Given the cost of C3 suspension upgrades would a better choice be C4 suspension?

JeffP1167

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Joined
Dec 21, 2009
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Yucaipa, CA.
I have looked into the aftermarket stuff offered to upgrade a C3 suspension, such as monoleaf front spring, tubular a-arms, steeroids, shark bite rear stuff etc etc.

I recently came into the complete suspension from a 1990 corvette for free minus the batwing and differential. Aside from that the rest is there including J55 calipers and rotors, FE7 sway bars, rack etc etc.

My 82 frame is completely rust free and I pondered with sending it of to be retrofitted to accept all this c4 suspension and then switch to modern 17" wheel and tires.

In the end what route would you all go? I really like the hub bearings of the c4 verses the c3 setup and what I am looking for out of this car is excellent handling like my 90 vette has.

I really love the looks of my 82 over the 90 but hate the ancient things about it. I just want it to be a nice all around driving car, so given the free suspension stuff which route would you guys go? I see places on the internet that will do the frame mod for around 3500.00 and while this is a good chunk of change I figure just a after market rack and pinion steering system will set me back close to a 1K.

I have the front and rear springs as well just no pics of them. The car this all came fron was a FX3/Fe7/Z51/J55 6 speed car. I think given the hassle to change the front spring I would prefer to use front coilover setup but stay with the monoleaf rear spring since it is easy to change.

So guys, what route would you be more inclined to go?

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I dunno man, for all the fab work needed to get that C4 stuff in there, you can easy spend maybe a grand, and upgrade the C3 shit....buy a set of C4 17x9.5 wheels, a get some 50 series tires on it, roll on down the road...

rear plastic 360 lbs spring VBP....Bilstein shocks all round, 460 front coils,

Grand am rack steering, Hydroboost brakes, aluminum m/cyl...O ring the calipers, and

have it on the road in a week.....

do that C4 gear, and you got enough fab work to tax the facilities of some race car builders....
 
I looked at VB&P's website and a suspension package is around 2800 and a rack system is about 1200. But would that have a advantage over a c4 conversion? I have never liked the steering on this 82 since I bought it. The rear doesn't bother me so much just the front suspension.
 
I bought my '72 vert which was totally mechanically stock as a stove...about 16 years ago....I too had a '88 vette serp setup so on it went, then the aluminum radiator keeping the '87 vette fan in the stock shroud....worked good in Maryland....here in Florida, I finally gave up and Dual Spals went in, curing that hot running in traffic on 110f days...

the 360 plastic rear spring was like 250 bux, 16 years ago, Bilstein shock were the last thing some years ago, replacing the KYB's I had on there....460 front springs were less than 100 bux....new bushings and ball joints obtained locally, adjustable strut rods in rear used and like 100 bux total....

and of course the purchase of some used C4 wheels/tires for 200 bux off a club member up north....changed to '89 wheels of same 17x9.5 for a even swap money wise here....just bought front rubber 255/50/17 paid 260 bux out the door....

OH, VBP wheel adaptors were 250 for a set of four 16 years ago....

I am the guinea pig on them knowing the sizes to sell for that application, they are 2.5" thick, for same wheel/tire centerline, you need move the ebrake cable to top or behind the rotor....easy do....

years later came the rack, before anyone made a kit....200 bux total....junkyard snag on a fresh rack, made/designed my own brackets that are still there today ten years later....junkyard for input universals...

so by time done you got a grand, maybe 1200 into the project,

were I suppose you would spend 5x that amount just to get the C4 gear under there, and it's not going to buy you a thing on the street.....

maybe for Pikes Peak hillclimb events...
 
I bought my '72 vert which was totally mechanically stock as a stove...about 16 years ago....I too had a '88 vette serp setup so on it went, then the aluminum radiator keeping the '87 vette fan in the stock shroud....worked good in Maryland....here in Florida, I finally gave up and Dual Spals went in, curing that hot running in traffic on 110f days...

the 360 plastic rear spring was like 250 bux, 16 years ago, Bilstein shock were the last thing some years ago, replacing the KYB's I had on there....460 front springs were less than 100 bux....new bushings and ball joints obtained locally, adjustable strut rods in rear used and like 100 bux total....

and of course the purchase of some used C4 wheels/tires for 200 bux off a club member up north....changed to '89 wheels of same 17x9.5 for a even swap money wise here....just bought front rubber 255/50/17 paid 260 bux out the door....

OH, VBP wheel adaptors were 250 for a set of four 16 years ago....

I am the guinea pig on them knowing the sizes to sell for that application, they are 2.5" thick, for same wheel/tire centerline, you need move the ebrake cable to top or behind the rotor....easy do....

years later came the rack, before anyone made a kit....200 bux total....junkyard snag on a fresh rack, made/designed my own brackets that are still there today ten years later....junkyard for input universals...

so by time done you got a grand, maybe 1200 into the project,

were I suppose you would spend 5x that amount just to get the C4 gear under there, and it's not going to buy you a thing on the street.....

maybe for Pikes Peak hillclimb events...

do you have pictures of all your mod's?
 
I was also considering trying to mount a 90-96 vette cooling capsule in my 82. Seems like it is raked back enough for hood and header clearance but seems like the hood hinges need the radiator support for strength. Maybe try and buy a upper and lower 90-96 shroud and and test fit it and see if the stock 82 airdam would be able too deflect air into it. If doable this would aloow simple dual electric fan installation.
 
Strength wise how does a C4 dana36 compare to my 82 dana44? I will always have an automatic in the car however might at a later date put a LT1 in the car. But for now it is just a stock CFI motor ... Also would stock FE1 softride springs work well with my 82? Can the C4 front cradle be added in the event coilovers are not used? When converted I assume I will have to use 88-96 offset rims but will 275-40-17's fit in the front and rear wheel wells?
 
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You should be more worried about the rear end. It has more to do with your steering than you think. Maybe not at low speed or simple lane changes, but carving twisty mountain roads, it works to make steering that much less enjoyable. The advantages to the rear are the dual links give you a longer effective pivot point than our single trailing arm. Marck could explain it much better than I could, but there is a lot of rear toe changes as the suspension compresses and releases.
Now if you're talking about slop in the steering, I think it has less to do with the type (recirc ball vs rack & pinion) and more with the general condition of the system. I for one will not be making the jump to Steeroids because I just don't believe the advantage is there. Worth-to-shit ratio doesn't support it. Go with the Borgeson steering box and be done.
You'll get mixed responses to the Dana question. Both guys here that have built multiple differentials will tell you our Dana 44s are "iffy" at best. My measily personal experience tells me they will work fine for around 300hp, maybe more, but that's just with two units I've run. I have never personally rebuilt one and don't claim to have any experience with them beyond R&R. The upside to the 36 is it is already configured to accept the rear toe rods. The down sides are you will have to figure out what you want to do about the torque arm and I believe the bat wing is ever so slightly narrower so it will require a bit of fabrication to fit it.
As for the suspension and tire fit, that will all be determined by where you place the a-arms. You will have quite a bit of engineering ahead of you as the pick-up points for the upper a-arms are inboard on our cars and outboard on the c4. You will likely have rub issues with a 275. It might be minimal, but almost guaranteed contact at lock. I have run up to a 255 with no issues on the front, I think right now I'm running a 245.
 
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By far the best mod/upgrade that Ive done to the vette.Do the c-4 swap!
It's worth it!:thumbs:
 
They convert to pinion mount. I did that too, made mine adjustable

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it's just a C4 diff: it's the red big bushing in the middle of the rear roll cage section

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No, still sitting in the corner.

Still working on the TA trying to cram this in there

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No, still sitting in the corner.

Still working on the TA trying to cram this in there

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24e3eeae8699af.jpg




Sent from my GT-I9000 using Tapatalk

where do you find all this strange stuff? Ok a question, could my front frame rails be moded like say replacing the coil spring areas with flat steel to make rectangular rails to mount a c4 front cradle?
 
do any of you have really detailed pictures of the front and rear frame sections of an 82 frame? Really need detailed pictures of the spring area on the front.
 
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