STS Miata Suspension Advice

Noted this in another thread and thought it would be better to break off to another thread rather then derail a build thread.

(counting on Miata in the title attracting Keith, but wanting to kind of pool the Miata knowledge in one place to get all the data points and have different ideas on the table)

Keith Tanner wrote:

Apexcarver wrote:

DaveEstey wrote: with the NB tophat conversion

I think that is what might make a big difference there. That gives you more travel, he is probably hitting bumpstop a lot. I need to get the tophats for mine (and stiffer springs)

Old comment, but it's wrong. The NB mounts do not give more travel. That was bad info that's still being propagated by some vendors. The reason the V-Maxx ride well is because they're better specified than the Bilstein/Eibach combo. And because they have better bumpstops than a stock NA Miata.

Curious...

You are counter-indicating what the STS build in the project cars says. In there it is indicated that you can run a lower ride height due to the increased travel (specifically in the rear), or at least that it somehow makes it so you are not on the bumpstops as much.

I very much trust what you have to say because you are the established expert, just want to know the truth because I was ready to pull the trigger on upgrading the tophats on my STS car so I could get away with a lower ride height.

Any chance I could get more clarification?

I am trying to figure out the best setup for the suspension on my STS car before I start dropping money into ECU stuff.

Currently running Koni/GC/550F/375R/No rear bar/ RB 2-hole front. I think the bumpstops are the Koni parts or whatever came with the GC setup and have been pondering if cutting them in half would be a good thing (have seen some documented cases) or if I should bite the bullet for FCM stops.

Caveats: I know that 550 lb/in is a lot to ask of the Koni Yellow (sport, SA) and is right around the upper limit of what the stock valving can handle. This is a holdover setup for upgrading to 700/450 later if/when I get race valved fronts.

The nb mounts do not give more travel. They do give more travel for a given ride height though. They are shorter than the na ones.

Ah, just meaning not overall travel, but wheel up into wheelwell travel.

Guess it was a confusion of my wording. By travel I was meaning upward range allowing the car to be lower, not the overall range increase. (who really utilizes all of the droop travel anyways?)

Apexcarver wrote: (who really utilizes all of the droop travel anyways?)

And one I can't hotlink here.

Well, rallycross is its own kind of monster...

mw wrote: The nb mounts do not give more travel. They do give more travel for a given ride height though. They are shorter than the na ones.

Nope, not that either. They put the top of the shock in a different place and the top of the spring in a different place. Installing a set of NB upper mounts on an NA suspension will result in a drop in ride height and a loss of bump travel. If you mess with the thickness of the bushings, you can add a bit more bump travel, to the point where you have slightly more than the NA mounts gave you IIRC.

Overall bump travel is not improved - and since it's the one we need the most, it's the one that's most often discussed. Overall travel (bump + droop) is a function of the shock shaft length.

There's a lot of misinformation out there about this, and quite a bit of it was propagated by a vendor who specialized in autox, so it's not surprising it's still around the autox world. Luckily, it's easily dispelled with some simple measurements of the parts in question. I've posted measurements on Miata.net in the past, I don't have a link handy.

I always get confused about it since I have an nb. Lol. Just ground control it with some konis, its what everyone says.

I still dont get it, the shock mount is raised but that doesnt alow more travel? I know it doesnt "make" travel I just thought it freed up some that was left on the table with lower na mounts. I haven't hit bumpstops in a while but I guess its my imagination and not the fact I changed strut mounts?

To bring the thread full circle, I ended up going with ISC racing tophats. Those do give more bump travel, but I have to give a somewhat mixed review of them for Koni applications.

Had to drill out the hole, clean up welding slag (that had been powdercoated over). Furthermore, due to thread engagement issues, I was unable to run a lockwasher on the top of the shock. (I check it for backing out often and used loctite)

edit Ran my 2nd scca autocross (I mostly run with other clubs) and got 37th in PAX out of 195 at a DCR Fedex event. Gotta work on my driving and some other tidbits still.

If I can jump in with my own question (Keith, you should approve here). My '97 Miata has the FM 2.5 suspension system (Tokiko white shocks) usine the front bar but no rear bar. A swapped in rear diff (4.3 torsen unit from a '99). Alignment seems right.

So here's the question: without spending a pile of money what would be good improvements to make over the winter? I autox the car but I DD it and don't want to get so hardcore that it sucks to drive.

What would you consider to be an improvement? What are you trying to address?

I run the same suspension on my street Miata, only I have a rear bar as well as the front. It's fun.