I have an 89 RS with a 305 swapped to a 350 with a mild cam, a completely custom built transmission (by a high performance transmission specialist) and a eaton posi with 3.73's. Probally guestmating about 250 horse to the wheels. I have a serious wheel hop issue. I know it is easily capable is spinning the wheels, but i recently got some new tires. BFgoodrich G-Force, About 10" wide. And i give a shot at a brake stand or a slow roal burnout, and the back end hops like crazy. Could it just be shocks and springs are dead or the rubber is just too sticky? I am pretty foggy on this subject, can i get some help????

 

check some of the sponsors for LCA relocation brackets, it fixes that problem.

 

LCA 'rb's help most on a lowered car. They'll still probably help anyway, but if you car is raised in the back from taller tires, that might not be the issue.

How are your rear shocks and springs? worn rear shocks are also a big cause. Along with totally wiped out LCA/torque arm bushings.

 

lca relocates may band-aid the problem, but they don't fix it.

Wheel hop is the suspensions in-ability to control cycling of the suspension. You're shocks/springs/bushings are how old? Start with the basics. Suspensions need "tune-ups" just like the motor, stuff wears out.

 

In my case it was so bad, I blew a T top off the car in a race.....Same setup your talking about 350, and fat tires...Shocks solved the problem, I really didnt know how bad they were......

 

Well yea everyone should have good shocks, should just be a given like having gas in your tank. Chage them suckers every time ya get tires. They don't cost crap anymore, to simple to change. Struts are what blows the bank but they last forver somehow.

I run coil over shocks on my Bird, clamp on type.
They are installed unloaded.


rust dirty pics, been while since it was done.

 

i'm surprised those coil over shocks haven't blown through the thin sheetmetal back there on the car. Even stock rear shocks blow through the top mount on these cars.

 

Ain't no way they are gonna blow through, even on a stock car unless it get rusty. But all 3rg gens are just held together with crapy spot welds. If only a few rust, it oculd come apart in pieces. But It would need really stressed.

Both 2nd n 3rd gens have a habbit of rusting out in the back area where you can't see it until its to late. Only way to find it is to gut the rear half. Though my car has been gutted and fixed. All body seams and joint have been welded proper. Dug all the goop out of the v channel that runs along the door sill and welded it. Much much better over stock, which you know they only use just enough spots weld and not 1 more to cut cost.

 

Have you looked lately? Even as weenie as that U-bolt arrangement is, given the way that just regular stock shocks blow out the floor pan and especially if they're actually doing anything, I'd expect to see those holes just about all the way flexed out of the sheet metal. Because that's all they go into, you know; UN-REINFORCED sheet metal. And it'll be just that much worse if those things are actually doing any work; i.e. if the actual springs are yerbasic typical weak stock garbage.

I should have taken pictures of mine when I got them welded back together, when the right one blew the hole completely out of the floor pan, punched out a piece about 3" in diameter. The left one wasn't far behind.

 

Sucks to be you
had mine installed for 7+ years.

Though I caught mine before any searious damaged happened.
Some folks never notice till their rear end falls off.
Anyone who see this thread and never yanked your rear half carpet, do yourself a favor and look. From under the car the rust was not visable.
Car still had its factory look from below.

before



after

 

you cut out the old piece and got a new chunk there and welded it in? Where'd you get that piece (the new sheet metal part?)

and what's that reddish stuff?

 

I only cut out what was needed and patched in metal. It didn't look as bad once cleaned up. Most of it was just the wheel well area pulling away. Though from even inside the wheel well I couln't see it.

I welded every seam I could find. [Them cheesy factory spot welds do suck.]
I then sprayed all the weldes with a rust inhibator and covered them with fiberhair bondo to seal out air / moisture. That pic was just mid way through. When ya get working its hard to stop and take pics.

 

It'd be interesting to take a look at it now, and see if it's punched out the sheet metal right around the shock bushing, like they always do.

All of that seam welding and all of that, while NO DOUBT helpful in other ways, has nothing whatsoever to do with the issue at hand.

Meanwhile, to get back to the original post, I'd advise against the JC Whitney u-bolt thing, regardless. To cure wheel hop, first make sure that ALL of your rear suspension wear parts are in good shape; springs & shocks, primarily. Then, the defective suspension geometry that these cars left the factory with, should be corrected with LCA lowering brackets. That by itself usually is the SINGLE BIGGEST BANG FOR THE BUCK mod, after necessary repairs ("repairs" meaning, replacing worn-out stock crap springs and shocks) have been made. Then, any other components that can bend, and thereby store & release energy, should be upgraded; that would be the LCAs themselves, and the torque arm. With those things fixed right there, your car should be good for well down into 1.6x sec 60' kind of launch.

Of course it goes without saying that the car should have SFCs installed on it.

 

you don't have a picture of how you reinforced that area sofaking, but can you explain?
If you just weld a big washer there, you're still welding a thick washer onto thin sheet metal, and just moving the weak point out a little further, right?
so..? Brackets?

 

No pics unfortunately...

But you're right, there's not just a whole awful lot that can be done. Even the repair, such as it is, is pretty weak. I welded 2 enormous washers there, one on top and one on the bottom; they are so big that the edges of them contact the vertical portions of the sheetmetal there, such that all of the horizontal portion of the sheet metal that's visible in Gumby's pics, is reinforced with them. They're welded all the way around their edges where they butt up against the verticals. I thought about maybe making a strip of material out of about 1/8" x 2" strip stock that would weld all along the area behind the seat, then bend horizontal with a hole for the shock, then bend up vertical again and continue on to the top of the rear end hump there; but I didn't. Maybe next time it breaks I'll do that.

 

I appolgise SAMRS350 for the hijack, Folks keep asking questions and it snow *****.

I used 4x4in or 6x6in squares of steel bent in half, over laped and steped.
All the ones I used in the wheel well were galvanized metal to hinder further rust. Just note galvanized give off nasty gases when welded, don't breath them. You can kinda see one in the first after pic

The fender well area isn't really anything special. Why it didn't rust into the car more, that line there is the rear sub frame section. It owuld take more years then I got to rust into it.

Do a search under my name for "back halfed" Should find 3 parts to the long story 900 pics. Read them all cause I was chasing my tail for a while.


Here are recents pics of the back area though. Taken in Feb 06.




Funny has it everyone on this site said the rear STB would do nothing because the rear section is so strong, there is no flex. Yet you guys think the shocks are gonna blow through the floor if I run over a pebble?

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That bar going across is kinda weird. I'm going to have to read your posts here and learn all about it. (like how you mounted it), I also want to know more about these squares of steel you say.

https://www.thirdgen.org/forums/v6/1...ht=back+halfed

https://www.thirdgen.org/forums/v6/1...ht=back+halfed

https://www.thirdgen.org/forums/v6/2...ht=back+halfed

I'm going to read these soon.

 

Nothing special, probably find a whole selection at any lumber store. I use to do roofing on new construction. And all around the job site they would just leave a variety of metal squares all over. If they dropped one they left it. Different sized thickness and types. Funny as it may sound but license plates work good for some stuff. I got one in my back seat floor. Them suckers last forever and are stiff. Though it just the inner floor as none of that rust I found is or was visable from under the car.

Rear STB
https://www.thirdgen.org/forums/v6/3...light=rear+STB

 

Two other good thread

search under my name for "side pipe" & "brake light mod"