always faster

Ok im asking this question because when i was all stock(stock driveshaft,stock torque am and stock 10 bolt) my car never make any sound or vibration.

When i ve installed my adjustable sphon torque arm that mount to the tunnel brace(last year only mod) i noticed a steady deep noise/maybe friction as the speed goes higher above 60mph.Like this :rrooommm.....rrooommm.....rrooommm.....etc.

Since then i ve tried a couple of times to check and adjust the pinion angle .

HERE IS THE WAY THAT I VE DONE IT:

-Raise the car on 4 ramp
-Put the angle finder on the ds, the arrow of the gauge point the first mark a the left of the zero mark( so i call it -1 )
-Then put the gauge on the flat part of the torque arm,the arrow point also the first mark before the zero(so again -1)

Conclusion: the ds ad torque arm are at the same angle so there should ok...but is this the good way and the good angle? Could the ds and torque arm have the same angle but still not the good angle compare to the car.

I ve since changed a lot of parts.Now i got a new Sphon hd driveshaft,new Strange 12 bolts,koni suspension,umi lower control arm and panhard rod and still got the sphon adjustable torque arm.

I still got the annoying noise so im a little lost right now and never made it over 75mph because its beggining to be to loud?

Could a bad angle cause noise,like the u joint would bind or something?

Something else?

Every help would be really appreciated.

Thank you

always faster

Bumpy bumpy

Dave '97 Z28 M6

You gotta compare the driveshaft angle to the rear end's angle (measured at a flat part under the diff). The difference between the two is the pinion angle. I don't know if you're getting an accurate measurement of the rear end's angle by measuring the angle of the TA - is that how Spohn says to do it? Note that the suspension must be normally loaded, as though the car was sitting on the ground when you do this.

I would have thought that the aftermarket adjustable TA's would be set for 0* pinion angle when you take them out of the box, but who knows. I've got an adj. TA coming for my car, so I'll soon see how it goes.

Is it possible that there's always been a noise/vibration in the rear end / driveline... and now with the more rigid TA (plus the poly attachments, and the mount to the chassis) you're only now able to notice it? Aftermarket TA's are known to increase the noise level.

angel71rs

The angles shouldn't be equal or else it will end up positive with torque wrap. It should be -3 or 4 degrees so engine/tranny centerline ends up parallel with pinion shaft centerline under power.

http://www.clubfte.com/users/jniolon...nephasing.html

always faster

So my -1 for the ds and -1 for the TA are not ok from what ive read...

If i understand properly i should have:

EXAMPLE:

-1 for the DS
and
+1 for the TA

so this would give me 0 degree

is that correct?

Thank you

Injuneer

You don't want "0" and you don't want -3 to -4deg on the street. For a really big HP setup, -4deg might be necessary for the track, but you would reset it to -1 to -2deg for the street.

You vant a \/ with the angle pointing down. To get the angle, you SUBTRACT the two values, so -1deg -(+1deg) would be -2deg. As long as the \/ is pointing down, you are OK. Otherwise its hard to verify your measurements, because we don't know which way you are looking at the angle finder and which way you are reading + and - .

And to clarify, you should put the angle finder on the flat part of the TA mount, directly under the flats of the housing casting.

always faster

I m really happy that i receive help because im still very confused.I tried to modifiy my angle to find the good one.

I ve tried to make this post as clear as possible.Take this link:

http://www.tunerschoice.com/xq/aspx/...tLargeView.htm

Im using this type of angle finder.The arrow point toward the upper zero,just like on the pic when apply with the magnet to the car ds or flat of the TA..

When i put it on my DS the arrow point the 3rd mark on the gauge at the left off the upper zero digit.

When i put it on the flat part of the TA the arrow point the 2nd mark on th gauge on the upper right of the zero digit.

So this give me
DS:3
TA:2

Is it normal?What normal number should i expect?

I hope that im clear enough...Is it the good way or im still totally lost.

Since i dont know how to post pics ,i ve send 2 of them to injuneer.

Thanks

Injuneer

Looking at the pictures you sent, the +3 reading is to the left side of the "0" and the -2 reading is to the right side of the "0". That's a 5 degree angle.

Still can't tell if its +5 or -5, since I assume the engle finder was pointing down, not up when you put it on the pinion and then on the DS, and I don't know which side of the car you were on.... DS to your left or DS to your right. But 5 degrees is too much, even if it is "-".

always faster

With the pics that i ve sent you , im looking from the driver side.So the DS on the left and the TA on the right.

The gauge is was pointing down but the arrow point up.

So i got a 5degree angle(wich is not good) wich way should i turn the adjuster bolts.Do i extend the TA or do i decrease it?

Trully thank you for your effort

always faster

Still need help

Injuneer

Its straining my brain to reconcile this, but to get the angle you show for the DS (+3deg) and the angle you show for the TA (-2deg) appear to mean you have a -5deg pinion angle. The DS is sloping this way "\" and the TA is sloping this way "/". So the "V" is in the correct position, but the angle is too large. That would put a strain on the U-joints.

You want to tilt the pinion angle up closer to horizontal, which would mean you need to turn the adjuster on the bottom tube of the TA in the direction that shortens the bottom tube length.

Somehow its a lot easier when you are standing there looking at it.... or when Steve Spohn is adjusting it for you using an electronic level.....

FirstYrLS1Z

Your 3 degrees to the left-driveshaft and 2 degrees to the right-torque arm/rearend is supplying you with a -5 degrees(pinion centerline is pointing downward relative to the driveshaft centerline)pinion angle.
You need to shorten(opposite of extend) the lower part of the torque arm.This will be drawing the pinion upward and reducing the 5 degree difference.Adjust to attain a 1-2 minus pinion angle.
Adjust too far and a positive pinion angle will start to be attained.When the pinion centerline points upward relative to the driveshaft centerline.

always faster

I quite far away from Steve But i think that i ve understand.

When you adjust it ,you want to have a positive number on the DS side +1 or +2 or +3 and a negative one on the TA side -1 or -2 to keep the "V"shape .You dont want the TA to have a positive number because it would give a positive(uppward)pinion angle.

So a good example would be:

DS :+1
TA:0
or
DS:0
TA:-1

Am i right?

Thanks you all for your help.

Injuneer

Correct.... you want the "V" pointing down, and the difference between the two numbers to be between 1 and 2.

always faster

Ok i just came back to defenetly adjust the pinion angle.

I put the ds to approx:+0 to +.05
I put the TA to approx:-1

So this would give me something around :-1 to -1.5 degree of pinion angle

Right?

The bad news is that i still got this deep steady noise.I hear it really well over 65mph and it is louder as the speed goes higher.

I hear it also much better in 6th gear.

Should i be worried or this is just normal.

Thank you

Eric