KenGPW

Let me start out and say that I have been searching 4 ever and have had no luck finding info on my exact problem. I have a my00 with 40,000 miles. Stock clutch, and diff. My mods that relate/or linked to the problem are Comptech S/C, Spugen duel Ti, Bilstine coilovers, 19 inch rims. Everything else is stock that connects to the wheels. I.E. breaks, rotors, calipers, axels, etc........

My car has been vibrating for the longest time now. It has gotten worse in the past month since I installed the Comptech S/C. The vibration seems to only happen when I am accelerating past 3500 rpm in any gear. It does it very bad at like 25% throttle. And it is coming from the rear of the car. It vibrates so bad that I can't see in my mirrors. But as soon as I take my foot off of the gas a little and hold the rpm's steady the vibrations stop. If I lean into the gas a little it shakes the hell out of me.

My first guess was my 19's were out of balance or just making the car act like that. So I put my stock rims on with new S-02 and the vibrations were the same, if not worse. So I put the 19's back on. I am not sure if it has something to do with the CV joints, the Diff, or even the clutch (pp). Right now my clutch is on its way out so I will be dropping the trans in the winter. I want to try to take care of this vibrating problem while the car is down for the clutch. I am so afraid of breaking the diff with the S/C on the car now and the more aggressive clutch.

Could it also be a alignment problem????? I am running 19x10 in the rear so my camber is off so the wheels will not rub. Right now the camber is set to the same way it was with the stock suspension. The car is lowered about 2.5 inches in the rear.

Any feedback would be a great help to try to figure out the problem...........
Thanks in advance,
Kenny

jojipoji

did you ever have clicking? i had the shakes and it was because my cv joints were pitted.

KenGPW

I only have that slight click when starting off in 1st or reverse.........I think tighting the axle nut to 220 ft lbs wil take care of that problem.

xviper

Although there could be something else going on here, you should direct your attention to the CVs. Another possibility would be the diff (outer pinion bearing perhaps).

AZS2000

You might look at the wheel bearings. As you accelerate the wheels force the wheel shaft to press forward into the wheel bearing (for the rear wheels). If the bearing has a wear spot, or pit in the front, you may be feeling it only when pressure is placed into the front of the bearing (accelerating).

Does the frequency of the vibration increase as your speed increases?

AndyDoh

have you curbed the car at all or could one of your rims be buckled?

KenGPW

Car has never been curbed....... The vibrations get worse as i go faster but when I hit about 6500 RPM every thing seems to smooth out..... It is very noticeable in 2nd and 3rd gear.......
What should I be looking for??? Is it something I can visualy inspect???? I actually have the car on jackstands right now fixing my Feels rear lip. Had to do some adj for the Spugen Ti........ How hard is it to replace the CV's????? Where can I get new ones and how much $$$$. I would be doing the install myself, I am not a newbe to turning wrenches.......

mikegarrison

I don't see how it could be anything other than the engine or clutch. He says it is RPM dependent rather than speed dependent. The CV joints, differential, wheels, etc. all "see" vehicle speed, not engine speed.

Hmm. Except he says it is coming from the back of the car. Some suspension resonance maybe? Something where the engine vibration frequency is the forcing function?

Or maybe something in the transmission is bad at those engine speeds, and it transmits the vibration to the rear wheels, which puts the whole car into resonance?

xviper

If it's happening at the same rpm range in multiple gears at any road speed, then I'll have to agree with this.

Can you feel it through the shifter? As soon as I put my Vortech on the engine, a fairly heavy vibration started to come through the stick. I attribute it to the blower changing the harmonics of the engine vibration conducted themselves. These, too, were rpm related. However, mine has never gotten any worse than from the first day the blower went on. Perhaps something in the way the S/C is mounted (do you have the newer rubber mounts?) or the engine mounts themselves have changed over time (wearing out?).

AndyDoh

Bit of a red herring but, maybe a problem within the diff if your saying gearbox related then couldn't this also include the dif and as its at the rear it seems to make sence..........or does it?