Turbo Tie Rod / Turbo Steering Rack Questions

[antares]

Have any of you installed just a turbo steering rack and turbo tie rods in your stock 911 ? I seem to recall that the factory parts book shows for example a 1979 turbo to not only have a different steering rack and tie rods but also control arms as well. So if one was to install a 930 rack into your stock 911 along with just turbo tie rods, would the result be an overall positive upgrade or somewhat of a more overall final tighter but more finicky steering wheel sensation compared to that of a stock turbo since you would not be replacing the control arms ? ...

[cabmandone]

I only did the tie rods in my car. As I understand it and from what I felt after installing, unless your original tie rods are really worn at the pivot joint you aren't going to notice much difference. I know I didn't notice any difference when I installed mine.

[panzerfaust]

i bought a standard 911 rack and quick ratio R&P to put into my factory wide body.

930 turbo steering rack is different from a 911. the mounting bosses on the bottom are shorter on the 930. i suppose this will add a more bumpsteer especially if your car has been lowered?

i can use a 930 rack since i ended up not putting my 911 rack in... let me know you are interested in selling or swapping?

regards
pf

[911obgyn]

More road feel through the steering wheel. I dont know about the difference in the rack, just turbo tie rods.

[antares]

… I am asking this cause I recently was going through the factory parts book available on line and it got me thinking noticing that the turbo had an additional different suspension parts to that of the stock 911 these being as the turbo has a different strut linkage piece, a different adapter bushing which goes onto the auxiliary center main cross member support which is used for either 911 or Turbo, and a the turbo has a different wish bone ( lower control arm) so not having the turbo wishbone and using keeping the 911 wishbone could mean something and that is the point of this post …. btw just for the record I did acquire and rebuilt a 930 rack and installed it into my wide body but other wise stock 1979 Targa. The car has not been on the road since the install. Before installing the 930 rack I had like many others here, installed the turbo tie rods along with the teflon 4 metal braided front brake lines as an agreed upon upgrade within the community. I noticed a little tighter steering control but nothing overwhelming in comparison … then when I had the engine out and doing body work and rebuilding the entire front end components decided to swap out the stock rack for a turbo rack. I rebuilt it and installed new bearings. While on the bench a side by side comparison found that the turn out to turn out was less than my stock 911 rack by I believe a couple turns … I am going by memory here since it has been a while and have yet to be at that point to take the car out as it is not road worthy and still a work in progress …

Back then I believed it was common to do not only install the tie rod upgrade but some installed a turbo rack as well …just can't recall the outcomes ... BTW the 930 rack bolted right up into the same mounting location since as per the Porsche parts pdf the auxiliary center support mount cross member is the same as noted above, I confirmed that the rack was indeed a turbo rack so not sure about what pf is referring to as having shorter mounting bosses on the cross member as this is not indicated in the parts pdf

http://www.porsche.com/all/media/pdf/originalparts/usa/911_USA_78_83_KATALOG.PDF


So anyways, just wondering if anyone else has done this and what the out come was on their otherwise stock 911 suspension … I suppose if it proves to be squirrelly and unstable I suppose the stock rack will have to go back in ...

[panzerfaust]

antares

did you not notice the difference between the two racks when you rebuilt it? pic 1

anyhow on the wishbones, i believe they are the same with the exception is the early 3.0 930 had different roll bar mount for the body through type. laters 930s i gather should be the same even if the part numbers are different? later 930s had roll bars mounted like the 911s

same cross member but on the 930 its mount higher up in the fronk pan. this was for the anti dive inclination geometry not found on standard 911's. this is why the 930 rack has shorter bosses. (pic2)

so if you put a 930 rack in to a 911, all things being equal you should induce more bumpsteer in to the geometry. now if you lower the car this will become much worse since the tie rod angles will be more diverged.

sounds like you already have a stock rack so i will refrain from asking you if you would like to trade :-)... im in need of another 930 rack for my car to put in my quaife quick ratio.

hope this helps a little... pf

[Walt Fricke]

The 930 aluminum cross member mounts several millimeters higher up (closer to the tub) than the 911 does. So it makes sense that the joint between the rack and the member is shaved (the nearly flush part in those super photos.

In regular 911s, if you lower the car you can raise the rack to keep the bump steer down to a dull roar. But there is a limit - at maybe 3/4" of spacers the rack starts hitting the sheet metal, but worse the steering linkage gets out of whack and you can't get the intermediate bearing in that linkage to bolt back to the tub as it should. With standard rack spacers you are already distorting the rubber bushing in the bearing assembly.

Seeing the larger flange makes me wonder if a couple of the steering linkage parts are also different - as in shorter. Shorter hockey puck? Shorter connecting shaft with the U joints on each end?

[panzerfaust]

pucks are the same... whats odd is the yoke is mostly likely in the same location but the flange is higher

maybe the 911 rack in a 930 tub would help a lowered car if one can fit it?

[Walt Fricke]

Maybe the higher flange is just to hold the plastic cover on better?

I think you could just shim up the 930 rack and get the same effect as to where the tie rod attachment is relative to the steering arm or axle center. There is only so much room to raise the rack, and with the 930 there is even less room to do this.

If you are serious about bump steer, the way to deal with that is to space down the steering arm end of the tie rod, preferably welding on a plate below so you have the extension in double shear.

Me, I think bump steer may be, to some extent, a bit overrated, and that lowering the car too much creates its own adverse suspension geometries, over and above causing problems getting into and out of driveways or closed trailers.

But it is always good to understand the quirks of our Porsche models.

[antares]

… today I just happened over some old invoices and found that i purchased a turbo spacer kit for the mounting so I must of installed it and now your photos bring back what i have forgotten as back then I was head deep into the porsche mantra and no doubt obsessed over the rebuild as it has been over 10years ago … and then everything as I recall hooked up like silk stockings …. I seem to recall that I had to do some measuring to make sure the turbo tie rods had a certain free drop and such and yes the hub of the 930 unit it taller … thanks for the photos and all the clarifications fellas, the car is on my lift doing other things so I'll drop the pan and take photos of the mounted rack and the turbo tie rods and such as this should make for a good discussion … get back to you with photos soon … dave

[antares]

… Reporting back with some photos of my rack, rack spacers, tie rods and steering linkage … you can see the red spacers I installed on the 930 rack to take up the difference in the 930 rack mount having thinner mounting tabs and how the turbo tie rods align with the rack install … completely rebuilt everything from the struts to the steering wheel bearing hub including tie rods, steering rack, rack couplings, u-joints, boots and even found a new steering link assembly at Porsche Heaven ( back when it was called that ) the link connects from the steer wheel mount down into the boot to the auxiliary steering diff and into the plastic cup of the steering rack as can be seen in the photos … seem to recall I had to use the 930 cup and auxiliary diff as well …. bought the Bilsteins new, then sent them back and had them revolved for my specs then installed the stainless hoses ...