Need help with weird vibration
07-25-2005, 03:21 PM
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Need help with weird vibration I just installed my Spohn tunnel mount torque arm, and i set the angle to -2 and i double checked that. 1st off, it makes a huge difference and I am definitely glad i got it.
When under heavy acceleration or decel it feels fine. When under normal to light accel/constant speed between like 30-50mph the entire car vibrates slightly. It feel similar to the vibration I used to have with bad tie-rod ends and my old driveshaft at high speeds, but alot slower, obviously because I am going slower. Do I need to look at the angle again, maybe go a bit more toward 0 or could a bolt on it be loose? (I tightened them all real well, but maybe?) Or is it something else?
Any input is appreciated and thanks in advance.
When under heavy acceleration or decel it feels fine. When under normal to light accel/constant speed between like 30-50mph the entire car vibrates slightly. It feel similar to the vibration I used to have with bad tie-rod ends and my old driveshaft at high speeds, but alot slower, obviously because I am going slower. Do I need to look at the angle again, maybe go a bit more toward 0 or could a bolt on it be loose? (I tightened them all real well, but maybe?) Or is it something else?
Any input is appreciated and thanks in advance.
07-25-2005, 03:29 PM
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The torque arm and pinion angle settings are a bit out of my current realm of knowledge, but from what I understand, the more negative angles are for drag racing where launch and traction is ideal, while 0 is the best for U-joint wear. Just based on that, my assumption ( I know... I'm dangerous... heh) is that the pinion wants an angle closer to zero, hence the vibration. Hopefully someone who actually knows what they're talking about can come in and confirm that for me.
07-26-2005, 12:08 AM
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neg 3* is probably a bit far.... I did some consulting this evening and the number I hear that's pretty decent is -1*. Also there's some sort of debate that continuing to decrease the pinion angle doesn't actually help launch at all. Take it as you will, but if it's iffy and I can increase the longevity of my u-joints... all while elminating vibration, I'll take that option. 
07-26-2005, 03:16 AM
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oh no that sounds much better. i'm bringin my car back tomorrow to get it fixed. How hard is it to adjust myself? I just got it and i really have no idea about that part of the car...
07-26-2005, 08:30 AM
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Its not hard. Just a two nuts to lock it in place and then the actual adjustment shaft. Let me know if the vibration goes away after you have it adjusted.
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07-26-2005, 09:27 AM
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Right, well sorry it was early. I was talking purely about the mechanical aspect. You have to use the angle finder on the driveshaft and on the mounting plate where the torque arm attaches to the rearend.
07-27-2005, 10:02 PM
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pinion angle has nothing to do with trans tailshaft on these cars... It just has to do with the angle between drive shaft and rear axle...
The red numbers are not what your protractor will read, but they are the numbers of the imaginary line through the driveline. Hope this helps.
The red numbers are not what your protractor will read, but they are the numbers of the imaginary line through the driveline. Hope this helps.
Last edited by OldeSkool; 07-27-2005 at 10:11 PM. Reason: fixing picture link again
08-28-2005, 10:46 PM
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So did you guys ever get this solved? I am having vibration/shaking past 60mph. I can look over and my passenger seat and see it shaking. I have a BMR adj that i set to -2 or -3 and I am hoping that is what is causing it...
09-01-2005, 02:26 AM
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nope the shop ASSURED me that neg 3* is the BEST and ULTIMATE position for this tq arm to be at, but instead, they are checking to see if it's my new lpe driveshaft, then the output shaft on my trans and then the ring and pinion gears....
09-01-2005, 12:16 PM
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I have mine at negative 2 for sure, I have checked it several times. I still get some vibrations at highway speeds, but it got better. I don't know how to totally solve it yet.
09-01-2005, 08:51 PM
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Guys have any of you installed relocation brackets? Check your rear end to see if it is square, meaning that...each wheel is centered in the wheel well.
I asked BMR about my vibration problem and I told them that after I did the relocation brackets (exactly as instructed), my rear end is now out of square, it is forward about an inch on the left side and back about an inch on the right side.
Well, I asked them if I needed adjustable LCA's to fix the prob and they said that the adjustable LCA's should fix the vibration problem, and will of course set the rear end back to its centered position.
I asked BMR about my vibration problem and I told them that after I did the relocation brackets (exactly as instructed), my rear end is now out of square, it is forward about an inch on the left side and back about an inch on the right side.
Well, I asked them if I needed adjustable LCA's to fix the prob and they said that the adjustable LCA's should fix the vibration problem, and will of course set the rear end back to its centered position.
09-06-2005, 06:45 PM
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nope, no relocation brackets - i just got my trans checkout, and no problems there either. So if it's not the pinion angle, not the trans, not the driveshaft, that leaves the rearend...
i dunno if it's related, but when viewed from the rear, the right side of the car is sitting ALOT lower than the left. the shop replaced by ball joints (not sure if thats related), but just thought it might be a symptom, only b/c i'm running out of parts to replace.......
i dunno if it's related, but when viewed from the rear, the right side of the car is sitting ALOT lower than the left. the shop replaced by ball joints (not sure if thats related), but just thought it might be a symptom, only b/c i'm running out of parts to replace.......
