NA Miata Alignment Suggestions

[paultg]

I have a '91 Miata with complete Mazdaspeed Bilstien shock & top hat setup from a later NB series. The springs are H&R race springs (for an NB), 325/300 are the spring rates. I also have flying Miata front and rear adjustable sway bars. The car also has a Torsen differential from a 1994 vehicle.

Anyone have any suggestions?

Info:
I did some reading on Miata.net and decide to use settings noted below but my tires were pretty shot (Falken Azenis 205/50R15). I ended up putting sway bars to full stiff in the front and rear with this setup and the car still wanted to plow. I'm thinking of changing the rear camber now (down to -1.5 degrees) as new tires are going on today or tomorrow. I've noticed now that the spring rates are somewhat not typical of other setups(rear rate being much closer to the front) I'm not sure how that impacts decisions like this. I'd like to get a good baseline alignment and then tune it for slight oversteer (off throttle) with the sway bars. I autox the car alot, will be using it on the highway alot as well, and am planning for track days with Com.

Ride Height (not adjustable): F:12.5" / R:13"

Front
Caster: Max
Camber -1.5 degrees
Toe Out: 1/16" per side

Rear
Camber: -2 degrees
Toe In: 1/16" per side

[breakaway500]

Those alignment numbers look good to me.You could go a bit more camber up frt (up to 2.0) at the expense of some additional tire wear. I like neutral toe at the frt,leaning toward toe in (about 1/16" total)...but that is just my preference.Everyone says toe out is better for turn in..but personally,I can't feel the difference and I will gladly sacrifice some turn in snap for in line stability at 125mph..

[boltonite]

Take the car to someone who knows what they are doing to get a good baseline setup and some data (corner weights, cross weights and accurate toe/camber #s) so you know where you are starting out, and THEN mess it up.

[Stynger]

First, tires are everything. Worn out tires are not going to act the same as new. What will you be running?
You probably don't have much more camber available at those ride heights.
If it's plowing, soften the front bar.
Understeer in a Miata on an autox is common. It usually takes an adjustment in driving style. People tend to brake way too late and push through a turn.
On the track it is less of a problem, people tend to get their braking done before turning and power through a corner.

Your set up is OK. Tires, pressures and driving style will help get what you want.

[paultg]

I'll be going with brand new Falken Azenis RT-615s again. They are being mounted today.

I've been autoxing for a while but do know part of it is me getting more used to the car (rwd). I started with AWD, then FWD. I can tell you it isn't me bombing into the turns way to hot though with the wheel cranked and hard on the brakes! It was more like not getting the steering response at turn I'd prefer, and then it just getting worse as I tried to exit the turns and add some power. I've had much faster folks drive it last year and say it felt that the tires were limiting grip.

Mark knows the courses I run on, they aren't typical autox courses, more like a miniature road course setup.

Thanks for all the tips. Just knowing I'm not way off is great. I was leaning towards leaving it and seeing how it goes with the tires before making a change anyway (trying to do one thing at a time), but wasn't sure if the current setup was way off for the spring rates.

Paul G.

[breakaway500]

After seeing you on course last year,the car looked good..and was not doing anything odd..but it really is impossible to tell much more till you drive it. Like Les has stated,tires are everything! I like the RT615's for a nice all around street tire/track tire.It is not the best DOT tire out there for purely track use,but does the double duty well. I'd leave the suspension as is.April 3rd is right around the corner...

[TroyV]

+1

Your Falkens felt as if made from fresh cut plywood when I drove the car. The new tires will help a great deal.

[horizenjob]

am planning for track days with Com

COM is everything, the rest of life is just waiting.

If the car is plowing, it probably just means you are ready to step up to a formula car!

Your set up is OK. Tires, pressures and driving style will help get what you want.

Les' advice is good, it's just the hardest thing to fix.

[timmmy]

This is the setup Les put on my NB years ago, and I have to say it is absolutely perfect! The car is super neutral and predictable on track, and on the street one of the nicest handling Miata's I have driven.




Take it down to Les and have him set it up for you.

[CP]

Scott at Fastrack in Peabody can do any alignment you want too. Try going a half degree additional negative camber on both ends. Soften up the front bar too if you're looking for less understeer. FYI, the SM suspension kit from MS uses 700# front springs, 325# rear. Be sure to align the car on new tires or the numbers will be off due to old/used tires (uneven wear across the tread).