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What is a good caster setting for de powered racks?

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Old 09-11-2011, 12:57 AM
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Originally Posted by Savington
BTW - I think that with stock suspension the classic "Lanny" alignment is probably not all that bad, but as soon as you knock up to a 375/250 GC setup or anything in the 5xx/3xx or 7xx/4xx range you should stop sucking and run more front camber.
Imma be running 5xx#F/3xx#R with the car soon, what would you recommend I run? Something like:

Front:
1/16 toe out per side
-1.75* camber
3.5* caster

Rear:
1/16 toe in per side
-2* camber

On Azenis tires?
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Old 09-11-2011, 01:54 AM
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On the street, 2.2F/2.0R camber, 3.5 caster, no toe.

On the track, 3.0F/2.5R camber, 3.5 caster, no toe up to 200whp, 1/16" rear toe-in up to 250whp, 1/8" rear toe-in above that. Adjust rear camber per tire pyrometer readings.
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Old 09-11-2011, 02:46 AM
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What is the benefit of the Caster at 3.5* aside from ease of turning?
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Old 09-11-2011, 12:02 PM
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Originally Posted by Savington
On the street, 2.2F/2.0R camber, 3.5 caster, no toe.

On the track, 3.0F/2.5R camber, 3.5 caster, no toe up to 200whp, 1/16" rear toe-in up to 250whp, 1/8" rear toe-in above that. Adjust rear camber per tire pyrometer readings.
Awesome, Thanks. Ill have to borrow the pyrometer from Pitt's FSAE team.

Originally Posted by theshdwconspracy
What is the benefit of the Caster at 3.5* aside from ease of turning?
Nothing really. Usually in racing you run a lot of caster, as it improves both directional stability when driving and gives you a little more camber gain under bump.

But since it also makes the steering heavy and I don't have p/s anymore, I am reducing it to 3.5* to make it easier to drive (beneficial for the tight turns of AutoX)
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Old 09-12-2011, 06:43 PM
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Originally Posted by Savington
Bob, what kind of camber numbers do you run, and how even are your tire temps? I run 3.0/2.8* in the rental and get even wear, but if I try to run 2.8R in the black car I just cook the insides off the rears. I'm down to 2.5* and the tire wear is still **** (although 0.60* of toe-in isn't helping) but at least the pyrometer is happy now.
~2.8 front 2.5 rear. fairly even tire wear maybe a tad on the inside with NT-01's on the track and mostly inside edge wear on the rear. I might be a little bit more negative now though because I lowered it a tiny bit without re-aligning since going to 800/500#springs and XIDA. street driving on RA-1's tends to wear the inside edges quite a bit. 275/35/15 Hoosers on 9" rims tend to wear the outside shoulder when I autocross and it gets much worse if I try and run less than 34psi in them. not sure if the hoosier issue is a camber issue or a wheel width issue squezing them on 9".

always been deminishing returns for me going much more than 2.5 in the rear. I haven't gone past the point of deminishing returns yet in the front that I know of because I basically have it as far negative as the adjustment range will let me get.

I run zero tow all around and for autocross I screw each of the tie rods out 2 flats while Im changing wheels to geve me some tow out. it seems to help quicken transisions a tiny bit.

Bob
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Old 09-12-2011, 07:01 PM
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Originally Posted by Savington
BTW - I think that with stock suspension the classic "Lanny" alignment is probably not all that bad, but as soon as you knock up to a 375/250 GC setup or anything in the 5xx/3xx or 7xx/4xx range you should stop sucking and run more front camber.
Sav,

Having a 375/250 GC setup. how much more camber would you recommend as a good starting point?
I was thinking of running 949's -2.8, -2.5 0 toe setup to see. Would you recommend anything other than that? or should that suffice for a n/a 1.6?
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Old 09-13-2011, 12:52 AM
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Originally Posted by Gryff
Sav,

Having a 375/250 GC setup. how much more camber would you recommend as a good starting point?
I was thinking of running 949's -2.8, -2.5 0 toe setup to see. Would you recommend anything other than that? or should that suffice for a n/a 1.6?
Originally Posted by Savington
On the street, 2.2F/2.0R camber, 3.5 caster, no toe.

On the track, 3.0F/2.5R camber, 3.5 caster, no toe up to 200whp, 1/16" rear toe-in up to 250whp, 1/8" rear toe-in above that. Adjust rear camber per tire pyrometer readings.
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Old 09-13-2011, 01:46 AM
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Not going to lie, I run like 5.5* on a 320mm steering wheel, and I thought I was being a *****.
If anything it helped me to not cross my arms (cause I can't even turn then)

< I'm on right
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Old 03-14-2017, 05:09 PM
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Hi guys,
I will try to bring this topic back to life...
After running my car for one year with depowered steering I really need to make a change NOW ! I always knew that I have to focus on like 3.5-4deg of caster. The problem is it seems like impossible to get anything under 5.5°. I have about 2degrees of camber with about 12 1/4" front hub to fender ride height. What could be wrong ? I believe that only "logical" thing is that my FUCAs are bended backwards, but that doesnt really make sense as I would also gain a camber with that bended. and 2.2deg of camber is like maximum I can have. I have prothane bushings all around btw as well.
my idea is to try swap left and right arm visa versa and see if that makes any difference. Could anybody give me any tips what I or better said shop should be doing bad ? I´m with mechanic all the time and telling him what to do, so it´s more about me than about him.
any help much is apreciated !
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Old 03-15-2017, 06:47 AM
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Post a pic of your camber bolts and we can tell if he is truly maxed out.

By the way bended = bent in freedom english
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Old 03-18-2017, 04:29 PM
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Hello, and thanks for correction (really thanks)
Bellow is the picture of the left front camber bolts. other side is the same just mirrored. It looks about right to me for as low caster as possible or not ?
edit/ now I see that front bolt could be turned clockwise - https://www.miata.net/garage/alignment/ is this describtion correct here ? I will want to go with more camber this year, but I wanted to stick with 1.5-1.7deg in front last year as I felt that the reaction for steering wheel was faster with this little camber on AD08R tires. Now I will run narrow 205 FZ201 (which are actually more like 225)
Attached Thumbnails What is a good caster setting for de powered racks?-lf-caster-camber.jpg  

Last edited by AndrewG; 03-18-2017 at 04:41 PM.
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Old 03-18-2017, 04:46 PM
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That's maxed out for caster, looks like you ha EA some adjustment left in your other bolt so you should be able to maintain your camber as you reduce caster.
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Old 03-18-2017, 05:24 PM
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Originally Posted by cardriverx
Just wanted to post, I just put on a 2" steering wheel spacer behind my Momo wheel. Made a world of a difference, the car is much eaiser to drive (my arms were nearly straight when driving before, knees real close to the wheel). I feel like when I get the caster back to 3.5* she'll feel smooth as butter.
achieving a proper driving position can be a challenge but is a crucial and often overlooked part of the formula. fyi with your back strait against the seat you should be able to easily drape your hand wrist over the top center of your steering wheel. the hand should be loose and basically bounce when you move your arm as proof the hand is fully over the wheel, not wresting on it. just a thought for those who might be unsure or not realize because they are accustomed to something else and think it is fine. driving position is one of the first thing a decent instructor will look at
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Old 03-18-2017, 05:35 PM
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Originally Posted by psreynol
achieving a proper driving position can be a challenge but is a crucial and often overlooked part of the formula. fyi with your back strait against the seat you should be able to easily drape your hand wrist over the top center of your steering wheel. the hand should be loose and basically bounce when you move your arm as proof the hand is fully over the wheel, not wresting on it. just a thought for those who might be unsure or not realize because they are accustomed to something else and think it is fine. driving position is one of the first thing a decent instructor will look at
I have setup like this, but what I found is that when I´m crossing my hands on wheel my biceps is hitting the harness buckle really hard and bad. It is quite funny but after an autox events I usualy feel pain in the biceps because of this - true is that I ride in Tshirt normaly (when competition does not require long sleeves)
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Old 04-15-2017, 07:36 PM
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wish I could help. I don't autocross and I don't have massive biceps. I'm sure you've tried to adjust you harness to get the buckle lower? you might need to look at some different harnesses because that is not normal. That or stop going to the gym everyday.
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Old 04-16-2017, 06:48 PM
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Originally Posted by AndrewG
I have setup like this, but what I found is that when I´m crossing my hands on wheel my biceps is hitting the harness buckle really hard and bad. It is quite funny but after an autox events I usualy feel pain in the biceps because of this - true is that I ride in Tshirt normaly (when competition does not require long sleeves)
My son's buddy is 6-3" 260#, and my son is 6-5" 245#. Both can drive the car without such issues. The car did not come like that however!

We adjusted seat height, seat for and aft, seat back angle, steering column height, QD/spacers to move the steering wheel for and aft, steering wheel diameter, and played with deep and shallow set steering wheels....
We also had to ditch the NB center console, and we are making up flush door cards to give him a little more room.
We spent quite a while getting it right for him. Now he is as comfortable in the car as a big and tall person can be.

Set your car up to fit you.


Hope that helps,
Jamie
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Old 04-17-2017, 12:58 PM
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Would extended lower ball joints and the sadfab delrin kit make it easier or more difficult to hit a lower caster target? I measured at 6.5* with a depowered rack, and it is extremely difficult to turn past maybe 10*on the steering wheel.

Last edited by thumpetto007; 04-17-2017 at 03:13 PM.
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Old 04-17-2017, 01:53 PM
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Originally Posted by thumpetto007
Would extended lower ball joints and the sadfab delrin kit make it easier or more difficult to hit a lower caster target? I'm at 5* with a depowered rack, and it is extremely difficult to turn past maybe 10*on the steering wheel.
Harder. At a little over 2* camber with the ELBJs the lowest I could get was over 5* caster.
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Old 04-17-2017, 02:16 PM
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SADFab offset delrins do not make it harder to get low caster, since they just move out the front pivot of the FLCA.
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Old 04-17-2017, 03:12 PM
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Yeah thanks, now I'm waiting on regular oem style lower ball joints.
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