Cascade Crew

Twilightoptics · Posted: Sun Aug 26, 2007 7:43 pm Post subject: Let's talk Rears! Leaf or Arm

So Leaf or Torque Arm setup. Cost is similar... dirt cheap. Consider weight mainly, and fabing into a Unibody with no real provisions.

Primary function is Drag Race and some street time.

No four link stuff, etc as that costs more. Using a GM 7.5" 10 Bolt from a 2 wheel drive S10. Perches could be welded to torque arm setup.

Which weighs less? Which is easier to setup? Pinion angle adjustment/setting/maintaining?

I think the leaf setup would be the way to go so far with weight and ease of just welding in shackles.

Sellmanb · Member Joined: 30 Nov 2004 Posts: 727 Location: Tigard, OR

For your Chevette or Camaro ? Wink

If for the Camaro, I guess I'd have to ask what you're expecting out of a movement to leaf springs?

Xophertony · Posted: Sun Aug 26, 2007 10:56 pm Post subject:

i assure you bobby it's for the vette'.

to be honest paul i would go with leaf springs. this way you can adjust the ride hieght and spring rate more cheaply. i know you had talked of possably making this thing a "screw around on trails" car as well. slap a seecond set of shackles on it in a farther out location and put on a longer set of leafs and just like that it will sit higher and be depending on how many leafs you use will be harder or softer. and you can used leaf springs for dirt cheap from junkyards.

seems like there is going to be alot more engineering into a tourqe arm setup then a leaf spring setup as well. but i realy only have experiance with 4x4s when it comes to leaf setups... i know you can get away with an awfull lot of bad engineering when it comes to trail rigs (ie it does not matter if your rear likes to pull to the left in dirt at 4MPH)

Quasi-Traction · Posted: Mon Aug 27, 2007 12:49 am Post subject:

AFAIK this is not a "screw around on trails" car.

this is a "Go-really-fast-in-a-straight-line-with-two-less-cylinders-than-a-third-gen" project.

The existing Chevette rear has some kind of weird torque arm that mounts on the bottom (ground facing). its a 2pc driveshaft.

I vote for keeping the weird ass rear with a yoke change when it gets a new engine/trans.

lets weld the spider gears and see if we can blow it to smitherines!

Sellmanb · Member Joined: 30 Nov 2004 Posts: 727 Location: Tigard, OR

Dewey316 · Posted: Mon Aug 27, 2007 8:39 am Post subject:

Can I vote for neither? Go 4 link, it will probably be just as cheap as the others, and is more adjustable. Just get the brackets from summit, and weld them up.

The issue with the others, is that the setup you need for all that traction isn't so much the pinion angle, you really need to dial in the anti-squat, the leaf spring you are sort of stuck with what you go, you can't adjust it, torque arm, you can adjust it, but only so much. A 4link can be done for cheap, and if you are really wanting to go fast it is the way to go.

What were you going to get the torque arm stuff from, all of the factory aplications I can think of, would be WAY to long for a chevette.

The other question would be, how much hacking are you going to be doing? You could possibly fab up a crossmember for a 3link, it would be the lightest of all, and if you slightly offset the upper link, it should launch dead straight.

--John

blue89 · Posted: Mon Aug 27, 2007 8:48 am Post subject:

Don't forget that I know what kind of 60V6 you need to assemble, what parts you will need, and where to find them.

Twilightoptics · Posted: Mon Aug 27, 2007 12:28 pm Post subject:

Dewey316 · Posted: Mon Aug 27, 2007 12:50 pm Post subject:

Paul, what type of rear suspesion does the vette have now?

A three-link is sort of like a torque arm, but it has one upper arm that keeps the housing from rotating. Here is a descent diagram. since the upper arm is smaller, it is very light, and very adjustable.

Dewey316 · Posted: Mon Aug 27, 2007 12:53 pm Post subject:

Twilightoptics · Posted: Mon Aug 27, 2007 2:37 pm Post subject:

So just weld spring perches on.

Make LCA's essentially. And a top control arm say like the LCA's I made for the car... aluminum w/ rod ends. And a support for it to attach to.

Yes?

What about lateral forces? Does this need a panhard of sorts or is that where the LCA's coming inward takes care of?

Dewey316 · Posted: Mon Aug 27, 2007 2:44 pm Post subject:

Correct on the 3-link. And yes you would need a panhard for lateral support.

Hrmm, is that a torque arm on the stock suspesion. If so, why are you going to something else?

--John

Twilightoptics · Posted: Tue Aug 28, 2007 12:15 am Post subject:

hehehehe it's not a torque arm.

It's a 4 bolt housing that "encases" the driveline if you will. It's bolted to the center section about 2 feet up, and to rear housing itself.. It's REALLY weird.

It's a 6.5" 10 Bolt I rear somewhere.

If I need a panhard I may as well go with a torque arm esque 3 link.

3xLCA/Panhard/Springs/perches/brackets

weigh + or -

leaf springs/4 shackles.

Dewey316 · Posted: Tue Aug 28, 2007 7:47 am Post subject:

the thing with the leaf springs, is that you have zero adjustability other than shim kits. Its easy sure, but not elegant.

--John

blue89 · Posted: Tue Aug 28, 2007 8:08 am Post subject:

Dude, he's putting this behind a V6. I don't think its going to be an issue. I think that the stock rear will handle it just fine. The most the stock bottom V6 block will handle is 300hp anyway, and a stock 10 bolt will do that no problem. Unless there is something weak about the 6.5" 10 bolt.

I vote to keep the rear stock, unless you can't figure out how to interface with that weird driveline. Then I would do a leaf rear with S10 axle. Simple, but definetly not elegant.

Xophertony · Posted: Tue Aug 28, 2007 9:30 am Post subject:

Dewey316 · Posted: Tue Aug 28, 2007 10:42 am Post subject:

there is a lot more to adjust than ride height. if he wants to launch it good, there are other things in the setup you want to set up. Pinion angle for example, with leafs you have to shims to set it, if it is incorrect when you change the height.

Quasi-Traction · Posted: Tue Aug 28, 2007 11:23 am Post subject:

paul and I had a talk about the advantages/disadvantes for Leaf VS 3 Link.

leaf springs are also heavier, and there's always the possibility we could use a 3rd gen rear, retain the stock panhard and LCA's and just put in one bracket on the top for the third link.

We still have to get under and take a measurement of the flange to flange width of the stock rear to figure out just what were up against and and which would be most cost effective/easiest to fab/saves weight/gives us traction (in that order).

Dewey316 · Posted: Tue Aug 28, 2007 11:41 am Post subject:

if that is the order, that brings up the big question, of why not use the stock chevette stuff? Maybe a even more discriptive plan is needed. The stocker stuff is alreay there, no fab or money needed. Maybe see what happens, and if you break it, you break it, you can fab from there. If you are going for performance and traction, 3 link is going to do it, if you set it up right. there is more math, and setup involved, you have to dial in the LCA and 3rd-link geometry. Leafs are going to be easy, set the pinion and go, but you wan't have the adjustability, especialy if you are changing ride heights. Maybe you shoudl explain a little about the plan, is this going to be a race car, or is it going to be a toy to drive around, cut the top off of, and hit the gravel roads in? If it is the former, you are going to want an suspension with adjustability so you can dial it in at the track. If its the latter, just toss whatever you can get for free or find laying around, and go from there.

Quasi-Traction · Posted: Tue Aug 28, 2007 1:57 pm Post subject:

Really, you'd have to ask paul what the "plan" is. I'm just a helping hand for whatever. The way I understand it is he wants a Street/Road Course/Dragstrip car. I know were trying to do this as cheaply as possible (for now) but perhaps later the 3 link is an idea.

I've been trying to say keep the stocker chevette rear (for now), but he doesn't have much faith in it.