Suspension Upgrade - Your Advice Desired

[wswilburn]

My suspension is softer than I like. I'm planning this winter to go to stiffer torsion bars and shocks, and while I'm in there, I'd like to replace bushings, etc. Basically anything that should be done before corner balancing and aligning. To keep the price and time reasonable, I'll save things that don't affect these parameters for the next winter (swaybar bushing, tie rods etc.) Here are my parameters:

- 1988 Carrera (Boge shocks), stock except camber brace and adjustable rear swaybar
- Daily driver, 3-6 autocrosses/DEs each year
- Currently race on street tires, may go to R-compound in the future
- Am willing to spend money if it helps performance or longevity, but am not gold-plating
- I have lowered, corner balanced, and aligned an SC, so I know the process, but I am no expert on what settings to choose.

After reading many great posts, here is what I am thinking:

- 22/29 mm torsion bars (F/R)
- Bilstein HD/Sport shocks (F/R)
- Stock front swaybar
- Existing adjustable rear swaybar
- Stock spring plates
- New bushings front and rear (see below)
- Existing camber brace
- Corner balance for equal diagonal weights
- 1/1.5 deg. negative camber (F/R)

Here are my main questions:

- Are these choices reasonable?
- What should I do about bushings (rubber, polybronze, etc.)?
- Should I replace upper strut mounts? Stock?
- What am I missing?

Thanks for any help.

[rickdm]

Scott, there are a lot of racers running SC's-Carreras in our region. The optimum current setup seems to be;

22-31mm torsion bars
Smart Racing 31mm front sway bar
Smart Racing 28mm rear sway bar
Reinforced sway bar mount (Buckley racing)
Custom valved Bilsteins to match
Polybronze bushings all around
Elephant Racing front strut bar
I am running 1.9 & 2.5 degrees of negative camber (all I could get)

With this setup you are ready to toss in a cage and go race. You can decide how much to back off from there. It is a stiff but not unbearable ride.

[kucharskimb]

Depending on the life your 911 has lived, the upper strut mounts may still be fine.

A warning about the upper monoball mounts... the spherical bearings were never designed to take large axial loads. If you ever bottom out your suspension, which is completely likely on a lowered car, the strut will send a force though the system that will try to beat the races apart. Once a few thousandths of slop has developed, you will hear a knock/rattle/tap every time you hit a bump. Ask me how I know...

I'm not sure if anyone has used the new poly upper strut mount inserts, but this seems like the only longer term solution to stock rubber.

Your car is heavier than mine, so I'll defer to Steve @ Rennsport, who suggests what you have stated for torsions, shocks and sways, per his website.

[ChkbookMechanic]

In my opinion your choices seem reasonable and I would probably use Polybronze bushings instead of rubber.

Have you thought about doing something to take care of bump steer?

[oceanvue]

I have an '89 and went 23/30 and sports all around. A-arm bushings were huge and don't forget to take care of that little cylinder bushing in the steering column. I wouldn't change a thing on my setup.

[wswilburn]

Thanks for the replies. It's good to know I'm on the right track. I was leaning toward polybronze bushings, I think the advice here clinches it.

ChkbookMechanic: I don't plan to go much lower. Simple rack spacers will probably do it.

Matt: Thanks for the warning on upper strut mounts. I may investigate the polygraphite kit. Are there similar problems with the rear trailing arm to body connection, or are polybronze OK there?

oceanvue: What is the steering column bushing you refer to?

Thanks,
Scott

[mmn710]

Looking to do the exact same thing....hope all works out

[oceanvue]

There is a little plastic bushing in the steering wheel column that degrades and adds to alot of slop and wobble. Easy fix replaceble with aluminum replica. I drive alot of cars at PCA meetings so they can compare and vice versa. Almost all have the steering slop from warn bushing and can't believe the dif. after the fix. Pelican or tweeks or Perf. Prods. sell them for a bout $15. I've got some if you can't find 'em.

[AlfonsoR]

info, more info.

[RWebb]

- Daily driver, 3-6 autocrosses/DEs each year

so, I would back off the 31 rears a bit and same for other components. Elph. Racing has a pretty good chart based on use.

It is always a compromise/horses for courses/generalist vs. specialist/yada yada

[Bill Verburg]

you can cheat a bit and get the best of both worlds by using user adjustable shocks and sways, I've found that to work well for my track setup 993 which is ok for the street as long as the suspension is relaxed a bit. W/ stock t bars, Bilstein hd/sport are fine dual use but for bigger t-bars you'd likely want revalved Bilsteins or adjustables

[TT Oversteer]

I have a similar setup to what you are considering. I'll throw in my recommendation for:

polybronze bushings

custom valved bilsteins for the torsion bar size you choose and weight of your car

Wevo RARB consoles

[dede911]

Hi,

Avoid monoballs as a strut mount...don't ask how I know...
Life time is very short on a road car...

I converted back to superflex ...best compromise IMHO


Regards,

André

[Flieger]

Rebel Racing front A-arm bearings are better. They do not need any maintainance and provide the smooth motion of a proper bearing. When I installed them, I was amazed how the ride was smooth and silent compared to the old squeaky, harsh Urethane stuff. The smooth suspension motion makes corner-balance easier since the car does not need time to "settle". Using spherical washers on the front mount also adds some anti-dive geometry. I used to cring over any bump in the road, now I motor over pavement ripples without feeling anything but the sharp steering and quick turn-in of the RSR bearings and monoballs.

Suspension1

[GaryR]

Originally Posted by Flieger

Suspension1

They look really well made. How are they lubricated? One of the main reasons I like Polybronze is the fact that I can grease them.

[Trog]

The best advice I can offer is to have a chat with Chuck over at ER. He's well versed in 911 suspensions and will make recommendations commensurate with you needs.

T...

[911nut]

On my old SC I went with Elephant bushings all around and upped the rear torsion bars from 24.1 to 26 mm (no change to the fronts). End result was a tossable, responsive chassis with minimal understeer that could still handle Michigan roads.

[RWebb]

Originally Posted by Flieger

Rebel Racing front A-arm bearings are better...[/url]

than what?

Than the Elephant polybronze?

If so, in what way?

They are certainly pretty!

[Flieger]

Originally Posted by GaryR

They look really well made. How are they lubricated? One of the main reasons I like Polybronze is the fact that I can grease them.

Originally Posted by RWebb

than what?

Than the Elephant polybronze?

If so, in what way?

They are certainly pretty!

They use a dry lubricant: the Polytetraflouroethelene-impregnated thermoplastic liners. The electro-polished steel inner races are bonded to the A-arm and when a load is applied, the coefficient of friction drops from negligable to greased-lightning smooth. There is a small amount of assembly lube but no subsequent greasing is required because there is no danger of metal-to-metal rubbing.

They are better than Urethane bushings, rubber bushings, and Polybronze bushings because they allow smooth suspension motion and do not require regular greasing. I did not want to think about if I am greasing them enough, if the grease is attracting grit, or go through the hassle of crawling under the car on my back and reaching around with a grease gun (which I do not have).

I will say that Polybronze will provide good, smooth performance; but at a higher maintainance cost.

Feel free to ask me any more questions about the bearings.

Best Regards,

[RWebb]

Thx - have you tested them back to back - in car or on a bench?

sounds like they may not be smoother, just less maint. (?)