GT2RS Inspired 997 Turbo build...
#346
08-15-2017, 03:33 PM
OK I have a new update. Finally had the suspension upgrade carried out. I can confirm it has transformed the car! Enjoy!
https://youtu.be/QKWn8Ujrc8o
https://youtu.be/QKWn8Ujrc8o
Great video
how are you finding the Ohlins?
#347
08-17-2017, 03:33 PM
Hey there.
As per the pm I sent,.. you'll probably end up having to add an additional 5-6 turns of pre-load on the front springs (In addition to the 5mm pre-load they recommend),.. and an additional 3 turns in the rear. (Then adjust accordingly for ride height at the bottom. Otherwise your bump-to-droop will be way off.
Presumably they installed the shocks without springs in them first and measured the stroke, then installed the springs and got the bump-droop right. The settings in the manual will leave you with about 25mm of bump and 45mm of droop. Which is backwards for a race car,.. and street cars should be something like 50/50. Erring towards slightly more bump.
To do a rough check,.. measure the height of the front fender at rest,.. then jack up both sides of the front of the car until the tires can juuuust be turned a bit by hand. (Just touching the ground a little). Themn measure again.
The front shocks have a motion ratio of 1-1,.. and a stroke of 80mm. So you'll want to see just about 42mm of delta in those 2 measurements. If it's more than that,.. add a few turns of pre-load on the spring (raising the lower spring perch),.. and then also raise the bottom coller and allow the strut to sink into the upright by the same number of turns. Repeat on the other side and both rears. Drive the car to settle it and measure again.
The rear has about the same shock travel,. but has a motion ratio that's less than 1-1,.. so there is a bit more than 80mm in wheel travel. So you'll want to see something like 44 mm or less of droop travel.
Being that you have installed solid top-hats,.. you'll want to have the shocks re-valved.
The rubber bushings in the stock top-hats effectively reduce the dampening of the shocks by 30%. To compensate,. the shocks are over-damped from Ohlins. So much so that they are past critical for the included 400 lb-in front, 686 lb-in rear springs.
If your techs are Ohlins dealers like mine is,. then it's no big deal to strip them down, re-valve, then re-charge.
As per the pm I sent,.. you'll probably end up having to add an additional 5-6 turns of pre-load on the front springs (In addition to the 5mm pre-load they recommend),.. and an additional 3 turns in the rear. (Then adjust accordingly for ride height at the bottom. Otherwise your bump-to-droop will be way off.
Presumably they installed the shocks without springs in them first and measured the stroke, then installed the springs and got the bump-droop right. The settings in the manual will leave you with about 25mm of bump and 45mm of droop. Which is backwards for a race car,.. and street cars should be something like 50/50. Erring towards slightly more bump.
To do a rough check,.. measure the height of the front fender at rest,.. then jack up both sides of the front of the car until the tires can juuuust be turned a bit by hand. (Just touching the ground a little). Themn measure again.
The front shocks have a motion ratio of 1-1,.. and a stroke of 80mm. So you'll want to see just about 42mm of delta in those 2 measurements. If it's more than that,.. add a few turns of pre-load on the spring (raising the lower spring perch),.. and then also raise the bottom coller and allow the strut to sink into the upright by the same number of turns. Repeat on the other side and both rears. Drive the car to settle it and measure again.
The rear has about the same shock travel,. but has a motion ratio that's less than 1-1,.. so there is a bit more than 80mm in wheel travel. So you'll want to see something like 44 mm or less of droop travel.
Being that you have installed solid top-hats,.. you'll want to have the shocks re-valved.
The rubber bushings in the stock top-hats effectively reduce the dampening of the shocks by 30%. To compensate,. the shocks are over-damped from Ohlins. So much so that they are past critical for the included 400 lb-in front, 686 lb-in rear springs.
If your techs are Ohlins dealers like mine is,. then it's no big deal to strip them down, re-valve, then re-charge.
Last edited by Duckstu; 08-17-2017 at 03:51 PM.
#349
09-06-2017, 05:40 AM
Hey there.
As per the pm I sent,.. you'll probably end up having to add an additional 5-6 turns of pre-load on the front springs (In addition to the 5mm pre-load they recommend),.. and an additional 3 turns in the rear. (Then adjust accordingly for ride height at the bottom. Otherwise your bump-to-droop will be way off.
Presumably they installed the shocks without springs in them first and measured the stroke, then installed the springs and got the bump-droop right. The settings in the manual will leave you with about 25mm of bump and 45mm of droop. Which is backwards for a race car,.. and street cars should be something like 50/50. Erring towards slightly more bump.
To do a rough check,.. measure the height of the front fender at rest,.. then jack up both sides of the front of the car until the tires can juuuust be turned a bit by hand. (Just touching the ground a little). Themn measure again.
The front shocks have a motion ratio of 1-1,.. and a stroke of 80mm. So you'll want to see just about 42mm of delta in those 2 measurements. If it's more than that,.. add a few turns of pre-load on the spring (raising the lower spring perch),.. and then also raise the bottom coller and allow the strut to sink into the upright by the same number of turns. Repeat on the other side and both rears. Drive the car to settle it and measure again.
The rear has about the same shock travel,. but has a motion ratio that's less than 1-1,.. so there is a bit more than 80mm in wheel travel. So you'll want to see something like 44 mm or less of droop travel.
Being that you have installed solid top-hats,.. you'll want to have the shocks re-valved.
The rubber bushings in the stock top-hats effectively reduce the dampening of the shocks by 30%. To compensate,. the shocks are over-damped from Ohlins. So much so that they are past critical for the included 400 lb-in front, 686 lb-in rear springs.
If your techs are Ohlins dealers like mine is,. then it's no big deal to strip them down, re-valve, then re-charge.
As per the pm I sent,.. you'll probably end up having to add an additional 5-6 turns of pre-load on the front springs (In addition to the 5mm pre-load they recommend),.. and an additional 3 turns in the rear. (Then adjust accordingly for ride height at the bottom. Otherwise your bump-to-droop will be way off.
Presumably they installed the shocks without springs in them first and measured the stroke, then installed the springs and got the bump-droop right. The settings in the manual will leave you with about 25mm of bump and 45mm of droop. Which is backwards for a race car,.. and street cars should be something like 50/50. Erring towards slightly more bump.
To do a rough check,.. measure the height of the front fender at rest,.. then jack up both sides of the front of the car until the tires can juuuust be turned a bit by hand. (Just touching the ground a little). Themn measure again.
The front shocks have a motion ratio of 1-1,.. and a stroke of 80mm. So you'll want to see just about 42mm of delta in those 2 measurements. If it's more than that,.. add a few turns of pre-load on the spring (raising the lower spring perch),.. and then also raise the bottom coller and allow the strut to sink into the upright by the same number of turns. Repeat on the other side and both rears. Drive the car to settle it and measure again.
The rear has about the same shock travel,. but has a motion ratio that's less than 1-1,.. so there is a bit more than 80mm in wheel travel. So you'll want to see something like 44 mm or less of droop travel.
Being that you have installed solid top-hats,.. you'll want to have the shocks re-valved.
The rubber bushings in the stock top-hats effectively reduce the dampening of the shocks by 30%. To compensate,. the shocks are over-damped from Ohlins. So much so that they are past critical for the included 400 lb-in front, 686 lb-in rear springs.
If your techs are Ohlins dealers like mine is,. then it's no big deal to strip them down, re-valve, then re-charge.
#350
09-06-2017, 05:42 AM
So gents, I have just returned form the 'Shakeout road trip' in my (finished haha) 911 GT2RS project. I did 2,500 miles in 9 days from UK to Spain via Ferry, Bilbao to Montpellier to Monaco. Then up to the Alps and on N85 (possibly the greatest roads in the world!) Thought you may like to see the video I made in the Alps.
Car performed faultlessly and the suspension has transformed the car. More on that in a future video.
Car performed faultlessly and the suspension has transformed the car. More on that in a future video.
Last edited by isysman; 09-06-2017 at 05:46 AM.
#352
09-06-2017, 03:21 PM
Damn, you keep out doing yourself! I for one, can truly appreciate the time an effort you put in to yielding four minutes of footage! Very impressive.
Nicely done!
Cheers,
VID
Nicely done!
Cheers,
VID
#353
09-08-2017, 10:19 AM
This is by far one of my favorite 997 builds. You have done a really great job with the car and documenting your journey. I'd love to do some gt2 bits on my car (decklid, hood, and front fenders) but the parts are near impossible to source.
#355
10-06-2017, 06:57 PM
Hey Isysman, have a question for you about the center lock conversion kit you used. I'm undergoing the same operation, but getting custom wheels from HRE.
The problem, know one knows if after the factory centerlock kit is installed, if the car will have the same hub dimensions as the GT2RS and Turbo S?
I need to know this to ensure I size the offsets correctly.
Would you have that info?
Any help here would be greatly appreciated.
The problem, know one knows if after the factory centerlock kit is installed, if the car will have the same hub dimensions as the GT2RS and Turbo S?
I need to know this to ensure I size the offsets correctly.
Would you have that info?
Any help here would be greatly appreciated.
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