Suspension Options - Experienced Opinions Welcomed

[Cornpanzer]

Soon I will be bolting the suspension together on my 70S. Would appreciate some guidance on the set-up.

Car will be a playful street driver. I doubt it will ever see a track again. Firm is OK...harsh is not. I want the rear to be stiff enough that it doesnt allow the tires to get up into the fenders.

Engine is a 2.8 twin-plug based on a Turbo aluminum case. Limited slip diff. Tires will be Avon 185 front & 215/60 rear. All new Elephant Racing rubber bushings.

Torsions:
I currently have 19mm front and 27mm rear. Thinking of bumping the front to 21mm. Opinions? Which would be better to negate the natural "push" of the LSD?

Sways:
I have a 16mm front and either a 17mm or 18mm rear. Which would be better? Are these bars enough?

Thanks!

[Flieger]

Harsh is very subjective, and different people like different balance.

I run 22/31 torsion bars with no sway bars. Corner balanced and with plenty of camber I love the way it rides and handles. Probably a tad too low though. I was thinking of going 33 rears but got a good deal on the 31s (hollow).

My wheel rates are something like 200 lbs/in front, 300 lbs/in rear. I think I'd like something more like double that to be honest.

Your mileage may vary.

[keith]

I'm pretty certain I'm 21/27 on my targa; will check my records.

[Tspringer]

The tires you are planning on running to a large degree will guaranty that things are not too harsh. A 60 series tire will be plenty compliant and will offset very stiff suspension unless the roads where you are are not very smooth.

My '69S hotrod I ran rubber bushings in the front control arms and poly-bronze or monoballs everywhere else. Torsion bars were 22F and 28R and I ran SRP front and rear anti-roll bars - largish ones. On the street I would always set the anti-roll bars to as loose as possible and then changed that for the track and this worked great. I can custom valved Bilsteins with raised spindles in the front. Basically - a very hardcore stiff suspension setup. On the street I ran 205/60 tires front and rear and on the track I ran 225/45. The 60 series tires made the street handling just about perfect. Steering response fantastic and the ride very acceptable. BUT - if you hit a big pothole you were going to regret it. The roads where I am (north GA) are overall very smooth and in good shape. With the 45 series hoosiers on the car was completely different and only acceptable for the track.

My suggestion thus is to go stiffer than you may be thinking and keep 2 sets of wheels and tires.

[Cornpanzer]

When would I use two sets of tires if I am not planning on tracking the car? I am not looking for "hardcore" just a nice street performance set-up that will be fun to drive and not soft and wallowy.

Thanks...any other thoughts?

[stout]

Dave, if there's one thing that has stood out after all the years and all the cars tested, it's this: Spend your money with the right person on dampers.

You've got your tires figured out (nice choice). For your purposes, I'd go mild on the torsion bars, and run adjustable anti-roll bars—but nothing too crazy. Dampers are the place to do your research, imho. If you get the damper valving right, you can run almost any tire or torsion bars—even R-compounds and high spring rates. I drove a 911 SC club race car with BIG torsion bars and 16-inch Toyo RA1s on the street, and it rode better than my lowered but mild SC coupe. It was the dampers. Off-the-shelf Bilstein Sports can be awful; Bilstein HDs can be, too (mine are, being good on the low-speed compression but too harsh on initial impact—which leaves the car feeling "fidgety" over tiny bumps that it should glide over, especially on 65-series tires).

Back-to-back tests revealed the same Bilstein dampers revalved can be magical—making a Carrera 3.2 feel 20 years more modern and coming close to the sophistication of $,$$$ remote-reservoir dampers, which also have to be set up and can be a PITA to maintain over the long haul. The key is finding someone who understands not only the science of 911 damper valving, but has a feel for the "black art" of damper valving, too. If you want to go with off-the-shelf dampers, I prefer rebuilt Konis to new Bilsteins, as I prefer the Dutch company's damping philosophy. Anyway, that's just my personal preference—and I am sure mechanics will chime in and tell me I am baked and that Bilstein makes a superior product. If revalving is an option, I'm with them.

Happy hunting—your car is gonna be epic.

pete

[Cornpanzer]

Thanks for the input. I should provide more clarity to the my parameters. Everything has to appear "correct" to the car. Thus, I am compelled to run the original Koni struts and shocks and original appearing sway bars. My concerns are that it be responsive, firm but not jarring (my tire choice will help that) and not push due to the LSD.

Again, my questions are basically as follows:
Torsions:
I currently have 19mm front and 27mm rear. Thinking of bumping the front to 21mm. Opinions? Which would be better to negate the natural "push" of the LSD?

Sways:
I have a 16mm front and either a 17mm or 18mm rear. Which would be better? Are these bars enough?

[dlp72t]

Dave, I run 21mm front 30mm rear torsion bars, 22mm adj. sways both ends, solid bushings and custom valved bilseins. The car weighs 2388lbs. and has a Guard limited slip set at 80% on decel and 50% accel lockup. It has a 3.6 ltr. The ride is great... Firm but in no way harsh and I can drive it for hours without fatigue. I wouldn't change a thing. It turns in brilliantly and inspires confidence. It's very predictable. You want a shock tuned to the torsion bars and weight of the car. Get it low. You could use smaller sways to look right and have a less firm ride. Alignment settings are important to fine tune it.

[dlp72t]

Make that 22mm front torsion bars. Sorry

[Mr9146]

21/26 w/18mm bars front and back. Bilstein HD shocks and rubber bushings. Koni shocks suck, but you gotta do what you gotta do.

Your wife will even ride with you.