TT Oversteer

One of my New Year's Resolutions is to tighten up my sagging rear end (I know, too much information). Because my car is a '77 3.2 conversion with the extra "junk in the trunk" it has become clear that the stock 23mm rear torsion bars are not up to the task. So here's a few suspension topics to ponder:

1) What is the best size bar to use in the rear to achieve a firm and good handling 3.2 street car without completely destroying the ride?

2) If I do the rears will I be wasting my time if I don't upgrade the front T-bars too?

3) Are the hollow bars that much lighter/better to justify the extra $$?

4) What are the best shocks i.e. Bilstein Sport, HD, Koni to go with each size of T-bar?

Here's to a firm yet compliant and well-dampened new year!

Steve Weiner-Rennsport Systems

Hi,

You'll find a lot of different opinions so all I can offer is mine,...

1) If you stiffen the rear, you MUST stiffen the front to maintain balance and thats especially important on a narrow-bodied street car. Suspensions are matched, integrated systems; not simply an al la carte list of parts,... Without knowing a lot more detailed information about you and how you drive, I'd be pressed to offer anything constructive.

2) Absolutely and further, you'll have a car with a degree of oversteer that can be VERY challenging at speed.

3) Its not a matter of solid vs hollow. Its all about the quality and fitment and for that, the Sander Engineering bars are far superior to the others. These are hollow, only.

4) By far, the best option would be custom-valved Bilsteins. Properly valved, the ride quality and handling are much improved over the off-the-shelf stuff. Valving is chosen to match the spring rates and usage of the car.

TT Oversteer

Thanks for your input, Steve. I believe all you said is correct. I am looking for a starting point from which to begin to build a better suspension system for my modified car. I understand it's a cohesive system but I don't have the $$ or desire right now to spec out a complete wish-list suspension. I'd like to start with T-bars and slowly build from there. I just don't want to go too big and end up with a car that's barely usable on the street. As a starting point how does 21mm front and 27mm rear sound? Then I can play with shocks possibly with custom valving, adjustable swaybars, adjustable spring plates, etc later. I assume your reference to "very challenging" oversteer is due to the heavier 3.2 combined with the narrower rear tire contact patch? Thanks again for your comments.

Steve Weiner-Rennsport Systems

With all respect,....some aspects of these upgrades aren't something you can do incrementally. For example, upgrading torsion bars without installing matching shocks results in a poor ride and bad handling. If the rubber bushings have sagged due to age, you should replace those with one of several options, otherwise you will need to do the whole job over again including cornerweight & alignment. This also applies for a turbo tie-rod upgrade or ball joints if those items need replacement.

My best advice to you would be to assemble a realistic budget and save your money so you can do the torsion bars, shocks, bushings, (and ball joints/tie-rods, if needed) all at the same time. Anything else can wait until later,..

21mm/27mm is OK.

The oversteer issues stem from having the same front & rear tires and increasing rear spring rates without the appropriate increase up front.

rusnak

yup, if you make the rear suspension way stiff and leave the front soft (rolly) then you'll have massive oversteer and some funky handling. Same principle with anti-roll bars. Think 1980's Stephen J. Cannell tv shows "chase scenes" (Rockford Files, A-Team, Hardcastle and McCormick) and you'll get a good mental picture.

TT Oversteer

HaHaHa! Let's not forget Bo and Luke's Charger in a full-lock slide or Starsky and Hutch's Torino catching air and bottoming out its suspension!

Funny, right now my front suspension is very stiff with new bushings and new bilstiens and the rear is set up really soft with its little torsion bars, worn shocks and no swaybar due to torn swaybar mounts. The PO really had some strange priorities about where to spend his $$ on this car. The way it handles right now would be downright comical if is wasn't scary.

911S3.6

Sounds like someone has already made a hooptiewagon out of it with their frankenstein experiment...LOL!
You're just going to make it worse, playing hit and miss, and WILL spend the same money over and over and over trying to get it right.
S.W. says 21/27 is ok- that means "just ok" not good.
I have a 1975 911S with a 3.6 etc.- believe me, this is not a guessing game, nor is it something for
the faint of heart.
Get professional help.......it's cheaper in the long run, and the the car will be sublime.

TT Oversteer

Wow! You make it sound like a black art to which only the chosen few are privy. Care to share some of the secrets the professionals have bestowed upon you? Can you tell the faint of heart how your car is set up? Or did the professionals just do it for you?

TT Oversteer

Here's an interesting response to this same post on the Pelican forum from Chuck Moreland of Elephant Racing:

For my 77s/3.2 combo:
22 front/29 rear if changing both sets of bars.
Or if using stock (19mm) front bars then use 25mm rear ones.

84_Carrera

TT -

I had Steve W put together a complete kit for my 84, one shot, did the swap myself. He used the right pieces, had great advice & was there via phone when I had a couple of questions. Highly recommended.

I ended up going a little stiff on mine, 22/29 hollows, Bilstein sport / HD combo, Elephant Poly-Bronzes, turbo tie rods, etc. etc.

I am still looking at the idea of larger sways this year, if I keep the car.

Good luck with your sagging rear!

Peter Zimmermann

Excellent combo, but you (TT) should still look into a little rolling of the rear flares so the next wider tire size can be used on the rear. This type of work gets really expensive as you do it again and again, Steve's suggestion about saving until you can do it once, and right, is your best bet.

TT Oversteer

Fred,

It sounds like several people are running the 22/29 combo. Do I read you correctly to assume the Bilstein sports are on the front and HDs on the rear? What size swaybars are you running now? Thanks.

TT Oversteer

Pete, I know at some point if I keep this car long term I will probably succumb and add SC flares with 8's or 9's and a ducktail. When I bought this car I had a middie-carrera look car in mind or possibly even an IROC. I'm............just................trying..................to........... .keep...............off............this.....slippery........slope.for... ..nowwwwwwwwwwwwwww!

Peter Zimmermann

Oh, I know! Hey, do you have 205/55 or 225/50s all the way around?

TT Oversteer

205/50/16 mounted on 16in. fuchs all four corners. That's the max I could fit on the rear without rubbing. I guess I could go to 195's up front to shift the balance of grip to the rear but that seems futile to me at this level of tire sizes.