Evo uprights....
10-24-2006, 01:38 AM
#31
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I tried may things this year to cure my bump steer problem (for me, it was hit the brakes hard for a corner and have the car decide to steer a couple feet to the right or left - it was not toe related). In the end, I had EVO uprights added (along with full mono-***** and a bump steer kit for the tie rods) and it's gone. My car is lower than RS (I don't recall the actual numbers but my front jack point is less than 3.25" off the ground and my front splitter is about 2" off the ground).
09-06-2011, 08:38 PM
#32
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i helped put pss10,s on a mates turbo 4 set the ride height to rs and it was not good lots of bump steer and the steering felt very dead around the center possition and initial turn in was not as crisp
looking at the angle of the steering rod it is easy to see why evo uprights essential
looking at the angle of the steering rod it is easy to see why evo uprights essential
09-07-2011, 05:30 AM
#33
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The only thing that is certain is that these cars are so old now that all of them are inherently different to drive.
First of all, let go of the wheel is good advice IMO. Drive it with 4 fingertips and let it find its own sense of composure.
Secondly, if you know you have a proper and good geo setup then I would analyse the ill effects carefully. What does kickback mean ? If the front axle of the car is actually trying to turn when you go over a bump then this is quite possibly bumpsteer and needs to be corrected with the angle of the tie rods. That said I would not expect a poor bumpsteer profile at RS +10 or 15mm.
Thirdly, its easy to confuse bumpsteer with camber chasing where the car darts left and right over the road surface chasing ridges and lumps and cambers. If you have a proper and sensible road geometry then you shouldn't experience this but once you go past RS angles then it will get worse and worse until its downright lethal.
Finally, if the car is unstable and pitching left and right a lot over rough tarmac then this could also be any number of problems stemming from the rear of the car. Anything from a worn ball joint to a shot bush or even bad engine mounts. Even soggy rear subframe bushes will make the car feel unstable over bumps. The same goes really for the bushes at the front and the tie rod and steering arm ball joints.
In summary, all cars are different and its important that you assess your car very carefully as a WHOLE and do what's right for it rather than following what someone else did.
Personally I needed the RS uprights on my car but then I have driven almost identical 993's on the same suspension, ride height and geo which have been a paradigm of good road manners on stock uprights. Best of luck with it.
First of all, let go of the wheel is good advice IMO. Drive it with 4 fingertips and let it find its own sense of composure.
Secondly, if you know you have a proper and good geo setup then I would analyse the ill effects carefully. What does kickback mean ? If the front axle of the car is actually trying to turn when you go over a bump then this is quite possibly bumpsteer and needs to be corrected with the angle of the tie rods. That said I would not expect a poor bumpsteer profile at RS +10 or 15mm.
Thirdly, its easy to confuse bumpsteer with camber chasing where the car darts left and right over the road surface chasing ridges and lumps and cambers. If you have a proper and sensible road geometry then you shouldn't experience this but once you go past RS angles then it will get worse and worse until its downright lethal.
Finally, if the car is unstable and pitching left and right a lot over rough tarmac then this could also be any number of problems stemming from the rear of the car. Anything from a worn ball joint to a shot bush or even bad engine mounts. Even soggy rear subframe bushes will make the car feel unstable over bumps. The same goes really for the bushes at the front and the tie rod and steering arm ball joints.
In summary, all cars are different and its important that you assess your car very carefully as a WHOLE and do what's right for it rather than following what someone else did.
Personally I needed the RS uprights on my car but then I have driven almost identical 993's on the same suspension, ride height and geo which have been a paradigm of good road manners on stock uprights. Best of luck with it.
Last edited by jackal2513; 09-07-2011 at 08:39 AM.
