I have 911 steering rack (7820900166) and I'm thinking of replacing my stock steering rack (91434701401) with it.
What are the differences between the two and are their any advantages?
Click to view attachment

I've always wondered

I've heard very little on this subject and a google search doesn't really say all that much....
I think the ratio is supposed to be quicker lock to lock, but dunno

Since Mark / 914rubber is rebuilding them, they might know the details. They are interchangeable.

I installed a 911 rack in a 76 914 a few years ago with no issues. Don't recall noticing any difference in the ratio.

Nice rack! I don't think there are any differences in the racks. The shaft that bolts to it is different. I can't remember but one is longer.

I did a side by side comparison the following

914 347 01401, 1973 914 steering rack

7820 900 166, 1978 911 SC steering rack.

They both took 3 1/8 turns end to end. No difference. Further, I really couldn't discern a difference in feel, or resistance in any way.

Its always been my understanding that they are identical. Makes sense given that the front end design is the same so all geometry and operating conditions are identical.

Different Supplier?

Similar but not identical. Actually are a couple different 911 versions depending g on the year.

Can you elaborate on what the differences in steering geometry are? Are there any series (years) that are more desirable to get the best geometry for autocrossing?

I installed a complete 911 front end in my 914. Other than the shaft from the 911 being different the racks appeared to be identical. The front end I used came out of my 1980 911. The entire front end is complete bolt in. I managed to squeeze a Benz master cylinder in place too for the front 930 brakes and 928 rear brakes. Here is a pic thread of my 914-6 build. Sorry not in order but the front end pics are in there. Mine is nearing complete! A bat out of you know where. Soon to paint.

Tim

https://goo.gl/photos/9LDBUmAeFohwkycT8

What kind of muffler is that pictured?

I never said they had different geometry, just a bit different. Porsche often makes small changes on parts and assembly's from year to year.

Looks like the CFR 6 headers and muffler to me.
Check out the Tangerine site.

Well crap.
I got the new turbi tie rods in and the 911 spare rack that I had and I still have a wobble :-(
Soooo.
I've replaced the
tie rods
steering rack
ball joints

and determined
balance ok (was done not long ago)
steering coupler and universals ok (inspected them all when I replaced the rack)
Bearings ok (no noise or play upon examination/testing)
sway bar bushings all ok

I suppose the only other things left are,
the upper shock bushing
the torsion bar bushings

That said,
Replacing the wheel bearings just for shits and giggles seems an easier elimination than the aforementioned.

Anybody else got any idea's?

Not sure if the 914 steering column is the same as my 86 Carrera 911 but on it I had a lose bushing near the steering wheel. Replaced it and all was fine and tight. I also question if your tires may have a flat spot on them. You said you did a balance but would it show up there.

Bob B

I assume you scanned closely for tire bubble/bulges?
I had one on my Travelall that was on the inside and was hard to see even off the truck. I balanced the tires normally and they were ok, later I had them static balanced and the guy noticed it.
A new front tires completely fixed it.

Good luck

-Andrew