C-4 suspension question
Thread Starter
Racer
Joined: Mar 2005
Posts: 303
Likes: 2
From: southeast Idaho
C-4 suspension question
Hey guys, a long time c-3 guy here. I built a twin turbo 468 motor for my 72 vette last year and now I am moving onto the next project for the car. I picked up a front and rear suspension setup from an 86 vette with a std trans and I am going to get it put under the car this next winter. My question is what do I need to do with the driveshafts, stub axles and center section ect to make them handle 8-900 ft lbs of torque? I am going to use a 4l80 auto trans with a 22 to a 2500 stall converter. This is going to be a street cruiser with all the acessories and I am hoping I can get 20 mpg on the highway with it. I will be running 18 inch tires with335/35/18's on the back and they will be tucked under the fenders with maybe a slight flare. Any help will be appreciated.
Mike
Mike
Team Owner
Joined: Sep 2001
Posts: 62,160
Likes: 1,733
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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There was a thread here within the last couple weeks about building up a car to handle that much torque, try to run searches for it above.
Quick answer is that you're better off thinking of a 9" solid than the C4 IRS. That much torque wont allow your U-joints, drive axle, spindles, or halfshafts to last long. Each will need upgrading and the D44 rear will benefit from cryo-treatment if you insist on using it. Driveshaft is something I would worry about least, but the halfshafts will likely obliterate themselves and take some bodywork with them.
Don't worry about the weight of parts, or their sizes, you must worry about strength alone. Carbon fiber shafts from Dennys, cryo-treated rear and spindles, and pray the Joints can take abuse in a race.
If its a street only car I wouldnt be overstressed because you wont hook it up on the street anyway, and its usually a good hook that destroys parts.
Quick answer is that you're better off thinking of a 9" solid than the C4 IRS. That much torque wont allow your U-joints, drive axle, spindles, or halfshafts to last long. Each will need upgrading and the D44 rear will benefit from cryo-treatment if you insist on using it. Driveshaft is something I would worry about least, but the halfshafts will likely obliterate themselves and take some bodywork with them.
Don't worry about the weight of parts, or their sizes, you must worry about strength alone. Carbon fiber shafts from Dennys, cryo-treated rear and spindles, and pray the Joints can take abuse in a race.
If its a street only car I wouldnt be overstressed because you wont hook it up on the street anyway, and its usually a good hook that destroys parts.
Thread Starter
Racer
Joined: Mar 2005
Posts: 303
Likes: 2
From: southeast Idaho
Yeah it will be street only, the nearest tracks are 4 hours in any direction anyways. I'm more of a high speed, road race type. I figgured the automatic will be a little easier on things than a standard would. The thing that concerns me is when you get up to 80 mph or so and can no longer break the tires loose then things are going to recieve full torque but I guess there wont be a big shock on the drivetrain at that point. So are you saying the half shafts are the weak link?
Pro
Joined: Dec 2002
Posts: 746
Likes: 1
From: salem or
You might want to consider replacing the axel shafts and driveline with steel shafts.
I've had alot of difficulty with these in my racecar. The driveline is a no brainer... when you twist it up to look like a crushed beer can it's easy to see that it needs to be replaced. However, not as obvious and especially dangerous are the halfshafts... as these also double as the lower suspension link. When they break the rear wheel turns and the car rear steers.
I've had alot of difficulty with these in my racecar. The driveline is a no brainer... when you twist it up to look like a crushed beer can it's easy to see that it needs to be replaced. However, not as obvious and especially dangerous are the halfshafts... as these also double as the lower suspension link. When they break the rear wheel turns and the car rear steers.
