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Posted by: jk76.914 Jul 26 2011, 04:23 AM

Just wondering what's the story with the stock tie rod design, the one with the rubber donut for an inner tie rod end. Porsche kept it in production for about 25 years (through '89), and then the 964 used the same approach, except reversed it with the yoke on the rack and the rubber donut on the tie rod. I've read a lot of testimonials for the turbo tie rod, but if it was that much better, why didn't Porsche convert over across the board? It couldn't have been cost- every econo-box I've ever looked at has ball type joints at both ends.

Maybe it was to add a bit of dampening? They used to sell steering dampeners for cars with light front ends (Corvair, VW, 356).

Maybe a bit of shock absorption to protect the rack from hard hits, like pot holes?

And while we're on the subject, I saw in PET that the 930 that first had the turbo tie rods had a different rack. Anyone know the difference?

Jim

Posted by: SLITS Jul 26 2011, 07:08 AM

The rubber doughnut was merely a device to dampen road shock being transmitted back to the steering wheel ... shock absorber of sorts. A cheap solution that worked until the rubber gave up and caused play in the steering. Angular movement is restricted to up and down.

The second shock absorber is the coupler on the steering shaft.

Turbo tie rods are a ball and socket coupler. Installing them gives you more "road feel" (supposedly). Angular movement is not limited.

Hey that's my nickel analysis.

A rack and pinion is a rack and pinion ... only difference is the number of turns lock to lock and whether it is power or not (kinda).

Posted by: Drums66 Jul 26 2011, 12:55 PM

....What's wrong with them??(stock tie rods)

Posted by: SirAndy Jul 26 2011, 01:45 PM

Nothing ...

Posted by: John Jentz Jul 26 2011, 02:43 PM

They require a factory jig to set the correct angle and depth on the inner tie rod end. Other than that, nothing is wrong with them.