alignment specs
May 30, 2011, 10:10 PM
#1
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alignment specs
I'm a little unsure of what my alignment specs should be after installing a tre rear diff.
Suspension Mods are
Mr. Bilstein with swift spec r springs
Swift rear sway bar
Modified front sway bar (stiffer)
And I have the tre 12 plate rear diff. Evo hankook 245/40/17 tires. How do i get more grip in the rear since my rear diff
Suspension Mods are
Mr. Bilstein with swift spec r springs
Swift rear sway bar
Modified front sway bar (stiffer)
And I have the tre 12 plate rear diff. Evo hankook 245/40/17 tires. How do i get more grip in the rear since my rear diff
May 30, 2011, 10:34 PM
#2
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Without going into too much detail (and partly because I left my spec sheets in a folder I'm away from) you'll want to spend a lot of time making sure your car is set at the proper ride height.
If you want to get super close, you'll go from proper ride height to corner weighting, but for most of us I get my corner weights about 90% correct with just ride height on a perfectly level piece of tarmac.
After that you can add as much camber to both the front and rear you feel comfortable with. For street I've hung around from 1.7 to 2.0 deg. front and 0.5 to 1.5 deg rear. Why so large a spread on the rear, literally its the sway bar. I hate to make the sway bar do all of the work, so I put the rear to as much camber I can live with and then tune in my rear weight transfer with the swaybar at the end.
If you're in the ballpark you don't need much rear sway for proper rear end traction. If you put in too much swaybar in the rear the car will tend to snap or transfer to oversteer on you really quickly. You want the rear to be "catchable" and not snappy.
Oh ... be sure to check that your rear springs are stiffer than your front springs. The rear on most Evo coilovers have much better damping control with stiffer springs in the rear. For instance on my R&T Ohlins I run 10kg fronts and 12kg rears.
Once you've got everything where you think you want it, then go into the alignment. First out of the box I suggest you don't run anything but 0deg toe on the rears. The rears have toe-in and toe-out already built into them from the factory geometry. You can really get into trouble if you start to play with that toe. For the fronts, I've never run anything but 0deg. but others here have their own ideas there. I'll let them comment on the front toe.
Good luck ... and welcome to the cult-o-suspension tuning
~j.
If you want to get super close, you'll go from proper ride height to corner weighting, but for most of us I get my corner weights about 90% correct with just ride height on a perfectly level piece of tarmac.
After that you can add as much camber to both the front and rear you feel comfortable with. For street I've hung around from 1.7 to 2.0 deg. front and 0.5 to 1.5 deg rear. Why so large a spread on the rear, literally its the sway bar. I hate to make the sway bar do all of the work, so I put the rear to as much camber I can live with and then tune in my rear weight transfer with the swaybar at the end.
If you're in the ballpark you don't need much rear sway for proper rear end traction. If you put in too much swaybar in the rear the car will tend to snap or transfer to oversteer on you really quickly. You want the rear to be "catchable" and not snappy.
Oh ... be sure to check that your rear springs are stiffer than your front springs. The rear on most Evo coilovers have much better damping control with stiffer springs in the rear. For instance on my R&T Ohlins I run 10kg fronts and 12kg rears.
Once you've got everything where you think you want it, then go into the alignment. First out of the box I suggest you don't run anything but 0deg toe on the rears. The rears have toe-in and toe-out already built into them from the factory geometry. You can really get into trouble if you start to play with that toe. For the fronts, I've never run anything but 0deg. but others here have their own ideas there. I'll let them comment on the front toe.
Good luck ... and welcome to the cult-o-suspension tuning
~j.
May 31, 2011, 01:31 AM
#3
^ Missed some points in his post.
No ride height adjustment or spring rate adjustments needed -- he has Swift Spec Rs. Those points will be static.
What is the car used for (street, track, AX)?
What grip? Lateral of acceleration? The rear diff will make the car rotate more. This comes down to driver control. Less go pedal. You can also disconnect one side of the rear sway bar. See if you need it now that you have the diff. You can go to an adjustable bar or to the stock bar.
Use the -2 bolt selection up front and get -1 to -1.5 in the rear. Zero toe all around. Zero thrust angle.
Missed some points in his post. No ride height adjustment or spring rate adjustments needed -- he has Swift Spec Rs. Those points will be static.
What is the car used for (street, track, AX)?
What grip? Lateral of acceleration? The rear diff will make the car rotate more. This comes down to driver control. Less go pedal. You can also disconnect one side of the rear sway bar. See if you need it now that you have the diff. You can go to an adjustable bar or to the stock bar.
Use the -2 bolt selection up front and get -1 to -1.5 in the rear. Zero toe all around. Zero thrust angle.
May 31, 2011, 01:56 AM
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^ Missed some points in his post.
No ride height adjustment or spring rate adjustments needed -- he has Swift Spec Rs. Those points will be static.
What is the car used for (street, track, AX)?
What grip? Lateral of acceleration? The rear diff will make the car rotate more. This comes down to driver control. Less go pedal. You can also disconnect one side of the rear sway bar. See if you need it now that you have the diff. You can go to an adjustable bar or to the stock bar.
Use the -2 bolt selection up front and get -1 to -1.5 in the rear. Zero toe all around. Zero thrust angle.
Missed some points in his post. No ride height adjustment or spring rate adjustments needed -- he has Swift Spec Rs. Those points will be static.
What is the car used for (street, track, AX)?
What grip? Lateral of acceleration? The rear diff will make the car rotate more. This comes down to driver control. Less go pedal. You can also disconnect one side of the rear sway bar. See if you need it now that you have the diff. You can go to an adjustable bar or to the stock bar.
Use the -2 bolt selection up front and get -1 to -1.5 in the rear. Zero toe all around. Zero thrust angle.
May 31, 2011, 04:38 AM
#5
Bring this to him:
Those are the settings I gave in my first post are what I used for AX.
Its going to come down to tires. Hankooks are good DD, but not top AX tires. Extreme Summer Performance tires are what you should start looking at (along with the RSB tuning).
Jun 21, 2011, 11:57 AM
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I was hoping to get some alignment advice without getting too beat up. I did some searching but i didnt find anything that applied directly to my set up (24mm rear sway,26mm front sway, nitto nt05s, fortune auto 500 coils 8k fr 9k r swift spring upgrade with rear helpers, 400awhp 350awtq) I do about 10 track days a year and also daily drive the car.its an 03. I plan on setting the height a little tiny bit lower than stock. Thank you for your time.
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Jun 22, 2011, 07:58 AM
#9
Without camber plates, you can get about -1.5* camber up front reversing the camber bolt at the strut and pushing it towards full negative as you tighten the bolts. Beyond that youll need camber plates.
If you do get something like the tein camber plates you can turn the tops to have them sit at an angle towards the rear center of the car instead of inline with each other. This will let you get a little more caster. I set mine like that at full caster, then adjust the camber with the factory adjustment bolt.
For rear camber Ive had luck setting it at 1/2 the front setting. When I was at -1.5*, I set the rear at -.8*. At -3* front I now have -1.5* rear.
Toe I set to zero all around, then when I race I turn the toe adjustment on each side 1/2 turn towards toe out. This should give you ~1/8in toe out and will help significantly with turn-in. Just remember to set it back after the event, and make sure you're turning it the right way.
If you do get something like the tein camber plates you can turn the tops to have them sit at an angle towards the rear center of the car instead of inline with each other. This will let you get a little more caster. I set mine like that at full caster, then adjust the camber with the factory adjustment bolt.
For rear camber Ive had luck setting it at 1/2 the front setting. When I was at -1.5*, I set the rear at -.8*. At -3* front I now have -1.5* rear.
Toe I set to zero all around, then when I race I turn the toe adjustment on each side 1/2 turn towards toe out. This should give you ~1/8in toe out and will help significantly with turn-in. Just remember to set it back after the event, and make sure you're turning it the right way.
Jun 22, 2011, 10:19 AM
#10
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If you're specifically after more grip in the rear, then set your front swaybar to full hard and rear swaybar to full soft. I run an bigger front swaybar and the stock rear bar with a TRE rear diff, and the car is very neutral. I expect that once I upgrade to a larger rear swaybar, it'll get a lot more tail-happy.
l8r)
l8r)
Jun 23, 2011, 01:22 AM
#12
As for my own experience - I'm pretty happy with alignment of 2.0F/1.5R with zero toe all around. This is with 255/40/17 R-S3, WL swaybars, GTWORX springs, PSRS and all the bushings and other stuff from WL.
No camber plates, -2.0F is max I could get from the stock mounts and bolts. If I needed more, I'd consider camber plates or camber bolts (latter is much cheaper way).
Jun 23, 2011, 02:24 AM
#13
If you do get something like the tein camber plates you can turn the tops to have them sit at an angle towards the rear center of the car instead of inline with each other. This will let you get a little more caster. I set mine like that at full caster, then adjust the camber with the factory adjustment bolt.
Jun 23, 2011, 07:56 AM
#15
Forgive me, but what I see is a camber/caster plate that has been installed such that you can reduce both camber and caster, but can't much add much if any. Aren't we looking at the right front as seen from the front of the car? In the configuration shown, it seems that you have the slot in the plate pointing to the front corner of the car, not the rear-center, such that your adjustment range allows you to reduce both camber and caster, but not add much if any. Am I misreading/misviewing the picture?