Input on suspension upgrades
 

I've read miles of suspension threads here but still would like to get some advice on where to go from now with my car. Its a 1978 SC that has been backdated and lightened. It's only a weekend toy for me so tyre wear and highway comfort are not something I worry about. I would rather achieve the most fun and responsive driving experience.

This is my current setup
7" and 8" x 15" Fuchs with Pirelli P6000
Bilstein B6 Clubsport shocks
19mm torsion bars front (stock)
26mm torsion bars rear
Turbo tie rods
Stock sway bars front and rear (20/18 mm)

My intention was to get Carrera 3.2 sway bars (22/21mm) with adjustable droplinks for the rear but then I started to read about torsion bars again and got the impression that perhaps I should start with getting bigger torsion bars. So what is your recommendation do I have suitable torsion bars and should go ahead with the carrera sway bars or should I consider bigger torsion bars first?

Thanks!



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Hi Johan,
Do you live in Colorado? did you meet up with Liam? Black 89 with a duck tail. Headed to New Mexico? If so I am Ian, Viper green 73 RS clone . Lets talk on the phone
Ian

Hi Ian,

No I live in Sweden.

Cheers

Johan, for street I would go (max) 28-29R/21-22F, have the Bilsteins re-valved for them, sport bushings (or polybronze and monoballs if you really want to tighten her up) and keep the stock sways. Drop link sways are noisy and to me would be annoying on a street car and going heavier TB's on the street is going to be a rough ride unless your streets are VERY smooth. I had 36R/24F on my SC race car with fairly large sways/drop links (you also need to replace the mounts with something stronger) and anything but a race track's-like smooth pavement would be unsuitable..

What about the current ride characteristics are you trying to change? What don't you like with the current set up? I ask because for my SC, I spent the first year of driving track and AX events to a) learn the car in its tired base form and then b) hone in on what I didn't like and how to improve it.

My street/de/ax 911SC for was ultimately upgraded to 22F/30R torsion bars with custom valved Bilsteins. The ride was "firm" but never beat me up. 22mm sways as well. And this was driving on roads in Northern NJ/NYC area which are not smooth to begin with.

22/28 torsion bars are a well proven upgrade as GaryR mentions. Sways can be used to fine tune. iirc, 22mm and larger sways will need some reinforcement at the mounts as they tend to tear away from the body under high loading.

Thanks for the input.

What I currently don't like is that the front feels a bit light and unprecise. Perhaps I should start by lowering the car a bit and see what I can do to get some more camber and caster. In its previous iteration as an SC it had 16" wheels and was much lower and the feeling going in to corners was much more confident and precise.

I have sports bushings for the engine and transmission and M471 "correct" insulation of the cabin (i.e basically non) so additional noise from solid droplinks isn't that big of a deal.

I have a Carrera and ran sticky tires on original suspension and wheels. I ended up ripping off the rear swaybar mounts and tearing up the endlinks. I had the reinforced mounts and solid rear links installed. I put wider and stickier tires all the way around and drove the socks off of it for 25k miles like that.

I always assumed I'd do a bunch of cool suspension upgrades. My friends and mentors reminded me that when I go to events I typically drive 800 miles (or much much more) each way and the stock stuff hasn't held me back during the rallies we attended.

I just got new Elephant rubber with Bilstein HD front and Sport rear shocks. We lowered it and set the camber fairly aggressive at 1.4F/1.8R. This past weekend we drove 865 miles to Targa Carolina, bombed all over the mountains for two days and then drove 865 miles home. The car was great and the suspension worked.

My opinion now is use the best of what Porsche used in their own evolution for road cars, so maybe the Carrera sways would be any easy and cheap upgrade. Then dial in your existing suspension ride height and alignment.

Hear, hear👍

I have a very light backdated '79 SC, and went with lowered ride height, 22/28 TB, Carrera sway bars, and all Elephant polybornze, monorails etc. It is firm and controlled, not harsh or unpleasant, even for long days driving to events. I drive on R tires, and feel the handling is superb on the track or hard charging mountain roads.

19/26 looks like an A/X setup it induces a great deal more oversteer than stock would have

a more neutral setup would be 21/26 or for just a tad more steering response 20/26

the bars effect on wheel rates is non linear

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http://forums.pelicanparts.com/uploa...1602086448.gif

assuming that the p6000s are 185/70 & 215/60 a change to 205/50 & 225/50 would sharpen handling at the expense of some ride comfort, it will also alter the handling characteristics so you need to consider all the changes involved

you are correct in thinking that you get the t-bars right then tweek w/ sways as necessary

for max fun lower the car, use 205/50 & 225/50 or 205/50 & 225/45 tires, the t-bars of your choice and stock sways, a digressive re-valve to match the t-bars/net wt of the car would be add significantly to the package

every ones comfort level and driving environment is different around here 22/28 or larger can be pretty uncomfortable on some of the roads, I really like 20 or 21 f and 26r for a street car, but to each his own.

Thanks everyone!

Current tyre size is 195/65 front and 215/60 rear.

I might start with stiffen up the front slightly with new t-bars, lowering, more aggressive wheel angles and take it from there.

Your car looks amazing.
I guess, if you have read every single thread with Suspension Rebuilds in the title, you know a bit about Suspension Rebuilds. The advice does evolve and taste changes over time. Seems like the desire for big number torsion bars has gone down a bit over the years, and Mono-Balls are no longer the end - all for a street car. If you compare the old advice to the new, its more apparent. But there is also some sage advice is in there, timeless, too I see
Bill Verburg (!) chimed in, worth his weight in gold, that guy.
If the car is pretty well dialed in as it stands, which I am guessing it is and if all components are 'up to date', then, if at all possible, make incremental improvements. Change one thing at a time and see how you like it, although it all works together as a system changing less at a time will give you better idea of if you did the right thing or not.. If your system has expired and all needs a refresh then also proceed with a bit of caution. Just my thoughts. All our cars are a work in progress, no?