Control arm bushing upgrade

Springs and shocks. What keeps your car tight around corners?
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Control arm bushing upgrade

Postby 87e30 » Sun May 12, 2013 11:55 pm

I searched around a bit, but didn't find any good write-ups on upgrading control arm bushings. If there is one, could someone point me to it? I just purchased a set of OEM M3 offset bushings, and a set of poly M3 offset bushings. I'm 99.9% sure I'm going to use the poly ones, but I have the rubber ones in case the ride changes too drastically for me.

Before I take anything apart I want to make sure there's nothing special I need to know. Will the new bushings just swap right in without any other changes? Does anyone have a picture or diagram showing the proper direction to install them? Should there be markings that need to be lined up? What's the worst that would happen if I didn't get them perfectly lined up, or even installed in a completely wrong direction?
Schwarz 5-speed 87 325is (newest project)
Arktisblau 5-speed 86 325e (current DD)
Schwarz 5-speed 87 325e (parts car/LS1 swap?)
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Re: Control arm bushing upgrade

Postby Yoshi » Mon May 13, 2013 12:32 am

http://www.e30performance.info/viewtopi ... =23&t=1784
IMO anywho.

The orientation is simple. line them up with the handle of the lollipop. That's basically it!
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Re: Control arm bushing upgrade

Postby 87e30 » Mon May 13, 2013 4:54 am

I read that thread before posting, but it didn't answer my question. So are you saying the holes should point toward where the bolts go?
Schwarz 5-speed 87 325is (newest project)
Arktisblau 5-speed 86 325e (current DD)
Schwarz 5-speed 87 325e (parts car/LS1 swap?)
Gazellenbeige automatic 85 318i (70,000 miles)
Alpine white 5-speed 87 325is (my first e30, possibly for sale)
99 Suburban
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Re: Control arm bushing upgrade

Postby Yoshi » Mon May 13, 2013 11:17 am

yes. towards the inside.

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Re: Control arm bushing upgrade

Postby 87e30 » Mon May 13, 2013 12:26 pm

Thank you for the picture. That's exactly what I was looking for. Now I know what they say the offset bushings do for you, but can someone explain exactly WHY they do what they do? How does moving the control arm 1/2 an inch improve steering and all?
Schwarz 5-speed 87 325is (newest project)
Arktisblau 5-speed 86 325e (current DD)
Schwarz 5-speed 87 325e (parts car/LS1 swap?)
Gazellenbeige automatic 85 318i (70,000 miles)
Alpine white 5-speed 87 325is (my first e30, possibly for sale)
99 Suburban
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Re: Control arm bushing upgrade

Postby Yoshi » Mon May 13, 2013 12:43 pm

I think technically moving the wheel forward also gives you back some positive camber. Which is good or bad. But it also lengthens your wheel base by a tiny amount. Which is also good depending on how you look at it lol.

Steering specifically? It adds caster. Caster also adds dynamic camber. Which is good/bad depending on your use. The dynamic camber should help your car grip mid corner. But the caster specifically (which is what I think you're asking) is what makes your car self steer back to center. Think of a shopping cart. The wheels follow where you steer it automagically. Same idea but different application for us.

further reading: http://www.acksfaq.com/caster.htm

Edit: like this one better - http://www.gomog.com/allmorgan/CAMBER_CASTOR_TOE.html
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Re: Control arm bushing upgrade

Postby 87e30 » Mon May 13, 2013 6:05 pm

Great reply. I do know quite well what camber and caster are as a certified Hunter alignment tech, lol. I have not even looked at what angles would be changed by using the off-center bushings. All I really needed to know is how it changed the camber/caster, and what else it changed (wheelbase, as you said). I probably wouldn't have needed to ask if I had actually gotten under my car to see for myself, but now we have this post for future reference. :-)

Now hopefully I can get everything installed tomorrow morning so I can actually do an alignment on my car so I don't keep burning through front tires.
Schwarz 5-speed 87 325is (newest project)
Arktisblau 5-speed 86 325e (current DD)
Schwarz 5-speed 87 325e (parts car/LS1 swap?)
Gazellenbeige automatic 85 318i (70,000 miles)
Alpine white 5-speed 87 325is (my first e30, possibly for sale)
99 Suburban
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Re: Control arm bushing upgrade

Postby Delanoso » Mon May 13, 2013 6:27 pm

So let me see if I understand this whole (probably very elementary) discussion. Would you say that the dynamic camber helps compensate for the understeer affects of castor?

Loosely:
Camber = stability while cornering
Castor = stability while exiting a corner
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Re: Control arm bushing upgrade

Postby 87e30 » Mon May 13, 2013 8:46 pm

And lookey here! A new user's first post on this thread. :-) Welcome aboard.

Camber is the angle of the wheel vs the ground. Basically 0 degrees camber would be a wheel perfectly flat on the ground. When you are in a turn weight shifts, and the tires can start to lose traction. The more negative camber your outside wheel has during a turn, the flatter the tire will be when weight shifts to that side, which will give you better control while in the turn.

Caster is the angle of the steering pivot point. The more caster you have the more camber will change based on steering wheel position. So with 0 caster your camber will remain the same from lock to lock of the wheel, assuming no other damage is present. Also with 0 caster the steering wheel will pretty much stay wherever you put it because nothing is trying to get it back to center. When you increase caster you are changing the angle the wheels steer. They are not just rotating left and right, but the wheel angle is also changing. The higher the caster the more the wheel angle (camber) changes as you turn to either side. Obviously this can affect your stability while in a corner because your camber is constantly changing. Naturally the wheels want to return to as flat on the ground as possible, so with a high camber your wheels will be forced to go back to center after you let go of the steering wheel.

Camber can be obvious just by looking at a vehicle, but caster can only be measured while steering from side to side.
Schwarz 5-speed 87 325is (newest project)
Arktisblau 5-speed 86 325e (current DD)
Schwarz 5-speed 87 325e (parts car/LS1 swap?)
Gazellenbeige automatic 85 318i (70,000 miles)
Alpine white 5-speed 87 325is (my first e30, possibly for sale)
99 Suburban
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Re: Control arm bushing upgrade

Postby Yoshi » Tue May 14, 2013 1:06 pm

Both camber/caster are stability creators mid corner. Static camber is a good starting point and caster can help/hurt mid corner seeing as you might gain TOO much camber. Too much camber hurts turn in (not enough contact patch) but too much caster means your contact patch in corner will be small too.

Camber == in corner stability BUT less straight away traction
Caster == unaffecting straight away traction, ALSO more in corner stability. Too much kills in corner stability.

IMO caster is awesome. Camber is a mixed bag.
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Re: Control arm bushing upgrade

Postby Delanoso » Tue May 14, 2013 3:15 pm

Thanks for the welcome, gentlemen! I'm think I'm on the right page now.

I'm not new to e30s or the mods on the but I'm new to the science behind it all. I have an 86 325es that was my daily driver for 10 years. I did a good bit of suspension work, had it chipped and tuned but never really connected all the dots.

It's been off the road for a long time (well garaged) but an impending promotion is going to allow me to get it running again. I want to know the whys as well as the whats and hows as that happens. Y'all are a gold mine where that's concerned. I'll put up a build thread with photos sometime soon. In the mean time I'll probably be probing the hive mind here and other forums.
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Re: Control arm bushing upgrade

Postby Yoshi » Tue May 14, 2013 3:32 pm

connecting what dots? Welcome! Need intro thread.
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Re: Control arm bushing upgrade

Postby Delanoso » Wed May 15, 2013 7:52 pm

I just meant connecting certain adjustments or upgrades to their affects. I knew that castor and camber were alignment settings but I didn't understand what they did or how you'd adjust them to get certain affects. There's probably a lot of that out there for me.

Looked for an intro category--just dump a thread in the build area?
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Re: Control arm bushing upgrade

Postby 87e30 » Wed May 15, 2013 8:17 pm

There is an intro thread somewhere, and you should definitely start a build thread with tons of pics.
Schwarz 5-speed 87 325is (newest project)
Arktisblau 5-speed 86 325e (current DD)
Schwarz 5-speed 87 325e (parts car/LS1 swap?)
Gazellenbeige automatic 85 318i (70,000 miles)
Alpine white 5-speed 87 325is (my first e30, possibly for sale)
99 Suburban
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Re: Control arm bushing upgrade

Postby Nsquared97 » Wed May 15, 2013 11:49 pm

87e30 wrote:There is an intro thread somewhere, and you should definitely start a build thread with tons of pics.

This. We really like pretty pictures around here.
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