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09-01-2020, 07:52 PM | #1 |
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Track only Alignment specs...
Finally going to full SPL Kinematics, took helper spring out on my MCS 2ways to raise Spring Perch. Will be running 18x10.5 wheels square with 305/645/18.
Looking for some specs/ideas for optimal performance, what are the hardcore track only guys running? Thank you |
09-01-2020, 08:37 PM | #2 |
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Will vary depending on driver, track, spring rates, ride heights, tires etc etc.
But roughly you'll want to be looking at: Front Camber: ~-3.5 to -4* Rear Camber: ~-2 to -2.5* Front Toe: 0 toe up front is the most common, but depending on preference and other setup settings anywhere between an 1/8in toe in and an 1/8in toe out (per side) is reasonable Rear Toe: I'd run at least a 1/8in toe in (per side) for the rear, up to 1/4in I can't remember the caster angle of the top of my head, I know I contacted BW and went off of their recommendation and haven't touched it since. 1/8in to 1/4in negative rake is the typical recommendation for 'track use'. This is a very simple and effective way to shift the handling balance of the car. Tire temps and tire wear should be used to determine 'optimal' camber settings. Front toe will be used to adjust turn in response and front end straight line stability and rear end stability using rear toe. Ride heights should be adjusted to alter handling balance. If you frequent numerous tracks, there will be no settings that will work optimally at more then 1 track, so keep that in mind. It will always be a compromise, so set the car up optimally for the track you visit most often and have small adjustments noted for alternative tracks. Again, this is all rough settings and it will vary per car, track and so on. Last edited by tsk94; 09-01-2020 at 10:47 PM.. |
09-02-2020, 12:12 PM | #3 |
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I am doing
-3.6 front -0.02 toe out each side -2.4 Rear Standard toe in. Would go more aggressive but I drive to and from the track I feel if I was going full slicks I would want -4 camber up front. Id need to slot the strut tower to do that with my current set up. I'd imagine with the SPL arms you would not need to. |
09-02-2020, 01:27 PM | #5 |
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Max camber I can get out of the KW Camber plates and strut tower up front is -3.6 rear is -2.4/2.5. 0 toe up front tiny bit of toe-in on the rear. I run 265/645 scrubs mostly, and get pretty even wear out of that setup. But I'm jealous you're running the 305/645's...that's the unobtanium size lol the only 305's I can get local are 660 or 680.
Biggest clearance issue will be up front, but should be able to make do with -3.5 or greater camber if your ride height's not crazy low or something.
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09-02-2020, 08:15 PM | #6 |
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Thanks for the info for those who chimed in.
I normally run 285 square Hoosier R7. Recently I made the change to 900lb front springs (now shorter 5") from the 6" And rear 1200lbs. Full front and rear aero. Last fall I ran 2:04 at the Glen on 275 square and slicks were shot pretty much chorded. July Ran 2:03 on 285 square but had a blow out front drivers tire. Lots of heat/scrubbing into the boot...luckily it happened into the braking zone going uphill. So now planning on going back in Oct on fresh 305 Pirelli full slicks, raised spring perch/collar, full SPL Kinematics, more camber ....and hoping Sub 2...I'll be happy with 2:01 but I know i can achieve Sub 2. |
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09-03-2020, 09:05 PM | #7 |
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I can’t understand how you guys can run higher than 2deg camber rear. I run at 1.8 and still eat through inside of the tires Very fast. Approx .10deg toe in each side.
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09-03-2020, 10:24 PM | #9 | |
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If you're consistently wearing inside rears, then go to less camber. You also are running quite aggressive toe which will certainly contribute and accentuate to the inside wear. |
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09-03-2020, 10:39 PM | #11 |
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.2 degrees total toe-in is ~3/32" with 275/35 tires. Not super aggressive.
Reason I asked about sliding - if you're sliding around a lot with the inside tire only partially on the ground (because it is effectively at a massive positive camber in relation to the lateral motion) it will destroy it pretty quickly if you're on an abrasive track. I had to stop having so much powersliding fun when I moved to softer tires. Otherwise, the rears would get destroyed in a tapered fashion within a few sessions at my primary tire eating track. Same thing with wheel spin, particularly inside wheel spin in slower corners.
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09-03-2020, 10:58 PM | #12 | |
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If that's the case though, then yeah, that's not much. |
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09-03-2020, 11:28 PM | #13 |
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The shops around here are all over the place. Inches, degrees, one even uses mm.
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09-03-2020, 11:35 PM | #14 |
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I prefer working in degrees but if you don’t have an alignment rack it’s not very practical.
0.2 degrees of total toe in will measure: 3/32” with toe plates (25” toe plate span) 1/16” on strings (18” wheel lip span) |
09-04-2020, 06:39 AM | #15 | |
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09-22-2020, 10:38 AM | #16 |
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All SPL parts are installed and alignment thank you to ACM in Fairlawn NJ🙌🏻
Here are the current alignment specs.... |
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10-15-2020, 05:30 PM | #17 | |
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I think that is a lot of rear toe isn't it? I don't know your exact tire size, but my 275/35/18 are .12 degree per side, .24 Total toe Everything else looks awesome to me! -4.1 front camber
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10-15-2020, 10:14 PM | #18 |
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Yea I run .21 deg rear toe total. I ran about 0 for 6 track days and it felt fine but the inner rears got blasted, probably from rear compression causing toe out, especially with the wang.
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10-15-2020, 10:44 PM | #19 | |
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I believe with stock arms and bushings the rear toes-in quite a bit under compression. This is eliminated, or largely mitigated, with spherical rear arms and bushings. I have no idea what these degrees translates to in terms of mm or inches of toe-in (as that's what I've always used). But I run ~4mm (just over an 1/8") toe-in per side (going to less next season, but not due to tire wear) and have very uniform tire wear with ~-2.5* of camber. |
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10-16-2020, 12:05 AM | #20 | |
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Also, the toe actually changes in the outward direction under squat. Somebody kept posting the opposite many times in various threads, and Malek finally confirmed that it was not true. His post is below. "The suspension is designed to reduce toe in during squat and will increase toe in when weight is transferred off the back end. Meaning if you have 3/32nd inch static toe in, during squat the toe will decrease to lets say arbitrarily 1/32nd-1/16th. It will NOT increase toe while squatting. Malek" I've also seen it first hand when I lowered the rear and then got a fresh alignment. The toe was actually out slightly in the rear, after lowering the rear. One one side it was lowered enough to gain -.3 degrees of camber and the toe changed outward over a mm on that side. As for the conversion, I'm running 2.4-2.5mm total toe-in in the rear currently which is ~.21-.22 degrees with my tire size.
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Last edited by Bartledoo; 10-16-2020 at 12:14 AM.. |
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10-16-2020, 12:10 AM | #21 | |
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I don't believe any of the rear suspension arms are 'spherically mounted' as the stock rear arms are still a rubberized bushing with a steel insert. I suspect any toe change that happens with the stock arms is eliminated when the rear arms are changed to a true spherical/ball-joint arm. And no the trailing arms are not - it's a rubber bushing (a fairly stiff one) that can be upgraded to solid as well where it mounts to the spindle and where it mounts to the subframe. |
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10-16-2020, 12:16 AM | #22 | |
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