Rear axle jumping

[tutin12]

Hi guys,

Can anyone give advice, I've the following problem: Sometimes when I'd give gas, usually from standstill, instead of the wheels spinning - my left wheel seems to start spinning, where the right one starts jumping up and down quite agressively. The whole rear-axle is shaking and it almost looks like my differential is going to drop behind me.

It hapenned a couple of times on the track before, but now it seems to happen more and more often.

If I take my foot of the gas to stop the wheel spin - naturally the axle stops jumping. I can push the pedal to the metal again and it would go as expected. Or may just start jumping again.

Weird thing is this seems to only happen on the right wheel side (non-passanger side) and never on the left one.

Any idea why this may be hapenning ?

At this point the car has about 450 horse power, about 350 on the rear wheels on the dyno.

Do I need some additional parts to strengthen the rearaxle or to attach it do the body somehow ?

All advice is welcome !

[Barbadian Camaro]

Re: Rear axle jumping

I would check all bushings in the rear and also it seems as though you may need shocks,the reason for having 1 wheel to react more than the othe is the shorter axle gives the power to the ground.You may have to get a locker or a spool to have both reacting the same,if you have in a LSD you may have to check the clutches or get a more agressive LSD.

[kristen]

Re: Rear axle jumping

get a nice set of lower control arms.

[Crazed98Camaro]

Re: Rear axle jumping

get a nice set of lower control arms.

Yeap, LCA's will solve this....

What's your set up for 450 horse??

[vr4gasm]

Re: Rear axle jumping

if you really had that much power you wouldn't be asking such a noob question.. i am throwing the BS flag up

[Richardcoelho]

Re: Rear axle jumping

if you really had that much power you wouldn't be asking such a noob question.. i am throwing the BS flag up

i agree:bs:

[RadRacer]

Re: Rear axle jumping

if you really had that much power you wouldn't be asking such a noob question.. i am throwing the BS flag up

i agree:bs:

Ditto :bs:

[tutin12]

Re: Rear axle jumping

Heh, throw what you will, because I am a noob. I don't work on my car, as much as I would love to - I'm just not handy with tools. And yes - the power is there and I don't see why you would say THAT MUCH. It's not THAT MUCH, it's quite not enough if you ask me.

Unfortunately where I live (Bulgaria) there are too few american cars and there are no garages that know how to service them, leave alone tuning. So I go the hard way - every thing I do with my mechanics is a first.

The car is actually quite heavily tuned by all means, however the more I tune - the more I realize has to be tuned / swapped as well.

At first I had a 3.4L Firebird. Last year I did an engine swap and put in an LT1 5.7 v8 engine + tranny. Then I swapped both springs and shocks with lowered / stiffer ones (H&R / Bilstein). Then I added front and rear sway bars. Then the wheels where changed from the standard 16" 205/55 to 19" 285/30. Then we started the supercharger project - Vortec highend supercharger (2 bars / 24+ psi) running at low .5 bars whilst internals are stock + Vortec intercooler (big one) + MSD ignition + reprograming of electronics + Turbosmart AFR + Turbosmart Blowoff + 75 lbs injectors + Edelb..

Need I to go on ?

The list is way too long, in fact let me do a copy / paste from cardomain :)
http://www.cardomain.com/ride/2954580

Engine and power upgrades:

* V6 engine out - V8 6.0L Stroker LT1 planted
* Vortec Race Supercharger (24 PSI / 2 Bar +)
* Samco piping
* Turbosmart Adjustable Fuel Controller
* Vortec blowoff
* 75 lbs injectors from RC
* Edelbrock Intake Manifold
* Edelbrock Throttle Body
* MSD Ignition
* H&R lowering springs
* KYB AGX adjustable shocks
* RPM 19" wheels
* 285 / 30 / 19 Michelin race tyres
* Perfomance headers by Pacesetter
* Performance pipes and exhausts by Pacesetter
* Eibach antiroll bars, front and rear
* Drilled rotors and pads - EBC

So yes - I am a noob, but I'm not an idiot. I'm a guy having a really tough time customzing and tuning the most powerful 4th gen in Bulgaria with absolute lack of local mechanics with experience and pretty much no access to literature besides the internet.

I would love to be in the US right now - easy access to parts, mechanics have tons of experience tuning those cars and what not. But that is not the reality.

So, all that being said - this problem could be solved by using LCAs ? Can you recommend a brand / part number ?

[tutin12]

Re: Rear axle jumping

Oh forgot to add this - naturally the stock fuel pump only lasted about 3-4 traffic lights. Now it's a Walbro highflow pump.

[RadRacer]

Re: Rear axle jumping

Wow; We were thinking you're still V6 based, not V8 swapped, hence all the negative comments. Off-topic, but how much do you have into the car?


And yes, LCAs should help (not saying will solve). Since you've lowered the car, you're also going to need relocation brackets. If it's still there after both those mods, I think a torsion bar might be needed (someone correct me if I'm wrong). I personally would go with BMR products as they have EXCELLENT customer service, and are very friendly.

[tutin12]

Re: Rear axle jumping

[tutin12]

Re: Rear axle jumping

Wow; We were thinking you're still V6 based, not V8 swapped, hence all the negative comments. Off-topic, but how much do you have into the car?

Sorry, it's been a while since i've posted. I should've started by mentioning it's a v8 now.

As for how much - to be honest - way way too much, but I love it :) Tuning (interior / multimedia / sound excluded) i've probably about 20K USD already. And it's looking as it'll double in the next 6 months to a year. Only the forged internals that should be placed in it this winter cost about 10k. Yes, it's dramatic. The sound inside is also above 10k. And yes - may be i AM an idiot :)

[tutin12]

Re: Rear axle jumping

Actually can anyone post some pictures of a properly setup suspension for a high-powered fbody ? Control arms and all... a shot from below the car or something ? Are there any other components that help keep the rear axle and diff in place ?

[tutin12]

Re: Rear axle jumping

Is this what I need ?
http://store.summitracing.com/partde...5&autoview=sku

But then, how about this (whole kit). Man, i'm wish I understood what I was doing.. I think this kit has it all, though there are too many questions in the options part that I've no clue about..

http://www.exoticperformanceplus.com....html?item=145

[pace2006]

Re: Rear axle jumping

Offhand, if you're still running the stock 10 bolt rearend, you may want to look at upgrading to a 12 bolt or 9 inch. Stock 10 bolts have a tendency to snap in higher power applications. I'm sure you already know something about this though.

As far as suspension. You may want to state what the intentions for the car are. If this is a track only car, you'll want to get some certain parts. If this is an in-town or dare I say, daily type car, with visits to the track, then you'll want to look at a different set up. At this point, I would recommend you look into LCAs, relocation brackets, an adjustable panhard bar to center the rear axle (because of the drop), and a few other things. But we can't get into specifics without knowing what the car's used for.