jason_c

hey all,
can some one tell me if any one has put a complete C4 suspension into a C3 and if they had how hard was it to do. I have a chassis here and all the C4 suspension and would like to do it. Then put a LT1 motor in. I think this would be good. What do you think?????

:crazy: :crazy: :crazy: :confused:

Desertdawg

Wait until Marck (Twin Turbo) see's this, he will give you all the poop about it. And why he gave up on doing his. :seeya

Twin_Turbo

front or rear? I didn't do the front, contact sakur (do a search), he has done it.

I tried to fit a rear in my 82 frame and you need to modify several things. You need to mod the frame mounts (and if you have a pre 80 frame you need to add them), make a front pinion mount for the diff (can be done by modding pre 80 front diff mount), you need a longer driveshaft probably. Then there's another problem, shocks and all will fit just fine but the problem is the track width, the C4 1/2 shafts are much longer than the C3 ones and therefore the hubs stick out quite a bit, requiring either neg. offset wheels or flares on the rear. If you want to narrow it by installing C3 BB 1/2 shafts (will bolt right up) you must shorten the toe rods. But this brings another problem, the front dog bone mounts will be inside the frame if you narrow it, could be problematic too and it involves cutting fiberglass. If you leave the track widt as is you can mount the dog bones on a custom bracket that sits in the trailing arm pocket (look at lohkays pics on corvettefaq.com, he has the proper brackets there)

So, it can be done and fairy easy if you don't mess with the track width and use C4 like wheels or flares. I dropped the project because I have 12" wide rear wheels with huge neg. offset to clear the calipers and in total that resulted in me needing 8" wide flares.

The C4 suspension is nice, I had a late model one which doesn't have the jacking problems of the earlier ones (87 and earlier) but I also felt that the gain over the stock c3 setup wasn't all that large. The system lohkay built will do the same for you but it's more work and it's heavier too. The best C4 like system IMO would be one that incorporated a 6 link like norval, brutus and others have built here, then delete the C-clips from the stubs (since the C4 still uses the 1/2 shaft as an upper control member like the C3.. YUCK)

I dropped the project too soon to iron out all the bugs and stuff but I think I nailed most of it. The pics I took are still on the corvettefaq under the suspensions section.



[Modified by Twin_Turbo, 5:11 AM 1/28/2004]

jason_c

Thanks for the advise this does not sound to hard at all. I have all the stuff of a C4 that i wrecked and the same with the C3. So i think this will be ok.

I will keep you all up to date on the progress but it will be a long project..
:crazy: :crazy: :crazy:

Flareside

Twin Turbo, would you happen to remember how much wider the C4 suspension was from hub flange to flange (corvettefaq link is dead)? I'm putting C4 suspension under my 68 (the chassis is being built now), but I'm still not sure where the hubs will fall under the fenders with flares. I hadn't thought about narrowing the suspension, but it's an interesting idea, so I'd like to research that option more. At the moment I'm planning to adjust the offset to compensate for the wider track, but a narrowed IRS would look a little better IMO.

stpman

TT

Is the C4 front suspension any better than the C3?
Would there be any benefit to trying to use the C4 front grafted to the C3 frame?

Steve :steering:

Twin_Turbo

the camber control on the C4 suspension is about the same as on the C3, the toe control howeve is far superior. the c4 suspension is a lot better, and it's a lot lighter too.

As for the width difference:





That's quite a bit of difference, add wide wheels to that and it spells trouble.

Tominator

I heard of it done to a C2 on the show "My Classic Car"


[Modified by Tominator, 9:09 PM 1/28/2004]

Flareside

Thanks for the pictures, that helps. The SRIII website says that their conversion includes a narrowed track width and shortened half shafts, so I guess it's possible. My concern is how close the knuckle will come to the upper framerail and diff mount once the links are shortened.

I'll probably ask the chassis builder to leave the rear dog bone mounts off so that I can weld them where they need to be.

Twin_Turbo

ues, that's another problem, if you narrow it the frame needs to be notched for the toe rod knockle. A major PITA.

GDaina

Contact Paul Newman Creations, they were the first to do this mod. They will sell you the frame, set up to accept both the front and rear suspension. If you don't have a jig for the c3 frame, it would be extremely difficult to do the cutting and welding and have the car track correctly. When done, the frame doesn't even remotely resemble a c3.

BB wowbagger

Theres a C2 here in Sweden with a complete C4 suspension and a SC 540 engine..Its really :cool:

Injected

I've had the pleasure of riding in a few of Paul Newmans cars with the C4 suspension(not C3's, they were both 55 Belairs), both were very impressive. Only down side is the $$, really close to 7k just for frame work without suspension.
I would like to find out more about this also, if anyone comes up with more please let me know.

Greg

Flareside

I don't expect a major PITA. The tube frame is thinner above the axle, so there's more clearance that a stock frame has. IMO, whatever it takes will be worth it to get rid of the 50's frame and suspension. I looked long and hard at the cost of building a C3 frame, rack and pinion, coil-over suspension, modern aluminum brake calipers, better rotors, and a 12-bolt IRS driveline to support big performance and power. In the end, the C4 stuff with coil-overs and a new frame is both better and cheaper.

Greg, once I have the new frame home, I'll post pics and info for everyone for sure. You can do this for less than the Newman prices, and you can sell the stock frame to offset the costs.

-Joe

Twin_Turbo

tube frame??? COOL, where did you buy that frame?

Flareside

Jamison is building it, it will be their second C3 frame.

Twin_Turbo

wow, totally sweet. Can I ask how much ?

PatsLs1vette

yeah joe how much just for the frame alone?

Flareside

$4995. Lots of money for sure, but when you consider that the Tom's 12-bolt rear alone was going to run $4700, and the Vette Brakes Performance Plus suspension is $2000, it starts to look affordable, sort of... :lol: Luckily, used C4 suspension and brake parts are dirt cheap compared to the aftermarket C3 stuff.

spikezz4

We have an 85 C4 suspension installed on a C3 frame. It's been laser aligned and all is well. The 85-87 (I may have missed the top year a year or two) is the same width up front as the C3, but wider by about 3" in the rear. For our purposes, we had to shorten each side by 15/8" for the new 17x91/2 wheels to fit under the fenders properly without using fender flares. It's definately a job for a professional builder. The 88-96 C4's are also wider in the front than C3's, so the earlier model years are better to use for the conversion.

I'll let you know in a year or so how well it rides and handles.

Spike