TonyG

Those are spring plate bushings. So yes on those or some Delrin busings.

http://www.racersedge-inc.com/racers...pen&id=11.3.17

and

http://www.racersedge-inc.com/racers...pen&id=11.3.17

But I was talking about these:

http://www.racersedge-inc.com/racers...pen&id=11.3.19

http://www.racersedge-inc.com/racers...pen&id=11.3.21

.... and don't forget that you need to get the trailing arm bushings as well. These are:

http://www.racersedge-inc.com/racers...pen&id=11.3.13


TonyG

TonyG

Ha! That's right. I couldn't remember whose car it happened to. It was yours!

Long time no see....


TonyG

pontifex4

I have tested exactly this. I reinstalled the spring plates with no torsion bars and the stock (130k mile) rubber bushings. In my case, as mentioned previously, the slump caused quite a bit of negative camber on the rear, but the car could still be aligned not to toe in or out and was drivable.

I believe that the fully weighted adjustment range was from around -2 degrees to -5 degrees of camber on the rear. Too much for a street car, and too loose for a track car.

pontifex4

Tony, I get the spring plate and torsion tube carrier bushings, but why the carrier block mounts if there are no torsion bars in the tube?

TonyG

The entire assembly (the torsion tube carrier) is rubber mounted. And that entire assembly is what your trailing is mounted on. If it moves... your trailing arm moves. That's why you solid mount them.

That said... it's not because you removed the torsion bars. It's just what you do if you want to take all the play out of the suspension, which in turn, allows you to run less toe.

TonyG

Oddjob

I have seen a few and heard of some other techniques to virtually eliminate the torsion bars (e.g. cutting the splined ends off and welding a 1/4" rod between them), while technically still complying w/ the rules. I never tried any of them, as machining the t-bars down to pencils or machining off the splines was more work than just re-indexing the bars (I dont have a lathe). So, I have either run w/ active torsion bars indexed to work in conjuction w/ helper coilovers, or I have removed the torsion bars altogether and run with just the coilover spring setup.

Yes, the adapter bolts do serve both functions, to push the standard shock body/rod away from the trailing arm, and to adapt the 1/2" bearing to the 14mm mount. The offset bushing eyes on the bilsteins are apparent in comparison to the centerline mounts on the 3012s.

Oddjob

That isnt the testing I was referring to. I was talking about measuring a difference in deflection under high cornering and braking loads. I would not expect the car's own static weight to cause a significant distortion problem. Are you sure you didnt have your camber/toe settings way out of whack when reinstalling the torsion bar carrier and trailing arms?


Tony - are you recommending all solid suspension bushings for street/DE cars, or just dedicated track cars?

TonyG

I love the feel of all spherical joints on the suspension with everything solid mounted...even on the street.

The feel is great. The road noise/vibration increase is minimal.

I always recommend the full Racer's Edge bushing treatment, front and rear. All spherical except the spring plate bushings which you should do either Delrin or something like the Elephant Racing (I run Delrin with zero issues after 4 seasons of track time on the spring plates).

Also... their camber plates are great too if you lower the car. They are 1" raised. This means that you get another 1" of travel before you hit the rubber snubbers at a given ride height.

TonyG

pontifex4

I am sure of that, yes. What I have to go on is that the "slump" in the trailing arms with old rubber spring plate bushings and no torsion bars meant that the camber adjustment range I measured on the alignment rack was from -2 to about -5 degrees on both sides.

In other words, resetting the rear wheels to close to zero degrees of camber wasn't possible with any adjustment. This was at more or less ROW ride height (about 1.25" lower than stock in this case).

I did test the car in this configuration, and it was certainly not great, but didn't feel at all dangerous, either. This is obviously only my opinion. One well-known 944 guy called that configuration "dangerously undriveable."

mikey_audiogeek

+1

Mike

Oddjob

Car still like that, or have you replaced the bushings w/ something else and now it aligns ok? What condition were the bushings on the spring plates? Were they falling apart?

Recall in the thread you started a few months ago, asking about spring length: there was another guy that jumped in the discussion with alignment problems (too much neg camber) after pulling the t-bars. And he stated that he already had solid bushings. Claimed the solution to his problem was to replace worn-out camber/toe eccentrics.

On your car, what was the toe measurement when trying to adjust the camber?

Adjusting the rear alignment on these cars can be a real pain to get desired camber and/or toe settings. And its not unusual for mechanics or alignment shops to give up or say something is wrong. I have had two different experienced Porsche shops have trouble w/ getting the rear toe/camber set right. And I struggle with it often myself, and have even had to set the car down, drive it around and put it back up on the rack and try again. So when having difficulty getting correct specs, it surprises me if there is actually something mechanically wrong w/ the rear suspension. That is just one of the quirks of the 944 rear end.

I ran two cars w/o torsion bars, originally retaining the rubber bushings, and did not have a noticeable deflection under static load. Again, my concern was with heavy dynamic loads during track use. So that is why I asked if it was possible you had something else going on. Not trying to be disagreeable, just looking to help define all the possibilities.

Oddjob

You two have a higher comfort threshold than I do. I have two cars with full solid suspension bushings/bearings, mostly RE stuff. They are dedicated track cars. Big improvement on feedback and response on the track. But I found that it noticeably stiffens up the car, and translates more noise and vibration. Feels actually harsh.

For me (personal taste), I would not install all solid mounts and bushings on a strictly street car due to the decrease in ride comfort, and the high cost of the parts (exceptions being camber plates, and the ER spring plate poly bronze bearings). For a dual use street/DE car, then its one of the many trade-offs to consider. For a track/race car, depending on the competition level, it becomes arguably necessary.

pontifex4

Understood, no problem.

I have polybronze bushings now. I don't have any pictures handy, but I do have the old spring plates with the rubber in question still on them, so I'll photograph them. They didn't look any different when installed in the carrier than they did with the torsion bars still in place. The rubber was in decent shape, though it is quite soft. Never having seen any others, I can't compare their condition, though.

On the alignment rack, I had the rear toe set at zero and ride height correct while trying to get a handle on the excess negative camber. Of note, the adjustment range was virtually the same on both sides. There's no denying that something could have been off, but the car had had factory alignment specs when we pulled the old suspension off.

Having said all of this, I still found the car quite drivable with stock rubber bushings and no t-bars. Obviously, this is only based on my own experience, and future readers of this thread should make their own judgements.

pontifex4

Do camber plates not increase harshness appreciably? I've been running the rubber strut mounts, but would love to change.

mikey_audiogeek

Camber plates can actually HELP the situation, depending on what springs you're running.

As your spring rate increases, it starts to couple with the resonant frequency of the stock strut mounts, increasing NVH.

Camber plates effectively eliminate this problem. Same with polyfilled gearbox mounts, and getting rid of the stock seats!

Cheers,
Mike