[sle39lvr]

I will be getting my coil-overs soon, and will be lowering a tad under Sports Package height. Right now it's on non-sport suspension.

When done, I want to get my alignment done correctly. Since this is not stock nor sport height, how would the alignment be determined?

For example:

Rear Camber (Specified by the dealer's machine)
Non Sport: -1º 30'
Sport: -1º 50'

For the height lower than sport, will be over -2 degrees due to natural progression of camber relative to height (lower these cars get, more negative camber you would have in the back). Do regular alignment machines calculate for this automatically? The dealer's machine will be able to?



For those of who went lower than sport suspension height and still maintained correct alignment, what values did you go for?

[DriftDreamzSS]

I just told them to put it within stock specs while staying equal side to side. I don't remember what my actual numbers are but they were able to get it within the range their computer calls for on a stock sport package car with KW V2's set pretty low.

[tofu-]

don't worry too much if your camber is a bit higher. as long as the toe angle is set to factory specs, your tires will wear fine.

[zeenon53]

I've always wondered If I should be running more than the factory camber on my lowered car as well. Hopefully we can get some good answers. I'm on KW coilovers and set it to the factory sport specs. I know M3's run more camber than us.

[MrRager]

factory camber for a sport suspension car is -1.8 not -1.0. either way, proper toe settings. (usually between +0.12 and +0.18) are okay

[vasillalov]

I usually max out the camber in the rear and keep the toe in spec. Right now with stock sport suspension, I have -2.5 rear camber. The tires are wearing evenly.

[sle39lvr]

Originally Posted by MrRager

factory camber for a sport suspension car is -1.8 not -1.0. either way, proper toe settings. (usually between +0.12 and +0.18) are okay

Where are you getting your -1.0 from?

[sle39lvr]

I got another alignment today.

I went to -1.5 chamber on rear from -1.1. Car rotates better in corners now.

However, I went from 1/4deg to 1/8deg toe up front. I feel the front end is wondering too much on straights. Also on hard cornering, front end pushes.

[CJ421]

Originally Posted by sle39lvr

I got another alignment today.

I went to -1.5 chamber on rear from -1.1. Car rotates better in corners now.

However, I went from 1/4deg to 1/8deg toe up front. I feel the front end is wondering too much on straights. Also on hard cornering, front end pushes.

Increased camber up front means you now have more grip up there. Add camber up front to reduce push/understeer. I'd shoot for -1.5 to -2 deg.

[sle39lvr]

I was asking if getting less Toe up front makes the front end to push and front end to wonder in straights...

[CJ421]

Right, and I pointed out that you increased in-turn grip in the rear by adding camber while presumably leaving the front alone - meaning the car will have an increased tendency to understeer/push. Toe settings don't affect turn grip; they affect the car's cornering response. Toe-in enhances straight line stability, which is why it's BMW standard alignment spec. Toe-out enhances turn-in response but can make the car a bit 'darty' at upper speeds.

Personally I run zero toe up front in an attempt to catch the middle ground between high speed stability and turn-in response; it works well for the race tracks I run. I haven't noticed any stability issues or wandering. An added bonus of zero toe is the least possible tire wear.

If you're still in doubt, put the toe back to what it was before and leave everything else alone.

It'd be helpful if you listed the make/model/sizes of your tires, and your full alignment specs for both axles.

[sle39lvr]

I appreciate your expertise in this matter.

I have:
-08 e90
-Non-sport Suspension (Coil-overs are coming soon)
-OEM 18" staggered wheels (225/255)
-M3 Control Arms in rear
-M3 Subframe bushings
-22mm M3 Rear Sway

Last alignment:

Front:
-Toe:0.10º (0.20º total)
-Camber: -0.7º

Rear:
-Toe:0.05º (0.10º total)
-Camber: -1.2º

New alignment:

Front:
-Toe:1/16" (1/8" total) (how much in degrees?)
-Camber: -0.7º

Rear:
-Toe:1/16" (1/8" total) (how much in degrees?)
-Camber: -1.5º

[CJ421]

Thanks.

Converting inches to degrees or vice versa - you need to use an equation. I found a chart here.

Your car is setup for understeer at the limits - the staggered factory tire sizes (225 front, 255 rear) are primarily responsible for that. Common sense would call for the same sizes all around given the E9x is 50/50 weight dist. But all street cars are equipped to understeer from the factory (safer).

Things you can do to reduce the car's tendency understeer at the limit (in order of importance):
A. Get a square tire setup - same size tires all around (245-255 mm are popular)
B. Increase camber up front - shoot for -1.5 to -2 deg
C. Stiffen the front suspension
D. Slow down

A is going to be 'instant gratification'. It's the only item up there that will increase the car's static amount of grip. The compound is just as important - not all tires are created equally. Michelin PSS rules the roost for street tires right now.
B will probably require you to get camber plates; you can drill out the alignment pins and install the M3 control arms/tension struts to get -1.1 to -1.5 (every car is different). You would actually save on tire wear with more camber during high performance driving (otherwise tire rolls over on sidewall).
C entails increasing spring rates and/or installing a stiffer sway bar. See what your coilover vendor offers in terms of rates. There is no benefit to having the front of the car roll.
D is the truth, though. If your car is understeering in T1 entering at 45mph, but not at 40mph, then go 40mph. The car has a static grip limit (determined by the tires) and cannot exceed that ...laws of physics. Faster lap times mean going slower sometimes.

P.S. The M3 rear sway is what's helping you rotate the rear since it reduces traction back there. It's detrimental to the car's performance for that reason; the rear needs to flex a bit to get power to the ground in turns, especially if you lack a limited-slip differential. I would say uninstall it, but that's such a bitch with these cars that you are better off working around it. Install the matching M3 sway bar up front, and maybe go with a slightly less rear spring rate with your coilovers.

I think I remembered everything. I hope that makes sense.

[CJ421]

P.S. I realized I didn't answer your original questions about alignment machines compensating for ride height ...I have no idea. I don't think the ride height is taken into consideration. Alignment is just a matter of trying to get the car within a certain spec.
Toe is your enemy for tire wear, not camber. The adjustment room built into the stock suspension is sufficient to get within spec at stock ride height only. These cars toe out when lowered so you may not be able to get it back within spec without buying aftermarket parts with the adjustability room.

My alignment specs (I am lowered):
-2.5 deg front camber, -2 rear
Zero toe up front, BMW standard spec for rear (slight toe in)
Front of the car slightly lower than the rear height-wise a la M3

[sle39lvr]

Tires
I did forget to mention that I do run PSS's and I can swear that the rear 255 is wider than other 255 tires I had in the past. So I will be going for a 245 in the back next time. Should help a bit. I love the tires, but I think I can live with a little a less aggressive set next time.

Camber
Since I already have M3 arms, after getting coil-overs, I will pull the pin out and get close to -2 as possible. But for rear, let me make it clear; less rear-camber is more over-steer correct? So I think I want to go back to -1.2 in the back next time. May be even less? Does that have any drawbacks? I want little understeer as possible.

Sway-Bars
I got the rear after giving a lot of thought since it was the most horrible experience I had installing along with subframe bushings. I know almost everyone votes against m3 rear bar when you don't have an LSD, but I have to say, I love mine. The problem is, I have to be real aggressive to get the best out of it. The harder I accelerate through the corner, the more rotation it gives me. It did made the rear end a little bumpy, but will see how it goes after coil-overs.

I will get M3 front bar at the end. I don't like stiff front bars, because I think it spoils the steering feel. Gives a 'boxy'-'robotic' feel. I had a GTi that I ran no front bar and loved it for 8 years. But the M3 bar shouldn't make things THAT worse.

[CJ421]

Yes, the rear will have less grip in turns if you go with less camber back there - thus making your car a bit more neutral. Personally I'd get camber plates and add more front camber, as opposed to taking away some in the rear. Camber plates are really a no-brainer upgrade along with your coilovers.. And the M3 front sway bar is a good upgrade for any E9x.

[VTECaddict]

Alignment doesn't take into account ride height. It's just whatever the camber and toe is when the car is sitting on the rack.

I agree on increasing front camber rather than decreasing rear. If your whole goal is to increase handling performance, you'll want to increase front lateral grip rather than decrease rear lateral grip. While the handling may be more neutral if you decrease rear camber, you are reducing overall cornering ability.

[Sparkee]

I also have an 08 E90 that had a non-sport suspension. Mine now has a full Eibach Sportline Plus suspension kit on it (springs, sway bars, and Bilstein shocks). The intent was (1) to get the roll out of the car which was killing the outside edges of my front tires and (2) to loosen up the back of the car a bit to get it to "rotate" into corners better.

After the install, I had it aligned to factory spec despite the lowered stance. After lowering, the camber was a bit more negative than stock, and we left it that way (especially in the absence of camber plates).

I can state from my most recent HPDE experience that my car with a square 235/40R17 Dunlop ZII tire setup, the above new suspension, and the alignment, the car is still a bit on the tight side. However, the roll is all but gone. The car rockets around corners, ZII's are awesome - if you don't mind road noise! The ZII's have optimal wear indicators on them to indicate how my car is riding on them. I can see from the front that I am over the outside edges a bit, and therefore I need to add some camber which should up the grip at the front of the car relative to the rear so it turns in better. Which means I need camber plates. The back tires are perfect as is.

My point is that adding camber does not universally add grip. Only because I know that my car is not riding on the front tires properly at the track will I consider adjusting it. And, I might ONLY add it at the track. Adding too much will cause the opposite effect, increasing wear on the inside edges and lowering overall grip.

[sle39lvr]

Originally Posted by Sparkee

My point is that adding camber does not universally add grip. Only because I know that my car is not riding on the front tires properly at the track will I consider adjusting it. And, I might ONLY add it at the track. Adding too much will cause the opposite effect, increasing wear on the inside edges and lowering overall grip.

Well that's the basic idea. BUT, with negative camber, if you toe in, tire wear will even out mostly. I guess there a lot for it, to talk about, but trial and error is the best.

I cannot believe how much more the front end pushes now due to less that .5deg more negative camber in the back. I really need to go back to low -1's next time.

[CALWATERBOY]

Originally Posted by CJ421

Increased camber up front means you now have more grip up there. Add camber up front to reduce push/understeer. I'd shoot for -1.5 to -2 deg.

+1

[sle39lvr]

Let me ask about toe:

With new alignment, I have:
-Toe:1/16" (1/8" total)

I guess I used to have more toe in. But now, the front end feels less stable on high speeds. So more toe-in = more steering stability?

On M3 forum, some people toe-out front and back. That's not recommended for street?

[CJ421]

Originally Posted by sle39lvr

Let me ask about toe:

With new alignment, I have:
-Toe:1/16" (1/8" total)

I guess I used to have more toe in. But now, the front end feels less stable on high speeds. So more toe-in = more steering stability?

On M3 forum, some people toe-out front and back. That's not recommended for street?

Yes - front toe-in will feel more stable in a straight line. Go with whatever you're most comfortable with.

Rear toe-out ...that's a new one for me. The rear should be toe-in on these cars. Front toe-out is a different story - I mainly see that used for autocross, as it enhances turn-in response. Racecars run it too, depending on the track.