The Fat Cat calculator.

According to the FCM suspension calc, if I go with my stock springs, and FM front and rear bar, my front roll couple will be 60.8%, with a roll stiffness of 1531lbs per degree.  

At this point I’m only autocrossing, and just trying to figure out what class I’ll be in, given the cars mods that it came with. (Gutted exhaust, COP conversion, 12lb NB wheels, short shifter, FM pedals, home brew aero undertray). 

Im wondering if I shouldn’t aim for a higher FRC %. Tires will be new, but crap federal 595’s. Not really willing to budge on the mods as this car will always be “cheap and useable around town”. 

Of course, all of this is based upon a calculator that was setup by a man that has had a questionable reputation on the internet Miata world. Some people hate the guy, others love him. 

In reply to _ :

I’m really happy with my 800f/650r springs & 1.25” RB hollow front swaybar. You definitely need shocks valved for that much spring though. 

I've never seen a Miata on stock springs not corner on it's bump stops. Even on all season tires. I think you can kind of make them happy with shocks and a big sway bar, but that's only if you're forced at gunpoint to keep the stock springs because you're in ES. 

I don't have a lot of miata tuning experience but do have a lot with my autocross s2000, which is pretty similarish in concept. My car has a 65% front weight transfer bias and I really couldn't ask it to handle any better!

I've codriven an ES miata a few times with a pretty big front bar and I still felt like it was more tail happy than I liked. 

Personally, I don't think riding on the bumpstops is that big of a deal. It's kind of hard to avoid when you have limited shock travel. It's also another tool in your tuning arsenal. My s2000's bump stops are precisely cut to never engage from normal pitching or rolling, but they immediately (though softly) engage during any more travel than that to compensate for the short shock travel.

Riding on the bumpstops is not so bad, depending on the bumpstops.  I think they sort of designed Miatas to do that.

Well, my car is staying on stock springs for now. Wife likes the ride, it’s our weekend car and road tripper. Plus it has brand new kyb’s and fcm street bumpstops. 

Thats why I looked for a sway setup to Give me plush ride with less roll.