Jeffs82TA

iTrader: (1)

Seems like a very popular swap with any car out there. So was curious why not many if any 3rd genners haven't tried and succeeded.

sofakingdom

iTrader: (1)

Pop the hood on one. (I'm guessing you haven't)

Then pop the hood on a 3rd gen. (I'm guessing you haven't on one of these either)

Then come back here and answer your question.

Apeiron

C4 uses a conventional double wishbone suspension. Thirdgen uses a modified Macpherson strut. You'd have to cut the car in half at the firewall and fabricate everything foward from there.

Jeffs82TA

iTrader: (1)

But the 3rd gen has frame rails so the vette suspension cradle should be mountable between them. Aside from removing strut towers and possibly reinforcing stuff doesn't look that hard.

//<86TA>\\

iTrader: (14)

I have measured that frame area of the c4 and the 3rd gen, and they are shockingly similar fyi.

sofakingdom

iTrader: (1)

Only problems being, there's no "frame" "rails"; the lower control arm would have to mount to the K-member, and th eupper would have to mount to the unibody chassis, which is about 1/10 as thick as it would need to be, to handle the loads. And, once you removed the strut tower, wouldn't be anything to bolt a shock, or a fender, to; and nothing to keep the car from folding up right behind where the shock tower was (base of windshield and the place where the top of the strut used to be, coming together) unless a cage type of member was added there.

Understand how a 3rd gen is built, and it should be obvious why that sort of a swap would be a major engineering ordeal. It's been done, although I don't recall seeing stock Vette pieces in there, I think it was some sort of stock car racing type of parts that were used.

Jeffs82TA

iTrader: (1)

Understand how a vettes suspension is, none of it attaches to the frame rail. only the cradle attaches to the frame

Mustang, tri-five, pickup, owners do it so why would a third gen be so hard?

Once you weld a c4 cradle to the front rails of a third gen it would make it quite strong. Only thing suspension wise that would attach to the rails is the shock mount.

for instance this is my 90 front rail yes no thicker anywhere then maybe 3/16th's steel





here it is done on a 65 mustang, why couldn't a 3rd's strut tower be cut sorta the same so it still made it possible to mount fenders and all?

AlkyIROC

If you have to question it, it probably can't be done. If you're convinced it can be done, go ahead and do it. Let us know how the swap turns out.

Anything can be done with enough time, money and fabrication skills. Is it really worth re-engineering the wheel?

//<86TA>\\

iTrader: (14)

I'm with the op on this simply because I have looked at doing this swap on a friends car. The c4 'frame' is the same width as a 3rg gens front frame. The vette crossmember and suspension could be swapped and bolted to the chassis of the 3rd gen with some creative fabrication, theoreticly. Obviously getting everything installed square and with the factory c4r geometry unaltered would require some careful measuring, but IMHO this work is far from impracticle if you feel the need.

Biggest question would be if the car would perform any better with this work done compaired to the work involved in the swap with stock parts and geometry vs the 3rd gen suspension upgraded? Then at that point, would you be better off just buying a c4?

Either way, I have full confidence that I could get the c4 front suspension in a 3rd gen without anything too crazy as far as fab.

T/Aperformance

I believe it is a good idea, the suspension geometry is better than on our cars,so it would handle better, You end up with rack and pinion steering, And you have better brakes. And upgrading the brake would be cheaper, Look for 92 or newer for the better suspension, and breaks.
You will have to fabricate your own motor mounts . If your plans for drag racing I would not bother, but if your looking for better handling maybe autocross I would go for it, A complete front suspension, brakes, r&p sway bar and shock go for around $650.

DBLTKE

iTrader: (1)

This would be very interesting...

Jeffs82TA

iTrader: (1)

What inside to inside frame rail measurement did you come up with?

//<86TA>\\

iTrader: (14)

I don't remember off the top of my head, but the 3rd gen front rails iin the area where the c4 crossmember would install are about the same. Sure there will need to be a little work to make it perfect, but its damn close.

T/Aperformance

The C4 front suspension cradle ends up being 1in narrower than the inside rails on the third gen, And the frame rails end up being a bit to wide and tall and would need to be cut down and reinforced so the A-arms would fit and work properly. You would need to figure out your steering since you would be going to r&p , this getting rid of a few lbs from the old steering system and no more worries about cracking the frame like before.
I do believe this is a very doable swap for a skilled welder, It would be lighter than whats on a stock third gen, Handle better, And for a skilled DIY it would be cheaper than to buy all the performance suspension ,brakes and rack parts to get close to the same performance, , Stay away from the 84 C4 front suspension as it is a one year only and not the best, Go for the 88 or newer, the Z51 handling package would be best.

Pablo

iTrader: (1)

All that work to put in a compromised stock suspension from another car. When you're done you have a stock suspension from a vette, with the risk of it being poorly executed.
Why? Is it because it's SLA? That all? Is that supposed to mean it's automatically better?
You do know that some of the best handling cars in the world make use of MacPherson strut style suspension right? Porsche and BMW M3 come to mind, and even the new Boss mustang which is faster than an M3 on the road course uses it. When I mention Porsche, that includes the 911 GT2 RS which literally is one of the best handling cars in the world.
If you put half the amount of work and thought into the macpherson strut susp. on our cars that you would to swap to the vette front suspension you'd probably be running circles around that vette front suspension.

If you are going to do anything like this, it would make a heck of a lot more sense to swap to the rear IRS if anything. That has clear cut advantages, but the front suspension? I'm not seeing the benefit vs the effort.

InfernalVortex

iTrader: (4)

Agree completely.

To the OP, the Mcpherson strut setup has been proven many times over and it was considered for our cars PRECISELY because of its proven performance heritage. It's NOT a bad setup. The only real drawbacks are a slightly rougher ride with the same effective spring rate and sometimes you have to deal with the strut mounts wearing out. The fourth gens have an SLA setup mainly for ride quality, I believe. They can get the same effective spring rate but with a much smoother ride.

If anything you need to put an IRS in the rear, but that's a huge undertaking. But at least for the effort, engineering, and fabrication work you put in for that you will get a very tangible improvement.

T/Aperformance

Doing a suspension upgrade like should only be done by someone who is skilled in fabrication and welding, I do not see how you can say the suspension would be compromised , In what way would it be compromised?
The upgrade would be more than just suspension geometry , You also get a rack and pinion that has a better steering ratio and is much lighter than the stock GM steering box. And you get better brake, And if you get the Z51 suspension its even better with really good brakes, Remember you can purchase all this for around $650 to $800, So lets say for at most a grand you have all this installed , Now after you add up everything you would need to buy to upgrade the stock front suspension on a third gen to get the same performance level and weight reduction, Well you do the math, new K member and A-arms Is around $1200. rack and pinion around $200, brakes over $400. STB wonder bar, And everything else and your over 2 grand, This would be the easiest way to go for the average DIY person with basic to moderate skill level, The corvette suspension is for the advanced.
Yes Macpherson Strut design is a very good suspension, And many performance cars running them And handling great, I do not see anyone denying this fact or saying that they are bad in any way,
The OP asked a question Some people here gave bad and misinformed advice And I thought I would give more accurate advice, I have thought about doing this to my car I did the research , But its not on the top of my to do list I also agree with you that the corvette rear would be more of a benefit, And also for the advance skill level, Now this one is close to the top of my list, and when I find a decent D44 at a reasonable price I will be fabbing it into my car,

DBLTKE

iTrader: (1)

The positive camber gain on a lowered third gen has always bothered me...

InfernalVortex

iTrader: (4)

I appreciate what you're saying, but say you go through the swap... you'll need to go around and replace shocks, get custom springs (different weight than the C4, different weight distribution too), replace bushings, upgrade this, upgrade that, repair this, rpeair that. It's still a 30 year old suspension, maybe if youre lucky closer to 20 years old by the time it gets in the car. It will need upgrades too.

Meanwhile a thirdgen can get by just fine with slightly cut stock springs and some good struts and bushings. No sense in getting caught up in the tubular suspension parts trend, I have my doubts about their necessity and safety.

And in general I imagine the reason you dont see it much with our cars is because other cars probably already have some form of SLA suspension so its an easier swap, and there's probably very little actual performance advantage to be had there.

T/Aperformance

I fully agree with you, except for cutting stock coil springs, I believe that is an unwise and unsafe way to go. . It is much easier to bolt on what is out there for our car to make the suspension perform better,
I was just informing others what is involved and it is not a something for just anyone to do or even try to do, It is something I have thought about doing, And if I find a complete Z-51 front suspension from brake to brake and rack and pinion at a decent price or for free I will do the swap, But my front for now is already upgraded and works great, I'm looking to do a corvette rear using the Dana44 from an 88 or newer, And yes I know its easier to buy what is out there to make the rear in our cars better,

danclemts

iTrader: (1)

Most of the cars they swap the corvette front in have full frames. 3gens are unibody cars, pretty big deal right there, You'd have to make a front half frame, it can be done, just seems a lot of time and money for not enough benefit. Make the most of what you have first.

T/Aperformance

Why would you need to build a new front frame rails on a third gen? Look whats already bolted up to it now, a heavy K-member, sway bar, Steering box, A third gen front frame is very strong,
Your opinion is not based on facts, If it was then all third gens have a week front end and would not hold up to whats in it now, If you do not believe me, take apart your front end and see what is all there, how thick is the frame it self, Those inner fender that hold the strut is also part of the frame, You would not be loosing them, You would cut a small rectangular hole about 3in high by 14in wide down by the frame, If by chance you would want some extra strength you could ad some round tube from the front of the frame to the firewall, I did my home work for this swap,
It can be done, No its not cheep, I believe it is worth doing, But bolting on what the aftermarket has is easier and I highly suggest most people go that route, Grafting on a corvette front suspension should only be done by a highly skilled fabricator.

danclemts

iTrader: (1)

They don't have a weak front end at all, its just they use the unibody for strength In a frame car you can unbolt the fenders and have no body at all from firewall forward, just the frame, In a Unibody car you can't do that, You have the inner structure that the fenders, core support etc bolts to. The tops of the struts bolt to the Unibody, the bottom part of the suspension bolts to a small frame extension from the unibody with that heavy cross member providing support. it is very strong with the Unibody, just not easy to hang a double a arm suspension on. I'm not saying it can't be done, just not as easy or straight forward as a full frame car. Thats why the Drag cars have a full cage with tubes going up into the engine bay to hang their suspension on.

I think it would be neat to see a 3rd gen with corvette suspension and props to the guy who does it, just not gonna hold my breath

T/Aperformance

OK thi is the lat thing I will say on this subject as it getting very old, Yes I know very well that our car has a unibody ,that is welded to the tub of our cars the inner fender and strut tower is part of it and welded to the fire wall making the frame stronger. The K-member of the third gen is bolted to that frame by six bolts and it does make the frame even more rigid, The corvette K-member would also be mounted at 6 points but it would be using a wider mounting points then a stock third gen K-member, Now a very popular car that uses the corvette front suspension for an upgrade is the first gen mustang, that is also a unibody car, That car frame is the same width as the C4 corvettes frame, And yes drag cars and track cars run full cages, the front down tubes in the engine bay is to stiffen up the chassis as a whole. And this would not be something that someone would do for a drag car, this is mainly for handling, auto cross, r.oad race, track car, I understand that a lot if not more than half of the people who race on this site drag race
Now I've bean working on cars and doing fab work for over 20 years, And last night after being on here I was tempted to buy a wrecked corvette just to do this swap and show those people that are giving wrong information that it can be done like I have said, I even looked at the local corvette salvage yard, But this swap is for next winter, So ya don't hold your breath. right now I'm finishing up on my body modification on my Trans Am and getting my new engine installed in my RV,
There is someone on this site that is doing this swap, Just do a search,

InfernalVortex

iTrader: (4)

There are a lot of legitimate, real caveats to cutting springs, but for our cars in our applications, cutting half a coil out of the fronts and 1/4 out of the rears (the limit to keep spring rates balanced front to rear) is perfectly safe. A lot of the stigma is from coilovers where to get a 1 inch drop you need to cut 1/4 to 1/3 of the total spring mass. That and people doing it with torches which damages the integrity of the steel. A spring is just a metal rod bent in a circle and they have to be cut to length by the manufacturers in the first place.

danclemts

iTrader: (1)

Eh, Not trying to argue, just discuss. Anything can be done with enough time and money. hell, I have a 3rd gen drivetrain in a 4 door Volvo. I guess if you had the parts, a welder and the skills, sure. I just don't see the need myself, 3rd gen suspension is not that bad, but if you want to build the ultimate 3rd gen, that would be a good way to go, front and rear Corvette suspension.

FlyDoc

I don' know if this is what your talking about.
https://www.thirdgen.org/forums/fabr...-z06-long.html

I have Spohn K & A-arms, with Race Craft spinals, I'm considering putting in upper A-arms.