C4 IRS Camber Bar Question

[orphancars]

Chicane -- thanks -- that's the kind of info I was looking for! What do you mean when you say to "set the camber rod positive"? I'm planning on running about 1/2 to 1 degree negative camber @ ride height. Also, you are correct -- that is 4" of travel measured at the shock.

Frank -- always a pleasure to get your inputs ........ I called you a while back when I was trying to get the driveline set up.

So is the general consensus that running less than 2 degrees of angle on the halfshafts is good? I have to see how that affects my ride height -- I already have the rear end set in the car. Luckily, I have the car with a little rake dialed in -- I can drop the rear if needed. Also, I think if I lower the rear so that there is about 1 degree of angle in the halfshafts, the car will probably be level......thought a little rake made the tiny car look aggressive!

thanks for all the inputs!!

-jeff d

[chicane]

Positive would be, the wheel side of the camber rod being located below the inner or it having a down angle in respect to the half shaft towards the outside... very much like the camber rod is displayed in Franks picture above... just not as exaggerated.

My normal alignment setting for the C4 IRS is -3/4* camber with 1/16 to 1/8" total toe in. I would do a geometry sweep, once you get it all together, and make the determination of the final toe setting then.

Yes, having less than 2* is ok. I would want at least some in it... but anything over 0.00* is "some".

[orphancars]

Thanks for the advice Chicane...............I think I'll mock up a fixture for the inboard mount of the camber arm and another fixture for the trailing arm mount before I fix everything in position. I did a couple paper models over the weekend and I see how the location of the camber mount can affect how the suspension moves.


thx!

-jeff d

[orphancars]

After taking a couple months out of car building to indulge in the purchase of a lathe and subsequent rewiring of shop. installing a rotary converter for 3-phase, and rehabbing a 50 year old lathe, I'm back into the suspension on the car.....

The question is for those folks that have done a camber sweep of a C4 IRS under full compression and rebound -- should the camber change "a bunch??" I'm seeing 0* at ride height, about 1/2 to 3/4* positive @ full extension, and about 1 to 1.5* negative @ full compression. Is that right/normal??

I don't have the trailing arms mounted, so this was just with the toe arm and the camber bar installed, the bottom of the knuckle resting on a bottle jack. I plan on getting the trailing arm brackets done in the next couple days. Also, the inboard mount for the camber bar is just tacked in place -- I did that just so I could find the best location for it (ie., minimal camber change) before I fully welded it into place.

Also, I don't have the coilover mounted yet -- will that make a difference?


thanks in advance,

-jeff d

[chicane]

That sounds about spot on. It should be right about -0.75* per inch of travel with the range of motion being around 5" total.

At 0.00* static ride... you should see about -1.75* at bump. Or there abouts...

[orphancars]

Thanks for the help Chicane!!

Should have some pics thrown up to this thread in a couple of days once I get the trailing arms put in place.

thanks again!!

-jeff d

[orphancars]

Well, here are a few shots of the suspension tacked into place so I can find the optimum location for the camber bar. Oddly enough, I get the best results with the camber bar located right under the half shaft....getting just a little over a degree positive camber in rebound, and a little over 1.5 degree negative in bump.

Using .120" plate for the boxes for the trailing arms, and the boxes will be just that -- fully boxed on the inboard side with gussets top and bottom on the outboard side.

Thoughts? Something tells me that .120" is too light for mounting the trailing arms, but the main tubes are .120" wall for the chassis, and these will be fully boxed sections, not just three pieces of sheet tacked together.

-jeff d