Strut brace installation

[|ncary 0]

You are going to gain camber at the front by lowering untill the control arm passes by 90 degrees in relation to the strut (in pink) My quick little pic shows how at different heights the strut is at different angles. I've shown a massive range of motion which you wouldn't actually get in reality.

The angle between the wheel and strut is always the same (angle x on the pink and black heights)

See the angle between the arm and strut on in green is very acute, so lots of camber gain when you get a bit of body roll happening..

And the angle between the arm and strut in the pink is 90 degrees: max static camber but you will lose negitive camber when getting the turns on, and this folks is why it is bad to lower your car too much...

(Or you can run it really low and have stiff springs to match, to stop the arm and strut going past this 90 degree threshhold.)

(Or you can run camber plates so the top of the strut shifts to the right in this example, and the car can be lowered more because the 90 degree threshold will be furthur away)

*claified picture showing the 90 degree angle I mean (in yellow)

Edited December 8, 2009 by Incary

[Apex 693]

Nice, thanks for that, that’s what I assumed. Running any more camber on mine would make it a bit nervous and tramline, it already finds some interesting ruts that I don’t want it too.

Speeding up the steering would make me a happy man.

[bravo 35]

Hey while you're here Henry - what has your research told you about toe settings for a moderately lowered street car?

[DRTDVL 0]

the pug boys rave about 0 toe in the front... but it will make the car twichy... a few of them are running 1-2 degrees pos - but things supposable get rather funky at speed epically on a rougher surface.

there is also comments about fwd creating some natural toe in when on power - but have no idea about that... not that it's relevent.

Edited December 8, 2009 by DRTDVL

[westy 614]

I have 0 toe on the E36 with about 2.5 deg neg camber.

Not twitchy to 200k with the right tyre.

E: E30 could be a different story though.

Edited December 8, 2009 by westy

[|ncary 0]

People can be biased when it comes to Toe settings. But it's another win-lose kind of adjustment, you can win mid corner grip and lose stability (toe out), or vice versa

I see no need for front end stabilty when you have the steering wheel in your hands, if the car goes off line at all it takes is a 1/10 of a second to react and move the wheel 10 degrees (can make the dead middle zone in the e30 rack feel even more dead). But mid corner grip is fantastic on a front heavy car..

If you think about toe out when turning, the inside is turned at a greater angle, sort of pulling the inside of the car around the corner by taking a shorter line. So many other factors though. I like it.

Ooo a good webby site read

http://www.ozebiz.com.au/racetech/theory/align.html

Edited December 8, 2009 by Incary

[|ncary 0]

I did say in the diagram post that you wouldn't find movement near to as shown in real life.

* Oh and yes, the wheel will come in once the arm gets past horizontal, but still gain camber untill the 90 degree point from pivot>hub ball joint>strut top.

Edited December 9, 2009 by Incary

[CamB 48]

1) E30 & E36 camber is not adjustable - wrong I can change mine from +.5 to -2.5 in 10 minutes and I do not have adjustable mounts.

Well, how then - no need to be deliberately obtuse. Does the E30 have offset mounts or are you using another clever technique.

* Oh and yes, the wheel will come in once the arm gets past horizontal, but still gain camber untill the 90 degree point from pivot>hub ball joint>strut top.

I think this is correct too, FWIW. It becomes a more serious problem more quickly on a 2002 as the angle on the strut is steeper.

Edited December 9, 2009 by CamB

[thorburn 121]

Adding washers between the lower strut mount and the hub carrier will add negative camber to the e36

[|ncary 0]

You are impossible to comprehend.

Looking underneath my standard-ly lowered e30, the control arms are on a 20 degree approx downward angle. I don't understand where you got 0.2mm of movement from to get .008 degrees of camber change from what we were talking about? But if you were to lower the car more, even from a already nicely lowered height, the camber would increase quite noticeibly. And that's all we were talking about before.. The Camber gains when lowered, but you lose the amount of travel you have where you still gain camber.

And everything I have read about racecar setup has Toe Out on the front wheels, google 'racing alignment settings' and just the first page has some great info, I bet actual books written by race engineers would have the same thing.

Here's a whole page of real people using Toe Out on BMWs http://www.e30tech.com/forum/search.php?searchid=2292028 Making their MacPherson strut cars handle amazingly.

Another http://forums.bimmerforums.com/forum/searc...archid=14872889

[CamB 48]

I see where you (Ron) are coming from (ok, had to draw some pictures), and while I still think Henry's right (actually, that you're both right), given the length of the strut vs the lower control arm the point at which camber must start increasing is going to be well beyond the arc in which the wheel can actually travel (edit - only if it was possible for the strut to be short than the control arm??).

I'm not going to rehash whether camber's good or bad, and whether caster can properly substitute (for a racecar), mostly since I have no idea.

Also, please explain:

1) E30 & E36 camber is not adjustable - wrong I can change mine from +.5 to -2.5 in 10 minutes and I do not have adjustable mounts.

Edited December 9, 2009 by CamB

[Driftit 2078]

Just saw this post. Have the strut brace that you guys are fitting. Went on with no trouble at all while the car was sitting on the ground. This is my E30 series car which has had quite a bit of use.

Oh and my E30 does NOT have adjustible camber from factory.

[sp8s 1]

Many years ago when I was doing alignments in Wellington we used to make up strut braces for the good old Ford Escort which had a habit of sinking in the middle. The braces we made had a threaded center part of the bar so we could adjust the camber to suit how far the Escort had sunk - the tops of the struts moved inwards, some were so bad you couldn't open the bonnet.

This was quite popular with some of the rally guys as the adjustment was huge and camber could be dialed up to what ever road/track you were racing on.

[bravo 35]

Ron, please elaborate how to alter camber in 10mins without adjustable mounts or offset bushes. I'm not trying to be a smartarse, but this would be great info to have!

Alignment results: NO CAMBER CHANGE WHATSOEVER! from my last alignment roughly 12 months ago. There was about 10' diff between the two, but that's hardly enough to say it actually changed. Also, as I've always known, the car is slightly lopsided - more camber on the LHS. I spoke to the alignment tech about toe-out, and he wasn't convinced it'd be the go with the amount of camber I have, but I'm not convinced he is qualified to give me that sort of advice - I just thought I'd ask him. Unfortunately where I live the talent pool for alignment techs is not as good as in, say, Auckland. These guys would probably be the best up here though.

Toe on this machine is measured in mm. I'm guessing positive toe is toe-in? In which case it's currently set at close to factory. I hadn't read the toe discussion before I spoke to the guys about what I wanted for the alignment, but next time I'll get them to dial some out, and see if there's a difference.

[westy 614]

Jeez I'm good

This does mean that the brace is now in compression.

Considering the out side strut housing is forced outwards under corner load, does that mean that the strut brace is now helping it on its way????

[bravo 35]

Don't know. Obviously for the first say 5-10mm, but then it would be resisting any further movement.

I havn't time until next week, but I think I'll take some measurements:

Brace installed, suspension at rest.

Brace installed, Suspension at full droop.

No brace, same situations.

After driving the car a bit more, the most noticeable improvement is less bump steer. The rest may yet prove to be placebo, but for now I'm sure there is a positive difference, albeit very small.

As we've always assumed, strut braces on e30's (and probably most BMW's) are probably mostly for show. A stiffer brace than this one is probably what is needed. So a job for me in the future is to weld some gusset plates into the bends to reduce flex of the bar.

Interesting link

[DRTDVL 0]

Bravo: got a local unitec or something up there? you could be all geekie and throw some stress/strain gauges on the bar and go for a drive..

[CamB 48]

So camber generally increases as you lower it, with the rate of increase higher when the lower control arm is below parallel?

Isn't that sorta what has been discussed all along?

1) E30 & E36 camber is not adjustable - wrong I can change mine from +.5 to -2.5 in 10 minutes and I do not have adjustable mounts.

So how was that?

Edited December 11, 2009 by CamB

[Driftit 2078]

Just thought I would add something to this.

On Sunday I was at Hamton. And was sick of the massive understeer I was getting. I removed my strut brace as a test and dropped 1/2 a second. Car turns in a little better. I think the old girl needs the flex.

[Matty104 0]

So how was that?

Jack it up... Slowly!

[hybrid 1043]

My experiences with a strut brace on the e46 where interesting.

there where positive and negative things about running one.

In the limit the car was great. Around taupo the 330 was out performing e46 m3's in the handling department.

On the road for day to day sriving it was interesting. Defanite turn in improvements however I found it just a bit too hard for me and non forgiving when driving over uneven surfaces in the road.

Open road I did not like having the strut brace on.. it made the car too 'alert' which after a drive to gisborne from akl was just a pain in the ass.

these days I run without one for daily driving.

the other thing is, a strut brace is only as good as the rest of your components. If you have worn shocks / control arm ball joints and bushes .. there isnt much point going for one. Do the basic maintaince first.. then look at buggerising around with bracing.

[CamB 48]

1) E30 & E36 camber is not adjustable - wrong I can change mine from +.5 to -2.5 in 10 minutes and I do not have adjustable mounts.

Bump for answer please. Don't be shy.

[CamB 48]

Oh I see - you only meant the E36. I thought there might be a magic way for the E30. Never mind.

Edited December 16, 2009 by CamB

[hybrid 1043]

Really you need to do the full set up , drive it and then fine tune it for how you drive.

yeah, I found after I replaced my control arms with e46 m3 ones it fixed a lot of the turnin problems anyways (and after a full alignment).. no need for a strut brace.

Another very strange behalvior I found with the strut brace on was the fuzzy grey line of on the edge and loosing grip was very small. The car wasn't as forgiving.

Very fun to drive and agile .. however.

[turboprop 0]

Mine fitted straight on without jacking up the car, and no suprise there either! The holes are slotted like a hookers... nevermind.

Anyway, no time to drive it, but I will try it tommorow and I might have a gadget to measure front end flex between the strut towers while im driving in real time. Also might hook up some accelerometers and measure acceleration and cornering g forces.

Edited December 16, 2009 by turboprop