jmann

Run softer springs, you'll have more rebound travel, I think 1000# springs are to much for a miata on the track, can't speak for autox. I am running MCS's and haven't had issues with not having enough bump travel also I'm not running 275 hoosiers.

emilio700

iTrader: (3)

When there is enough grip, 1000# fronts are needed along with the 1.25" Racing Beat or larger front bar.

jmann

IMO there is alot more to, it then grip. The weight of the car , roll couple and alot of other stuff has alot to do with it. I am no suspension tech. but I do know that nascar cup cars are running less then 1000# springs on the right side sometimes and they weigh a lot more then our miatas and lots more grip and aero.

bbundy

Yea it was interesting I learned some stuff last year fiddling with stuff. Adjusting in small increments of front bar stiffness smaller than most people ever have and found some magic at about the point the inside front tire will lift powering out of corners, stiffer relative front than that didn't help and softer than that was slower. ended up with way more front roll stiffness than I ever thought would work well. I think this was because my prior setup knowledge of balance was based on the flawed experience of the front being too deep in the bump travel on the outside front tire. the back is soft with no bar but it still feels balanced and puts down power well. keep in mind with the boost turned up this is a 400hp car with a splitter 6" past the front bumper and a GT1000 rear wing running 275 A6 Hoosiers on 15X11 wheels.

hector

There is another school of thought out there regarding droop travel. From Penske:

At ride height generally you will want as much bump/compression stroke as possible, and roughly 1"-2" of droop/extension travel.

Obviously the word "generally" makes this statement apply to everything and nothing all at once. FWIW, my shocks have little droop travel and therefore don't require a tender spring in the front. The front tire does not come off the ground. The rear is a different story and is probably unseating during a run. I don't have wheelspin issues but then again I don't make any power. Maybe a tender spring in the rear might affect the front's behavior?

wannafbody

iTrader: (1)

What is the reason for running at 4 inch at the pinchweld ride heights? I know on some cars, if you lower too far you can mess up the roll centers. Does this happen with the Miata? I've also read that angled A arms aren't optimal and cause bumpsteer. At what ride height do you reach a point where you are hurting more than helping?

bigben

On a very stiff car (or race car), which is probably very aero driven, not having a lot of droop makes sense. Miatas are not race cars to begin with. Different designs can work well, setup is the key. Always compromises.

Very interesting discussion btw.

Ben

jmann

What Hector said. I have seen pics of my car in sharp corners and the inside isn't much higher then when it is sitting still. The outside fenders are down over the tires a little more. I am also running 6" of splitter up front with end plates and a wing in the rr with a wickerbill. I think if anything the wing and splitter keeps the car planted on the inside in a corner. If the tracks were rough I would have helpers. When I used to race for real there was the age old debate on spring rates and that was a while back and it well most likely continue forever as with shocks.

NiklasFalk

iTrader: (1)

Yes.

Another symptom is that it only works well with about 23" (580) high wheels (unless you know how to compensate).

wannafbody

iTrader: (1)

Are you saying that 4 inches is the lowest before issues or that 4 inches is low enough to cause issues?

jmann

Yes you get into bump steer but there is a lot that can be done to help the situation. Go to 949's site and read the miata race alignment section. I used to run 3.75 frt. Emillio tested different heights quite some time ago and even though you get into bump steer the cars were faster low.

wannafbody

iTrader: (1)

My statement above is absolutely true, depending on several different factors. On my street Miata, at a 5 inch pinch weld height with Bilsteins, 450# 7inch front springs and a Energy suspension isolator at the top, the springs don't come lose at full droop. So, as I stated, depending on ride height, spring rate and spring length, you may or may not need a tender spring in the front.

Dietcoke

This is exactly what I've been trying to say but 95% of the no driving nerds here just refuse to believe it

Monk

iTrader: (3)

Savington

iTrader: (31)

If you run a soft spring, like a 450#, and you run with lots of ride height, like 5" pinch welds or any Exocet application, you probably don't need helpers.

If you run a stiff spring, like a 700# or higher, and you run 4.25" pinch welds or lower like most race-prepped Miatas do, then you have less spring compression and far more available droop travel (as measured from static ride height), you almost certainly need helpers to maintain proper suspension control in droop travel.

aidandj

iTrader: (5)

Seeing as we are in the race prep section, this should have been assumed by the nay sayers.

wannafbody

iTrader: (1)

It's true that most of you guys are hardcore track junkies with seriously prepped cars but there are lurkers and guys with double duty cars here. My ride height is dictated by being able to get the car in the trailer.

Arca_ex

iTrader: (2)

If your car is too low to make it in the trailer then you simply don't have the proper ramps for the job. That's not an excuse.

Savington

iTrader: (31)

"Race Prep"