GT Car Alignment Specs - Share your set-up / knowledge
10-12-2022 | 09:18 PM
#1127
Rennlist Member
Joined: Jul 2020
Posts: 646
Likes: 515
From: NY/NJ
I sometimes wonder if I should have gone that route.
I am not sure if I would have had to do the RSS Bump Steer Kit if I had done the camber plates, rather than the shims and caster puck. I am not an expert on suspension geometry, but I do know that the changes I did make made the steering wheel very jerky and hyper active and I needed the bump steer kit to fix that.
I am not sure if I would have had to do the RSS Bump Steer Kit if I had done the camber plates, rather than the shims and caster puck. I am not an expert on suspension geometry, but I do know that the changes I did make made the steering wheel very jerky and hyper active and I needed the bump steer kit to fix that.
But its true you don't necessarily need any of that stuff to get a sorted alignment. Why change 3 parts when you can just change one, introduces far fewer variables. When you start removing rubber from the suspension, the energy has to go somewhere. Invariably it comes up through the wheel.
10-12-2022 | 09:25 PM
#1128
Rennlist Member
Joined: Jul 2020
Posts: 646
Likes: 515
From: NY/NJ
The advantage of going the shim route is that you (1) add more track to the car and (2) it forces you to get rid of the rubber caster puck up front, which in turn adds a tiny bit of precision to the car. But agree that camber plate is probably easier than changing potentially 3 parts.
I run just camber plates and rear toe links on totally stock suspension. I post laps in both the 718 and 981 lap times thread - I am not going slowly. People are so quick to throw mods on cars when its not necessarily going to help them achieve their goals with the car.
Sometimes I think about just starting a new thread and laying out if you want a proper alignment, this is what you need. As there seems to be so much confusion and over complication around getting these cars setup properly.
10-12-2022 | 09:39 PM
#1129
Rennlist Member
Joined: Jul 2020
Posts: 646
Likes: 515
From: NY/NJ
10-13-2022 | 12:25 AM
#1130
Racer
Joined: Aug 2019
Posts: 422
Likes: 359
From: Portland, OR
Side note #1: I shared my observation with shop #2 that my car's ride height looks off side to side (measures ~0.25" lower at the fender openings front and rear left side vs right.) It's his understanding these cars are corner balanced (approximately, at least) at the factory & he only messes with the ride height when people ask to have the cars lowered. I assume this is something he was told in his prior life as a Porsche dealership master tech - has anyone else heard this? I'm still going to ask him to measure mine while he has it in the shop to make sure it's at least in the ballpark of the recommended height.
https://rennlist.com/forums/gt4-spyd...cant-rake.html
10-13-2022 | 11:25 AM
#1131
Intermediate
Joined: Jul 2022
Posts: 41
Likes: 17
From: Southeast PA
It is common that fender gaps/heights don’t match. The proper way to measure ride height is under the car. There are points under the front tub and rear subframe. My fenders measure off, but underneath is level.
https://rennlist.com/forums/gt4-spyd...cant-rake.html
https://rennlist.com/forums/gt4-spyd...cant-rake.html
I also checked my strut tops to see if the shop actually had them pushed all the way in as I mentioned to them was necessary 3x and they verified every time they had. Guess what? None of the bolts were more than 3/4 of the way to the inboard edge of their slots and most of them were barely ~2/3 of the way. There were no fastener marks in the paint indicating they'd been moved either. I think they just pulled the cover and saw slot exposed on the outboard side of the slot and none showing on the inboard side and figured they were already pushed all the way in. Obviously the flange on the nut obscures your view of much of the slot so you have to at least loosen them to see what's going on (I pulled them one at a time and replaced/retorqued before pulling the next one to keep anything from shifting.) Driver's side was even skewed clockwise as much as possible given the slots are barely wider than the studs, which helps explain why the tech was having to use so many shims - appears to be >14mm of shims on that corner, so no thread exposed past the nuts on the LCA.
"Good news" was that after all the concern over tie rod engagement, I measured the exposed thread right at the 35mm max that TPC says is safe. I'm guessing that amount will go down a bit once re-aligned with the strut tops pushed all the way in, but will have to wait & see.
10-13-2022 | 03:01 PM
#1132
Banned
Joined: Mar 2020
Posts: 511
Likes: 64
From: Berlin, Germany
Originally Posted by jmlmr2
Yep - I measured last night and that was the case for my car. Front measuring points were dead even side to side at 109mm despite fender heights being off by >5mm.
10-13-2022 | 03:15 PM
#1134
Burning Brakes
Joined: Feb 2015
Posts: 1,003
Likes: 505
10-25-2022 | 12:01 PM
#1135
Intermediate
Joined: Jul 2022
Posts: 41
Likes: 17
From: Southeast PA
I hear you regarding camber plates - but I'm really not looking for the full track rat setup. Was just trying to get what seemed by consensus to be an achievable alignment with just shims and rear toe links. If that means I can only get 2.2-2.3 up front that's fine, I just want the rear .3-.5 less to keep the front bias. Was mainly sharing my frustrations with an audience for the therapeutic benefits as well as to increase the pool of knowledge here. Across this billion page thread, my car was the first I heard of that ran out of front tie-rod well before -2.5, but it seems at least one other car has had the same issue.
I'll post back with results of the re-alignment.
I'll post back with results of the re-alignment.
12-07-2022 | 05:20 PM
#1136
Intermediate
Joined: Jun 2021
Posts: 43
Likes: 8
Is there a secret sauce caster number?
I have -3 camber up front and my caster has gone up to 10.5 and 11 degrees. Is 10 a good number, or 9?
I need a touch less corner exit and mid corner understeer and I'll be doing some caster testing myself, but wondering if anyone has already found a solution.
I have -3 camber up front and my caster has gone up to 10.5 and 11 degrees. Is 10 a good number, or 9?
I need a touch less corner exit and mid corner understeer and I'll be doing some caster testing myself, but wondering if anyone has already found a solution.
