Fixing the rear geometry once and for all...

[e304me]

oh i was talking about the one matt was making. I wish that setup worked for regular e30s!!!

[Mike B.]

Matt,

Yep, you're right M3-only (works for me though :)). Still really interested in what you come up with though.

If you haven't already, check Gustave's site, LOTS of good suspension info there. Should help in avoiding some basic pitfalls before you start fabbing.

E304me,

The spacers are bolted into place with aerospace grade hardware - should be strong enough.

[e304me]

does it require welding? just make sure that shits strong enough

[matt]

You can already do that for $150.

http://gsperformance.com/products/rc-spacer/pic-2.jpg

Those only work with M3 struts, not standard e30 ones. My solution will work either way. (and for e36s also)

[Mike B.]

we should also look at lowering the front control arms outer mounting point to bring back some of the camber gain. I wonder if the inner bushing would fit in place of the outer bushing? that would make it easy as all you would need is a special spacer and a welder.

You can already do that for $150.

[Mike B.]

From Gustave's site...



If you can create something like this, with CAB's around the same size as the Treehouse racing one's - count me in!

[matt]

I already have a solution in the prototype phase for the front end. Results will be posted as they become available. (This will be installed on the WR car.)

[e304me]

you may be able to barrow parts from the ultima gtr, although it seems like it may be a dated design. The car holds like 1.15 gs on the skidpad on street tires but it doesnt have much body roll.




we should also look at lowering the front control arms outer mounting point to bring back some of the camber gain. I wonder if the inner bushing would fit in place of the outer bushing? that would make it easy as all you would need is a special spacer and a welder.

[matt]

How much of a benefit? A lot.

Will the car be as fun to drive? Who cares, if it's faster.

GRM = www.grmotorsports.com

The only way I can see doing this is to use two a-arms mounted to a new rear subframe around the diff. 2 A-arms and a fixed tie rod to control rear toe.

[e304me]

whats this grm you guys are talking about

[e304me]

while in the market for suspension for the GRM, i had that idea of rocker geometry open game as motorcycle components are easy to come by and rebuilt relatively cheaply/easily. i already have some sketches for component design in that regard, in case you want to discuss that topic further.
But thats all second hand to what has to happen first, the suspension arms and frame.
What about a trailing arm from stock subframe (Groupe-A style) for lower-front a-arm, a cross bar from equal distance perpendicularly for lower-rear, and the upper arm mounts perpendicularly to the trailing arm from under the car's frame. ..the geometric complexities from the resulting setup makes my head spin :)
lets work with a different car that already has this suspension, eh?

that seems like it could work, if you could get the lower rear a arm to be in a position to keep toe constant through the travel range. seems like that would be damn hard though

[e304me]

Ive thought about this too. I was going to wait till i designed FSAE suspension first to really start thinking about though. I think with brain storming we can make this happen. The question is how much of a benifit would it be and would the car be as fun to drive. If you intend on designing the suspension, i really hope you know what your doing, not just from a stay together standpoint, but also from a roll center camber gain standpoint

[xLibelle]

no, you just adjust your rocker geometry... your loss is suspension travel though

thats the main reason i gave up with considering it for the GRM, too much shit to learn and understand to design the thing with such little time

[matt]

My suspension guy goes "if you aren't going to actually take the time to model the car and develop the suspension, just copy lotus."

And the problem with adding a motorbike shock based rocker arm system is that it would be sprung very softly, so the damping and spring rate would be way off for a pushrod deal on a heavier car.

[xLibelle]

while in the market for suspension for the GRM, i had that idea of rocker geometry open game as motorcycle components are easy to come by and rebuilt relatively cheaply/easily. i already have some sketches for component design in that regard, in case you want to discuss that topic further.
But thats all second hand to what has to happen first, the suspension arms and frame.
What about a trailing arm from stock subframe (Groupe-A style) for lower-front a-arm, a cross bar from equal distance perpendicularly for lower-rear, and the upper arm mounts perpendicularly to the trailing arm from under the car's frame. ..the geometric complexities from the resulting setup makes my head spin :)
lets work with a different car that already has this suspension, eh?