Orthojoe's GT4 track thread and ramblings
04-04-2016, 03:51 PM
#166
Nordschleife Master
Thread Starter
The problem with going even stiffer front sway bar is that you will induce even more understeer, no? I'm good with how the car handles on full stiff oem sway bars, but I'm not sure if we want to go any more stiff?
04-04-2016, 03:59 PM
#167
Burning Brakes
Martin originally went down this path because he felt the car was diving too much under braking. I'm just wanting to increase roll stiffness to reduce the camber increase in coeners - we should be able to accomplish this with swaybars, no? Stiffer springs, in addition to potential PASM issues, will make the car harder on tires in general, all things being equal.
04-04-2016, 04:08 PM
#168
Burning Brakes
IIRC, the Cup 2s actually have a harder-wearing compound on the outer edges, at least compared to the original Cups. This was mentioned in an AP video and, by all accounts, the Cup 2 does wear better than its predecessor.
04-04-2016, 04:41 PM
#169
Rennlist Member
However, the outer edge should still be softer than the the inner edge. The idea is that with some camber you ride on the inner edge on the highway (cup 2s are dual purpose tires), so they make that harder. When you go to the track you'll ride on the outer edges more so they are made to be softer to have more grip.
04-04-2016, 04:47 PM
#170
Burning Brakes
However, the outer edge should still be softer than the the inner edge. The idea is that with some camber you ride on the inner edge on the highway (cup 2s are dual purpose tires), so they make that harder. When you go to the track you'll ride on the outer edges more so they are made to be softer to have more grip.
04-04-2016, 05:00 PM
#171
Nordschleife Master
Thread Starter
Originally Posted by Beantown Kman
Damper valving will generally work with a wider range of spring rates than you might think. In the case of the GT4 we have the added advantage of a PASM system that increases the range in which they will work effectively.
04-04-2016, 06:43 PM
#172
FWIW, a friend of mine installed this in his 997.2 C4S for the track session last weekend and it made a substantial decrease in body roll. I was quite suspect that there would be any gain, but it did work quite well. No idea if the GT4 version will work but maybe it is an easy option to test. 4 half days in and my fronts are shot as well.
https://rennlist.com/forums/gt4/8952...sc-module.html
https://rennlist.com/forums/gt4/8952...sc-module.html
04-04-2016, 07:21 PM
#173
Addict
Rennlist Member
Rennlist Member
FWIW, a friend of mine installed this in his 997.2 C4S for the track session last weekend and it made a substantial decrease in body roll. I was quite suspect that there would be any gain, but it did work quite well. No idea if the GT4 version will work but maybe it is an easy option to test. 4 half days in and my fronts are shot as well.
https://rennlist.com/forums/gt4/8952...sc-module.html
https://rennlist.com/forums/gt4/8952...sc-module.html
04-04-2016, 07:31 PM
#174
Oh, ok. Not sure, but Leo's black C4S was a wallowing pig a couple weeks back and not too bad yesterday. He said they have good service, may be worth reaching out to them.
04-05-2016, 12:14 AM
#175
Drifting
Joe how much worse is your GT4 front tire wear compared to your GT3 at the same track? If it's significant, I'm curious if you have any thoughts as to what might account for the difference (assuming you have a similar alignment and suspension mod setup in both cars), seeing as the two cars share front suspensions and tires (right down to the size) and weigh about the same amount. I know the GT4 has a somewhat more forward-biased weight distribution, but I don't see that being responsible for a major difference in front outside tire wear, though I am of course no expert.
04-05-2016, 12:25 AM
#176
Nordschleife Master
Thread Starter
Joe how much worse is your GT4 front tire wear compared to your GT3 at the same track? If it's significant, I'm curious if you have any thoughts as to what might account for the difference (assuming you have a similar alignment and suspension mod setup in both cars), seeing as the two cars share front suspensions and tires (right down to the size) and weigh about the same amount. I know the GT4 has a somewhat more forward-biased weight distribution, but I don't see that being responsible for a major difference in front outside tire wear, though I am of course no expert.
I have spoken to a GT3 owner who has been told that the GT3 needs stiffer springs as well and he is currently testing them in his car.
04-05-2016, 12:33 AM
#177
Three Wheelin'
Porsche needs to change to double wishbones / multi-link and then this problem would be solved while using street spring rates. Strut camber curve isn't ideal.
Still amazing that we get this kind of performance out of struts though.
Still amazing that we get this kind of performance out of struts though.
04-05-2016, 02:27 AM
#180
It appears to be getting more and more clear that the oem spring rates are just too soft for serious track duty. Everybody is chasing understeer and excessive front tire wear with more and more negative camber. But that doesn't appear to be working.
Martin, I think you've commented on this previously but would you mind telling us again how the stiffer springs on your car affected ride quality on the street? Are you driving your car on the street?? I would think 450/550 would be quite stiff for a street car but not quite bone jarring. Are you happy with how your car handles now? Have you changed the ride height?
Martin, I think you've commented on this previously but would you mind telling us again how the stiffer springs on your car affected ride quality on the street? Are you driving your car on the street?? I would think 450/550 would be quite stiff for a street car but not quite bone jarring. Are you happy with how your car handles now? Have you changed the ride height?
On the street I mix it up between Regular and Sport. On the track, it's Sport on all the time.
