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Old 08-13-2012, 05:03 PM   #1
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Default Ride Height/Alignment discussion for soft spring rates (6k/4k)

Hi everyone,

I have a 97 NA and the car came with a set of Yonaka coilovers installed on the car. My plans for the car include weekend driving along with road course events.

I figured that rather than purchasing a set of Koni/GC, Stance, BC, etc.. coilovers this late into the season, it would be better to use the current suspension that I have on the car for the remainder of the year while I save up for some Xida ClubSports.

That being said, the spring rates that coilovers came with are:

6k (335 lbs/in) front
4k (224 lbs/in) rear.

Stock sway bars front and rear.
Konig Wideopens 15x8 +20 with 205/50/15 Star Specs

I know that for performance-oriented driving, the spring rates are incredibly soft (makes for a very comfortable ride though ). Therefore, I'm worried that if I set my ride height/alignment settings according to the 949 alignment page for a race alignment (<12.0"), the soft springs will result in rubbing issues and excessive oversteer.

SuperMiata Race Alignment

<=12.0"

3.75~ 4.25" front ride height measured at forward most straight section of pinch weld with 205/50/15 or 225/45/15 tires

Front camber: -3 (or as close as you can get to it)
Caster: >+4.5 or max available once you reach camber targets
Front total toe: 0

Rear camber : -2.6
Rear total toe: 0


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

>=4.5" front ride height measured at forward most straight section of pinch weld with 205/50/15 or 225/45/15 tires

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


Do you guys think I should just go with the alignment specs for DD? (>=12.0")Is there anything else you guys would alter that could possibly help accommodate for the softer springs?

Thanks in advance for your input.
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Old 08-13-2012, 06:29 PM   #2
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Yes, you are going to need travel. Elevate your ride. Remember, 335lb/in springs absorb as much energy in two inches of compression as 670lb/in springs do in one inch. You can stay off the bump stops in the corners (if you want to) by giving yourself a little more travel before you touch them.

As for alignment, in our cars negative camber increases as your wheel travels up into the fenderwell so the higher you are the less static camber you require to reach optimum amounts. And if you have too much static negative camber, when the nose of the car dives under hard braking, your front tires' contact patches won't be very square which isn't optimal for braking or tire wear.

This is all bandaids for having the optimal spring rates, ride heights, etc., but it is the best you can do with what you have.

IMO, if you are elevated you won't need more than -1.6 camber f/ -1.6 camber r with Hoosiers. Lowered cars will be different.
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Old 08-13-2012, 07:03 PM   #3
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Thank you for the informative reply sixshooter.

What ride height would you define as elevated with these spring rates? I'm not sure what exactly the stock spring rates are, but I was hoping to at least get a little lower than stock with the coilovers currently on the car. Keith at FM suggested 12.5F/13R.

Also, I know you said -1.6 degrees f/r camber would be sufficient for hoosiers with an elevated ride height, but would those values apply to my Star specs?

Quote:
Originally Posted by sixshooter View Post
Yes, you are going to need travel. Elevate your ride. Remember, 335lb/in springs absorb as much energy in two inches of compression as 670lb/in springs do in one inch. You can stay off the bump stops in the corners (if you want to) by giving yourself a little more travel before you touch them.

As for alignment, in our cars negative camber increases as your wheel travels up into the fenderwell so the higher you are the less static camber you require to reach optimum amounts. And if you have too much static negative camber, when the nose of the car dives under hard braking, your front tires' contact patches won't be very square which isn't optimal for braking or tire wear.

This is all bandaids for having the optimal spring rates, ride heights, etc., but it is the best you can do with what you have.

IMO, if you are elevated you won't need more than -1.6 camber f/ -1.6 camber r with Hoosiers. Lowered cars will be different.
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Old 08-15-2012, 12:39 AM   #4
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I would highly recommend investing in a set of sway bars to help with rubbing issues and dialling in your under/oversteer preferences.
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Old 08-15-2012, 12:42 AM   #5
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Oh btw for RB bars, 2 hole adjustment for both front and rear. Believe for your '97 this is the case.

Maybe you can google around to see if people run RB's with similar softer spring rates.
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