Ok so I have thought about going double a arm suspension and the idea of grafting a setup off a different car flat out scares me (math sucks and upper/lower aarms/spindles = money!) and why start from scratch when the car already has the lower arms mounted and aligned? I might have come up with a cheaper solution and it would be using stock thirdgen spindles, one less part to buy. By keeping the lower a arm and factory mounting points on the lower a arm, it would make mocking up a double Aarm suspension really easy I think. There's also the possibility of lengthening the lower A arm and tie rod adjusters 2" so I can get rid of the pesky wheel spacers.

Here's the jist of it.. Just cut out the fenders and weld a plate over the spring pocket area, to this plate would attach the upper a arm mounts, cycle the suspension, then tack weld the upper a arm mounts close to the right location for proper geometry (ok so maybe a little math would be involved), shims could fine tune the rest once an alignment is done. Mounting the upper balljoint onto the spindle could be done using the two empty strut holes on the spindle. Colemanracing sells tapered balljoint inserts that could be welded in to a fabricated upper BJ mount, upper Aarms, balljoints, shims, coil overs, and the rest is standard circle track stuff which would probably cost a lot less than a C5 frontend.

Does it sound possible? I don't think it will ever get past the planning stage for me so I was just hoping to get some discussion started with it!
-Ben

Edit, here's a pic..

 

Or why not mod a 4th gen upper to fit the stock location and use a 4th gen spindle?

 

I think Fatal88 is running a setup like that, but his car is basically a 3rd gen body on a 4th gen subframe. Its possible but it would take alot of fabrication.

 

easiest would probably be to graft the whole 4th gen front clip on...not that thats going to be easy at all, but once its squared up your steering wont be as much of a hassle...

But the question is why do you want to do this? just to be different? try something new? Obviously from your rides you like trying new creative thing and thats fine. But theres nothing practical about this move...you can make these cars handle as well as just about anything out there...no im not trying to detur you...but it may be cheaper just to start with a 4th gen car

 

using upper A-arms from an 2WD S10 would seem like a much more logical idea, and spindles from one as well.

 

actually, I would think it would take less time to fab up some tube upper a-arms than it would to try to carry something over. - I see it a lot in the 4x4 community. Brace this, tie that, add this here....hope it quits twisting...at some point you have to realize that there would be a lot less work in simply building a 2x3/2x4 box chassis, or in this case, tube a-arms. I like the S10 spindle idea though...or maybe the new spindles listed in this months hotrod.
- I agree though, why would you want to go double a-arm? I'm going to a custom full chassis and I'm still sticking with the factory type struts(aluminum w/ coil-over, but 3rd gen replacement).

 

4thgen parts just might work, any available used parts would be cheaper than new. I've already seen 4thgen's at pick-a-part Jyards...

There are several practical reasons a double aarm suspension is nicer, the tires maintain better contact to the ground through the suspension travel compared to a strut style suspension which requires high spring/shock rates to reduce the amount of camber under load. In theory a double aarm suspension could run softer springs/shocks and provide equal cornering as a much stiffer strut frontend.

I don't really know why I want to do this or am even thinking about it, the car handles like a race car as it is and the ride quality is nice enough. For the handful of times I will actually push the limits of the front suspension it's probably not worth it to gain .01 g's of cornering force (estimate, of course) by switching suspensions.

 

Oh snap, those mustang guys already did it...
eBay Motors: FFR Cobra , Mustang SLA suspension , double A arm (item 8061689440 end time May-07-06 19:54:23 PDT)

 

I’ve been contemplating this swap for a while, even thought about making it as a kit since there would be very few fabricated parts that would be needed. I own a Monte Carlo, which is a G-body, incidentally they use the same lower control arms as a camaro, and also a 2wd S-10. Also S-10 and G-body front suspension are identical. My brother owns an F-body, my plan was to use a G-body spindle, and a cheap UB-machine upper control arm. They run 80$ a pair and you can use stock G-body ball joints. The upper a-arm mount can be fabbed from the circle track mounts that are sold pretty much everywhere. My plan was to make a bolt on mount that the avg. driveway mechanic could bolt on with nothing more than a drill and hand tools. You also have to keep in mind that you would be removing your shock with this install. Luckily you can mount the shock in the middle of the A-arm ala G-body. The only modification needed would be a stepped washer on the upper shock mount to make the hole in the frame small enough. For some reason this hole is larger on the F-body than it is on the G-body.

The reason I haven’t done this yet is that I don’t have the software or the time to figure out where to mount the upper control arms. This has to be perfect, a 1/8” can drastically affect suspension geometry. Also G-body spindles have much shorter tire rod arms, this will quicken the steer a good bit, but it will also change your ackerman. My best WAG is that it will decrease ackerman, which may not be what you want. Again some time is needed with a suspension analyzer program

 

While what everyone suggests here is entirely possible to do, my question is...why? Having owned a couple third gens, multiple 4th gens, and a few G-bodies, to me the handling of the third gen is far superior. Any of the above can be improved with aftermarket parts (or in the case of the F-body, scrounging parts from other F-bodies), but I see no benefit in changing the suspension to any of the above designs. If you're determined to go to a double a-arm setup, at least use a better one like the C4 or C5 Vette. I see them all the time at swap meets for $5-700, and anyone capable of fabbing up their own suspension could mount one of these. You'd have the added benefits of trick aluminum a-arms, larger brakes (and plenty of aftermarket choices for even larger), and rack and pinion steering.

 

If you've driven a G-body then you'll know how horribly they handle. So yeah swaping G-body parts on to your F-bod sounds like the worst idea in the world. Your ignoring one huge part of this swap, and why I don't think the avg. Joe could pull it off. It's GEOMETRY. If you could duplicate vette geometry with G-body parts then you would get vette handling (this is much more complicated than that, but you get the idea). There is nothing voodoo about corvette parts, you don't have to have corvette spindles and A-arms to get a certain camber curve and no bump steer. It's all in the pickup points. My point is you might as well use readily available cheap parts to design your suspension around instead of high dollar rare stuff. Again it's all in the design, and the truth is 99% of people out there don't have a clue on how to setup a suspension system.

The reason why a Double a-arm setup is better by design is that you can get more camber gain than you can get with a strut setup. You can also get more anti-dive, put your roll center any where you like, and the whole system is much more compact to boot.

 

We're thinking sort of along the same lines, but the reason I suggested using the Corvette stuff is the ease of adapting it to nearly anything. As you said, the geometry is more the issue, but if you put everything where the General intended with the Corvette stuff, you are far ahead. Use stock G-body geometry, and you have a car that handles like a '55 Chevy (not knocking either, I have owned both!). Most of us don't have the expertise (or the computer programs) to properly design a good front suspension,or even modify the geometry, so something like the Vette setup is ideal .The parts aren't prohibitively expensive (you could get a whole C4 front end for less than the cost of a brake upgrade for any front end you choose), and youre virtually unlimited with possible upgrades.

 

I see where you're coming from, I guess it all goes back to the old adage that knowledge is power. If you knew that a vette had a camber curve of say 1deg/inch of travel and X% of ackerman then you could duplicate those numbers with cheaper, more adjustable, and probably better fitting parts.

If you can take the time to lay out the basic suspension geometry on paper then you can figure out almost all the important parameter with nothing more than a strait edge and measuring tape. Bump steer is another more involved issue, when I designed our SAE mini Baja buggy we didn't have much time or money, we also didn't have access to suspension techniques program either. What I did is laid out the suspension design on paper and got the camber curve I wanted, (pretty simple if you read Carroll Smiths "tune to win") and then we took those a-arm lengths and mounting points and put them on the chassis. So what we had was a suspension system that had 14" of travel and gained .5 deg of camber per inch of travel. We did this with no regard as to what the bump steer was going to be. We then took our steering rack and made a best guess as to where it needed to be, we then cycled the suspension and found we had over 2" of bump steer over the full length of travel…..doh! No biggy since we just tacked it on and we're planning on moving things around. All we had to do is move the rack up .5" and rotate the upper control arm in a forward sweep slightly (when viewed from the side, this also increased our anti-squat) and we got our bump steer down to 1/4" over 14" of travel. With just a little thought and some trial and error you can have a suspension system that works very well.

I think you'll have problems duplicating the vette suspension pickup points on a camaro. Packaging is the biggest problem. The lower a-arm is pretty much mounted in the only position it can be mounted and have any semblance of exhaust clearance. So if we left that alone and designed the upper arm mount around this then I think we could end up with a suspension design that had any camber curve you wanted, zero bump steer, a decent roll center height, decent ackerman, and possibly accept a steering rack which you just can't do with the stock spindle steering arm length. Also keep in mind that brake upgrades are readily available for g-body spindles as well, since they are used on most dirt track cars. I also pioneered the first LS1 brake swap on a g-body and there are several others who have done it since. Actually Ed offers a kit with either the LS1 setup or with the 13" vette rotors and calipers so brake upgrades are available.

I've been thinking about this for a while, I might develop a double A-arm setup for 3rd gens. If things in my life slow down this winter I think I'll get busy on it and see if it's even feasible. I would like the kit to be a bolt on deal that the avg. backyard mechanic could tackle. If things work out well, and the end user sources some of the junk yard parts then the kit could possible only cost somewhere in the 500-750 range. I'm an engineer by trade, unfortunately I work in an industry that isn't related to my car hobby so I think a project like this would be fun while letting me stretch my engineering muscles.

Would anyone be interested in a kit like this? Would it be more attractive to use the stock spindles? Would a complete turn key kit with shocks and all parts (used and new) sound better?

 

The Carrol Smith books are really good, though I haven't read the one you mentioned. I heard that he wanted to call his book on racing fasteners "Screw to Win", but the publisher wouldn't let him!

 

LOL, yeah I've heard that one too. If you're interested in turning corners at all you should really pick that book up, it's the best out there and gives you all the info you need without too much theory.

 

All of his books are great. I wish I could have met the man. Got the chance but he died a few days before my first FSAE competition. He was the main judge.

Back on subject; I don't think a camaro needs double wish-bone. It could use IRS but up front the McPherson design is extreamely effective. There are less parts and overall lighter than most other setups that don't use aluminum arms/spindles. Don't over-complicate and if you're dead set on it don't half-*** the car... go all out with a full spaceframe front clip that blends into a cage and to the rear.
Best bet for increased handling is better tires. Hands down tires do 90% of the work so long as the rest of the suspension is "close".

 

Have you guys looked under the hood of an f-body? If you put UCA’s in, presumably mounted to the top of the front subframe rail after some reinforcing, where exactly do you plan on running the headers? Spark plug changes sound like fun also, I’m hoping at the very least this car doesn’t have manifolds on it which would make this all impossible.

If you’re going to do it, about the only way that wouldn’t end up being a PITA to work on would be custom fabbed UCA’s that have adjustable links front and back so they could be mounted to stationary points on the frame, rather then a shimmed link bar like the factory setups.

Well, I guess you could mount the engine higher to make room and run a 4” cowl that you won’t be able to see over and move your center of gravity upward also…

 

Actually mark the frame looks exactly like the G-bodies in this area so there is plenty of room for an 8.5" to 9" upper arm. The pole position arms would fill the bill perfectly if you didn't want to use an adjustable mount, they run around 140$ each. I think you might be exagerating the space constraints a bit. Steering geometry is going to be a much bigger problem.

John, your right that the stock strut setup is light and does work for 90% of people out there. I know there is room for improvement though, if you look at any racing series that allows it guys dial in as much static camber as they can without running the tires into the motor. That tells me they can't get enough dynamic camber and their wearing the outside edge of the tire. Plus all that static camber can't be good for braking. In the scheme of things this means diddly squat to most street cars.

 

I donno, I’d bet that the framerail to framerail distance is about the same between the 2 and most of the difference in engine bay space is because of the height that the engine is mounted at, and that is exactly where things get really tight in the f-bodies.

Actually, not really… the LCA’s are the same length, but who knows where the spindle bearing mounts an tie rod knuckes are located… but who cares… if you make the center link the same amount shorter as any difference in the distance between frame rails, adjust the height of the idler and steering box to match that of the g-body (what, at worst re drilling a few holes?) and you’re 90% there. Most of that last 10% would be improving what would be very close to the stock g-body geometry to whatever you’re looking for.

I don’t know here either, I haven’t seen many people runnig significantly more static camber then they would with a S/L LCA setup, usually a little less then a degree more which is not that much more…

I’d bet that someone that is really comfortable with maximizing both setups would be hard pressed to show a significant improvement on a road course. I haven’t seen anyone run any faster in 4th gens even though they supposedly have a much superior front end geomentry and are otherwise the same.

 

Actually I bet the f-body frame rails are further apart than the G-bodies because the headers pretty much come off the motor and drop strait down where on a g-body they have to make a turn back towards the motor to make it past the frame rail. F-bod's are wider and I bet most of it is in the frame rail spacing since they both use the same lower control arm. We need to get some hard numbers and quite guessing. I haven't really thought of it any further than just conjecturing that it could work.


Actually changing the center linkand tie rod length width DRASTICALLY changes your bump steer characteristics. Think of the arch that the tie rod moves in and the arch of the steering arm moves in, these two have to match up in order to avoid bump steer. If you change the arc of either component you're going to effect bump steer. With a SLA setup you're going to be changing both with the different steering arm length, which will dictate a tie rod length change. The over all arch that the spindle moves in is of course going to change since that's the whole reason for the swap. Again measurements will tell the tale.

I'm basing my observations off of American Iron cars, the 3rd gens and fox bodies always have the top of the tires burried in their fenders while the 4th gens don't show this so much. I know for a FACT that a SLA will have more camber gain than a strut setup, especialy in a 3rd gen because of the ride height and angle of the lower control arm. Wheather or not you actually need more camber is the question. I know on my highly modified G-body suspension that has .75 deg/inch of camber gain that it's no where near enough, my tire temps are always 20 deg warmer on the outside edge. with about a 1deg of static camber. If this is at all possible I would like to use as many stock parts and as little welding as possible. If you really have to hack up some things to make it work this type of modification is probably best left to the experienced chassis builder.

 

That’s just it, and that is what I said the first time, if you adjust the center link length you woudn’t have to change the tie rod length or any other piece, with minor adjustment you’d be in the right ballpark.

 

Thats just it, you HAVE to change the tie rod length, the stock f-body lenght won't match up to the new camber curve, and the G-body length won't match either since it has a positive camber curve from the factory, thats right the wheel tilts out as the suspension compresses.

What I'm saying is there is a tie rod length that will match up with the new camber curve, you can't decide on your tie rod length untill you know what your camber curve is. I can say with out a doubt that it will NOT be the same as stock, if it is you went through all the trouble of putting a SLA setup on your car to duplicate the stock camber curve. See what I'm saying?? This stuff is way too complicated to discuss without some pictures and moving models.

 

I understand exactly what you’re saying but you’re missing the point. Model it and I’d bet that you’ll find that one or the other tie rod assembly will come out very close to right within it’s adjustment range

 

Maybe it will, maybe it won't....without modeling it or at least mocking it up I don't see how you could say it would or wouldn't......way too much theory and not enough hard numbers right now.