What is a good caster setting for de powered racks?
 

Hey guys, I de-powered my rack awhile ago but I did not start DD-ing the car till now.

The last alignment was done with P/S, so the caster is set at 5-5.5 degrees. I just cannot live with this anymore (I have a smaller momo steering wheel and I want to autox the car, which would be very hard right now with the steering effort).

So, what kind of caster do you guys run with de-powered racks? I did some looking up, seems 3-3.5 degrees is reasonable. I just wanted some input, especially if you have autox experience on a de-powered rack.

Thanks for the help!

3-3.5*

Thanks dood, I was half expecting you to just tell me to stop being a pussy :laugh:

I'm running 5 on the . but need to dial it down a hair too. Was thinking 4 but might try the 3.5. Just a pain in parking lots and wants to push a bit in the throttle in U turns. Like I'm only using the side walls.

I'm a pretty strong guy and thought 5* on an NA w/depower was tough to drive on the track. 3.5 is much easier and the car seems to handle fine. I believe we put 5* in the power-steering cars to slow-down the rack, but don't quote me.
lol, that too.

A local asked what to use and I demanded he go with 3.75 over the +5° of conventional m.net wisdom Lanny alignment. He argued pretty hard with me about it, but eventually decided to take my advice.

He called me later that week and thanked me for reinstalling power steering back on his car.

Great to hear, ill have to get a new alignment asap.

Thanks guys!

Yep, 3-3.5* caster is pretty much what I end up with on both track cars, both depowered. Tried more, it sucks.

I remember Emilio writing about going back to high caster, but not sure on what car and why. Maybe his DD for highway stability :P

Everyone who bitches about how heavy depowered steering is at speed is either a huge, huge pussy, or runs 5-6* of caster.

All of our shop cars get 3.5*.

The difference between 5-6* and 3.5-4* in caster is huge. I changed to about 3.5* on my depowered DD after trying it at 5+* for months and it was much easier to drive.

The Dallas "adult" crew still runs more camber in the rear than the front, and pretty much disagrees with everything 949 comes up with. I guess that's why we're going faster than they ever did with 60hp less whp, on r-comps (they run Hoosier). lol

I am not a princely track stud as you are, but from just a basic suspension 101 perspective, how can more camber in the rear than the front possibly be an advantage?

Teach me please. It's a question I've had for a while.

Funny thing is my girl drives my depowered '97 with a '93 depowered rack, on 205 BFG's that I think are pretty sticky for street tires, 5deg caster, on the street all the time with no complaints. She just puts her boobs into it. Well, wines about the lack of AC but she'll get over it.

Yes, positive camber would ruin your handing. But this thread is about caster.

I determined that M.net wisdom on Alignment had no basis in what actually worked years ago. I maximize front camber first. then just try to get castor the same on both sides from there. ends up around 4° but I’m kind of a strong guy plus I like to space my steering wheel close so I have good leverage without my arms being fully extended.

The whole preaching that thou shall have 1/2° more camber in the rear than the front thing is also interesting in that it is based on no testing and it is just plain wrong for maximizing performance.

I arrived at pretty much the same conclusions as 949 say through my own independent trials prior to 949 publishing it. And Emilio also keeps coming up with the best products to make my car faster as well. The guy cuts through the BS and gets the picture I’m impressed.

Bob

I KNOW! :facepalm:
Typo on my part. Replace 'camber' with 'caster' which is what I meant. The rest is fine.
Not that it matters much, but is it even possible to set a stock Miata suspension for +5* camber? I doubt it.

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.

I have the mazdaspeed 360MM wheel and still run max castor and camber in the front. I don't think the steering input is that difficult.

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 shit (although 0.60* of toe-in isn't helping) but at least the pyrometer is happy now.

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?

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.

What is the benefit of the Caster at 3.5* aside from ease of turning?

Awesome, Thanks. Ill have to borrow the pyrometer from Pitt's FSAE team.

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)

~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

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.

Not going to lie, I run like 5.5* on a 320mm steering wheel, and I thought I was being a pussy.
If anything it helped me to not cross my arms (cause I can't even turn then)

< I'm on right

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 !

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

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)
https://www.miataturbo.net/attachmen...=1&d=148986887

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.

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)

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.

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

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.

Harder. At a little over 2* camber with the ELBJs the lowest I could get was over 5* caster.

SADFab offset delrins do not make it harder to get low caster, since they just move out the front pivot of the FLCA.

Yeah thanks, now I'm waiting on regular oem style lower ball joints.