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      04-13-2013, 09:28 PM   #1
dre99gsx
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BC BR Coilovers, Apex ARC8, need camber suggestions

Vehicle has BC coilovers and APEX ARC-8s (18x9.5, et35, 255/35 R888 up front). There seems to be sufficient room between inner tire and coilover spring perch, so no wheels spacers are needed.

I'm trying to get this Z4M to run the least amount of front camber, it is dropped quite low though.

What is the best approach for testing how much camber you need to clear the front fenders (coilovers have camber plates) while turning lock-to-lock and under full compression going straight? I would prefer to not have to run -2 deg or more camber...
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      04-14-2013, 06:43 AM   #2
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I think fine tuning is the only way you will find out. Start at -1-1.5

And let's see a pic of your car and how low it's sitting
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      04-14-2013, 08:34 PM   #3
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This is a bit tricky. I just aligned and corner balanced a Z4M coupe. The rear fender lips were shaved off with about 1/4" lip left to retain some strength. The rears with -2.8 camber and about 130lb of tools and "stuff" in the trunk, a drop where you can only fit one finger, and the BC coilovers at full stiff, the rear tires were still shredding up on the edges. Must be the square-like sidewall of the R888 (275/35/18).

Not sure how you guys can run these ARC-8s (18x10, et25) back there unless you are flaring out the rear fenders? I may have to resort to that last step. Raising the rear is another option, but under racing and full compression, I'm afraid this vehicle will still rub on the sheetmetal.

Fronts are at -2.8/-3.0 with 0 toe, no rubbing with the BC BR camber plates at full negative. Also noticed about 1/4 to 1/2" gap between inner rim and shock, so it looks good from there. Not sure how these will scrape under full cornering. I'm considering reducing some of the camber, but last time I had a fiasco like this, the front tires at full tilt bent and ripped my front fender apart (a different vehicle).
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      04-14-2013, 09:41 PM   #4
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I figured out a lot of different measurements when I had my gti, but can't say I know what you are looking for haha

just curious...why are you looking to run less than 2*? less wear?...around 2.5*-3* seems to be a good spot for killing understeer from what i have been seeing with the track guys on here

those bc's must be killing you on full stiff, my buddy's old bc's in his sti were awful on full stiff
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      04-14-2013, 10:14 PM   #5
dre99gsx
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I'm simply not used to running that much. In my past,we tend to run positive camber in the rear due to the high power squat of the Supra and needing full contact patch to put the power down. With the Z4, how do you guys maintain full contact patch in the straightaways with this much rear camber?

The fronts were always a toss up, but 3deg seems very track-specific.

Anyone running this much camber on a daily or weekend vehicle without wear issues? (Toe zeroed out)

Agreed the BCs on full stiff were not soaking anything up. I was cringing in the coupe anytime I went over simple man hole covers; it was that bad. They need to be softened up as they run fine that way, but I am fighting keeping the tires from shredding at the moment. I'm also certain part of the issue here is the 130lb weight in the rear, which isn't normal (I was dragging all of my corner balance and alignment equipment to a location for a demo using the Z4). But, with another passenger in the car, this may still be a concern.

One other thing on the rears: Instruction manual is very vague on adjusting ride height at the spring perch vs. adjusting the shock body. It seems to suggest perch and shock body need to both be adjusted equally. Unfortunately, there was no reference point for the shock, thus I just left it as it was from the box. Need to call BC to figure this out.

The fronts are on full negative lock. I essentially dropped the shock a tad, slide over the shock pillow mount as far possible to the inside (engine bay side), locked the allen screws, and then pushed the shock in even further on its three mounting studs. This gave me nearly -3deg on both fronts.

While I'm at it, corner balanced to 50.8%, with 50.8% weight in the front, 49.2% in the rear. Vehicle weight 1/4 tank gas: 3130lbs.
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      04-15-2013, 08:59 AM   #6
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Those toyo tires run pretty big. I'm running hankook v12's and no rubbing. I'm going to be rolling the fenders soon.
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      04-25-2013, 08:20 AM   #7
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Have you figured out any solution yet? I am hoping to run ec-7's with nt05's so it would be good to know ahead of time haha

platinum brought up a good point on rolling fenders...not sure why it didn't pop into my head haha...with the fronts rolled, you can probably run less camber
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      04-25-2013, 09:38 AM   #8
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First of all, I had exactly 170lb of tools and equipment in the trunk. So, it was exacerbating any bump. I ended up raising the car a few millimeters in the back. I also went back in and found it was rubbing against the rear portion of the wheel well. Basically, right at the junction point where the rear fender meets the rear bumper. I trimmed more metal from that area, but it is still to close for comfort. I trimmed enough from the upper well edge metal (rolling the fenders wouldn't get me this much clearance) where it can travel fully without ever touching the tire, even with a bit less camber.

I also adjusted all four shocks to 3 dampening value (goes from 0 to 32) to soften it up. Big difference in daily driving. I think anything more than 8 is just too stiff and aggressive for these cars (on the street).

My liner is getting worn both on the inside and on the outside edges. I agree with Platinum: these tires are extremely square.

As for the fonts, I haven't noticed a clearance issue but rolling the fronts seems like a tougher task since there isn't much metal in the way there. Seems to be the liner which is causing more issues, especially where the front bumper meets the fender.

I'm at a point where I can drive fairly aggressive and not rub anywhere, granted no pot holes or major road dips are encountered. Once I have a 150lb passenger, I have to slow down. These cars drop quite a bit when there is just a small amount of weight added.

This could have all been solved if I went with less aggressive sidewall tires or narrower tires.
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      04-25-2013, 09:53 AM   #9
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How much toe are you running in the rear.

As well, running full stiff wasn't too good of an idea. But it seems you got that sorted out. Let the dampers do their work.

OEM suspension here w/camber shims in front

I'm running -1.6* in the back at -1/16 toe

-2.3* in the front at 0 toe

I'm still getting more outside wear than inside, just due to me constantly autocrossing
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