bump steer on the 993
 

In reading through the archived posts, it seems that one way of reducing bump steer (and possible adding a lttle more precision to the steering) is with the addition of the Evo uprights along with either the ERP or RS/GT2 tie rods.

a couple of questions: 1) if the bump steer is not bad and I am looking for simply some extra steering precision, is it adviseable to simply switch out the tie rods? If the answer is yes, is it adviseable to go with the RS/GT2 variety? I know they are not adjustable like the ERP, but does it matter if the uprights aren't added with it?
2) I looked for RS/GT2 tie rods in the PET, but didn't see any thing for 95-98 carrera... only the stock tie rods. Am I looking in th wrong place for them?

thanks

Drive down the highway and twitch the steering wheel back and forth rapidly about half an inch either direction. If you don't feel the front end move, might change the tires to a more aggressive pattern or check your tire pressures (my Bridgestone RE750s are comparatively "mild" but I can feel the car move when I twitch the wheel like this- even with 86K miels on original rods/suspension arms). If you DO feel it move, leave everything alone - car is fine. Remember, like me, "pothole" is a common and very well known word in this part of the country.

Alex

Unless you are at or below RS height at least and you track aggressively you should not need the bump steer kit. Steering precision does not really get impacted, Ray's suggestion is spot-on. It is rather to avoid the front from "bumping" and drifting when you hit a road/track imperfection.

The GT2 tie rods can be bought from Porsche Motorsports or a third party vendor such as Gert for instance, you will not find them on PET.

thanks for the advice. Yes, I seem to have a bit of a disconnected feel through my steering wheel. My tires are Pilot Sports with correct pressure.
I guess its all relative. I have a friend with an m5. When he drives my car, he can't believe how responsive the steering is. I, on the other hand, am not satisfied unless every twitch of the wheel translates into front end response.
Would the gt2 tie rods by themselves help with the responsiveness?

As I recall, one of the more track-oriented cars like the 964rs had a manual steering box... I think that there was someone here who had converted their 993 over to that manual rack. Anyone recall? I may be incorrect as I am running on only a couple hours of sleep.... :(

I have consistently considered going to manual steering and my mechanic keeps trying to talk me out of it. He says I will hate it for the street. I would love to know if anyone has done it andlikes the result.


Kim - Evo uprights, rs tie rods and you still don't feel connected? wow! I'm glad you told me that. Its saved me a lot of expensive mods. Have you considered the GT2 tie rods that go specifically with the evo uprights?

Hi Jean:

Just so you know, Rennsport Systems carries ALL of those race parts you mentioned here (and then some) as well as Porsche Motorsports since they do not stock much 993 stuff anymore.

Sorry, Sir,.......I couldn't resist,.....:)

After I installed the ERP monoballs in the front and rear of my car the steering became extremely precise. Any amount of steering input results in the car turning. It made my 97,000 mile car feel better than new! I don't think I'd switch to manual steering. My beater Sentra has manual steering with 195's on it and it's a royal pain. I even overfill the tires a little to try and make it a little easier. I couldn't imagine the effort it would take with 225 SportCups!

Dear Steve

If you run a search, you will see how often I recommend your shop :) Even more so in private! You have always been very helpful. I recommended Gert instinctively because I still have the pictures of his bump steer kit in my mind, but of course you both, and other sponsors are top notch people. ;)
Definitely easier to get the tie-rods from you guys than Porsche Motorsports.

Alex

The 993GT2 street and Evo versions came both with the power steering (some teams did remove them) so IMHO, the benefits far outweigh the downsides especially for a (mainly) street car.

I've had manual steering in my 964RS-A for 11 years now and it rocks. Even for long 6-8 hour drives I love it and over the years I have come to hate the lack of feeling you get with power steering in other cars. It makes everything else feel like your driving a school bus. You have to remember that in comparison to cars like a Nissan Sentra the Porsche 993 has almost no weight over the front wheels.

As I recall, one of the more track-oriented cars like the 964rs had a manual steering box... I think that there was someone here who had converted their 993 over to that manual rack. Anyone recall? I may be incorrect as I am running on only a couple hours of sleep.... :(

Jason, do you have the part number for your rack? I am thinking about converting over. I show a part #964 347 011 02 in PET, but I am thinking that there is another application and part numnber from another model... cheaper than an RSA rack.

Also, are the other tie-rods solid ended as opposed to rubber on the inside as is stock on the 993? The turbo tie rod conversion I did on my 87 Cab made a HUGE difference, and they were solid ended.

Thanks

I am also interested in understanding the tie rod differences. From my research, the RS tie rods have a harder rubber than stock while the gt2/Evo tie rods are completely solid (they are also about twice the cost of the rs tie rods). Am I correct in my thinking?

in addition, my understanding is that the turbo tie rods are used to cure bump stgeer on on pre-993 style 911's. Are the turbo tie rods therefore different than the RS tie rods (I would imagine these are the ones used on the 993RS, maybe the 964RSA??)

The solid ones are what I am interested in. Anyone have Gt2 tie-rods on their 993s?