bump steer kit with original up rights,
07-24-2013, 10:53 AM
#4
Nordschleife Master
I don't see how this changes anything w/ the geometry. Isn't the OEM ball joint oriented the same as this rod-end setup you've installed? Other kits I've seen move the ball joint further away from the carrier arm pick-up point.
07-24-2013, 11:36 AM
#6
Three Wheelin'
>that ball joint really looks at the limit of angle before there is interference
Should that spacer (if it is a spacer) between the nut and upright infact be between the rosejoint and the upright (correct geometry permitting). Something doesn't look right...
Should that spacer (if it is a spacer) between the nut and upright infact be between the rosejoint and the upright (correct geometry permitting). Something doesn't look right...
07-24-2013, 11:42 AM
#7
Addict
Rennlist Member
Rennlist Member
Appears to be installed upside down. Tie rod should be on top of the knuckle not below
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07-24-2013, 11:42 AM
#8
Addict
Rennlist Member
Rennlist Member
07-24-2013, 11:47 AM
#9
Addict
Rennlist Member
Rennlist Member
The ERP kit was designed for the early torsion-bar cars. From what I have seen, the ERP kit has only been used on 964s with the 993 RS type uprights which significantly changed the position of the steering knuckle relative to the stock 964 pieces. You should probably call Steve W. at Rennsport.
07-24-2013, 01:09 PM
#10
Three Wheelin'
Thread Starter
Hi Guys,
not trying to convince anyone do the same, what ever fitted my car may not fit yours and if you decided to have this conversion done the same way as I did, it is at your own risks ...
the story is; I wanted to have something more accurate for the steering rods that what's in there originally....... and correct geometry as the car is quite low....
this kit is in did suppose to fit with the 993 RS uprights;
back around January I decided to buy the kit and see if it fits the in the 964 upright, obviously before buying it I had done a lot of research ....& measurements, I was almost convinced it would fit, but at the end of the day if it would not, I could always sell it here in France for good money....
I took the car to HPRS in Cannes a Porsche specialist who looks after my car and have extensive experience preparing rally cars, they first try to see if the kit would fit, they mention 3 things,
a) the top spacer/adapter is to long so I would need to have the same narrow spacers/adapters as the bottom ones to be fitted on top (witch I order)
b) the bolts would need to be shortened...
c) new nuts would need to be ordered to fit the 993 inner rods,
they obviously had the wheels hanging with suspensions fully stretched when doing the test.
from the pictures it looks on the limit and it is.... but even when the suspensions are fully stretched and the steering is turned fully left and right it doesn't touch anywhere the ball bearing hosing, when the car is on the floor the tie rods are absolutely parallel to the ground so that mean geometry have been correct ; at least from what it was before...when the tie rods were up in the air ....
there is a few fast bumpy corner around here I will test drive the car and let you know,
just to have more clearance, I may have an adapter made in future between the rose joint and the adjuster, but saying that ... I may not bother,
actually when the shock would compress by braking hard or hitting a bump, it would certainly not be any issues,
not trying to convince anyone do the same, what ever fitted my car may not fit yours and if you decided to have this conversion done the same way as I did, it is at your own risks ...
the story is; I wanted to have something more accurate for the steering rods that what's in there originally....... and correct geometry as the car is quite low....
this kit is in did suppose to fit with the 993 RS uprights;
back around January I decided to buy the kit and see if it fits the in the 964 upright, obviously before buying it I had done a lot of research ....& measurements, I was almost convinced it would fit, but at the end of the day if it would not, I could always sell it here in France for good money....
I took the car to HPRS in Cannes a Porsche specialist who looks after my car and have extensive experience preparing rally cars, they first try to see if the kit would fit, they mention 3 things,
a) the top spacer/adapter is to long so I would need to have the same narrow spacers/adapters as the bottom ones to be fitted on top (witch I order)
b) the bolts would need to be shortened...
c) new nuts would need to be ordered to fit the 993 inner rods,
they obviously had the wheels hanging with suspensions fully stretched when doing the test.
from the pictures it looks on the limit and it is.... but even when the suspensions are fully stretched and the steering is turned fully left and right it doesn't touch anywhere the ball bearing hosing, when the car is on the floor the tie rods are absolutely parallel to the ground so that mean geometry have been correct ; at least from what it was before...when the tie rods were up in the air ....
there is a few fast bumpy corner around here I will test drive the car and let you know,
just to have more clearance, I may have an adapter made in future between the rose joint and the adjuster, but saying that ... I may not bother,
actually when the shock would compress by braking hard or hitting a bump, it would certainly not be any issues,
Last edited by kos11-12; 07-25-2013 at 10:41 AM.
07-24-2013, 01:50 PM
#11
RL Technical Advisor
JMHO,.......
You cannot alter the bump steer on these cars unless you raise or lower the attachment point on the upright. For the stock 964 steel units, this would require some rather major modifications which are not really feasible.
When we need to resolve bump steer problems on 964's, we install the 993 GT-2 (EVO) uprights and matching tie-rods when the car is lowered sufficiently to require such modifications and the results are quite noticeable.
You cannot alter the bump steer on these cars unless you raise or lower the attachment point on the upright. For the stock 964 steel units, this would require some rather major modifications which are not really feasible.
When we need to resolve bump steer problems on 964's, we install the 993 GT-2 (EVO) uprights and matching tie-rods when the car is lowered sufficiently to require such modifications and the results are quite noticeable.
07-24-2013, 02:34 PM
#13
Three Wheelin'
The stock rod end sits on the top of the "arm" of the upright, whereas the one in the pics sits under it, thus lowering the pivot point by a good few inches. I'd say this setup would have a measurable effect on the kinematic geometry, the key as the OP says is that the steering arm is horizontal when the car is on the ground.
07-24-2013, 04:16 PM
#14
Three Wheelin'
Thread Starter
JMHO,.......
You cannot alter the bump steer on these cars unless you raise or lower the attachment point on the upright. For the stock 964 steel units, this would require some rather major modifications which are not really feasible.
When we need to resolve bump steer problems on 964's, we install the 993 GT-2 (EVO) uprights and matching tie-rods when the car is lowered sufficiently to require such modifications and the results are quite noticeable.
You cannot alter the bump steer on these cars unless you raise or lower the attachment point on the upright. For the stock 964 steel units, this would require some rather major modifications which are not really feasible.
When we need to resolve bump steer problems on 964's, we install the 993 GT-2 (EVO) uprights and matching tie-rods when the car is lowered sufficiently to require such modifications and the results are quite noticeable.
Thanks for your input,
Big respect on your work and comments
on this forum
But i think yes you can alter the geo, actually on the 993 RS it moves down 45 deg rather than on the 964 of 90 deg so it more or less the same if not could get lower on the 64 , with the 993 RS the bolt is almost shaving the rim ( balance weights) ...
07-25-2013, 12:51 AM
#15
Instructor
Konstantin, while this kit can be good for track car, I'd be careful about using it on the street. There are couple of obvious design flaws
1. It uses bolt/nut to connect tie rod. Usually tie rod ends are held by conical (tapered) joints - those joints will hold even if nut is loose. With this ERP design - sizable stone can get between wheel and lower nut and shave it. You got no steering after that.
2. Ball joints better be covered by rubber boots - dust and dirt (not even saying snow/salt) will destroy ball joint in couple of months.
Oleg.
1. It uses bolt/nut to connect tie rod. Usually tie rod ends are held by conical (tapered) joints - those joints will hold even if nut is loose. With this ERP design - sizable stone can get between wheel and lower nut and shave it. You got no steering after that.
2. Ball joints better be covered by rubber boots - dust and dirt (not even saying snow/salt) will destroy ball joint in couple of months.
Oleg.