them there again. You are not a first person who advices on re-valved PSS10 with stiffer springs, perhaps it is the best possible budget way.
I have GT3 front LCAs with default bushings, not steel inserts, I believe. Are GT3 LCA bushings also problematic in the same way as C2 stock?
I did put JICs on ebay but got no interest at all.
Will post them there again. You are not a first person who advices on re-valved PSS10 with stiffer springs, perhaps it is the best possible budget way.At the rear you could use another pair of GT3 control arms (same as the front), and gain the camber with shims, you will reduce plenty of deflection using the GT3 control arms in the rear. Also a pair of Tarett, ERP, RSS, GMG toe links help at the rear. The upper dog bones (affordable) with monoball help a lot to the rear. Then you can easily set front camber at -3.5 and rear camber at -2.5. Remember that a front right GT3 LCA is to be located at the rear left, and front left at the rear right.
For tires, if you pass the National level driver test (within 2 secs of a top National talent, or within 1 sec of a local hot-shoe), and your budget allows it then run A6. A6 are expensive, serious autocrossers go through 4-12 sets per season. The anticipated cost of tires can cover your suspension costs. It isn't worth it to spend money on tires if the driving levels are not at the limit.
In my Cayman, the difference between RE-11 and my wider A6 on a 60 secs course is just 2 secs.
For sway bars, I would go with the GMG Racing 997 GT3 sway bars front and rear. They work quite well.
Once you have the car setup properly, you can run 255/315 A6, or Yoko AD08 255/295. RE11 and Z1 are not made in proper 997 sizes.
06-04-2010, 04:07 PM
#22
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If you already have GT3 front lower control arms, you have no problems in the front, as the GT3 uses stiffer bushings. The LCA controls 2 of the 4 links (subframe and trust arm). The upper front strut mount in the GT3 is monoball, while the 997/997S is rubber. Both use the same steering rod type.
At the rear you could use another pair of GT3 control arms (same as the front), and gain the camber with shims, you will reduce plenty of deflection using the GT3 control arms in the rear. Also a pair of Tarett, ERP, RSS, GMG toe links help at the rear. The upper dog bones (affordable) with monoball help a lot to the rear. Then you can easily set front camber at -3.5 and rear camber at -2.5. Remember that a front right GT3 LCA is to be located at the rear left, and front left at the rear right.
For tires, if you pass the National level driver test (within 2 secs of a top National talent, or within 1 sec of a local hot-shoe), and your budget allows it then run A6. A6 are expensive, serious autocrossers go through 4-12 sets per season. The anticipated cost of tires can cover your suspension costs. It isn't worth it to spend money on tires if the driving levels are not at the limit.
In my Cayman, the difference between RE-11 and my wider A6 on a 60 secs course is just 2 secs.
For sway bars, I would go with the GMG Racing 997 GT3 sway bars front and rear. They work quite well.
Once you have the car setup properly, you can run 255/315 A6, or Yoko AD08 255/295. RE11 and Z1 are not made in proper 997 sizes.
At the rear you could use another pair of GT3 control arms (same as the front), and gain the camber with shims, you will reduce plenty of deflection using the GT3 control arms in the rear. Also a pair of Tarett, ERP, RSS, GMG toe links help at the rear. The upper dog bones (affordable) with monoball help a lot to the rear. Then you can easily set front camber at -3.5 and rear camber at -2.5. Remember that a front right GT3 LCA is to be located at the rear left, and front left at the rear right.
For tires, if you pass the National level driver test (within 2 secs of a top National talent, or within 1 sec of a local hot-shoe), and your budget allows it then run A6. A6 are expensive, serious autocrossers go through 4-12 sets per season. The anticipated cost of tires can cover your suspension costs. It isn't worth it to spend money on tires if the driving levels are not at the limit.
In my Cayman, the difference between RE-11 and my wider A6 on a 60 secs course is just 2 secs.
For sway bars, I would go with the GMG Racing 997 GT3 sway bars front and rear. They work quite well.
Once you have the car setup properly, you can run 255/315 A6, or Yoko AD08 255/295. RE11 and Z1 are not made in proper 997 sizes.
I did not do enough research to find out failure rate of those JICs and did not call my mechanic and it was dual mistake, well, I admit it totally. I re listed those JICs again on Ebay, will see it it will sell.
For rear toe arms I have tarett, regular adjustable ones without bump control. they are sort of good to -2.5 degrees, I was not sure if I needed more than that camber in rear, right now it is at -2. Rear sway bar is from gt3, front one comes on car in the end of June. I was not planning to install upper dog bones yet, may be I should.
From what was done so far car`s handling got significantly improved and felt great. I did not have tire wear issues ever so that is why I was quite surprised with those eaten up A6s.
thanks for detailed tire advice, it helps. I do not plan winning any championships but I had some budget I wanted to use just to try those things out. I finally got correct rims now - 9" wide fronts and 12" wide rears 18" ccw c14, so will continue experimenting. thanks again, your response was way most informative so far I`ve seen in whole a last year.
Last edited by utkinpol; 06-04-2010 at 04:27 PM.
06-04-2010, 04:31 PM
#23
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No need for toe links with bump steer adjustment, as you are not running the car lower than stock right now, and with a new suspension you should not lower it more than 40mm (1.6"), as long as you stick to the 600#/800# rates.
The Cross-JIC-Tein are the same stuff. They don't fail, they just ignore the click settings, as their adjustments are all over the place, sometimes you need an adjustment between #9 and #10 because there is a huge gap there, and 2 or 3 clicks don't have change at all. They are adjustable shocks not better than stock Porsche shocks.
Depending on the gt3 rear bar part#, your car will understeer again when the 997 GT3 bar gets installed in the front.
There is a 997 GT3 rear bar that promotes push (earlier cars), and a late part# which matches the 997 GT2 rear bar. If you have the old part#, you will eventually need to get rid of it, as there is no matching adjustable front bar, unless you decide to stay with the old 997 GT3 rear bar and the softer 997 non adjustable front stock bar.
I would get the GMG front and rear, they are cheap. The dog bones from RSS are cheap. Springs are super cheap, I have enough springs at home to start a shop. PSS9 and PSS10 cheap.
997 and 997S are great cars.
The Cross-JIC-Tein are the same stuff. They don't fail, they just ignore the click settings, as their adjustments are all over the place, sometimes you need an adjustment between #9 and #10 because there is a huge gap there, and 2 or 3 clicks don't have change at all. They are adjustable shocks not better than stock Porsche shocks.
Depending on the gt3 rear bar part#, your car will understeer again when the 997 GT3 bar gets installed in the front.
There is a 997 GT3 rear bar that promotes push (earlier cars), and a late part# which matches the 997 GT2 rear bar. If you have the old part#, you will eventually need to get rid of it, as there is no matching adjustable front bar, unless you decide to stay with the old 997 GT3 rear bar and the softer 997 non adjustable front stock bar.
I would get the GMG front and rear, they are cheap. The dog bones from RSS are cheap. Springs are super cheap, I have enough springs at home to start a shop. PSS9 and PSS10 cheap.
997 and 997S are great cars.
06-04-2010, 07:42 PM
#24
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Thread Starter
Depending on the gt3 rear bar part#, your car will understeer again when the 997 GT3 bar gets installed in the front.
There is a 997 GT3 rear bar that promotes push (earlier cars), and a late part# which matches the 997 GT2 rear bar. If you have the old part#, you will eventually need to get rid of it, as there is no matching adjustable front bar, unless you decide to stay with the old 997 GT3 rear bar and the softer 997 non adjustable front stock bar.
I would get the GMG front and rear, they are cheap. The dog bones from RSS are cheap. Springs are super cheap, I have enough springs at home to start a shop. PSS9 and PSS10 cheap.
997 and 997S are great cars.
what would it be - old one or new one?
06-06-2010, 11:33 PM
#25
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06-07-2010, 11:00 AM
#26
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BTW, where did you see 'cheap' dogbones? they are usually $1K per set, it is not overly expensive but still, not quite cheap.
And for COs I`m getting JRZ RS now, as it seems. Will see.
Last edited by utkinpol; 06-07-2010 at 01:45 PM.
06-16-2010, 12:54 AM
#27
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... just saw your post.
I have a 986S with PSS9s, GT3 front bar, GT3 lower control arms in front. The car is not quite 1.5" lowered and I run A6s.
Just for a data point, with -2.7 degrees camber front and rear and 39 lbs. pressure (hot), my rears just get hammered on the outside shoulders. They do whether I have the Tarett rear adjustable monoball toe link or not.
The rear has about 1/16" total toe in and is 'relatively' stable. I rarely spin out. I'm reluctant to go to about -3.5 rear camber as it's also a street car - but I think that's what it'll take with a 3000 lb. car. It's the most camber hunger tire I've had.
good luck,
kj
I have a 986S with PSS9s, GT3 front bar, GT3 lower control arms in front. The car is not quite 1.5" lowered and I run A6s.
Just for a data point, with -2.7 degrees camber front and rear and 39 lbs. pressure (hot), my rears just get hammered on the outside shoulders. They do whether I have the Tarett rear adjustable monoball toe link or not.
The rear has about 1/16" total toe in and is 'relatively' stable. I rarely spin out. I'm reluctant to go to about -3.5 rear camber as it's also a street car - but I think that's what it'll take with a 3000 lb. car. It's the most camber hunger tire I've had.
good luck,
kj
