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      09-09-2013, 09:12 PM   #1
VictorH
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Is -2.5 degrees of neg camber enough?

There's a poll going on for optimal front camber setting and the best overall compromise seems to be -2.5 degrees of neg camber up front. I have been running this setting for the past 2 years in my daily driver with no adverse tire wear issues.

However, for the track, I would say that based on my observations it's not enough. I've just now worn out a set of RE-11s which have been great and were used exclusively on the track but most of the tire wear is on the outer 50% of the tire. There were several E92s and a couple of E90 M3s (what I have) for every car that I checked (didn't get to talk to every driver about their camber settings but -2.5 seems to be the consensus as well) the tire wear on the fronts was just like mine, mostly on the outer half of the tire with not nearly as much wear on the inner 50%. Looks like it doesn't matter if it's R-comps (most of the cars there) or street tires.

So the questions are: 1) What is the optimal camber setting for the track?; 2) Does anyone have a reliable method to change the camber (that's easy enough) and measure it reasonably accurately (that is much more challenging in my opinion). I don't think the toe change from -2.5 to say -3.0 or -3.2 would be huge, but if optimal is -4.0 then the toe change is going to be too great (and I bet my tires would rub the top of the shock/coil) to be feasible without changing both toe and camber, i.e. you're going to the alignment shop.
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      09-10-2013, 06:25 AM   #2
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The other camber threads are about the best compromised camber setup for a street-track car. A dedicated track car, especially if running r-comps or slicks, will require more than a street-track car setting.

There is no single "optimal" camber setup. The best way to determine the correct camber for your car is to have someone measure inner-middle-outer tire temperatures when you pull into the pit lane after a series of hot laps - want very little delta between the three measured temperature (per tire). Don't want until after a cool-down lap and then driving to your paddock spot because the tire temperatures will be much lower and have a different distribution. Testing is the best way to determine the correct camber for your car and setup.
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      09-10-2013, 08:07 AM   #3
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As we all know the e9x M3 will push a little with -2.5 camber in the front. Ideally you would want around -3.5 or even more for optimal performance on the track on the e9x m3. For reference but different car I run -4.4 on my trailered E46 M3. The front tire wear is very even. Personally I don't think it would be worth my time to change camber at the track.......or precise enough for my liking if I did.
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      09-10-2013, 08:45 AM   #4
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It is still a compromise setup. -3.5+ is ideal, but is completely unstreetable (unless you live 10 miles from the track or something).
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      09-10-2013, 09:23 AM   #5
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Quote:
Originally Posted by Porschefile View Post
It is still a compromise setup. -3.5+ is ideal, but is completely unstreetable (unless you live 10 miles from the track or something).
dont know if that is true. i have -3.5 in my e46 and drive 100 miles to and from the track and not that bad at all.
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      09-10-2013, 09:31 AM   #6
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Quote:
Originally Posted by 1MOREMOD View Post
dont know if that is true. i have -3.5 in my e46 and drive 100 miles to and from the track and not that bad at all.
+1
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      09-10-2013, 09:33 AM   #7
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A lot of it depends on toe too, but cars that see a good bit of street use will destroy the inside fronts at -3.5. I had to junk fronts due to inside wear at -2.8 or so when the rest of the tire was roughly half tread (and the set had probably seen a few thousand miles and 6-8 track days).

Driving 100 miles to the track, tracking it, and driving home does not a street car make.
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      09-10-2013, 10:02 AM   #8
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Quote:
Originally Posted by Porschefile View Post
A lot of it depends on toe too, but cars that see a good bit of street use will destroy the inside fronts at -3.5. I had to junk fronts due to inside wear at -2.8 or so when the rest of the tire was roughly half tread (and the set had probably seen a few thousand miles and 6-8 track days).

Driving 100 miles to the track, tracking it, and driving home does not a street car make.
i know it doesnt. i also change wheels and tires once i get there. its a track car i can drive to the track basically.
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      09-10-2013, 10:32 AM   #9
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Quote:
Originally Posted by 1MOREMOD View Post
i know it doesnt. i also change wheels and tires once i get there. its a track car i can drive to the track basically.
Right on! My point was just that very high camber doesn't work for a true dual purpose car, like mine, that sees a few thousand street miles too.
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      09-10-2013, 10:43 AM   #10
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Quote:
Originally Posted by Porschefile View Post
Right on! My point was just that very high camber doesn't work for a true dual purpose car, like mine, that sees a few thousand street miles too.
mine sees probably 50-50 street to track due to distance to and from and gas and bedding pads and such.
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      09-10-2013, 10:54 AM   #11
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When I had Vorshlag camber plates installed (suspension otherwise stock) I asked for the best combo setup; I trust the shop I use since the owner is a former SCCA racer and now instructs at HPDEs I attend. The shop settled on -2.3 because they found that although the plates could get them to -2.6, at that point toe-in was either 1/8" or 1/4" (can't remember which), whereas -2.3 allowed them to have just 1/16" toe-in, which they thought was better overall.

I've read conflicting information about the direction in which camber affects toe; does it vary in different car models? How are people running high negative camber on the E9x avoiding substantial toe-in?
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      09-10-2013, 11:32 AM   #12
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"Ideal" depends on how much street vs. track driving you do, your spring and swaybar rates, tire compound and size, vehicle weight, ride height, toe, etc...

Measuring your hot tire temps on track will give you a good idea how your setup is working and watching tire wear over long periods of street driving will show you how aggressive it is for street driving.

FWIW Grand-Am CTSCC cars like Turner Motorsport's E92s are limited to -3* of camber.
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      09-10-2013, 11:46 AM   #13
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Quote:
Originally Posted by jphughan View Post
When I had Vorshlag camber plates installed (suspension otherwise stock) I asked for the best combo setup; I trust the shop I use since the owner is a former SCCA racer and now instructs at HPDEs I attend. The shop settled on -2.3 because they found that although the plates could get them to -2.6, at that point toe-in was either 1/8" or 1/4" (can't remember which), whereas -2.3 allowed them to have just 1/16" toe-in, which they thought was better overall.

I've read conflicting information about the direction in which camber affects toe; does it vary in different car models? How are people running high negative camber on the E9x avoiding substantial toe-in?
They are adjusted independantly. I ran -2.5 front on my e90 with zero toe. Some like to add slight toe out for crsiper trun in but that can accelerates wear.
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      09-10-2013, 11:53 AM   #14
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Mine is my daily so street vs track is 98% street vs track, but I have at least 8,000 track miles on my car. Most of us have adjustable camber plates, so can we just adjust it? I can easily get -3.0 neg with my set up, but how accurate is that -3.0 that I measure at home (home made digital angle meter)? Is it going -2.7 to -3.3 or is it going to be -3.0 plus-minus 0.1 degree (I'd be fine with that). What tool would you use for this? I know Longacre has a camber tool and others have similar tools but how accurate are they, do you need a turn plate to go with it?

So far on this thread it doesn't sound like anyone is adjusting their camber between street and track use. Is there a reason not to adjust it (again just for a track weekend and then switch back)?
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      09-10-2013, 11:57 AM   #15
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The reason against adjusting it is that when you change camber you change toe so have to have a reliable way to get both accurate for street and track setting. Otherwise you risk not know what setup your running and better off with setting it one way and leaving it alone.
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      09-10-2013, 12:21 PM   #16
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Quote:
Originally Posted by 1MOREMOD View Post
The reason against adjusting it is that when you change camber you change toe so have to have a reliable way to get both accurate for street and track setting. Otherwise you risk not know what setup your running and better off with setting it one way and leaving it alone.
Yep. Our suspension geometry is such that a camber change (say, from -1.5 to -3 for track) will change toe dramatically. You can really only do multiple settings if you compensate for that on the toe adjustment (which would have to be pre-determined, how much to turn the adjusters to make toe the same as it was).
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      09-10-2013, 12:53 PM   #17
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dumb question but how hard is it to adjust camber at the track with vorshlag camber plates? I'm considering buying them and have the same concerns about setup as my car is now more track than street about 60/40 split.
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      09-10-2013, 04:49 PM   #18
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I had my chamber set at -2.8 and it ate up the inside of my street tires in like 2000 miles. Currently dropped down to -2.2 or -2.3 and seems pretty good for both ( still some outside war on the track but acceptable for me).

Have adjustable ground control plates, but never bothered to change them at the track ( just another thing to play with and the cash prize for winning the HPDE event just didn't cover it).
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      09-10-2013, 10:56 PM   #19
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I've run -3.5 on my car with Continental scrubs, but the outer edge of the front tires still wear way too quickly. I suspect something around -4.0 might work better.

At -3.5 your street tires will get killed after a few thousand miles on the highway.

In terms of adjusting camber, there are plenty of gauges readily available on the market for a few hundred bucks (Intercomp, Long Acre, etc.) There are apps for it as well. Just make sure you are on a level surface.
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      09-10-2013, 11:32 PM   #20
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One thing to mention if you are running a lot of camber. Run the pressures up on your street tires. Maybe 38-40 cold to save the insides
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      09-12-2013, 02:41 PM   #21
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Interestingly, I'm running around -2.3 or -2.4° front camber with Toyo Proxes RRs (newish R-comp, semi-slick, 40 treadwear rating) on the track, and I've been seeing more wear on the inside of the tread. Wear is visible on the outside shoulders where the tire rolls over a bit in cornering, but not down beyond the sidewall triangle markers. That's the expected part. But what seems weird is that the tread-depth holes or dots on the tread surface show significantly more wear on the inside portion of the tread surface vs. the outer portion.
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      09-12-2013, 03:16 PM   #22
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Once you use an r-comp its pretty hard to get even wear. The inner edges will get worn under hard straightline braking and acceleration. Just comes down to driving style then. Do you threshold brake and are poor at midcorner speed? I have -3.5 front and am close to even wear on the edges. Middle not as much.
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