Stock 951 Control Arm Weakness?
#1
Pro
Thread Starter
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Hello all,
Thanks in advance for your responses. I recently purchased my first 951, a 1986 951 with 137k miles. Its main purpose is to use at the track, but the car will remain street legal and I won't be stripping it. One of the possible changes I've been back and forth on are control arm replacements. I've read about their weaknesses in racing applications, and possible problems resulting from geometry changes on cars that have been lowered or run bigger sway bars. I don't want to spend a lot of $$ on something that may not be a real problem in my particular situation, but I need more information to figure this out. Specifically, if I run an M030 front sway bar, 18" wheels with track tires, and 400# springs, how much can the car be lowered before I risk binding the ball joint or otherwise damaging the control arm?
Thanks!
John
Thanks in advance for your responses. I recently purchased my first 951, a 1986 951 with 137k miles. Its main purpose is to use at the track, but the car will remain street legal and I won't be stripping it. One of the possible changes I've been back and forth on are control arm replacements. I've read about their weaknesses in racing applications, and possible problems resulting from geometry changes on cars that have been lowered or run bigger sway bars. I don't want to spend a lot of $$ on something that may not be a real problem in my particular situation, but I need more information to figure this out. Specifically, if I run an M030 front sway bar, 18" wheels with track tires, and 400# springs, how much can the car be lowered before I risk binding the ball joint or otherwise damaging the control arm?
Thanks!
John
#3
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
You'll probably find that you will also start stripping it over time. Some of the best mods are taking stuff out.
#6
Pro
Thread Starter
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
![rockon](https://rennlist.com/forums/graemlins/rockon.gif)
Trending Topics
#8
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Naples? Don't worry about stripping your car, they'll do it for you. lol
Still, an hours drive from Positano has to be a plus. What a place. As for driving in Italy, well good luck
Still, an hours drive from Positano has to be a plus. What a place. As for driving in Italy, well good luck
![Big Grin](https://rennlist.com/forums/images/smilies/biggrin.gif)
#9
Rennlist Member
#10
Addict
Rennlist Member
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
I don't think the control arms should be classified as weak, there are just better options for the track. However, if you choose to run factory arms, get another set that you can have ready to install and rotate them out, have the old ones rebuilt and crack checked.
We did this for almost 3 years on the car in the avatar, then we got charlie arms, with a set of spindles already done. Still keep the old arms and spindles in the trailer, just in case.
Track time just puts undo stresses on all parts. Factory arms weak - no but there are better bushings available for the ball joint if you want to use the factory arm, stock ones are plastic. Even if you do have other style control arms, you should do good maintenance and checks.
Have a set of these still
![](http://gallery.rennlist.com/albums/JABRacing/a_arm_pass.jpg)
now these
We did this for almost 3 years on the car in the avatar, then we got charlie arms, with a set of spindles already done. Still keep the old arms and spindles in the trailer, just in case.
Track time just puts undo stresses on all parts. Factory arms weak - no but there are better bushings available for the ball joint if you want to use the factory arm, stock ones are plastic. Even if you do have other style control arms, you should do good maintenance and checks.
Have a set of these still
![](http://gallery.rennlist.com/albums/JABRacing/a_arm_pass.jpg)
now these
![](http://gallery.rennlist.com/albums/JABRacing/charlie2.sized.jpg)
#12
Advanced
Join Date: May 2008
Location: Toronto/Mosport
Posts: 93
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Yes (ish) Markus Blassak makes 951 control arms by modding Eibach replacement BMW 3 Series arms, they are steel and make sense if you're going to drive your car on the road.
One thing people forget is that the rubber is there for a reason - it gives. When you're tooling around and hit a pothole with a race suspension (no give) you will bend or stress things that will fail later.
I broke a control arm in Turn 2 @ Mosport, and don't want to experience that again, so I went with steel, I like the fact it can bend/give a little, protects the other components, like the bushings and mounting points (a bit) and doen't seem to hurt my performance in any noticeable way.
One thing people forget is that the rubber is there for a reason - it gives. When you're tooling around and hit a pothole with a race suspension (no give) you will bend or stress things that will fail later.
I broke a control arm in Turn 2 @ Mosport, and don't want to experience that again, so I went with steel, I like the fact it can bend/give a little, protects the other components, like the bushings and mounting points (a bit) and doen't seem to hurt my performance in any noticeable way.