jackal2513

Thanks for that. I am aware of all that and it's a fair suggestion on your part but kind of presupposes that I am a bit mentally backward or only got into cars a few weeks ago. Seriously, I'm not the sort of person who would mistake the removal of a bit of rubber for quicker steering.

Let's just say that for a given steering input my car turns more than it used to with stock uprights. Maybe I have a strange car or maybe someone sneaked into my garage at night and changed the rack without me knowing.

Like or not, that's the way it is with my car and every person who has driven in (including people who have GT2 tie roads already installed on their cars but not the RS uprights) has remarked upon it.

jackal2513

The GT2 runs the following racks:

18.48 (LHD)
17.87 (RHD)


the stock C2/C4 runs:

16.48 (LHD & RHD)


So quite different.

Slower rack + shorter steering arms = fast rack + regular steering arms.

jackal2513

Also incorrect according to my data.

The RS M002 and M003 run the following racks:

18.48 (LHD)
17.87 (RHD)

Bill Verburg

yes, lhd and rhd racks are different, I am only familiar w/ a referring to lhd models

Bill Verburg

The lhd GT2 Evo is the one I referred to and it is 993.347.011.00, this is the same rack used in a normal lhd 993.

Bill Verburg

This the relevant page from WKD 424 520. Factory tech specs

jackal2513

You said 18.25 though which isn't correct for LHD or for RHD models.

I note from google that you've been quoting these figures on various forums for a number of years now. The expression "can't read a spec sheet" springs to mind !

Bill Verburg

post #36
steering wheel ratio (rhd) 18.25(17.65)

steering wheel turns (rhd) 2.73(2.64)


for 993RS the rhd rack is faster than the lhd but neither is as fast as a normal rack

I can post a pic but from the same spec book
993
ratio(rhd) 16.48(16.60)

turns(rhd)2.47(2.49)

jackal2513

Bill, your tech specs have been wrong before... like in this post when you incorrectly stated that the 993RS does not use the 964 rack:


https://rennlist.com/forums/993-foru...3-rs-rack.html

In fact that whole thread is a rehash of what we're saying here. Except that that time we had some experienced people chime in to confirm my findings.

You might want to see Premier Motorsp's post:


"993 RS is indeed using the 964 rack. The total steering ratio is determined by the rack's gear ratio AND the geometry of the tie rods and hub carriers.

The "Evo" hub carriers (which are not Evo at all, there are on 993 RS and all 993 based race cars, Evo or not) change the distance from the lower ball joint to the outer tie rod end, so the ratio is changed.

My own preference is to use a 993 rack with the RS hub carriers etc. This gives fast steering, which may not be appropriate for autobahn driving. This setup is used all 993 based race cars except the Cup, which has the ridiculous unboosted 964 RS rack. "


My findings exactly. RS uprights on a stock 993 speed up the steering. In fact i'd say that mine is a bit too quick and for road driving i'd like to dial it back a little with a 964 rack. This is probably why the 993RS had the slower 964 rack in the first place so as to make it more user friendly.

Bill Verburg

Well if the factory is wrong then I'm wrong too

but until I see believable data to the contrary, I will stand by all of my statements

You of course are free to believe whatever you choose to believe.

I do not see that CC's comment belies anything that I have said as all of my statements have been based on the installed published factory data

GTgears

All I know is Bill is posting factory sheets to back up his numbers. The real easy way to resolve the steering rack question would be if someone could post PET of the PN for the RS rack...

Bill Verburg

Is this Paul or Matt?

anyway, that's not the issue here, we all agree that the 993RS uses the 964 power steering rack which is 964.347..009.04 for lhd cars this is the same rack used on '91 up 964 lhd w/ power steering, the 964RS used a manual rack 964.347.011.02 for lhd cars, I have is no listing for a rhd 964RS

trophy

As another point of reference, has anyone actually measured the difference in the steering arm length (horizontal distance not angled distance) between the RS and the stock uprights? I did a very rough measurement (the number is not important, the relationship is) did this in a drawing package that dimensions between 2 points. Judge for your self.

PS Don't shoot me for doing this on a photo, if someone has them infront of them (actual pieces) do the measurement.......

Bill Verburg

yes the arm is shorter but when in stalled in a lowered car it only restores the geometry that existed at the higher ride height, that is the design purpose of the tie rod/upright system.

At normal ride height the stock upright/tierod has a given geometry, ideally the tie rod will be level at static ride height, now lower the car, the geometry has gone out the window, the tie rod is no longer level and will impart excess steering input to the wheel on every excursion up or down. To restore geometry to the original neutral(or as neutral as can be) state the arm is shortened which raises the tie rod back to level. The geometry is now as it was before at the higher height w/ the longer arm. I can clearly see this on mine you can look at the pics I posted earlier.

Or not, it's up to you.

trophy

I am with you in this one Bill, the above pic shows that there is no additional 'leverage' that Jackal is talking about.