Question on Koni Adjustments & General Suspension Advice

[Tidybuoy]

I'm wondering how others have their Koni's adjusted (soft/firm) and how you have the rears set.

here's my issues: '1974 Coupe

Car is new to me since October 2011

Cannot get in touch with prior,prior owner who set up the suspension. He is a very knowledgable Porsche Mechanic, worked at Canepa Design, and used the car for Auto-x.

I do not currently know the torsion bar setup. Sway bars are 20mm front, 19 adjustable rear. Adjustable rear spring plates. 16" Fuchs. Rear camber is 2.5 degrees, front is 1.5 degrees, Caster is 6 degrees, front tow is 15 degrees (I think), rear is zero.

The car is bouncy on the road, very stiff, no binding of bushings - just firm. Sometimes when you hit a bump, the wipers turn on.

If you push down on the front bumper, the car rebounds slowly and stops. My 944 is completely different where it comes right back up and stops.

I just changed the rear shocks to full soft and now the car feels very swervy. I once read somewhere about front to rear settings where it had the affects on oversteer based on spring rates.

Does anybody have a good link for suspension setup?

I'm wondering how a normal 911 rides. I feel much safer in my 944 as it is smooth and stable, the 911 is very twitchy.

On my 944, when I added Koni's, the ride got harsh until I got stiffer springs and then the ride mellowed out. I'm thinking that maybe my 911 front torsion bars could be needing the same.

Any advice would be great. I auto-x a few times per year but my primary driving is street and mountain curvy roads.

[Arne2]

I don't have much experience with Konis, but it sounds like you have way too much rebound damping.

[Tidybuoy]

Originally Posted by Arne2

I don't have much experience with Konis, but it sounds like you have way too much rebound damping.

That's kind of what I thought (and my Koni's are set at full soft right now).

I'm thinking that my front struts are too soft for the Koni's. I just purchased a set of 22mm bars and we will see if that changes things. They won't be here for about a week.

[Trackrash]

There are a number of things to consider when it comes to ride.

In your case, it would help to know what Konis you have. Are they the classic reds? Also the ride height is important. What are the measurements from the fender well to the ground?

With stock torsion bars and Koni reds, Koni says start with full soft. You might want them a little stiffer than that but only trial and error will let you know what is best. I ran mine about 1/2 to one full turn up from full soft.

Make sure you have enough ride height. If you are much lower than stock Euro you will be hitting the bump stops, which makes the ride very harsh. Especially in the front suspension.

[Tidybuoy]

Originally Posted by Trackrash

There are a number of things to consider when it comes to ride.

In your case, it would help to know what Konis you have. Are they the classic reds? Also the ride height is important. What are the measurements from the fender well to the ground?

With stock torsion bars and Koni reds, Koni says start with full soft. You might want them a little stiffer than that but only trial and error will let you know what is best. I ran mine about 1/2 to one full turn up from full soft.

Make sure you have enough ride height. If you are much lower than stock Euro you will be hitting the bump stops, which makes the ride very harsh. Especially in the front suspension.

I'm not sure about the fronts but the rears are Koni Yellows. My right height is set at Euro height - the front fenders are 25.5 inches from the ground.

[IROC]

Originally Posted by Tidybuoy

I'm not sure about the fronts but the rears are Koni Yellows. My right height is set at Euro height - the front fenders are 25.5 inches from the ground.

I was going to speculate that you had the yellows even before you wrote this. They are very stiff. I've instructed guys that had almost the exact same suspension set up as me, but with Koni yellows (I have the reds) and the increase in stiffness was astounding.

I have the reds with 22/29 torsion bars on a 2400 lb car and I set the fronts full soft on the street. I set them full hard on the track and that really settles the car under braking. The rears are set one click from full hard. That seems to work with the heavier 3.2.

I've had the Konis for probably 15-17 years and they're fine, but having spent time in cars with a nice Bilstein setup, I think the Bilsteins are better.

If you truly have yellows front and rear (and it sounds like you do), I would definitely try full soft and see what that feels like. In the end, you need to have the shock valving complement the spring rates, so if you're way off, some changes may be in order.

[T77911S]

Originally Posted by Tidybuoy

If you push down on the front bumper, the car rebounds slowly and stops. s.

this sounds like a mechanical failure. i have heard of struts getting "stuck" where people jack their car up and the wheel does not drop down.

could be something bent or broken or maybe binding, unless you made adjustments to the shocks to cause this.


the "bouncy" feeling could just be that the 911 is so much stiffer than what you are use to. if he has put the money into adjustable konis, he has put bigger T bars in there too, and if it is lowered, that alone can make it stiff.
make sure you have the rack spacers to raise the rack to reduce bump steer.