Howdy,

The guy that does most of my work also has an auto body shop with a frame machine. He casually mentioned that if I wanted more negative camber up front he could probably bend the strut towers out. I'm not totally sure if he was serious or not.

Has anybody done this? It strikes me as a cheaper way to get more neg camber than coilovers.

 

Well, there are those that have pounded out flat the beading that runs up the inside of the driver side (?) tower. This will make more room for the upper pearches to slide inward.
You can't actually "move" the towers if that is what he was saying.

 

 

I casually suggest that this is a terrible idea.

 

Sledgehammers and Mini's do not mix well, even in polite company.

 

I don't know how many degrees of camber it is to each really big hammer whack....
But ther are easier more precise, proven methods of doing this.

The answer to your question is YES ...
but you can also push you car to save gas ....

Looking at you BIO your not on a $ saving trip here.

 

I know, it's probably silly. It wouldn't involve hammers, though. His frame machine is designed to move bent frame/unibody parts back to precise angles. It could probably be induced to give a -1 degree bend to the unibody in those locations.

I'm almost surely not going to do it, but I find it an interesting idea.

 

Have fun fitting the motor back it after bending the towers.

 

To be fair, we used to adjust the towers on older cars this way (think '79 RX-7). But to be honest, this was because the towers were too weak and would droop together until the car had too much camber (for our customers, that is). The MINI towers (and most new cars now) have way, way stronger (and stiffer) towers.

 

The towers would have to move inward. Moving them out would make camber more positive. There are some specialty alignment / frame shops that have equipment to actually bend damaged struts back to spec. You might be able to have them bent the other way. Have this done at your own risk. Why not just install camber plates?

 

I wouldn't rule out the possibility that my car has had this done to it a little bit just from lots of miles on crappy CA roads - my camber after the IE fixed plates came out a bit more than I expected - but I don't think I'd do it on purpose.

 

I do have camber plates, but I'm limited to -2.5ish with stock-sized springs. I don't have $2k to drop on Biltsteins, and I won't put $1k p.o.s. coilovers just for the camber.

Now, maybe I can have the fenders bent as well and get the new Ultra-Wide Hoosier 15" A6's under the fronts as well.

 

$1Kp.o.s.???

Megan and BC, despite having non-barrel shaped springs, are limited to ~2 deg neg camber. That's enough for the street.

 

I'm an autocrosser who does a few lapping days. If I get a bar in I'll probably do a few time trials as well.

This could be another whole thread, but, since I have very little practical experience in suspension setup I have to pick somebody to listen to. I've had many conversations with Sam Strano of www.stranoparts.com . He's a 3-time National Solo champ and an Evolution school instructor. He's driven just about everything there is to drive. He's repeatedly advised against most of the coilovers out there due to personal experience/knowledge. Heck, he even talked me out of the Bilstein's for the time being. His web site stinks, but I'd recommend that anybody who has setup questions call him. He'll give you tons of his time and then, like as not, talk you out of buying something from him or buying something less expensive that he likes better.

 

Sam is well respected, helped me a couple of times.

 

Hi all,

To the question at hand: "Are there ways of increasing negative camber despite using stock type barrel springs?"

1) I, like others, have bashed the drain ribbing on the inboard side of the strut tower to give a little more clearance for a little more static camber and a lot less noise.

2) There is a fair amout of rearward clearance in the strut tower to move the top pivot backwards and increase the static caster. Increased static caster will result in an increase of negative camber in turns that require a fair amount of steering input, such as autocross. Here is a link that talks about this issue: http://sccaforums.com/forums/thread/234346.aspx

Food for thought,
John Petrich in Seattle

 

Great link John!

I know I am sometimes persistent, and so today is no different. Caster, as the article states, and like anything else in life, is good up to a point and has its place. And so...

Caster can wash out the affects of SAI because the outside wheel is raised and the inside wheel is lowered. As a result, the inside rear wheel recieves a given amount of cross weight in a turn. some folks think this is a good thing...except, if you find your self in an opposite lock condition trying to recover from a slide, the weight transfer is to the wrong rear wheel. And, I've been studying and consulting with a suspension engieer about the affect caster has on pneumatic trail. Why bother? Pneumatic trail is a function of a given tire, it is the rearward distortion of a tire in motion. The great thing about pneumatic trail is that it telegraphs tire slip information directly to the steering wheel - and this can be measured as steering effort. As a tire corners and builds up cornering force, the steering wheel becomes heavier. As the tire begins to lose grip, the steering begins to lighten. This is important information. Mechanical trail is simply the force vector the tire follows. We can have positive mechanical trail and no caster or positive mechanical trail and lots of caster. A shopping cart has positive mechanical trail and no caster, for example.

As John wrote, adding caster can aid self centering because it moves the force vector point farther in front of the tire's sideview centerline. The problem with this is that steering wheel effort is the combination of many things, but mechanical trail (positive caster in our case) and pneumatic trail combine to generate a given amount of steering effort. Problem is, if caster is set very high, it can over power the subtle slip messages transmitted by pneumatic trail. I don't know what the Mini's threshold is and I'm not suggesting anyone avoid caster. Just know what it can and cannot do...and where it is applicable.

If you have 2 degree neg camber or more, adding a degree or two of positive caster will help to get back some straightline stabilty - which high neg camber values erode.

Remember, that fastest drivers do not necessarily have the fastest cars. If a car telegraphs information about slip, and is vise free, the driver can consistently take the car to its edge.

 

Michael,
Agree 100%. Among your points is that there is no free lunch regarding suspension geometry trade offs.

As you know, my response was directed at the question of increasing negative camber in the narrowest sense. There are direct methods with chassis modifications, and indirect methods thru adjustment of other suspension geometry parameters. Whether the extra negative camber is desirable or not involves considering those trade offs you spoke to.

Am having trouble with your 'pneumatic trail' concept. I can see, feel and taste the 'mechanical trail' but the 'pneumatic trail' eludes me, at this point. You'll need to beat on me a bit more until I understand better.

Regards,
John Petrich in Seattle

 

where the contact patch gets "dragged" backwards a little bit due to friction, distortion, and tire scrub. But with this in mind, it depends on tire type, road surface, speed, and on and on and on.

While I understand what it is, I'm just not sure how it relates to optimizing compramized geometries like the Mac Strut. I'm still learning a lot here....

Matt

 

Matt,

Thanks for the capsule of knowledge. Re-read Michael's post and came to a similar level of understanding. The pneumatic trail is a dynamic sort of thing. Like the slip angle, it exists when the tire is in motion. No wonder that I cannot see it. I just have to 'experience' it.

Feel better, now.

John Petrich in Sammamish

 

The Dr. spoke John Think of a Fred Flinstone cartoon...imagine what the wheels look like as his car speeds away...even stone distorts in toon land Although, in reality only the bottom distorts...mostly. And as I wrote, and Doc wrote, pneumatic trail is totally a function of the tire, but geometry also affects what a particular tire will do.

Hope I didn't come across as trying to diminish your response John?

Some of these aspects of tuning are so subtle as to appear meaningless outside of a scientific community. But sometimes the subtlties make a huge difference in feel...we can feel much more than we can measure or explain away.

 

Michael,

Just perfect. There are answers to questions and ANSWERS to questions. You provided ANSWERS. That's why we are all here, isn't it?

John Petrich in Seattle

 

okay