Staffan

Hope to get some help here, don't know what to do.

I am replacing my stock dampers with a set of 964 Cup dampers.
Bought FVD:s camber plates which are supposed to work for all 964 cars.
My problem is regarding the installation of the front camber plates.

You can install the camber plate (or any top mount for that matter) in two ways.
Either with the nuts holding both the dampers closer to the middle the car (#1), or you can rotate the camber plates 180 degrees so that the top mount will lean the dampers towards the outside of the car (#2). I have a great picture from the manual but can't upload pictures.
But basically you could illustrate the difference in damper angels like this:
#1 / \

#2 \ /

In the shop manual, it says that #1 solution is used for 964 C2, C4, RS and CUP.
The #2 solution is used for 964 turbo and 964 turbo-look. I believe the difference is because the turbo and turbo-look has a wider track, but I am not sure.

I have dialed in as much camber as possible at the lower damper mount on both sides.

If I install the camber plates like #2 (the way I think they should be installed), with maxium camber at the top mount, I only get -2 degrees of camber, which is way to low and not right.

If I install the camber plates like #1 with minimum camber at the top mount (maxium at the lower damper mount), I get -5 degrees wich is way to much.

I am stuck, don't know what to do.
FVD doesn't answer my questions.
There got to be a number of racers out there who faced the same problem.

viperbob

You'll have to post some pics. Generally you want the adjustment area towards the inside of the car. On your number 1 scenario, what is the minumum camber you can get with the bottom on the minimum setting?

Oh wait a minute. You cant not just turn these 180 degrees and keep them on the same side. The pivot bolt for the part that adjusts the camber should be at the front of the mount on each side (I have never done an FVD set, but they look the same as the rest and this is how they are adjusted). These are generally offset a little towards the rear so that you maximize caster as there is no adjustment for caster. It you put these on backwards, I could see where the caster would be too low and the negative camber too high. Again if you can post a pic, it may help.

Staffan

Thanks Bob, I have sent you an email with pictures, would be great if you could post them.

Staffan

update
I recieved information from FVD, the camber plates should be installed like #2 \ /
they way 964 turbos have their stock dampers installed. I found that I have to switch sides on my camber plates, lets see if this makes it possible to dial in some more camber, I am afraid it won't.

I also got information that it's important to install the dampers this way on 964 turbos because the sway bar won't work properly otherwise. Starting to fear that there is some kind of difference between cup dampers for n/a 964's and 964 turbo's. Someone on this board told me he got stock 964 cup dampers on his 964 turbo, don't remember who, will check this to see how they were installed.

Geoffrey

I don't see how the dampers affect the front sway bar. The bar is attached to the hub carrier, not to the damper. There are a variety of camber plates available and they all work differently and have different amounts of adjustment. And you can install them 2 different ways on the shock tower depending on how much camber you need. Technically, inboard is for narrow track cars and ouboard is for wide track cars, however, you can use either in conjunction with the stock camber adjustment at the bottom of the damper to get the correct amount of camber.

Staffan

Thanks Geoffrey!
This is not my field at all, just so that we are clear on that.
But I have been told that the SAI angle would be affected by having the dampers mounted inboard and that it isn't a good thing to do. Anyone know the importance of this ?


Found this description for SAI on the a website:

"Steering Axis is an imaginary line through the upper and lower ball joints (pivot joints) on short & long arm suspensions. On strut suspensions, the steering axis passes through the lower ball joint and the upper end of the strut. Steering Axis Inclination is the angle of the inward tilt of the steering axis and is measured in degrees from true vertical. SAI provides good driving and handling characteristics through directional stability and weight projection. Directional Stability is the tendency of a wheel to straighten from a turned position and remain straight. As the wheel is turned, the spindle swings on a downward arc and the weight of the vehicle forces the spindle to return to the highest point in the arc, returning the wheel to a straight ahead position. Weight projection is the projection of the vehicle's weight to a point within the road contact area of the tire. The weight projection point at the road surface is the point where the wheel pivots for turning. SAI is determined by a true plumb line, placed at the center of the wheel at the point of road contact, and the projected line created by the strut or the upper and lower ball joints. The two lines will intersect at a point just below the road surface on most vehicles, but on some front wheel drive vehicles the point of intersection will be just above the road surface. The distance between the projected line and the vertical line at the road surface is called scrub radius. Scrub radius is positive when the projected line is inward of the true vertical line at the road surface and the point of intersection is below the road surface. Positive scrub radius forces the front wheels to toe out when the vehicle is in motion. This is usually found on rear wheel drive vehicles. Negative scrub radius places the projected line outward of the true vertical line and the point of intersection is above the road surface. This forces the front wheels to toe in to provide stability when braking on front wheel drive vehicles. SAI is a directional control angle. The point of intersection is designed by manufacturers to provide a pivot point for the front wheels when cornering. SAI is not adjustable on most vehicles. SAI can be affected by loose, worn or damaged suspension parts or by frame damage. "

nathanUK '81 930 G50

That explanation of "steering axis", confused me.

So it isn't the same thing as castor angle?

Premier Motorsp

Steering axis is viewed from the front, whereas caster is viewed from the side.

Fooling around with the camber plates IS going to change the SAI. Porsche cleverly designed the front end of the 964 so it could use two different track widths with identical steering geometry.

To solve this problem, I would use a 993 camber plate. This is going to put the 'guts' of the plate right in the middle. This is what they did on all the 993 race cars so you can rest assures that the resulting SAI won't cause major problems.

The standard camber adjustment at the bottom of the strut (which is the correct way to do it since adjusting it doesn't change SAI or Caster) should give you a pretty wide range. Usually you can't get enough negative if the car is too near stock ride height.

Chris Cervelli
Premier Motorsports

nathanUK '81 930 G50

Thanks, now I get it.

Staffan

After trying every possible way of installing the camber plates I finally got it right.
When the camber adjustments screws was facing the rear of the car and the mount was installed outwards (wide chassi way), I managed to dial in -3.0 which is what I was looking for.
The angle of the damper "axle" now looks right, before it looked tilted.

Of course this was the way I installed them the first place, but got confused by some information I got from FVD, the usual Murphy situation!

Thanks for all the help!

tasracer

just did the same install with the same shocks(964rs bilstien cup)... same prob on install... also on first track event setting moved ... still looking for sway bars also... gonna check spring rates too... car is not dialed in right yet

tasracer

with the monoballs my strut brace wouldnt work... need a strut brace compatible for the new monoball set up

any sugestions?