Another crash bolts alignment thread
 

Installed the OEM crash bolts last week for autox. Loved the added camber so I got aligned today. My toe really wasn't that bad after the crash bolts, it was within spec. But I adjusted everything anyway.

Here's where I ended up:

Front camber: -1 left, -1 right
Caster: 5.5 left, 5.5 right
Toe: 1/32" out left, 1/32" out right

Rear camber: -1.4 left, -1.6 right
Rear toe: 1/8" in left, 1/8" in right

EDIT: UPDATE 9/19...realized rear toe was too aggressive. Had it changed to between 1/16" and 1/32" in, per side.

Looks good thats about where i want to be maybe a touch more negative up front. What are you lowered on?

stock suspension.

How did much negative camber in the rear did you have stock?

It's not adjustable so that is what he had stock, unless he loosened parts up tried to move things around but that's kind of a PITA.

OP, just curious whether it would be better to keep front toe at zero (instead of toe out) and lessen the rear toe in instead? Also, were you not able to get more front camber with the crash bolts?

Yeah that is why i asked i didn't know we had -1.5 in the rear already.

Correct. I didn't alter the stock rear camber at all.

Well, there's a lot of possible routes one could go. I considered zero toe up front. But I like a pinch of toe out for that initial turn in response. 1/32" is very little (.03"), so I'm not overly concerned that it will make the car darty or wear the tires too fast. As for the rear...1/8" in (.125) is within spec, and I like the straight line stability it gives. I had absolutely NO trouble hanging the tail out at my last AutoX, so I'm not worried about it. ;)

Originally, I wasn't planning on changing the rear toe at all because the crash bolts wouldn't affect the back. But after getting it on the rack, it was apparent that the factory alignment was pretty sloppy, so I figured I'd get it perfect.

And no, I was not able to get more that -1 camber with the crash bolts. It seems some people have managed to eek out a little bit more, but I'm fine with it.

I'm running a lot more toe out up front and it feels good. I do have camber plates so I'm able to pull that toe back to zero when not racing. So the nice benefit with camber plates is that as you push for maximum negative camber for racing you can set your toe out to where you like and then as you pull back closer to an aggressive street alignment you can zero out your toe.

I was shocked at how much toe in the rear had OEM. So far though I have not been compelled to take any out based on how the car feels on the race track. I would think rear tire wear will be really bad for anyone going with a staggered fitment as they won't be able to rotate the tires.

IMO that's way too much rear toe. In my experience with the S2000, more toe is good for nothing, and bad for everything (handling linearity, responsiveness, tire wear, fuel economy). I never found big rear toe to give increased stability over *reasonable* rear toe (~0.2 - 0.3 degrees total), and at the high/excessive end, it can DEcrease stability over bumps/undulations and in traction-challenged conditions.

You have 1/4" total rear toe or 0.57 degrees total. On the AP1, this is enough to give spooky/nonlinear handling behavior, impair turn-in response, and cut tire life literally in HALF.

The conventional wisdom is that big rear toe is more "stable", but in my experience it can be a lot less linear and confidence-inspiring, again, particularly over bumps/undulations and differential traction conditions between the rear tires (frequently happens in rain).
And of course it kills tires.

Waste of rear tire traction and life to have them continually scrubbing against each other at all times!

I would dial out some of that rear toe, especially with that little camber in the front. Only time I ran that much rear toe-in was for the Z06 so I could put down power earlier in a turn. Also, I wonder why you couldn't more negative camber, that's by far the lowest I have seen with crash bolts.

is the 'OE crash bolt' basically another lower bolt you just put thru the top hole? its not lobed like the whiteline right>?

It is. It's identical to the lower bolt, you just push as hard as you can and tighten things down.

I didn't push hard, I simple pulled out on the bottom of the rotor and in at the top and tightened it down and got -1.6 on both sides.

you know, you guys made me realize that they dialed in the toe inches to what I wanted in degrees, lol.

I should probably get that rear toe in check. The car does feel really good though.

Oh it should drive relatively fine. It will just have more understeer during throttle on and lift than it should/could. It will naturally scrub the tires quite a bit as well.

for whatever reason, it has much less understeer than it had stock and much less than it had with just the crash bolts and no alignment.

It feels really planted in the back, but the car turns in amazingly well. At my last autoX, with crash bolts only, the car had a lot of initial understeer but with enough throttle I was able to switch over to oversteer. There wasn't a whole lot of middle ground either. So it was either plow or drift. I chose drift for the fun, rather than good lap times.

This is why one setup doesn't work for everyone. The exact same setup on my car was fine with whatever the stock rear alignment is. This weekend I'll take some runs in it the same except with good tires and see what that does but I've never liked a lot of rear toe.

I use .12 toe in in the rear, on purpose and it works great in autocross. I have more oversteer than I wanted even on RS3s. Don't get me wrong, there is still PLENTY of oversteer available whenever you want. I;m still getting MORE rotation than I want and it cost me a very fast run this weekend (rear swung too much, clipped a cone while coming back around in a slalom, costing me a run that was nearly on par with the CS-Rcomp guys with my RTR-RS3 setup)

I'm not sure where you guys feel the car is loose. On mine, its transitionally loose, not in steady state along with some corner exit wheel spin. So toe in wouldn't help me fix those problems - front bar and shocks would so I'm waiting for those.

You're right, it's not steady, but yes, in transitions such as a slalom, I was getting more oversteer that I'd want. Still get more than enough but it's reduced.

A front bar would help that but I'm waiting as the choices are slim. Waiting on Sam (patiently! not rushing you! :bonk:) to finish his.

.12 deg or .12". Total or per side?

There is a ton of factory rear toe in but not 1/4" total like you have. I went and checked my notes for the oem alignment was 1/8" in total. You probably want to get closer to OEM just so you aren't scrubbing so much.

I'm sure most of that toe in is negated with bushing flex when cornering however. With my current setup it's good as is but when I stiffen front roll with a bigger bar I may need to pull some toe in out.

.12 deg each side, .24 deg total toe in. Is that about 1/32" each side I think?

I know you guys are tracking the car but are you autocrossing as well? On Sebring, the car was perfectly balanced with this setup but in autocross where it's quicker turning and a little more abrupt, it's definitely more tail happy

OK, so you have much less toe than me.

I actually thought I had more but I looked at my alignment sheet before posting.

I wondering if I should have gotten more toe but I dont want crazy wear.

well, I'm going to go get mine pulled back to sane levels ASAP. My bad for not noticing they did everything in inches and not degrees.

I wonder if I should pull in my front toe out from 1/32 to like 1/64?

the car does feel really good, so I kind of hesitate messing with it...

Hesitate to bring this up, as I don't autoX...

At the track, anyway (where there are never any 1st gear turns), getting on the gas generally induces more UNDERsteer, not OVERsteer, particularly in a modest power/weight car.

Getting OFF the gas will reduce understeer and help point the car.

Even in a lower gear, or with massive power surplus, I've never had occasion to get ON the gas to induce wheelspin to point the car exiting a corner, as this always reduces front end grip. While rear wheelspin will act to keep the car pointed in the right direction, you're *still* drifting wide of the desired line. Whereas getting off the gas will add front grip and bring it back toward the desired line.

If I'm going wide on corner exit, I'll get off and back on the gas rather than planting the throttle. At least I think that's what I do...

Anyway, in general:
on the gas => understeer
off the gas => oversteer

At a track, that is completely accurate but there are cases in autocross where you have the chassis on the verge of oversteer from tossing between pylons quickly, where throttle WILL bring oversteer.

The car probably feels so good based on what you did to front and not so much the rear. I think your toe in the front is fine for aggressive driving/track. It will rotate better will less toe in for the rear. You theoretically should be able to dive into the turns harder because the rear will want to rotate easier. This will offset some of the push you'll get in the front by going in faster.

You should invest in some toe plates so you can tweak the toe settings at the track. As long as you start with a good alignment you won't mess anything up. Adjust each side equally and see what you like.

Like I said I'm happy with 1/8th toe in but I would like to dial that out over time. For the record my suspension and tires are highly modified for racing so your car may feel different but still I would try OEM toe in the rear.

The AutoX events that I go to don't have any 1st gear sections, but the entire course is mostly 2nd and 3rd gear. Yes, I could lift to reduce understeer and keep a tidy line, but driving neutral on the stock tires at AutoX, the car wanted to initially understeer and then could be provoked to oversteer with the throttle...especially after the stock tires got nice and overheated on the hot asphalt.

Here's a vid of one of the runs. This is stock tires, camber bolts, no alignment changes other than that.

[ame="http://www.youtube.com/watch?v=p6N22M2YdV4"]BRZ at nein nein SD BMWCCA AutoX - YouTube[/ame]

Is OEM rear toe (per side) 1/16" in or 1/32" in?

I'm planning to install my springs about a week before getting an alignment. Could I also install the crash bolts and just try to set them to max...and go for the week without the alignment? Would it would be tough to get both sides even? Am I better off sticking with the stock non-crash bolts until I go in for the alignment? Thanks.

If you are putting in lowering springs, you will already gain camber. Since you are doing lowering springs, I assume top level handling isn't a high priority so why would you want/need more negative camber or are you talking about dial some out?

well, I'm headed back in for alignment today. Based on my math, .125 degrees = .055 inches. So if the alignment shop has no means of changing their machine to degrees, I'm going to be requesting somewhere between 1/16" and 1/32" toe-in on the rear (per side), with aim of being closer to the 1/16" side of the scale.

I think I will stick with 1/32" toe out (per side) up front, which = .07 degrees.

Anyone have any comments or suggestions before I go ahead with it?

I didn't check your math but toe conversions are based on the wheel diameter. So here's the chart I use to check:

http://www.abqautoxer.com/toe.jpg

Well I'm installing the RCE springs which is a minimal drop designed with handling as a top priority. I got the Lite pack which comes with the front camber bolts and rear adjustable camber bushings.

I'm planning to install the springs a week before my alignment, and I'm having the alignment shop install the rear camber bushings. I'm just not sure whether to install the front camber bolts myself when I install the springs, or wait to have the alignment shop install them.

sweet! My math had the wheel diameter factored in. ;)

But it's good to see a chart that confirms it.

total beginner here just had OEM crash bolts installed on front and alignment done. How's this look for daily driver/autocross (RTR) on stock tires:
Front: toe 0, camber -1.5
Rear: toe in total .32 degrees, camber -1.0

Looks good and what I would start with for rear toe.