front control arm lengths

[bengal taiga]

Friend just reminded me there are two different front control arm - lengths.

Early front control arms through 8-73 were 381mm long, while the later arms were 402mm in length. Strut tension rods are also two different lengths 231mm vs. 252mm.

Does this mean the front wheels in older model may stand slightly inboard (21mm) than same wheel on later model?

Has anyone tried running the longer components on an older model? With what results? Increased camber? How much? Tire clearance issues?

Just wondering out loud.

Thanks.

 

[Malc]

Not confusing E3 and E9 by any chance?
Malc

 

[Bill Riblett]

I don't think there is any difference in wheel position, i.e. camber. The mounting holes in the front subframe are closer to the center of the car for the longer arms.

 

[bengal taiga]

Friends discovered long forgotten parts stored with them from the days of e3 ownership. These included control arms. I had attached note with measurements and relevant dates but not models. When I got the call about the various lengths, did not consider the different models. Been too long. Given Malc's prompting, a glance at the parts catalog confirms the length and date changes apply to the e3, although it appears the e9 used the shorter arms only.

Bill's comments have piqued my curiosity. Bill said "The mounting holes in the front subframe are closer to the center of the car for the longer arms."

I assume Bill is referring to the e3.

First, any idea why the change in the e3? 20mm is not that dramatic a change, but there is occasionally a method to the madness. Was there an acknowledged handling/braking/load capability improvement or cost savings?

Second, basic geometry tells me that increasing the control arm length on the e9 would cant the top of the strut inward and have a measurable albeit small effect on camber. I suppose even 1/2 degree might make a difference to some. I vaguely recall thinking about this when after installing new strut cartridges, the alignment shop suggested bending the struts to correct too much positive camber.

Your thoughts are appreciated.

Thanks.

 

[Malc]

Personally if i wanted to "play" with caster and camber I would use "adjustable" turret tops, the ones that allow you to shift the top of the strut around, (back and fore, in and out) available from any good racing shop etc.
Trouble is with changing the arms you only have a choice of two positions :wink:
Then again changing arms and adjustable turret tops would make for a large number of possible setups!
Malc

 

[Bill Riblett]

Friends discovered long forgotten parts stored with them from the days of e3 ownership. These included control arms. I had attached note with measurements and relevant dates but not models. When I got the call about the various lengths, did not consider the different models. Been too long. Given Malc's prompting, a glance at the parts catalog confirms the length and date changes apply to the e3, although it appears the e9 used the shorter arms only.

Bill's comments have piqued my curiosity. Bill said "The mounting holes in the front subframe are closer to the center of the car for the longer arms."

I assume Bill is referring to the e3.

First, any idea why the change in the e3? 20mm is not that dramatic a change, but there is occasionally a method to the madness. Was there an acknowledged handling/braking/load capability improvement or cost savings?

Second, basic geometry tells me that increasing the control arm length on the e9 would cant the top of the strut inward and have a measurable albeit small effect on camber. I suppose even 1/2 degree might make a difference to some. I vaguely recall thinking about this when after installing new strut cartridges, the alignment shop suggested bending the struts to correct too much positive camber.

Your thoughts are appreciated.

Thanks.

I don't know why this was done.

Apparently I'm wrong about moving the mounting holes for the longer arms. Looking in the E3 and E9 parts books, the front subframes are the same for E3s and E9s, except for early E9s and that change appears to be related to the strut arm bushings. Maybe there are 2 holes in the subframe?

I remember people in the 70s 'moving' the inner control arm mounting point on 2002s to get more caster, but maybe I am fuzzy about that too!