SuperMiata / 949 Racing 89-05 Miata set up tips
All content on this page copyright Traksport LLC 2016
Updated Dec 13, 2016
Disclaimers: Performing any modifications to your car based on advice from this FAQ page is dangerous, might hurt you and and kill a kitten somewhere. IOW, read, assume, implement at your own risk (don''t sue us if you mess your car up and crash)
These settings may not be compatible with your vehicle, driving style or conditions.
The race alignment shown below are the maximum performance settings to generate the best balance of turn in, steady state lateral grip, braking grip/stability and power application in competitive type driving environments.
The Race Alignment assumes:
* Either factory sport package Bilsteins, Koni's or high performance aftermarket dampers
* At least 550# front springs
* At least 1" front sway bar
* EHP (<=200UTQG) or R compound tires, not hard compound street tires
* You are comfortable with potentially less high speed directional stability than the Mazda factory alignment settings may provide
There are several ways to measure ride height. The most common are fender height & pinch weld height. If you are always using the same tire diameter, I recommend using pinch weld height as it's easier to get more precise and repeatable measurements. We always use pinch weld height method of measurement at our shop.
Measuring pinch weld height
Requires that you always measure with the same size tires. Take measurement from forward most and rearmost straight area of lower unit body pinch weld at it's lowermost edge. If you measure frequently, a small dot of contrasting paint or other mark on your measuring point is a good idea. Pinch weld heights listed below are assuming a 22. 7 to 22.9" tall tire which when loaded, will have a static loaded radius of about 11.25". Verify tire pressures before measuring ride height.
Measuring fender height
This measurement allows comparison between two cars with different tires. The actual fender shape and location can vary on a 10-20 year old car so this method is less precise. You must locate the exact center of the hub and this is difficult to do accurately. If you hold the measuring tape next to the hub you induces an error because the tape will not be 90° the ground plane. The fender lip on an unrolled fender can be 3/16" thick so two different people will often interpret the exact point differently. For these reason we recommend you not use this method and instead learn to use pinch weld heights for any future suspension tuning.
Before you start
These settings work best with the factory Torsen or OS Giken differentials. Ideally you will change the front to rear spring rate and anti-roll bar differential (FRC) biased towards the front. The OE FRC is only slightly front biased but the lower front camber serves to keep the car more or less neutral. We have found that setting the front camber from -.2° to -.5 ° more than the rear provide best grip and lowest lap times. Doing this on an otherwise bone stock Miata will result in an excessively loose, tail happy car so don't!
Make sure your car is basically healthy before trying to tune for more grip. This means carefully inspecting the entire suspension for worn, cracked, broken or mismatched parts. We often see high mileage Miatas with broken OEM end links, rubber bushings pushed out of control arms, bent suspension pivot bolts causing binding, bent wheels, mismatched tires, etc.
There is no "best" alignment for every condition, only the"best" compromise that suits your needs. To maximize the performance in a competition environment you need to test, test, test. That means, same tires, same driver, same conditions, change one thing at a time. Record tire temps with a probe type pyrometer (no lasers!), lap times, tire wear patterns, tire pressures and most importantly, driver impressions immediately after run. The more you are trying to squeeze out of the car on given course or track on that day, the more you have to test, record adjust, repeat. What works that day with the sun out, might be less than optimum 30 minutes later with the sun behind the clouds. You shouldn't expect to be able copy the settings published on this page verbatim and have it turn out 100% perfect for every possible car, driver, course. That's why race teams have highly skilled full time engineers constantly tweaking the cars to milk more speed out of the car for the conditions at that instant. Two different drivers under the exact same conditions can generate very different tire temps and require different set ups. The settings you finally settle on are your setup, which is different than my setup. My setup optimized for a given track, weather, hardware, will not be ideal for you. We are merely providing you with a starting point.
Most DOT R compound race tires will develop their peak steady state lateral (cornering) grip at camber, toe and pressure settings that won't necessarily show even tread temps or wear. Generally when temps are evenly tapered across the tread and peak temps are within 15° at every corner, you are pretty close. The pyrometer is your friend, learn to use it! http://949racing.com/using-a-tire-pyrometer-949-racing.aspx
I usually shoot for tire temps 15~20° hotter on the inside than the outside with an even gradient to the cooler outside shoulder. Don't assume anything when reading tire temps or any other measurement. Drive it hard, pay attention to the car and experiment. Clocks don't lie.
We can't predict how your tires will wear because there are too many variables. Tire wear must some times be sacrificed if you are looking for the fastest possible setup. In general, when the car is at it's fastest and you have a good balanced set up, the tire wear will be pretty even. Once can not achieve ultimate grip and response on track while acheiving lowest possible tire wear in gentle street driving conditions. A compromise must be made with an honest assesment on how the car will be driven. Our criteria
Street No competition use. Significant expressway/highway driving.
Dual Duty Occasional autocross or HPDE, mostly street and highway driving
Race Optimized for competition, autocross or track
My Miata isn't symmetrical!
The unitbody of the Miata is rarely perfectly symmetrical. This means one side might have pinch weld heights that are not even with the other side. In this case, average out the measurements to reach your target. Test drive then determine if you need to make further adjustments.
Supermiata Street Alignment
For most street driven Miatas, tire wear is the most important parameter. Excess toe in or out will usually cause more tire wear than somewhat aggressive camber will. The OEM alignment numbers with more rear camber than in front, are designed to induce a bit of understeer. Lawyers ultimately dictate the OEM alignment, not the clever engineeers that designed the suspension. The actual suspension geometry is designed to require greater front than rear camber. The SuperMiata Street Alignment will generally result in no increase in tire wear over OEM and possibly a reduction in tire wear if you occasionally load the tires to maximum cornering forces. In general, this Street alignment is conservative and intended for cars that never slide their tires and spend almost no time at maximum conrnering loads.
NOTE: This alignment will require a slightly larger front sway bar. NB factory, FM or Racing Beat 1" solid bars will work. The Racing Beat 1.125 bar is too much for normal street tires (>240 treadwear). The Street Alignment may cause a 100% stock Miata to oversteer, or be too "loose" so it is recommended to use the front sway bars described here.
5.00 ~ 5.5" front pinch weld height
.06 ~ .18" rake (rear higher)
Front camber: -1.4°
Front total toe: +1/16" .03"
Rear camber : -1°
Rear total toe: +1/8" .06"
SuperMiata Dual Duty Alignment (cars that see regular street use and some track/autocross)
In general, the Dual Duty alignment is intended for cars that will occasionally reach the limits of traction and slide the tires but don't want to give up too much tire wear for daily driving. To reach target camber and ride height will usually require adding Extended Lower Ball Joints
4.5 ~ 5.25" front pinch weld height
.06 ~ .18" rake (rear higher)
Front camber: -2.5°
Caster: +3.5 ~ 4.0°
Front total toe: 0
Rear camber : -2.0°
Rear total toe: + 1/8", .06"
SuperMiata Race Alignment
The Race Alignment is intended to win national championships. YRMV
4"~ 4.7" front pinch weld height.
Zero rake (with driver and fuel)
Front camber: -3.2° ~ 4.2° depending on pyrometer readings
Caster: ~ 4.0° or max available once you reach camber targets
Front total toe: 0
Rear camber : -2.8°
Rear total toe: +1/16 for <200whp. ~1/8" for greater than 200whp
Fine tuning with rake
The Miata seems to work best with about .25" positive rake (rear higher) measured at the pinch welds without driver in car and about 1/4 tank. It seems the the roll center axis doesn't like to be too far out of sync with the roll centers. In general, you can lower the rake to increase rear grip and improve transitional stability up to the point that the rear suspension begins to bottom. Lower the front to increase front grip and turn in response, again, until it begins to bottom the suspension excessively. In general, once we have an alignment we like, the only tuning we do at the track is to raise and lower the rear to fine tune. Lower to add rear grip, raise to reduce it. Too low and the suspension will bottom so that's your limiter.
What ride height?
Ultimately, the lower your Miata is, the faster it will be in competition. The limiters are bump travel and ground clearance. If your suspension bottoms to frequently, bouncing over bumps instead of saking them up smoothly, it's too low. Gorund clearance for street driven cars is really up to you. Decide how much ground clearance you need to clear obstacles in your daily driving such as steep driveways, speedbumps, drainage dips, etc.
Sway bars (anti-roll bars)
Disconnecting the rear sway bar on a lowered Miata allows the inside wheel in a turn to droop further. Since the inside front with swaybar still attached will not droop, rake changes. This means the front stays low, the rear jacks up in a turn. The effect is slight but it changes the roll axis, camber gain and a few other things. For autocrosser, this compromise is usually worth it as it will greatly reduce wheel spin and reduce oversteer during low speed transitions. For track use however, this will usually result in terminal understeer on corner entry that will have you pulling your hair out trying to fix. In short, if you can get your autocrosser to work with the rear bar, keep it hooked up. If your budget or autocross class restrictions don't allow you to get good balance with the rear bar connected, then you have to ditch it. For track use, save yourself the headache and leave it on.
In general, the Miata likes a much stiffer front sway bar than stock, on the order on 3-4x more rate. For street only use, we prefer a smaller diameter front bar and OEM rear. For track, autocross or canyon driving, we prefer a 1.125" front. For autocrossers, usually the OEM 11 or 12mm rear bar or sometimes nothing. For track cars, we like a 14mm rear bar. We have yet to find a car or environment that needs more than a 14mm rear bar. If you have a rear bar larger than 14mm and want to keep it, don't. Bike the bullet and get the correct sized bars for your usage.
Miatas over 180whp or so can run +1/8" total toe in at the rear to attenuate corner exit power oversteer. Autocrossers forced to run wheels much narrower than optimum for the tire width will usually benefit from 1/8 to as much as 1/4" front toe out (CAUTION, this front toe out rapidly wears your tires on the street).
We're finding on some tracks that we are faster with as much as -4.5° front camber, sometimes only on one side. Record tire temps and test to see what works for you. If you can't get enough front camber with you 89-05 Miata, welcome to the club! Our best solution is our Extended Lower Ball Joint (ELBJ). ISC Racing offers a offset front upper Delrin bushings optimized for 7" SCCA ITA wheels but they reduce bump travel with 8" or wider wheels. The only front lower bushing that will work is a custom Delrin or Acetal offset that is pinned in place by a bolt or stud. Only the forward bushing should be used in conjunction with a normal (not offset) urethane or rubber bushing. Installing a delrin/Acetal in forward and aft postions of the front control arms will cause binding. The lower the ride height, the more static front camber you will get. The NB front subframe has a slightly higher roll center and more camber gain. For this reason, it is the best solution to gain more front camber and help keep the roll center closer to the CG after lowering. If your class allows the NB front subframe, do it.
It is sometimes not possible to get enough negative camber, particularly on the NA chassis. One new option is the Extended Lower Ball Joint or ELBJ for short. They will typically allow another 1.2° of negative camber from whatever you have now.
More caster can help mid to low speed turn in, makes steering heavier, may increase wheelspin in very low speed turns with a Torsen or open type differential. Higher caster values will increase stering effort. Lower values reduce steering effort. If running power steering, go for caster settings above 3.5°. If running manual or depowered rack, lower caster can reduce steering effort. The Miata platform likes caster greater than 3.5°. Balance that against the steering effort you prefer. Running caster beloow about 2° can result in very vage steering with little or no self centering force.
Favorite performance alignment shop in SoCal: West End Alignment Darren Nishimura
18008 S. Vermont Ave Gardena, CA 90248
Darren and his crew can also set up coilovers, cornerweight and generally get everything dialed