Custom Suspension Alignment (Camber) questions

Hey guys,

 

I've gone to the first couple SCCA autoX's down here in AZ & they set up tracks that are BIG & FAST. I'm getting the hang of the higher speeds, but I NEED to change something about my suspension setup. I currently have IPD swaybars F&R (22 & 19mm respectively) and AVO endlinks, but that's it.

 

At first - I thought I just wasn't getting high enough pressure in my tires because I was seeing excessive rubbing on the sides of the tires so I kept cranking it up - until finally at my last race I was at 57psi in the front & still rubbing! Well - after 12 runs, I can see pretty clearly what's going on - the suspension geometry (and probably excessive body roll) of my XT is putting pos camber on the wheels & absolutely destroying the outside edge of the tires. Clearly - this isn't helping my track times either.

 

So - 1: there are no camber plates for the XT available & 2: MR coil-overs would help with body roll, which might or might not help with camber problems indirectly, but they're $$'y.

 

Camber plates would be ideal. Coilovers obviously wouldn't hurt, but it's a lot of $$. Stiffer sway bars may also be in order - not sure...

 

My question is - would I be ok just getting an alignment with some negative camber to drive on all the time? If so - how much? I was thinking -1.0 to -1.75 deg in the front, -0.5 to -1.0 in the back... Thoughts??

Megan (and many other coilovers) come with camber plates built into the front. For the rear, get Perrin adjustable control arms. Then align with -2.5 degrees camber front and rear.

Let me clarify - I drive an OUTBACK. I'm not willing to swap to LGT suspension height, so the only coilovers available are MR Outback coilovers - which do not have camber plates - they reuse the stock top-hats & are not compatible with the LGT camber plates (AFAIK). I wish they were...

 

That said - the Perrin control arms may be compatible.

 

Assuming I could temporarily adjust camber on track days - -2.0 or more camber would be great, but assuming I run it all the time as a daily driver - that seems like too much right?

 

If I run less, but still neg camber - should it be even front & back? I saw a LOT more rubbing in front than in the back (indicating to me, a much greater positive camber problem).

Why not get camber-plates from DMS or somthing similar for the front, and the perrin arms for the rear? Also, what tires are you running? A tire with a stiffer side wall and lower profile tires and rims may help your situation.

K - I'm clearly not getting this point across, so maybe I'm incorrect in assuming it won't work. Would aftermarket camber plates for LGT be compatible with oem OBXT suspension? If so - that's what I would do - I thought I explained that already - I just didn't think it would work...

 

Perrin arms for the rear & Cusco or DMS camber plates in the front sounds like a possibility, assuming the camber plate is compatible. At that point though (~500-600 for both) - would my $$ be better spent on coilovers instead?

 

I'm currently running 215 45 R17 Goodyear Eagle F1 DS G2s. They are lower profile (and narrower - not ideal, but I got them used for cheap) than the 225 55 stock tires. They are Z rated, so I would think they have adequate sidewall. The inside edges are fine, so it's not rolling both ways, I'm only burning off the outside edge. Once I kill them, I'm planning on getting 235 45 R17 competition tires (R-compound), but I want to make sure my suspension is right before I destroy $1200 in tires in 2-3 days.

I think they will be compatible. the camber plates are just top hats, and the obxt tophats should be be the same as the gt tophats even though the truts are different. Also, the eagle F1 GSD3 have soft-ish sidewalls. the outsde of te tire is burning cuase you are understeering too, pushing wide. a stiffer read sway bar may help alittle too to prevent that, but with such a heavy car, you are always gonna push alittle. better driveng skills will remedy that.

I actually found over the course of the day that pumping up the rear tires was enough to get it fairly neutral, but yes - understeer is always a problem to some extent - it's a big arse, heavy wagon I'm throwin' around!

 

Still - understeer alone shouldn't burn up only the outside edge of the tire unless the geometry is wrong. I think getting a new alignment with -1.0 camber all around & adding another 1-2 degrees of camber in the front on race days with adjustable camber plates would be enough for goverment work right? The rear arms sound like overkill & they're pretty spendy for what they are...I'd rather spend the $$ on tires.

I think dialing in more camber up front should be enough. You do have some range with the stock camber bolts. Even with my camber plates on the coilovers, I adjust or have adjusted the stock camber bolt to max. neg. before messing with the tophat camber plate. You should see up to -1.2* up front I believe.

maybe the other train of thought is to just not turn the wheel so much.. change up your style of driving instead and take advantage of the slow-in fast out approach. You can try to dial in as much caster as you can so that you get more dynamic camber.. while this makes the car harder to go through slaloms, it will be easier to hold the car in a sweeper.

 

Im not sure if you are trying to flick your car around, you could take out camber in the rear and dial in more toe-out up front to get the car to pivot on the front tires and use the parabolic line instead of the classic line through a turn.. again, this is in combination of your driving skills.

 

I've been in your situation before where you could have tried everything in the book about changing things on the car except for the driver's mind about going through the course.

 

Try running a different line theory and see if it works better for you to combat the understeer. There are times where I would run lower pressure up front and drive a more conservative slow-in/fast-out line and bump up the rear tire pressures to make it really loose upon entry, especially if you mastered your trail braking to get the car to really tank-slap your way into the next turn.

I think I know what you're saying & I think I'm already doing that to some extent as far as - trying to use the weight shift front & trail braking to get the back end to come around on sharp turns, but these guys don't do that much in their tracks - they're *really* heavy on slaloms - to the point of being almost exclusive - like 4 slaloms & 2 sweepers is a course to these guys.

 

Here are their last two courses:

http://www.pbase.com/image/87845254.jpghttp://www.pbase.com/rsrock/image/88570810/large.jpg

 

I'm also not having that much trouble with understeer (unless I screw up) - like I said, I've got the car fairly neutral handling, I was just concerned about the uneven tire wear. Regardless of driving technique - I think it's pretty safe to say I could benefit from some negative camber up front.

I bet the car is pushing more than you think. just cause you are still able to turn does not mean the car isnt pushing alittle as you turn. I think you may be overdriveing the car alittle. I agree with keefe. changeing drivng style might help. try no worrying about weight transfer as much and focus on driving to maitain front grip. Slow in, fast out, and brake in a straight line. And most of all, be smooth with the throttle. you'd be surprised how much that will affect tire wear.

Even with the MR coilovers I could not get negative camber in the front on my Outback XT. Before I put the coilovers on I noticed that the tires had excessive outer tire wear.

 

I'm thinking that these OB XT have some serious positive camber issues in the front from the factory.

 

I've got the front set at 0.5 degrees and that was the best I could do.

just found this thread looking for information on how to adjust camber on the OBXT with the MR coilovers that I installed today. My tires with only 12K miles on them are very worn on the outside edges both front and rear (more front). I don't autocross, so that's not the cause of my tire wear.

 

One thing I noticed on my car (39K miles) is that the CA bushings in the front are destroyed. I can feel the looseness of the front end because of this. I think that this is impacting camber because of the looseness.

 

I am going to get some bushings fedexed to me on monday (recommendations for who has these in stock?).

 

I am getting an alignment this week once I get the bushings new. I am also seriously thinking about putting some camber plates in place of the stock OBXT tophats.

 

Thoughts?

What are "CA" bushings?

 

I'm thinkin' I might as well try camber bolts to start with - for $30 - there's not much to loose.

they are the bushings that came on California emissions based cars. They are a little different than the 49 state cars.

 

CA=Control Arm

Such as the AVO caster kit - http://www.rallitek.com/avocaadbusy.html -

Should produce some camber as well as caster.

Camber correction bolts can give the Legacy GT one more degree of adjustment. Note that the GT takes the larger 16mm bolt (like Ingalls I-81280) which is not what the Ingalls catalog specifies for that car. Not sure about the outback. Good bang for your buck.

http://www.legacygt.com/forums/showthread.php?t=90790

These could help a lot for the rear.

http://www.legacygt.com/forums/showthread.php?t=98132

I agree w/ Keefe, but w/ positive front camber to start with, you're doomed to outside tire wear.

 

With the camber correction bolts mentioned earlier, an autox-savvy alignment shop might get an OB -1.5 degrees up front. (That's a guess based on the -1.9 for the GT). As you already have a larger front bar, go to a larger rear swaybar (21?, more?) to make the rear outside tire work harder, and the OB may show some oversteer which you can control by adding power. You'll definitely reduce front tire edge wear.

 

Anyhow, -1.5 front camber with 0 toe should be fine on your front tires. Especially if you choose to go w/ a Street tire so that 1) you have slightly less grip & less roll, 2) you can wear the insides of your tires w/ daily driving. I'd wait on the rear mods until you figure out the balance. Remember to be careful on snowy/slippery roads.

 

By the way, I have those Eagles on my Mazda3 and they just don't have the grip to be good AX tires. They aren't even great rain tires. Check to see what folks are using these days, but I'd give the Bridgestone RE01Rs (which I have) or the new Dunlops a look.