Ultimate miata suspension

He also says take budget out of most of it. KyAllroad I am guessing you are referencing autocross specifically? What are the rear paco arms for?

Lof8 said:

it doesn't seem logical to be discussing Xida and Fox suspensions for a car that is meant to be "Challenge legal" per the original post. 

"take the budget out of it", he says. Xida and Fox are challenge legal, just difficult to do for the price if you're dealing with MSRP Every time we start with a new platform, I have to build a coilover setup from scratch out of parts I have around. There's no reason someone couldn't do that with the Challenge. Takes time, effort, tools and knowledge - but isn't that the key to Challenge success?

Paco arms get you a lot of rear camber.
https://www.flyinmiata.com/paco-control-arms-complete.html

In reply to Keith Tanner :

Aahh, yes. Interesting combination of parameters :)

It's a logical way to do things. Figure out the ideal, then figure out how to build it within budget.

Keith Tanner said:

It's a logical way to do things. Figure out the ideal, then figure out how to build it within budget.

EXACTLY. 

Thats the logic behind the thread. 

I may not have enough time and resources to get to ideal, but im going to try.

Chassis will be stitch welded. 

Drivetrain will be an aluminum headed six cylinder. 8.8 swap is intriguing. Can y'all elaborate more on that? Reason being, the 4.30 gearing and open diff are far from ideal for this.

The only spring rates i saw listed was 800/500. Why these rates?

The fox/xida/penske shocks: what makes them so much better? Just the valving?

Now, if we're talking Challenge - to get more camber, I'd be welding on stock control arms if I didn't mess with pickup points. The Paco parts and the extended ball joints are good stuff, but simply sectioning an upper control arm after mathing it out will do the same. On the front, you may have to extend the lower instead due to tire clearance.

8.8 rear is fairly heavy but probably a good junkyard potential. Halfshafts are going to be the high-dollar part. Junkyard CTS-V diffs are pretty cheap, though.

Those are the rates recommended for a Supermiata, I think. Autocrossers tend to go higher, although your car is going to be a different case due to (likely) different weight distribution and torque output. Autocrossers also tend to set up with a little more front roll stiffness to make it easier to lay power down out of a corner.

Valving is a big part of it. So are things like internal friction and details in piston design. You can do a lot with a set of junky Bilsteins if you know what you're doing, although I've always found they've got more internal pressure than I prefer so the "air spring" becomes a factor.

I think its early in your process to be selecting spring rates.  800/500 would be a good starting point though, assuming you are doing a big front bar/no rear bar.  The important thing is to get out there and get testing time in.

I'm a little surprised to see so much camber recommended.  I guess that much more roll is generated on R comps.  600/350 rates on my the STR Miata I ran and it had just under 2 degrees of camber.

Again, I think that will come down to testing as well.

I was able to get to -4.5 degrees of camber on the rear of my Challenge Miata, which is beyond what Hoosier recommends. The front required the extended ball joints though, and I could have avoided spending that money by cutting and welding, but I was intending to put the car back together for street use. Is there any practical use for rear camber at the kinds of range the Paco arms allow? I do like that each turn is a precise amount of change.

The amount of possible rear  camber in the Paco arms is in the ridiculous range. I'm sure there are some VIP enthusiasts that run them at max tuck, but mostly it's a matter of "there's no downside to making them adjust THIS far..."

Of course, Paco also makes the 3" lift kits. So you need a fair bit of adjustment if you want to get any real rear camber at that altitude.

ProDarwin said:

I think its early in your process to be selecting spring rates.  800/500 would be a good starting point though, assuming you are doing a big front bar/no rear bar.  The important thing is to get out there and get testing time in.

 

I'm a little surprised to see so much camber recommended.  I guess that much more roll is generated on R comps.  600/350 rates on my the STR Miata I ran and it had just under 2 degrees of camber.

 

Again, I think that will come down to testing as well.

The "hot setup" which I ran on my track car, is 800/500 with one of the RB front bars and the MSM 14mm rear bar (or wide Hoosiers and a lot of aero guys are running 1000 up front). Of course that's track work, not playing around in parking lots. :)

Everyone is forgetting the key of "I used this, I used that" without tires, track, relative pace to a known quantity, what you used on your car is really pretty meaningless.

 

The small rear bar, vs no rear bar seems to be more driver preference. No rear bar being more understeery. I had the RB tubular front, no rear, but my spring rates were much lower

Yeah, I don't understand the requirements.  If the car is "ultimate" like the title says, then you probably want to skip Xida and Fox altogether and go with Penskes or the like.  They cost three or four times as much and are (AFAICT) what go in the top national-level autox cars.

If it's an autox-only car, spherical rod ends for all of the suspension arms are probably the best choice.  They're terrible in anything but a pure race car though. :)

Edit, I see the posts about the "no budget" reasoning now.  Unless you've got a mill and a lathe and are up for making your own shocks after melting down scrap aluminum to make your own billets, I'm not sure how useful the shock discussion is :)

Jaynen said:

The small rear bar, vs no rear bar seems to be more driver preference. No rear bar being more understeery. I had the RB tubular front, no rear, but my spring rates were much lower

It comes down to venue. Autocrossers tend to prefer the no rear bar option for traction off tight corners, road racers want a bit more rotation. Rally drivers want to be looking out the side windows all the time

Of course, there are a lot of different factors, that's a simplification.

Back on the rear diff topic - you can use clutch type LSD's and ring and pinion's out of 2nd gen rx7's (and old 626's and mazda pickups) in the miata housing.  Modding the clutch stack for more lockup is a known thing. 

don't know if you can get tall enough gears to work (3.90's were common, so a little taller than the miata, maybe 3.60 or so in old 626's).

lighter, cheaper, and less fab than an 8.8 swap...but wait you asked about the ultimate build, so nevermind 

In reply to sevenracer :

That sounds very promising.  I may even know a rx7 guy....