[ckucia]

Check out my other threads regarding the potential of a AWD hotrod.

My question...

Lets assume I had picked out a modern (60's or newer) front chassis for a rod with IFS based on upper/lower control arms (not struts). Lets say the donor car weighs in about the same as the project vehicle, but the donor was RWD.

Also, lets assume that I can swap in spindles from a 4wd vehicle to accomodate the front driveshaft, relocate springs as necessary and can package the whole shebang between the framerails and around the engine.

Would the stock frame and particularly the control arms, balljoints, etc be able to support driving the front wheels without significant bracing/modification?

My first inclination was no, but then I thought about the braking. The front wheels do most of the stopping, so they probably have to accomodate at least as much force (although in the opposite direction) as the drive wheels do pushing.

What do you guys think?

 

[Triaged]

Did you already buy a chassis? It would be ALOT easier to just start with a 4wd chassis.

 

[ckucia]

No. I'm still doing research.

I originally thought a 4x4 S-10 chassis would be the way to go.

However, its pretty narrow, and has some issues with its roll center, from what I've read. Widening it is a possibility.

Then I read that the G-body is essentially the same suspension. That's a little bit wider track.

The G-body doesn't have provisions for the torsion bars, but the S-10 guys have managed to build a coilover modification that clears the front axles using revised control arms. It also supposedly addresses the roll center issues.

So, I thought I could use the G-body chassis with the spindle and modified control arms off the S-10 and get the best of both.

But then I wondered how important the control arm strength varies between 4wd vs RWD. If I could just swap 4wd front spindles onto an existing suspension (like a Vette, which is exactly the right track for my needs) I could get the benefits of a better suspension design, and rack/pinion steering and without hacking and rewelding the suspension. I would have to find a way to mount springs, but that seems more straightforward than ensuring that a sectioned suspension is going to work as well as stock.

 

[Triaged]

4x4 s10 front ends have NOTHING in common with a 2wd s10.

The chassis, control arms, spindles, all the steering parts, anti-roll bar, and just about anything else you could think of is different. As far as I know the 4x4 suspension doesn't have the under ground roll center, bump steer, or any of the other problems that a 2wd does. It is also 4" wider (wms-wms) and uses wheels with alot of backspacing to get the scrub radius to where it should be (needs to be negative not positive).

If s10 width (or lack there of) isn't enough for you you could think of using newer Colorado/Trailblazer stuff or some other midsize truck. You could also widen some s10 4x4 frame horns and use a R&P steering or lengthen the center link.

 

[farna]

Again -- you need to look closely at an AMC Eagle. Go to the library and pick up a Chilton's that covers AMC from 80-83. The Eagle was made through 88, but the last 2WD (RWD) AMC cars were made in 83. The Eagle is an AMC Concord that was converted to AWD. The upper control arms are the same on both 2WD and 4WD. There is no additional strengthening in the unitbody. The front suspension/engine crossmember is more substantial, but mainly just deeper because of the higher suspension mounting. AMC managed to package everything under the engine like you're thinking, but had to raise the car 2-3" to do it. The front axle mounts on the engine so it can be close to the oil pan with no danger of movement between the engine and axle.

 

[ckucia]

Thanks Triaged and Farna.

I've been trying to get as much info as possible via the web, but obvioiusly a lot of it is erroneous.

From the SyTy guys, it appears that the roll center issue is still a problem with the 4wd suspension. The coilover conversion apparently addresses it somewhat.

I finally found a good pic of the Quadradeuce front suspension. Although descriptions of the car state its a "corvette suspension", I think it is in geometry only. The springs are apparently above the differential using pushbars (a neat solution for that vehicle, but not necessarily useful for any other).

I think my best course of action is to go to a wrecking yard with a tape measure to see what can be adapted. Unfortunately, its getting more and more difficult to find a yard open on Saturday and which will let the public wander around. I do know of one, but its a 3hr drive.

In any event, I see why there aren't a lot of AWD rods out there, at least using cars as a base. The 32 Ford (Quadradeuce) has the front axle ahead of the engine. Anything else is going to require the engine to be set way back, or above the axle. Putting the engine behind the axle isn't necessarily bad, if there's room for the passengers, but it would be difficult to find a car where that could be accomplished - maybe something with a long hood that originally had a straight-8 would work. Putting the engine above the axle, like AMC did wouldn't normally be ideal.

Thanks again...