Need help from track racers/auto crossers. Need/want more oversteer

[The Driver]

6899


Linked to this thread are my current alignment settings. The reason for this thread, is that my car was under steering like a pig, during the track time @ Flyin Miata's Summer Camp.

Current set up is: 600/375 Fat Cat coilovers, FM front sway bar and no rear sway bar. I just bought a factory rear sway (NA6) from Skip Cannon, but can I do anything to add oversteer to my current set up?


I'd prefer not to have to use the FM rear sway. Also, using the rear sway (any) during my daily drives is not an option. I LOVE how the car handles/feels during civilian duty, I just need more oversteer during track duty. Another parameter, for tire even wear. Thank you for any assistance.

[revlimiter]

Miatas are not unique, despite m.net wisdom. Run more camber in the front than in the back, the same as most other cars do. You'll go faster.

[Blueiii]

It looks like there's still some info missing...

First, what heights are you running? I'm assuming that you've lowered the car. Did you also run adjustable endlinks? Did you have them set with you in the car? The front sway could be binding. With your spring rates, front bar and no rear bar you should be almost neutral with just a slight understeer bias. As mentioned, you're also backwards on your camber. You want more negative camber in the front than in the rear. Its possible that, at your ride height (ie: if too low) they weren't able to get any less out of the rear. If so - you'll want lift the car slightly to get your camber settings right. (Again, not sure what height you are running, but if you went too low, then you won't be able to get the correct settings.)

One last thought... I've found that in RWD cars I have a tendency of understeering when I brake too late. Might be driver error. (not saying it is, just saying it might be worth considering.)

[The Driver]

Height: 12.25 front, 12.75 rear. Adjustable end links on the FM front sway, set to stiff.

As for the under steer, Skip Cannon took my car for a lap, while I was a passenger. He is the one who yelled out "this car under steers like a pig".


So, if I adjust the camber, I won't need to run the rear bar? That would be awesome!

[Blueiii]

If you have a second (educated) opinion and its not brakes:

Jack the car up and put the jacks under the Lower Control Arms. Have someone your size sit in the car (or add ballast). Unbolt the end links first - do they slide out easily, or is there a lot of tension on them? If a lot of tension, adjust them as needed so they slip in with no tension. With them disconnected, I would also make sure that the bar moves freely. Mine was completely seized thanks to Energy Suspension bushings that were oversized. I ended up grinding them down and re-greasing the heck out of them. It really sounds like your front bar binding.

I would still adjust your alignment settings. These are not my settings - I copied them from Emilio's information on 949:

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.

>=12" front ride height (measured hub center to fender)

>=4.75" front pinch weld height

Front camber: -2° (or as close as you can get to it)
Caster: >4°
Front total toe: 0

Rear camber : -1.8°
Rear total toe: 0

On a lowered miata, its more about the balance between the front and rear camber when it comes to under/over steer. I've always worked with the guy doing my alignment to make sure he understood what I wanted. For example, if he could only get -1.4 negative camber in the rear, I'd probably have him dial the front in at -1.8.

Happy Ottering! Hope this helps!

[The Driver]

Alright, we'll give it a try. Thanks for posting!

[Blueiii]

You're very welcome! I haven't been on here much with now trying to research the speed3, but shoot me a PM (or email at bleuii78@hotmail.com) if you have any questions or to let me know what you figure out.

[The Driver]

Will do! In regards of the Speed3, PM PhatMiata, as he has one.

[Ciotti]

When I first bought mine it had the huge 1.25 front bar and Tein Flexes but no rear bar and 3 degrees of camber in the rear, it understeered like a pig. I put the oem rear bar back on, swapped the front bar to the 1.125, and had as much front camber dialed in as possible (-2) and as little in the rear dialed in (-2) and all was right in the world :)

[The Driver]

^ I'd prefer to go w/o the rear sway. The traction advantage w/o the rear bar is quite evident, primarily on wet/snowy surfaces. I try to drive the Miata when the weather is nice, but sometimes shit happens. I will wear the rear bar for my next track event, but ultimately I want to do what Blueiii suggested.

[DK Wolf]

http://949racing.com/miata-race-alignment-info.aspx


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.

>=12" front ride height (measured hub center to fender)

>=4.75" front pinch weld height

Front camber: -2° (or as close as you can get to it)
Caster: >4°
Front total toe: 0

Rear camber : -1.8°
Rear total toe: 0


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 that will have you pulling your hair out trying to get rid of. In short, if you can get your autocrosser to work with the rear bar, keep it hooked up. 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. We usually end up with 1.125" x.188 wall hollow bar. This front bar choice assumes at least 7" wide wheels and either EHP (Extreme High Performance) or R compound tires. 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 that needs more than a 14mm rear bar.

[The Driver]

^ Dude DK, thanks so much! That was VERY helpful!

[DK Wolf]

Doitashimashite!

[kung fu jesus]

OEM MSM rear sway. Adjustable endlinks should be perpendicular to the ground. Corner balance at 1/4-1/2 tank + you in the car. Alignment as mentioned above.

[The Driver]

Well, the car was corner balanced with 1/2 tank, when I had the alignment done it had 1/4 tank. And the "new" alignment will have to wait at least until next spring. A) Now I have two rear sways (FM and a 12 or 13mm bar) and I just spent a FORTUNE yesterday buying skiing equipment...