wider, fatter!
11-15-2007, 01:18 AM
#46
Three Wheelin'
Wish i could have seen the beast with near 600hp!! wow, that front would be a lot of fun, especially with the brakes and tires to slow you down!
Actually, there is no problem with size of tires as far as warming them up. if you warm them up properly, and have a hot lap, they will be more than sticky, no matter what the out door temp. (we race at thunderhill all year long, in fact, my last test day was Jan 1)
If the car feels a little un easy, it could be due to a pinned rear suspension (will induce a lot of oversteer if you are not used to it ), an alignment (you could have too much toe out under hard braking, ) or you just might be getting on the throttle too hard, too early. Heck, you have 230more HP than me!!
It could just be due to the 928 being a pretty heavy car, and if you havent set up the suspension for the weight and track use, it could be a handful.
Also, It could be the tires. what are you using???
However, once you are straight, that should never be an issue. Ive driven Andersons and Fan's, and actually raced Fan's. The power was never an issue with grip or handling. In fact, Joe's car just felt like mine with more HP
I run 335s and 275s, and usually 305s and 275s. the only change i would make would be to make room for the 305s up front and run a more balanced set up like Joe and Mark A. runs. the front fenders are a little harder to deal with in this area.
sorry to hear about the spin on the back straight! that is scary and probaby was just due to those big tires in the rain, like you say. when it rained, in the last part of our race last year, i had almost no control of the light 928 rear end due to the rear hydroplaning tires!
T-hill is a fun track, glad you had some dry laps to run on ! Drving the car there? thats the spirit.
Mk
edit: by the way, love the flares!
also, any car can push, and oversteer. Most of the time, its driver style (emphasis on "most"), especially on street cars.
Actually, there is no problem with size of tires as far as warming them up. if you warm them up properly, and have a hot lap, they will be more than sticky, no matter what the out door temp. (we race at thunderhill all year long, in fact, my last test day was Jan 1)
If the car feels a little un easy, it could be due to a pinned rear suspension (will induce a lot of oversteer if you are not used to it ), an alignment (you could have too much toe out under hard braking, ) or you just might be getting on the throttle too hard, too early. Heck, you have 230more HP than me!!
It could just be due to the 928 being a pretty heavy car, and if you havent set up the suspension for the weight and track use, it could be a handful.
Also, It could be the tires. what are you using???
However, once you are straight, that should never be an issue. Ive driven Andersons and Fan's, and actually raced Fan's. The power was never an issue with grip or handling. In fact, Joe's car just felt like mine with more HP
I run 335s and 275s, and usually 305s and 275s. the only change i would make would be to make room for the 305s up front and run a more balanced set up like Joe and Mark A. runs. the front fenders are a little harder to deal with in this area.
sorry to hear about the spin on the back straight! that is scary and probaby was just due to those big tires in the rain, like you say. when it rained, in the last part of our race last year, i had almost no control of the light 928 rear end due to the rear hydroplaning tires!
T-hill is a fun track, glad you had some dry laps to run on ! Drving the car there? thats the spirit.
Mk
edit: by the way, love the flares!
also, any car can push, and oversteer. Most of the time, its driver style (emphasis on "most"), especially on street cars.
I think the problem was poor choice of rear tires, unfamiliarity with the track and with this car on the track, and not very skillful driving. I didn't think about going until a few days before the event and put on a set of new Goodyear Eagle F1 tires that were 12 years old. I had them sitting unused. The Dunlop SP 8000 I had on were worn out. I couldn't get a set of fresh tires in time to leave. I had alignment checked and the rears have 1 deg neg camber with total toe of .34 deg. The rear suspension is not pinned. At the end of the two dry sessions I ran, the rear tire temps were about 108F on the inside, 100 in the center, and 95 on the outside. Just didn't seem hot enough to me. The fronts were about 138F all across after air pressure was adjusted for even temps. I could have been more aggressive going into the corners and that would have got the temps up more. I cannot safely use 3rd with WOT without wheelspin so I ran the course using 4th and 5th. I tried 3rd for turn 11, but it was counterproductive. More time lost shifting than gained by more rear wheel torque for a short distance coming out of the corner. The car has the GT transaxle. I expect that will change when I get stickier rear tires, and more practice.
11-15-2007, 03:21 AM
#47
Addict
Rennlist Member
Rennlist Member
Thanks for the track report Louie.
It's hard to imagine what T-hill would be like in my car but w/ twice the horsepower. And yes, T-hill can take a while to get used to. There are so many blind corners and you have to have faith in where the car will end up on the other side of the hill. I'm glad everything turned out well.
Target tire temps should be in the 175-195ºF range, but you have to push pretty hard to get there. That will come naturally as you get more seat time and get used to the car.
I hope you can make it out to a few DE's next year at T-hill so I can watch that beast run in person!
-Dennis
It's hard to imagine what T-hill would be like in my car but w/ twice the horsepower. And yes, T-hill can take a while to get used to. There are so many blind corners and you have to have faith in where the car will end up on the other side of the hill. I'm glad everything turned out well.
Target tire temps should be in the 175-195ºF range, but you have to push pretty hard to get there. That will come naturally as you get more seat time and get used to the car.
I hope you can make it out to a few DE's next year at T-hill so I can watch that beast run in person!
-Dennis
Hi Dennis,
Wish you were there... It was a DE day and I got educated. I found the car somewhat difficult to control. More power does not make a car faster around a track. Some of this I already knew, but it got reinforced. It was cool and those large rear tires don't heat up as much as they should for good grip. Sometimes lots of oversteer, sometimes not. It had been 5 or 6 years since I had been to TH so I spent some time getting familiar with the track. I had forgotten how odd it feels to go into the blind, slightly uphill and totally off camber turn 3. Or zooming up the approach to turn 9 with nothing but sky in the windshield frantically searching for the shack on the hill a mile away to aim the car at so you'd come over the top more or less aligned with the road. After lunch we were routed past the uphill kink at turn 5a and that's a whole different experience with another blind uphill off camber turn entry. About the time I was getting the track sorted out, it began to rain hard. I did two sessions in the rain. Near the end of the first rain session after successfully getting through the S's, turns 11, 12, 13 and gingerly accelerating down the back straight (4th gear), the car completely, without warning, broke the rear tires loose and did a nice 360 degree pivot around the front wheels. It was extremely rapid, almost violent, and I ended up going in the same direction I had been. The car stayed on the track, so I continued on. I completed the last rain session without incident. I did learn a few things. Wide tires don't heat very well when it's cold. Wide tires are handy if you have a lot of torque and the road is dry. Wide tires suck in the rain. I think I was the slowest of all in the intermediate group of mostly Miatas, WRXs, M3s, Audis, and 911s. I did drive the car home while one guy stuffed his in the wall and several spun off into the mud and gravel. Other than the driver, the car did fine. No lost oil (in the catch can) while on the track or entire 1300+ mile round trip. The GTS brakes are great. The engine is very smooth and it's a satisfying machine on a long trip. Overall 17 mpg. One person was wondering why one rear fender looks different than the other. The drivers side has an air inlet for the engine oil cooler that's mounted where the rear muffler usually fits. The right side has no air inlet.
Wish you were there... It was a DE day and I got educated. I found the car somewhat difficult to control. More power does not make a car faster around a track. Some of this I already knew, but it got reinforced. It was cool and those large rear tires don't heat up as much as they should for good grip. Sometimes lots of oversteer, sometimes not. It had been 5 or 6 years since I had been to TH so I spent some time getting familiar with the track. I had forgotten how odd it feels to go into the blind, slightly uphill and totally off camber turn 3. Or zooming up the approach to turn 9 with nothing but sky in the windshield frantically searching for the shack on the hill a mile away to aim the car at so you'd come over the top more or less aligned with the road. After lunch we were routed past the uphill kink at turn 5a and that's a whole different experience with another blind uphill off camber turn entry. About the time I was getting the track sorted out, it began to rain hard. I did two sessions in the rain. Near the end of the first rain session after successfully getting through the S's, turns 11, 12, 13 and gingerly accelerating down the back straight (4th gear), the car completely, without warning, broke the rear tires loose and did a nice 360 degree pivot around the front wheels. It was extremely rapid, almost violent, and I ended up going in the same direction I had been. The car stayed on the track, so I continued on. I completed the last rain session without incident. I did learn a few things. Wide tires don't heat very well when it's cold. Wide tires are handy if you have a lot of torque and the road is dry. Wide tires suck in the rain. I think I was the slowest of all in the intermediate group of mostly Miatas, WRXs, M3s, Audis, and 911s. I did drive the car home while one guy stuffed his in the wall and several spun off into the mud and gravel. Other than the driver, the car did fine. No lost oil (in the catch can) while on the track or entire 1300+ mile round trip. The GTS brakes are great. The engine is very smooth and it's a satisfying machine on a long trip. Overall 17 mpg. One person was wondering why one rear fender looks different than the other. The drivers side has an air inlet for the engine oil cooler that's mounted where the rear muffler usually fits. The right side has no air inlet.
Hi Mark,
I think the problem was poor choice of rear tires, unfamiliarity with the track and with this car on the track, and not very skillful driving. I didn't think about going until a few days before the event and put on a set of new Goodyear Eagle F1 tires that were 12 years old. I had them sitting unused. The Dunlop SP 8000 I had on were worn out. I couldn't get a set of fresh tires in time to leave. I had alignment checked and the rears have 1 deg neg camber with total toe of .34 deg. The rear suspension is not pinned. At the end of the two dry sessions I ran, the rear tire temps were about 108F on the inside, 100 in the center, and 95 on the outside. Just didn't seem hot enough to me. The fronts were about 138F all across after air pressure was adjusted for even temps. I could have been more aggressive going into the corners and that would have got the temps up more. I cannot safely use 3rd with WOT without wheelspin so I ran the course using 4th and 5th. I tried 3rd for turn 11, but it was counterproductive. More time lost shifting than gained by more rear wheel torque for a short distance coming out of the corner. The car has the GT transaxle. I expect that will change when I get stickier rear tires, and more practice.
I think the problem was poor choice of rear tires, unfamiliarity with the track and with this car on the track, and not very skillful driving. I didn't think about going until a few days before the event and put on a set of new Goodyear Eagle F1 tires that were 12 years old. I had them sitting unused. The Dunlop SP 8000 I had on were worn out. I couldn't get a set of fresh tires in time to leave. I had alignment checked and the rears have 1 deg neg camber with total toe of .34 deg. The rear suspension is not pinned. At the end of the two dry sessions I ran, the rear tire temps were about 108F on the inside, 100 in the center, and 95 on the outside. Just didn't seem hot enough to me. The fronts were about 138F all across after air pressure was adjusted for even temps. I could have been more aggressive going into the corners and that would have got the temps up more. I cannot safely use 3rd with WOT without wheelspin so I ran the course using 4th and 5th. I tried 3rd for turn 11, but it was counterproductive. More time lost shifting than gained by more rear wheel torque for a short distance coming out of the corner. The car has the GT transaxle. I expect that will change when I get stickier rear tires, and more practice.
11-15-2007, 01:37 PM
#48
Drifting
i have a similar experience to you louie (with tyre temps - not bhp!), the 315 rubber on the rear hardly heats up at the outer edge while the front 255 gets properly warm all over. my setup is not what it should be, ive got the front bar fully stiff and the rear fully loose while the front camber is only about 1.5 and the rear is something like 2.5
im planning to ajust the camber - probably an increase on the front and also to slacken the front bar, hopefully this will get both ends of the car more in sync. up till now my driving style has been really front end biased - heavy braking to load up the front and rolling through under neutral throttle. as ive gotten quicker im finding the car works better when i can get it to lean on its suspension more evenly front to rear in the corners.
im planning to ajust the camber - probably an increase on the front and also to slacken the front bar, hopefully this will get both ends of the car more in sync. up till now my driving style has been really front end biased - heavy braking to load up the front and rolling through under neutral throttle. as ive gotten quicker im finding the car works better when i can get it to lean on its suspension more evenly front to rear in the corners.
11-15-2007, 02:34 PM
#49
Rennlist Member
Louie,
Yes, your car is going to take a while to get used to. I drove the Devek car at T-hill and it had a ton of power, the GT gears, but it wasnt set up correctly for the track. It made all the difference in the world as far as handling. Ive set up 5 928s, and had them act exactly the same on DOT race rubber around t-hill. its a simple formula. 1.5 front camber, about 2 rear, 1/8-1/16" toe in, lower the car to about 120mm front and 140mm rear. 305s (or 315) rear , 275 front and you are all set. (a pretty stiff suspension helps, such as 450 rear springs and 750lbs front springs)
street rubber compared to Dot rubber, or really old DOT rubber on a cold day will be a handful, even for a well set up car. tires are pretty key here. However, i have to disagree that tire size helps them heat up. you put on any size tire and with out burning rubber, just driving, they will heat up the same. (or near the same) if not, you might have too much air, not enough air, or you might not be pushing the car through the turns enough. plus, on a cold day, the surface of the tires will cool faster , so you sometimes may need a hot pit to take temps. tire pressure is a good indication. if you get a 5-7lb temp rise, you are getting heat into the tires. If you cant take your car with 550hp and run a leasurely 2:00 flat, then its either you are not pushing the car hard enough, tires are gone, or the car is not set up well.
you might want to look at your HP curve, shift so you have an average of 350rwhp and see how the car reacts. that way, you can have the performance powerwise that we do, and then elimiate the HP variable. after you have the handling down, then, just put the hammer down when you are straight and you should take off like a missle!!!!
mk
Yes, your car is going to take a while to get used to. I drove the Devek car at T-hill and it had a ton of power, the GT gears, but it wasnt set up correctly for the track. It made all the difference in the world as far as handling. Ive set up 5 928s, and had them act exactly the same on DOT race rubber around t-hill. its a simple formula. 1.5 front camber, about 2 rear, 1/8-1/16" toe in, lower the car to about 120mm front and 140mm rear. 305s (or 315) rear , 275 front and you are all set. (a pretty stiff suspension helps, such as 450 rear springs and 750lbs front springs)
street rubber compared to Dot rubber, or really old DOT rubber on a cold day will be a handful, even for a well set up car. tires are pretty key here. However, i have to disagree that tire size helps them heat up. you put on any size tire and with out burning rubber, just driving, they will heat up the same. (or near the same) if not, you might have too much air, not enough air, or you might not be pushing the car through the turns enough. plus, on a cold day, the surface of the tires will cool faster , so you sometimes may need a hot pit to take temps. tire pressure is a good indication. if you get a 5-7lb temp rise, you are getting heat into the tires. If you cant take your car with 550hp and run a leasurely 2:00 flat, then its either you are not pushing the car hard enough, tires are gone, or the car is not set up well.
you might want to look at your HP curve, shift so you have an average of 350rwhp and see how the car reacts. that way, you can have the performance powerwise that we do, and then elimiate the HP variable. after you have the handling down, then, just put the hammer down when you are straight and you should take off like a missle!!!!
mk
11-15-2007, 02:37 PM
#50
Rennlist Member
2.5 on our cars for the rears is almost too much. I run near 2 degrees myself and still see some accelerated inside edge wear. when anderson changed from 3 to 2 degrees, he seemed to like the rear end handling much better.
with the front, near the same applies. our camber does increase upon compression, however with bumpsteer issues, the inside tire scrubs the inside edge on long sweepers. at tracks like Laguna, it doesnt matter much, but at off camber, long sweepers like Thill or buttonwillow, it can cook the inside tire after a few sessions. more camber just makes this issue worse.
mk
with the front, near the same applies. our camber does increase upon compression, however with bumpsteer issues, the inside tire scrubs the inside edge on long sweepers. at tracks like Laguna, it doesnt matter much, but at off camber, long sweepers like Thill or buttonwillow, it can cook the inside tire after a few sessions. more camber just makes this issue worse.
mk
i have a similar experience to you louie (with tyre temps - not bhp!), the 315 rubber on the rear hardly heats up at the outer edge while the front 255 gets properly warm all over. my setup is not what it should be, ive got the front bar fully stiff and the rear fully loose while the front camber is only about 1.5 and the rear is something like 2.5
im planning to ajust the camber - probably an increase on the front and also to slacken the front bar, hopefully this will get both ends of the car more in sync. up till now my driving style has been really front end biased - heavy braking to load up the front and rolling through under neutral throttle. as ive gotten quicker im finding the car works better when i can get it to lean on its suspension more evenly front to rear in the corners.
im planning to ajust the camber - probably an increase on the front and also to slacken the front bar, hopefully this will get both ends of the car more in sync. up till now my driving style has been really front end biased - heavy braking to load up the front and rolling through under neutral throttle. as ive gotten quicker im finding the car works better when i can get it to lean on its suspension more evenly front to rear in the corners.
11-15-2007, 03:37 PM
#51
Drifting
mark, thats really usefull feedback. i dont track the car as much as i would like and varying the setup seems to take months between thinking about it and making it happen so knowing which direction to go with my camber ahead of time is a good thing. lots of laps at the ring and the same result in tyre temps had me convinced that the rears have too much camber at 2.5 deg, just couldnt heat up the outer half of the rear.
11-15-2007, 03:54 PM
#52
Three Wheelin'
Thanks Mark. Good info.
Louie,
Yes, your car is going to take a while to get used to. I drove the Devek car at T-hill and it had a ton of power, the GT gears, but it wasnt set up correctly for the track. It made all the difference in the world as far as handling. Ive set up 5 928s, and had them act exactly the same on DOT race rubber around t-hill. its a simple formula. 1.5 front camber, about 2 rear, 1/8-1/16" toe in, lower the car to about 120mm front and 140mm rear. 305s (or 315) rear , 275 front and you are all set. (a pretty stiff suspension helps, such as 450 rear springs and 750lbs front springs)
street rubber compared to Dot rubber, or really old DOT rubber on a cold day will be a handful, even for a well set up car. tires are pretty key here. However, i have to disagree that tire size helps them heat up. you put on any size tire and with out burning rubber, just driving, they will heat up the same. (or near the same) if not, you might have too much air, not enough air, or you might not be pushing the car through the turns enough. plus, on a cold day, the surface of the tires will cool faster , so you sometimes may need a hot pit to take temps. tire pressure is a good indication. if you get a 5-7lb temp rise, you are getting heat into the tires. If you cant take your car with 550hp and run a leasurely 2:00 flat, then its either you are not pushing the car hard enough, tires are gone, or the car is not set up well.
you might want to look at your HP curve, shift so you have an average of 350rwhp and see how the car reacts. that way, you can have the performance powerwise that we do, and then elimiate the HP variable. after you have the handling down, then, just put the hammer down when you are straight and you should take off like a missle!!!!
mk
Yes, your car is going to take a while to get used to. I drove the Devek car at T-hill and it had a ton of power, the GT gears, but it wasnt set up correctly for the track. It made all the difference in the world as far as handling. Ive set up 5 928s, and had them act exactly the same on DOT race rubber around t-hill. its a simple formula. 1.5 front camber, about 2 rear, 1/8-1/16" toe in, lower the car to about 120mm front and 140mm rear. 305s (or 315) rear , 275 front and you are all set. (a pretty stiff suspension helps, such as 450 rear springs and 750lbs front springs)
street rubber compared to Dot rubber, or really old DOT rubber on a cold day will be a handful, even for a well set up car. tires are pretty key here. However, i have to disagree that tire size helps them heat up. you put on any size tire and with out burning rubber, just driving, they will heat up the same. (or near the same) if not, you might have too much air, not enough air, or you might not be pushing the car through the turns enough. plus, on a cold day, the surface of the tires will cool faster , so you sometimes may need a hot pit to take temps. tire pressure is a good indication. if you get a 5-7lb temp rise, you are getting heat into the tires. If you cant take your car with 550hp and run a leasurely 2:00 flat, then its either you are not pushing the car hard enough, tires are gone, or the car is not set up well.
you might want to look at your HP curve, shift so you have an average of 350rwhp and see how the car reacts. that way, you can have the performance powerwise that we do, and then elimiate the HP variable. after you have the handling down, then, just put the hammer down when you are straight and you should take off like a missle!!!!
mk
11-15-2007, 04:50 PM
#53
Rennlist Member
