95ONE

The step adapter above still doesn't change the swing angle. It literally does nothing.

xschop

It realigns the steering rod with the control arm that doesn't move in relation to the dropped X-member. I've got 1.25" drop blocks on mine and it fixes the BS.

95ONE

You can do a pretzel before that arm up or down, but the pivot angle still resides in the stock location. That block is just dead weight. I'm sorry it comes out harsh. I don't mean it to be that way.

333pg333

Thanks Van. That's thoughtful of you to draw that up. (I was reading your data doc last night too)

So are the longer pins that RE sell for example, trying to do what these B/S kits are?

If I could squeeze it into my budget I would opt for the CEP billet uprights that have all this built into them. A sideline advantage of these are also you can get them to fit different brakes and wheel options too.

xschop

That's odd, as it does fix the bump steer that I was getting when I originally dropped the X-member and it just replaces the custom chromoly drop pin that interferes with 16's

Also it actually puts the steering rod in a closer plane to the A-arm as the rod originally sets higher than the A-arm from factory. Also the pivot points on the inner tie-rod knuckles do not set even with the A-arm bolt-holes (1.5" diff) which is strange on these cars.

Van

I actually found that image on Google Images... don't give me too much credit.

The Racer's Edge control arm pins are *why* bump steer pins are needed for the tie rods. it really has to do with where the pivot points are in relation to the wheel (road) side and the car (chassis) side.

In stock configuration, the steering rack is placed so that the inner tierod joints, which connect to the rack, are about 1.5-2" above the control-arm-to-sub-frame joint. On the wheel side, the tierod end is about the same distance above the outer control arm joint. When the wheel moves up and down, and the suspension moves, the tierod and control arm move parallel to each other. Think of an extreme movement - as the wheel moves *way* up, it's going to move closer to the center line of the car - the track width gets narrower. If the control arm moved up to a 45 degree angle, the distance the horizontal distance of the control arm is really the arm length divided by the square root of 2. When the arm is fully horizontal, the wheel track is at it's largest.

Now, since the tierod is parallel to the control arm, and since it starts out at the same length, when the tierod is at an angle, it's the same angle as the control arm. At that same 45 degree angle, it horizontal dimension would also be the length divided by sq. root of 2.

Now, when people lower 944s by just changing the spring perch height, the control arms can angle up at the wheel side. This matters because there is a geometric thing called the "roll center" and this is the point of the car about which the body roll happens (from the cornering force applied to the car's center of gravity). The roll center is defined by the point where, if you draw an imaginary line along the control arms to the center of the car, those lines cross. If the control arms are parallel with the ground, the roll center is in-line with them. At stock ride height, when the arms are angled down at the wheels, the roll center is somewhere in the engine compartment. When the car is too low, the roll center is somewhere below the car - and sometimes below the surface of the road.

The car's body roll, and thus the tire's contact patch, is dependent on the distance between the CG and roll center. More distance, more leverage the force has and the more body roll you'll get.

To adjust where the front roll center is, people use the longer control arm pins - or, as RE calls it, the geometry correcting control arms: http://www.racersedge-inc.com/racers...pen&id=11.3.10

But now, of course, with the geometry correcting control arms, we have the roll center in the right place... but now the control arms are not parallel with the tierod. If the control arm moves up and it's horizontal distance increases by 0.1" (let's say it moves from sloping down to the wheel to becoming horizontal), but the tierod moves from horizontal (it's longest distance) to slightly pointing up, it's horizontal distance has now decreased - let's say by 0.1" again. What has effectively happened is the wheel has steered in a new direction equaling if you turned the steering wheel and moved the rack 0.2".

If you're mid turn and hit a bump, or if you're braking hard and the nose is diving, this can be a noticeable steering change.

anders44

moving the boltin at travese, but that doesn't really move up the caster mount part? how did you solve that? I know hansb "cutup" his chassis to solve it to get proper caster angles again.

Van

Anders, what Rob is talking about, is he spaces the crossmember down with spacers between it and the body - this helps the intake and throttle body of a v8 clear the hood. He also makes a longer steering shaft since the rack is lower than the stock position. His extra hole in the crossmember is so the control arm stays lined up with the caster block and *does not* affect the roll center. But, because the steering rack has moved down, the tierods are no longer parallel with the control arms.

anders44

aha then it makes sense, I know its quite common to just "space" the castermount as well.
honestly both solutions are horrible for a racecar.

with RH mounts, and stock hood its missing aprox 1cm, so a fiberglass hood with no frame will maybe need 2-3mm clearing, so will my plan is a small bump there/airvent or similar.


but back to hansb, do you remember his pics? very good solution.

Van

I remember his white car with red and blue graphics?? I remember it's awesomeness... but not specifically his suspension solution. Did he go with a 996 suspension or something?

anders44

no, he chassismodded the caster mount, to sit higher in chassis, also the traverse, that way he god perfect gemoetry.

wake up hans! we need pics again

xschop

I was going to make the drop blocks at the steering rack but that would be an engineering feat. Doesn't matter as eric will be doing FG hoods with humps for the TB clearance. Odu will need one for the FAST intake on his LS3 maybe. A Hood scoop will be mandatory for the 1uzfe swap that will go down

95ONE

I have completely cut out my caster block mounts and welded in a whole Spherical bearing mount thing. They sit higher with custom brackets and annoying amounts of work. Still working on this actually. Pics will be when I think I got it right.. And it matches a Hole I drilled out of the Front Crossmember, very much like in a pic above. Geometry is corrected. I have also physically dropped the steering rack about an inch. So my problem is compounded. I am now stalking these threads trying to find a kit that seems to do the trick so I don't have to re-invent the wheel on this one.

Hans' pics are still on here. I just searched and found them recently. I want to get out of the office ASAP so, I'm not going to go get them now. But they are there. Interesting stuff. Hans' suspension / car is absolutely first class and technically fantastic. Adjustable for different height tire sidewalls. Crazyness. Well done crazyness.

xschop

Drop spindles....

Is there any other 5x130 p-car with bolt-on wheel bearings like the C5 vette? Not talking about Boxster spindles either.

anders44

new spindles would be GREAT! its a very good and common way to do it, from racing old volvos, to yanks, to europeans.. but for 944? no...

now thats a product I would pay for *looks smiling at mr xschop"

billet you say?

wonder how "high" volume you would need to cast it, maybe getting misc 944 companies involved or similar to split cost would be an idea

for volvo 240's there is a clever cast part made by some yank, they fit under the front strut to do it.