Bent front thrust arm?

va122 · 03-30-2009, 10:02 PM

Hey,

I just got an alignment done and they told me that I couldn't get less then 3.5 deg of camber on front right. The other side is holding fine at 2.6 per my preference. I watched them for hours trying to get the right side correct and couldn't do it. They said this happened to another car and turns out the thrust arm was bent and when they replaced it they got the camber where they wanted it with no problems.

Has anyone heard of this or is it crap?

I get my camber from rotation of the strut tops not shims.

XLR8N-FAN · 03-31-2009, 02:12 PM

I suspect that "catching air" on Banner grade had something to do with the bent arm.

Leigh2 · 03-31-2009, 02:13 PM

I rotated my strut tops and on the RHS the LEAST amount of camber I can get is -2.8. On the left they could get -2.5 so I went with -2.8 on both sides. I can't really see how the thrust arm would affect the camber that much. You would think that the caster would be really different side to side if the thrust arm was bent. You might have to elongate the holes on the strut top.

Camber · 03-31-2009, 02:22 PM

What shim(s) is/are installed?

va122 · 03-31-2009, 04:43 PM

Caster is a slight issue too I'm a 8 deg both sides. I prefer 8.5 and had up to 9 so i'm not sure where the problem lies.

I have the notch in the strut tops already, from when I had this much camber before.

There is a shim on the RHS tie rod, but strangely there is none on the LHS.

I'm so confused.

And yes martin, catching air MAY have something to do with it. So I'll send you a bill vs giving you hoosiers.

Chuck Price · 03-31-2009, 05:03 PM

If you have a shim on the right, and you have too much - camber on the right, why don't you remove the shim? Are you referring to the shims in the control arm?

va122 · 03-31-2009, 06:18 PM

control arm, sorry.

Chuck Price · 03-31-2009, 07:55 PM

Well, the shim is added to give more neg camber, so if the shim is on the side with too much, that would be one place to start.

va122 · 03-31-2009, 08:25 PM

Unfortunately its the opposite situation.

I wonder if i should rotate the struts back and add shims to get the camber I want. It will shoot my castor up but my monoballs are adjustable for castor.

Ideas?

XLR8N-FAN · 03-31-2009, 08:34 PM

Quote:

Originally Posted by va122

And yes martin, catching air MAY have something to do with it. So I'll send you a bill vs giving you hoosiers.

Don't blame me if a 3/4 cup car has trouble keeping up with a stock Z06.

That day was like an episode of "Dukes of Hazard" complete with sheriff

va122 · 03-31-2009, 08:42 PM

My car has no business on the street in its present configuration. I could have used a skid plate that day.

Ok Martin, next time we're on track, both of us on hoosiers and see what happens. Actually you can be on anything you want but I'll be on hoosiers.

XLR8N-FAN · 03-31-2009, 08:52 PM

Your car is way beyond what street tires can handle. It's cruel to watch those PS2s cry in pain. BTW, have you seen this video with your buddy Saffronas?
http://videos.streetfire.net/video/H...-Vs_165902.htm

va122 · 03-31-2009, 09:16 PM

Ohhhh yea I remember this, with sammy. I rode with Sammy at o'fest cal speedway he was sideways the whole lap. Amazing car control. He was a test driver before the drift scene.

va122 · 03-31-2009, 09:26 PM

Stop Hijacking my thread Martin!

NJ-GT · 03-31-2009, 10:47 PM

Vic,

If your car is lowered, and the strut tops rotated, camber should be between -2.5 to -3.5 degrees.

A difference from 0.3 degress camber or less between sides locking the strut tops at the same location is normal. Adding 7mm of shims to the lower control arm increases 1 degree of camber, and increase about 0.3 degrees of caster.

Some shops use shims to adjust caster, and get the camber even with the strut tops. If you use rotating metal bushings, you can dial camber and caster with them + shims + strut tops.

The bent trust arm is a possibility, the lower control arms rarely bend they crack, but the trust arms can bend.

By the way, you want -3.5 on the front and -3.0 on the rear given your dedicated track/autoX. -2.5 is for street drivers with shared track/autoX use (like me, well not anymore).

I prefer to use the same size shims on both sides and use the metal center hole bushing instead of the adjustable one. This way caster may read different between sides, but even brand new cars have different caster reading L/R. Running uneven lower control arm lengths (due to different size shims) brings a new game of trust angles messed up between front and rear axle.

03-30-2009, 10:02 PM	#1
va122 Addict Rennlist Member Join Date: Jul 2006 Location: On Rennlist avoiding work Posts: 1,775	Bent front thrust arm? Hey, I just got an alignment done and they told me that I couldn't get less then 3.5 deg of camber on front right. The other side is holding fine at 2.6 per my preference. I watched them for hours trying to get the right side correct and couldn't do it. They said this happened to another car and turns out the thrust arm was bent and when they replaced it they got the camber where they wanted it with no problems. Has anyone heard of this or is it crap? I get my camber from rotation of the strut tops not shims. __________________ Victor Nationally certified PCA instructor.

03-31-2009, 02:12 PM	#2
XLR8N-FAN Addict Rennlist Member Join Date: Mar 2008 Location: ESCONDIDO, CA Posts: 76	I suspect that "catching air" on Banner grade had something to do with the bent arm. __________________

03-31-2009, 02:13 PM	#3
Leigh2 Addict Rennlist Member Join Date: Apr 2006 Location: Sherwood Park, Alberta Posts: 267	I rotated my strut tops and on the RHS the LEAST amount of camber I can get is -2.8. On the left they could get -2.5 so I went with -2.8 on both sides. I can't really see how the thrust arm would affect the camber that much. You would think that the caster would be really different side to side if the thrust arm was bent. You might have to elongate the holes on the strut top. __________________ 2005 GT3 Arctic Silver 2008 ML320 CDI Tow Vehicle 2006 Audi S4 carbon emitter 1973 BMW 2002 "Inca"

03-31-2009, 02:22 PM	#4
Camber Addict Rennlist Member Join Date: Dec 2004 Posts: 128	What shim(s) is/are installed? __________________ Jim

03-31-2009, 04:43 PM	#5
va122 Addict Rennlist Member Join Date: Jul 2006 Location: On Rennlist avoiding work Posts: 1,775	Caster is a slight issue too I'm a 8 deg both sides. I prefer 8.5 and had up to 9 so i'm not sure where the problem lies. I have the notch in the strut tops already, from when I had this much camber before. There is a shim on the RHS tie rod, but strangely there is none on the LHS. I'm so confused. And yes martin, catching air MAY have something to do with it. So I'll send you a bill vs giving you hoosiers. __________________ Victor Nationally certified PCA instructor.

03-31-2009, 05:03 PM	#6
Chuck Price Addict Rennlist Member Join Date: Jan 2002 Location: Ann Arbor, Michigan Posts: 873	If you have a shim on the right, and you have too much - camber on the right, why don't you remove the shim? Are you referring to the shims in the control arm? __________________ Chuck Price 2004 GT3 White '96 Polar Silver 993 '87 911 Red

03-31-2009, 06:18 PM	#7
va122 Addict Rennlist Member Join Date: Jul 2006 Location: On Rennlist avoiding work Posts: 1,775	control arm, sorry. __________________ Victor Nationally certified PCA instructor.

03-31-2009, 07:55 PM	#8
Chuck Price Addict Rennlist Member Join Date: Jan 2002 Location: Ann Arbor, Michigan Posts: 873	Well, the shim is added to give more neg camber, so if the shim is on the side with too much, that would be one place to start. __________________ Chuck Price 2004 GT3 White '96 Polar Silver 993 '87 911 Red

03-31-2009, 08:25 PM	#9
va122 Addict Rennlist Member Join Date: Jul 2006 Location: On Rennlist avoiding work Posts: 1,775	Unfortunately its the opposite situation. I wonder if i should rotate the struts back and add shims to get the camber I want. It will shoot my castor up but my monoballs are adjustable for castor. Ideas? __________________ Victor Nationally certified PCA instructor.

03-31-2009, 08:42 PM	#11
va122 Addict Rennlist Member Join Date: Jul 2006 Location: On Rennlist avoiding work Posts: 1,775	My car has no business on the street in its present configuration. I could have used a skid plate that day. Ok Martin, next time we're on track, both of us on hoosiers and see what happens. Actually you can be on anything you want but I'll be on hoosiers. __________________ Victor Nationally certified PCA instructor.

03-31-2009, 08:52 PM	#12
XLR8N-FAN Addict Rennlist Member Join Date: Mar 2008 Location: ESCONDIDO, CA Posts: 76	Your car is way beyond what street tires can handle. It's cruel to watch those PS2s cry in pain. BTW, have you seen this video with your buddy Saffronas? http://videos.streetfire.net/video/H...-Vs_165902.htm __________________

03-31-2009, 09:16 PM	#13
va122 Addict Rennlist Member Join Date: Jul 2006 Location: On Rennlist avoiding work Posts: 1,775	Ohhhh yea I remember this, with sammy. I rode with Sammy at o'fest cal speedway he was sideways the whole lap. Amazing car control. He was a test driver before the drift scene. __________________ Victor Nationally certified PCA instructor.

03-31-2009, 09:26 PM	#14
va122 Addict Rennlist Member Join Date: Jul 2006 Location: On Rennlist avoiding work Posts: 1,775	Stop Hijacking my thread Martin! __________________ Victor Nationally certified PCA instructor.

03-31-2009, 10:47 PM	#15
NJ-GT Addict Rennlist Member Join Date: Jan 2003 Location: Los Angeles Posts: 3,449	Vic, If your car is lowered, and the strut tops rotated, camber should be between -2.5 to -3.5 degrees. A difference from 0.3 degress camber or less between sides locking the strut tops at the same location is normal. Adding 7mm of shims to the lower control arm increases 1 degree of camber, and increase about 0.3 degrees of caster. Some shops use shims to adjust caster, and get the camber even with the strut tops. If you use rotating metal bushings, you can dial camber and caster with them + shims + strut tops. The bent trust arm is a possibility, the lower control arms rarely bend they crack, but the trust arms can bend. By the way, you want -3.5 on the front and -3.0 on the rear given your dedicated track/autoX. -2.5 is for street drivers with shared track/autoX use (like me, well not anymore). I prefer to use the same size shims on both sides and use the metal center hole bushing instead of the adjustable one. This way caster may read different between sides, but even brand new cars have different caster reading L/R. Running uneven lower control arm lengths (due to different size shims) brings a new game of trust angles messed up between front and rear axle. __________________ Rennlist Member #: 040525-3732 Autocross and Track Videos