991.2 GT3 track alignment
12-26-2017, 07:56 PM
#16
The community is not ignoring you Palting, there is actually a very similar thread already that has been answered
https://rennlist.com/forums/991-gt3-...nment-rwd.html
And as per Orthojoe's recent comments on the 991.2 go slowly. Too many changes too fast can mess everything up with no gains. My personal experience with the 991S was that some camber around 2 in front and a little more in the back helped my tires to wear evenly.
https://rennlist.com/forums/991-gt3-...s-awesome.html
(entry 23)
https://rennlist.com/forums/991-gt3-...nment-rwd.html
And as per Orthojoe's recent comments on the 991.2 go slowly. Too many changes too fast can mess everything up with no gains. My personal experience with the 991S was that some camber around 2 in front and a little more in the back helped my tires to wear evenly.
https://rennlist.com/forums/991-gt3-...s-awesome.html
(entry 23)
12-26-2017, 08:37 PM
#17
Nordschleife Master
Thread Starter
Thanks. Subscribed to orthojoes new thread. Man, my car better get here soon, I'm already subscribed to a dozen threads just because I'm getting too antsy! Only three more months, but it seems like forever.
12-26-2017, 09:36 PM
#18
Nordschleife Master
Here is what I believe to be true
1) For whatever reason, alignment changes from stock on the 991 GT3 and 981 GT4 DO NOT improve the performance of the car. Some changes could actually make the car perform worse.
2) In the past I would constantly be chasing for the right alignment to give me even tire wear and longer lasting tires. I was never able to find a setup that yielded in tires that lasted longer.
This is what I would do, regardless of what your skill level is and is what I plan to do.
1) Drive the car with bone stock alignment and dial out any characteristics you don’t like via the sway bars and see how long the tires last this way
2) Dial in max amount of camber up front before front caster gets to be too great and causes rubbing in the fender liner. I’m predicting you can probably get about -2.5 camber before the front caster turns into a problem. Dial in the rear to be about 0.3 less camber than the front (-2.2). Set the rear total toe in at 6mm, the front total toe out at 3mm. See what you think of the car then and see how many days you get out the tires.
3) Report back to me/us so I can just do one of the above and save some time and money. LOL
2) In the past I would constantly be chasing for the right alignment to give me even tire wear and longer lasting tires. I was never able to find a setup that yielded in tires that lasted longer.
This is what I would do, regardless of what your skill level is and is what I plan to do.
1) Drive the car with bone stock alignment and dial out any characteristics you don’t like via the sway bars and see how long the tires last this way
2) Dial in max amount of camber up front before front caster gets to be too great and causes rubbing in the fender liner. I’m predicting you can probably get about -2.5 camber before the front caster turns into a problem. Dial in the rear to be about 0.3 less camber than the front (-2.2). Set the rear total toe in at 6mm, the front total toe out at 3mm. See what you think of the car then and see how many days you get out the tires.
3) Report back to me/us so I can just do one of the above and save some time and money. LOL
12-27-2017, 12:24 AM
#19
Rennlist Member
Here is what I believe to be true
1) For whatever reason, alignment changes from stock on the 991 GT3 and 981 GT4 DO NOT improve the performance of the car. Some changes could actually make the car perform worse.
2) In the past I would constantly be chasing for the right alignment to give me even tire wear and longer lasting tires. I was never able to find a setup that yielded in tires that lasted longer.
This is what I would do, regardless of what your skill level is and is what I plan to do.
1) Drive the car with bone stock alignment and dial out any characteristics you don’t like via the sway bars and see how long the tires last this way
2) Dial in max amount of camber up front before front caster gets to be too great and causes rubbing in the fender liner. I’m predicting you can probably get about -2.5 camber before the front caster turns into a problem. Dial in the rear to be about 0.3 less camber than the front (-2.2). Set the rear total toe in at 6mm, the front total toe out at 3mm. See what you think of the car then and see how many days you get out the tires.
3) Report back to me/us so I can just do one of the above and save some time and money. LOL
2) In the past I would constantly be chasing for the right alignment to give me even tire wear and longer lasting tires. I was never able to find a setup that yielded in tires that lasted longer.
This is what I would do, regardless of what your skill level is and is what I plan to do.
1) Drive the car with bone stock alignment and dial out any characteristics you don’t like via the sway bars and see how long the tires last this way
2) Dial in max amount of camber up front before front caster gets to be too great and causes rubbing in the fender liner. I’m predicting you can probably get about -2.5 camber before the front caster turns into a problem. Dial in the rear to be about 0.3 less camber than the front (-2.2). Set the rear total toe in at 6mm, the front total toe out at 3mm. See what you think of the car then and see how many days you get out the tires.
3) Report back to me/us so I can just do one of the above and save some time and money. LOL
12-27-2017, 12:31 AM
#21
Not sure what’s worse - I have my new car but I’m surrounded by snow for hundreds of miles.
12-27-2017, 01:12 AM
#22
Nordschleife Master
Originally Posted by Wind911
Pardon my ignorance, what kind of caster problem will you run into if you have too much front camber？
12-27-2017, 01:32 AM
#23
Rennlist Member
Adding front camber via the lower control arm shims also adds caster. If you look at cars that have aggressive camber but aren't running adjustable thrust arm bushings the wheel is pushed way forward in the well and no longer centered. In my .1 when I had -2.7 up front the tire ended up rubbing a hole in the fender liner. You need adjustable thrust arm bushings to dial back the caster. I'm not going to deal with that this time around. Stock components only.
12-27-2017, 01:52 AM
#24
Pro
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Here is what I believe to be true
1) For whatever reason, alignment changes from stock on the 991 GT3 and 981 GT4 DO NOT improve the performance of the car. Some changes could actually make the car perform worse.
2) In the past I would constantly be chasing for the right alignment to give me even tire wear and longer lasting tires. I was never able to find a setup that yielded in tires that lasted longer.
This is what I would do, regardless of what your skill level is and is what I plan to do.
1) Drive the car with bone stock alignment and dial out any characteristics you don’t like via the sway bars and see how long the tires last this way
2) Dial in max amount of camber up front before front caster gets to be too great and causes rubbing in the fender liner. I’m predicting you can probably get about -2.5 camber before the front caster turns into a problem. Dial in the rear to be about 0.3 less camber than the front (-2.2). Set the rear total toe in at 6mm, the front total toe out at 3mm. See what you think of the car then and see how many days you get out the tires.
3) Report back to me/us so I can just do one of the above and save some time and money. LOL
2) In the past I would constantly be chasing for the right alignment to give me even tire wear and longer lasting tires. I was never able to find a setup that yielded in tires that lasted longer.
This is what I would do, regardless of what your skill level is and is what I plan to do.
1) Drive the car with bone stock alignment and dial out any characteristics you don’t like via the sway bars and see how long the tires last this way
2) Dial in max amount of camber up front before front caster gets to be too great and causes rubbing in the fender liner. I’m predicting you can probably get about -2.5 camber before the front caster turns into a problem. Dial in the rear to be about 0.3 less camber than the front (-2.2). Set the rear total toe in at 6mm, the front total toe out at 3mm. See what you think of the car then and see how many days you get out the tires.
3) Report back to me/us so I can just do one of the above and save some time and money. LOL
Quite honestly - I think alignment has a lot to do with the driving style of the user. I like a car that is fairly loose and rotates quickly.
I will report back as I plan to align it next week and taking it to COTA end of January.
Going to laugh as I suspect I will be not far off my cup car times due to higher speeds attainable on the straights.
- Chris.
12-27-2017, 10:26 AM
#26
Adding front camber via the lower control arm shims also adds caster. If you look at cars that have aggressive camber but aren't running adjustable thrust arm bushings the wheel is pushed way forward in the well and no longer centered. In my .1 when I had -2.7 up front the tire ended up rubbing a hole in the fender liner. You need adjustable thrust arm bushings to dial back the caster. I'm not going to deal with that this time around. Stock components only.
Orthojoe, first of all thanks for your many great posts on the 991.1 and now the 991.2, they have been very informative. I was told by a friend running a 991.1 GT3 that I need to use caster pucks (to keep wheel at stock caster and avoid any rubbing) after I install 19inch - 265's up front and about 2.5 camber (also likely some shims to get to 2.5). Based on your recent comments were there any major concerns that you ran into with just these changes?
12-27-2017, 10:31 AM
#27
Race Director
Your alignment for the track will depend on the tires you use. Also your track and driving style will dictate alignment. What works for one guy might not work for the other guy.
with that said....and I know my 991.2 GTS if different than your 991.2 GT3....I’ve found running Michelin Pilot Sport Cup 2 Tires...same Tires you all get on your GT3 is that -1.5 degrees camber all 4 corners with zero toe front and .14 degree toe in each side in rear ( I have rear steer) is working for me right now. I seem to be getting great tire wear at Sebring.
This alignment is far different than what I ran on my 997 2012 GTS.
with that said....and I know my 991.2 GTS if different than your 991.2 GT3....I’ve found running Michelin Pilot Sport Cup 2 Tires...same Tires you all get on your GT3 is that -1.5 degrees camber all 4 corners with zero toe front and .14 degree toe in each side in rear ( I have rear steer) is working for me right now. I seem to be getting great tire wear at Sebring.
This alignment is far different than what I ran on my 997 2012 GTS.
12-27-2017, 11:01 AM
#28
Nordschleife Master
I am planning similar but will run a little more camber front and rear due to higher speed track conditions. The other thing I noted is that my .1 did not like much toe-in rear, if any at all. The car would push and liked to load up the rear too much. I plan to run a neutral rear toe setting to let the car rotate faster and slight toe-out front.
Quite honestly - I think alignment has a lot to do with the driving style of the user. I like a car that is fairly loose and rotates quickly.
I will report back as I plan to align it next week and taking it to COTA end of January.
Going to laugh as I suspect I will be not far off my cup car times due to higher speeds attainable on the straights.
- Chris.
Quite honestly - I think alignment has a lot to do with the driving style of the user. I like a car that is fairly loose and rotates quickly.
I will report back as I plan to align it next week and taking it to COTA end of January.
Going to laugh as I suspect I will be not far off my cup car times due to higher speeds attainable on the straights.
- Chris.
Orthojoe, first of all thanks for your many great posts on the 991.1 and now the 991.2, they have been very informative. I was told by a friend running a 991.1 GT3 that I need to use caster pucks (to keep wheel at stock caster and avoid any rubbing) after I install 19inch - 265's up front and about 2.5 camber (also likely some shims to get to 2.5). Based on your recent comments were there any major concerns that you ran into with just these changes?
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AGO (06-26-2023)
12-27-2017, 11:05 AM
#29
Nordschleife Master
Your alignment for the track will depend on the tires you use. Also your track and driving style will dictate alignment. What works for one guy might not work for the other guy.
with that said....and I know my 991.2 GTS if different than your 991.2 GT3....I’ve found running Michelin Pilot Sport Cup 2 Tires...same Tires you all get on your GT3 is that -1.5 degrees camber all 4 corners with zero toe front and .14 degree toe in each side in rear ( I have rear steer) is working for me right now. I seem to be getting great tire wear at Sebring.
This alignment is far different than what I ran on my 997 2012 GTS.
with that said....and I know my 991.2 GTS if different than your 991.2 GT3....I’ve found running Michelin Pilot Sport Cup 2 Tires...same Tires you all get on your GT3 is that -1.5 degrees camber all 4 corners with zero toe front and .14 degree toe in each side in rear ( I have rear steer) is working for me right now. I seem to be getting great tire wear at Sebring.
This alignment is far different than what I ran on my 997 2012 GTS.
12-28-2017, 11:11 AM
#30
Race Director
Yes Joe...exactly...991.2 GTS running less camber than my 997.2GTS. I ran -2.5 front and -2 rear on 997.2 GTS on Nitto NT01 tires. I wish Nitto NT01's came in stock 20" sizes so I could direct compare but it seems like the overall 991 platform requires less camber than the 997 platform. You think so too?