tuning out steady-state understeer, effect on power-out?
07-23-2016, 06:54 PM
#17
Rennlist Member
Lower front tire pressure, go zero toe in front with max neg camber and report back.
07-23-2016, 09:25 PM
#18
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Ok, but is the car set up differently than factory spec?
Based on your responses, I'd say you're entry speed is too high. Or you need to trail brake in a bit to put some weight on the front end. Try entering a tad slower and then accelerating hard out instead of entering hot and giving neutral throttle. Once you cross the apex you should be able to lay harder on the throttle as you're unwinding the steering.
Have you done any auto cross in the rain? Or DE in the rain? That is so revealing of one's flaws.
07-24-2016, 12:46 AM
#19
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Adding a GT3RS rear sway to my 997.1 Turbo did a great job of dialling out understeer. Better turn in and much easier to push the back around when exiting. Need to be a little more careful however, but I really like the change in characteristics.
Last edited by nzskater; 07-24-2016 at 07:18 AM.
07-24-2016, 12:48 AM
#20
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Ok, but is the car set up differently than factory spec?
Based on your responses, I'd say you're entry speed is too high. Or you need to trail brake in a bit to put some weight on the front end. Try entering a tad slower and then accelerating hard out instead of entering hot and giving neutral throttle. Once you cross the apex you should be able to lay harder on the throttle as you're unwinding the steering.
Have you done any auto cross in the rain? Or DE in the rain? That is so revealing of one's flaws.
Based on your responses, I'd say you're entry speed is too high. Or you need to trail brake in a bit to put some weight on the front end. Try entering a tad slower and then accelerating hard out instead of entering hot and giving neutral throttle. Once you cross the apex you should be able to lay harder on the throttle as you're unwinding the steering.
Have you done any auto cross in the rain? Or DE in the rain? That is so revealing of one's flaws.
Even if I enter a long sweeper too slow, and I accelerate until I generate some slip angle and hold it, it understeers pretty heavily.
From the responses, it sounds like my alignment is pretty screwed up. I may get it aligned even before getting the GT3 arms.
07-24-2016, 02:11 AM
#22
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Yes I've done a DE in the rain, in a miata. Learned a lot.
Even if I enter a long sweeper too slow, and I accelerate until I generate some slip angle and hold it, it understeers pretty heavily.
From the responses, it sounds like my alignment is pretty screwed up. I may get it aligned even before getting the GT3 arms.
Even if I enter a long sweeper too slow, and I accelerate until I generate some slip angle and hold it, it understeers pretty heavily.
From the responses, it sounds like my alignment is pretty screwed up. I may get it aligned even before getting the GT3 arms.
Get a proper alignment at an Indie that services Porsche cars fro the track.
When you add throttle in the turn, you shift weight to the rear. Your front end lightens up and can create understeer. If you let up on the gas you'll get oversteer. You need to set up into the corner better and then accelerate as you unwind.
GT3 LCA's will just mask the problem. You'll get more tire on the road but your main issue, as far as I can gather, is that you haven't managed to develop proper weight transfer management for the 911.
I suggest you enroll in some DE & AX events in your 911 to maximize your skills. A Skid pad would also be helpful to learn how to use the throttle to shift weight between the front & rear for grip and throttle steering.
07-24-2016, 02:25 AM
#23
Nordschleife Master
A miata and a 911 are apples to oranges.
Get a proper alignment at an Indie that services Porsche cars fro the track.
When you add throttle in the turn, you shift weight to the rear. Your front end lightens up and can create understeer. If you let up on the gas you'll get oversteer. You need to set up into the corner better and then accelerate as you unwind.
GT3 LCA's will just mask the problem. You'll get more tire on the road but your main issue, as far as I can gather, is that you haven't managed to develop proper weight transfer management for the 911.
I suggest you enroll in some DE & AX events in your 911 to maximize your skills. A Skid pad would also be helpful to learn how to use the throttle to shift weight between the front & rear for grip and throttle steering.
Get a proper alignment at an Indie that services Porsche cars fro the track.
When you add throttle in the turn, you shift weight to the rear. Your front end lightens up and can create understeer. If you let up on the gas you'll get oversteer. You need to set up into the corner better and then accelerate as you unwind.
GT3 LCA's will just mask the problem. You'll get more tire on the road but your main issue, as far as I can gather, is that you haven't managed to develop proper weight transfer management for the 911.
I suggest you enroll in some DE & AX events in your 911 to maximize your skills. A Skid pad would also be helpful to learn how to use the throttle to shift weight between the front & rear for grip and throttle steering.
Last edited by ADias; 07-24-2016 at 03:08 AM.
07-24-2016, 07:17 AM
#24
Rennlist Member
Originally Posted by halo777
Do you mean a rear sway bar?
07-24-2016, 10:48 AM
#25
In my mind OP needs to verify his suspension settings are within spec, the state of his tires and pressures, and then rethink his driving style. My playtime is spent almost exclusively in driving the on/off ramps here in NY most of which can be described as long 2nd and 3rd gear sweepers.
In at high speed steady throttle, tap brakes just before entering for weight transfer, throttle on throughout turn, full throttle just before exit with a bit of countersteer allowing car to drift outward upon exit. No understeer and quick enough to hold my own against some more exotic stuff. At least until the road straightens out
Lifting off throttle to bring rear out? Just should not do that my friend.
I found some time at Porsche Driving School fun and useful.
In at high speed steady throttle, tap brakes just before entering for weight transfer, throttle on throughout turn, full throttle just before exit with a bit of countersteer allowing car to drift outward upon exit. No understeer and quick enough to hold my own against some more exotic stuff. At least until the road straightens out
Lifting off throttle to bring rear out? Just should not do that my friend.
I found some time at Porsche Driving School fun and useful.
07-24-2016, 01:02 PM
#26
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Come out to play with the AutoX folks with the SCCA. You get to see some cool cars and do some drive a longs. I have found the folks there very friendly and helpful. With AutoX or SOLO II you can test you and the car at the limit and the only thing you hit are some cones. My rookie year I spun the car about 6 times and put the car sideways many times. 3/4 of the time it was my driving the other it was the car setup. I also over drove the car a lot so I under steered.
As for only changing the front sway bar in the SCCA you can only change one sway bar and end links. I did try only a rear GT3 swaybar but I think I was backwards more the that facing the correct way. The picture in my avatar is with only a GT3 front swaybar with adjustable end links in a sweeper and I think that the car was hooking up OK. As for the toe in the rear my car is setup at 1/8 toe in but some very fast SOLO II cars run up yo 1/4 toe in. I also run Bridgestone RE71r's 255 35 18 and 285 30 18 for SoloII and run Bridgestone RE11 19's for the street. I like the 285 30 18 because they are about 2" shorter than the 305 30 19 and redline in second is 66 and not 72+.
As for only changing the front sway bar in the SCCA you can only change one sway bar and end links. I did try only a rear GT3 swaybar but I think I was backwards more the that facing the correct way. The picture in my avatar is with only a GT3 front swaybar with adjustable end links in a sweeper and I think that the car was hooking up OK. As for the toe in the rear my car is setup at 1/8 toe in but some very fast SOLO II cars run up yo 1/4 toe in. I also run Bridgestone RE71r's 255 35 18 and 285 30 18 for SoloII and run Bridgestone RE11 19's for the street. I like the 285 30 18 because they are about 2" shorter than the 305 30 19 and redline in second is 66 and not 72+.
07-24-2016, 01:25 PM
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In my mind OP needs to verify his suspension settings are within spec, the state of his tires and pressures, and then rethink his driving style. My playtime is spent almost exclusively in driving the on/off ramps here in NY most of which can be described as long 2nd and 3rd gear sweepers.
In at high speed steady throttle, tap brakes just before entering for weight transfer, throttle on throughout turn, full throttle just before exit with a bit of countersteer allowing car to drift outward upon exit. No understeer and quick enough to hold my own against some more exotic stuff. At least until the road straightens out
In at high speed steady throttle, tap brakes just before entering for weight transfer, throttle on throughout turn, full throttle just before exit with a bit of countersteer allowing car to drift outward upon exit. No understeer and quick enough to hold my own against some more exotic stuff. At least until the road straightens out
Lifting off throttle to bring rear out? Just should not do that my friend.
I found some time at Porsche Driving School fun and useful.
I do plan to go to a PCA DE day to pick up tips about driving a rear-engine car.
I don't want to go with stock front camber and chew up the front tires though.
07-24-2016, 01:29 PM
#28
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A miata and a 911 are apples to oranges.
When you add throttle in the turn, you shift weight to the rear. Your front end lightens up and can create understeer. If you let up on the gas you'll get oversteer. You need to set up into the corner better and then accelerate as you unwind.
When you add throttle in the turn, you shift weight to the rear. Your front end lightens up and can create understeer. If you let up on the gas you'll get oversteer. You need to set up into the corner better and then accelerate as you unwind.
I want my 911 to do the same!
07-24-2016, 01:34 PM
#30
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A stock 997, with proper tires and correct alignment (stock alignment with minimal rear toe-in), should not understeer on a 40MPH sweeper. Unless you call a sweeper a far tighter curve than I do... And in that case it means you are overdriving your 911. A classic 911 corner is taken slow-in, fast out. And the 'slow-in' means progressive braking in (not a slam) and 'fast out' means progressive, smooth, throttle not a slam either.
I would have students at the track after there 1st day or even they had been 2-3 times say, "my car isn't handling great, I'm going to buy..."then they list a series of mod's. I would reply you can waste your money if you want but it isn't the car that has the handling issue.
It's all about setting up for a curve...at 40mph sweeper there should not be any need for braking!
Not seeing you sweepers or curves and knowing you driving style the rule of thumb for a 997 chassis for better handling is:
More camber in front than rear...do not exceed .5 degree variable..example -2.5 degrees up front -2 degrees in rear. For a street car on street tires or DOT track tires you should not exceed this -2.5/-2 starting point anyway.
Also adjustable sway bars will help too.
Bit honestly it's all about driving the car and a 997 in stock form can really haul butt.