3 early 911 suspension questions

kucharskimb · 11-12-2004, 12:31 PM

gents

1) i have a 72 911 set at Euro heights 25.5F/25R lip heights.
i have read mixed reviews on using the bump steer spacer kit. some of you have said it's necessary. others have said that if this was Porsche's design height, then everything should fall into place. i have replaced the tie rods with the turbo tie rods.

the tie rods angle up at the wheels (lower at the steering rack) by about 3/8".

should i install the bump kit?

2) currently i have a front sway bar installed (factory) and no rear sway bar and koni adjustables. the car is a daily street driver and has never seen the track. is there any benefit to a

a) strut brace

b) rear sway bar

c) both

d) i would appreciate any suggestions for koni settings

3) i have the common bump sound from the rear shock towers as the shocks move back and forth and hit the sheet metal. again, i've seen mixed reviews. i currently have the fat ends of the rubber snubbers against the sheet metal, as perscribed by koni.

is there a rubber grommet/bushing that i need to install around the shock, or do i need to put the small ends of the snubbers together to pinch the sheet metal? seems to me that i'm bottoming out on the threads before i get a tight clamp on the sheet metal.

thank you very much for your time and insight. pictures coming soon. i want to finish polishing my wheels before i show her off

matt

Zeke · 11-12-2004, 01:09 PM

Can't answer the last question. I think the bump kit would be good. I would look into getting a rear sway bar (I have a stock 15mm bar and links if you're interested). I would set the Konis on soft at first (with stock t-bars) and see if they are fresh or need to be dialed up a bit due to age.

Tyson Schmidt · 11-12-2004, 02:44 PM

The rack spacers are really not a big deal if you are at Euro height. It's kind of a band-aid fix anyway.

To properly lower a car, you would raise the spindles the same amount you lower the car, and either space the rack up the same amount, or install the outer tie-rod drop-links of the same dimension.

Many racers remove all bump-steer from the car, but Porsche actually built-in bump steer deliberately from the factory. They set it up so that when cornering, the loaded outside wheel toes out in relation to the inside wheel. This makes the steering more predictable, and also accomplishes Ackerman-Effect (toe-out during turns) at the same time. Porsche therefore removed all Ackerman from the steering geometry, since they accomplished it with carefully designed bump-steer, which had the aforementioned double purpose.

In the 935, the steering arms were bent like the letter Z to remove bump-steer, (bylowering the outer tie-rod position in relation to the rack) and at the same time effectively shortened the steering arms. This had the effect of putting Ackerman back in the steering geometry that was lost be removing the bump-steer.

Oldporsche · 11-12-2004, 04:26 PM

Pay particular attention to rear sway bar mounts. You car might not have any. There are factory pieces available for this. Please take a look at the past threads on these pieces.

Good luck
David Duffield

kucharskimb · 11-13-2004, 05:29 PM

i have the ball mounts on the control arms and the plate underneath the left rear seat pan. are there other locations to look for?

Jeff Higgins · 11-13-2004, 06:02 PM

You are a step ahead of me, Matt. I have a '72 911T that I'm also trying to put the rear sway bar on. My car has no balls (on the control arms, guys...). The aftermarket bars don't mount there, they use the eccentric bolts on the spring plates. I'm not sure which plate you are looking at under the left side. If it's angled at about 45 degrees to the ground and has two bolt holes about two inches appart, that's the sway bar mount that holds it to the body. There should be an identical one on the right side. If they are not there, you can buy them and weld them on, or use the Welmeister adapter kit that clamps around the torsion bar tubes. Anyway, my car had neither the front nor the rear when I bought it. The front was a snap to install, and it made a noticable difference. Most guys here will tell you that with a front only the car can tend to push pretty bad. I have not had my car out where I can drive it hard enough to tell since I installed the front, so I can't comment yet. On the street, where I don't drive it that hard, it's been great. I hope to sort out how to mount the rear before I get to my next DE event, so I may never experience the front bar only push. That might be the only place it would be noticable, so if you don't track it, you might be o.k. right now.

kucharskimb · 11-13-2004, 06:12 PM

i does push notably on twisty roads. i understand that if i tighten down on the rear konis, that it will assist in negating the understeer.

so then i guess there would be no reason for the camber brace, either, huh?

Zeke · 11-13-2004, 06:51 PM

OK, I re-read your last question. There was a thread a while back about the rear rubber shock bushings. At the time, members said to put the narrower ends together to "pinch the sheet metal" as you say.

On mine, they squish down on the metal pretty hard. And, IIRC, there is a sleeve for the threaded part of the shaft that goes on first before the first big washer. Do you have those sleeves installed?

Oldporsche · 11-13-2004, 07:35 PM

Factory rear mounts can be bought from dealer. You can find where they go by reaching inside the frame rail. You will find a circular depression somewhere around where the rear torque tube goes through the frame. This is where the factory mount goes.

I have never done anything with the aftermarket clamping gizmos that go around the torque tube.

Good luck,
David Duffield

kucharskimb · 11-13-2004, 10:14 PM

zeke

i pulled the top shock mounts apart the other day to see what was in there. i don't think i have the sleeves that you mentioned, but i'll look tomorrow. if not, do you think i could use a plastic sleeve, or should it be metal? i have to get in there anyway to adjust the konis...

on a side note, i finished polishing the two rear wheels and have put a couple coats of clearcoat on them. look pretty nice. i'll post a separate thread with some pics...

Zeke · 11-14-2004, 04:37 PM

You can't use plastic! There's a lot of energy transferred thru the shock. It will destroy a plastic bushing in minutes.

HarryD · 11-14-2004, 04:52 PM

Quote:

Originally posted by old_porsche
Factory rear mounts can be bought from dealer. You can find where they go by reaching inside the frame rail. You will find a circular depression somewhere around where the rear torque tube goes through the frame. This is where the factory mount goes.

I have never done anything with the aftermarket clamping gizmos that go around the torque tube.

Good luck,
David Duffield

As seen on my 73.5 T.

kucharskimb · 11-14-2004, 08:08 PM

i have fixed the shock mount noise...

zeke, yes, after i thought about it, i knew i couldn't use plastic...

i did have the original shims installed. i guess i had remembered them as the top of the posts before the threads started. anyway, i realized that i needed a shim that would take up the space between the <1/2" stock shim and the >3/4" opening in the sheet metal.

i started by removing the entire shock. i cut the stock shim down by 1/8" to try to get more of a squeeze on the sheet metal. additionally i made a shim out of copper tubing. a stock piece of 1/2" tubing fit right over the shim. i then used a 1/2" "coupler" which fits snuggly over the 1/2" tubing. i cut it to the same length as the original shim (-1/8", as mentioned) and re-installed.

the combination made a nice fit. here are a few pics...
the first one shows the original shim with the copper jacket.
the second shows the 1/2" tubing and coupler.
the third shows them on the shock with the lower rubber snubber installed.

thanks for the assistance. i'm going to give the suspension a try with the konis at 2/2.5 turns to the right to see if it helps with the understeer.

kucharskimb · 01-22-2005, 08:29 AM

gents
working with zeke on a rear sway bar. even with the konis almost maxed and the fronts on min, still significant understeer. (all 4 konis are new)

could i get a picture of the early stock rear sway bar brackets mounted to the torsion tube mounts? in particular need to reference where the bolt holes go on the mounts.

thanks
matt