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-   -   Pistons... (https://www.miataturbo.net/engine-performance-56/pistons-36694/)

tyson87 Jul 23, 2009 12:16 PM

https://www.miataturbo.net/forum/t37356/#post433338
look again at post, not sure if the price chages, but it shouldnt

Joe Perez Jul 23, 2009 12:45 PM


Originally Posted by djp0623 (Post 433822)
I believe the site lists the 9.0:1 for the 85.5mm. I'm not overboring that much

The vendor may not have them all listed, but according to the supertech catalog, 9.0:1 is available in 84mm, 85mm, and 85.5mm.

Are you running turbo or N/A? For a non-turbo motor seeing track use, go for the high-comp units. For a turbo motor, go for the lowest CR you can get. The actual difference between an 8.6:1 and a 9:1 is going to be pretty trivial both in and out of boost, but it never hurts to have that little extra margin of safety.

aznDragonX Jul 23, 2009 03:51 PM

Joe..are you going for 1.8L ? I think I will ditch my 1.6L setup and get a 1.8L once for all.

SpyHunter Jul 23, 2009 04:52 PM


Originally Posted by Savington (Post 433732)
I wouldn't blame that on the Weiscos. If he's been through multiple motors, he needs to find a new builder. Damage on the skirts like that suggests that the builder just fucked up his clearances. You have to look at any secondary failures, like the coating chipping away, as a possible result of the primary failure.

BTW - Supertech recommends some insanely low clearances, like .0027". I built my motor much looser than that, the .006" range, after talking with the machinist who did the bore/hone on the block about what it was going to be used for.


http://photos-d-6.ak.fbcdn.net/hphot..._3472337_n.jpg

Look familiar? My Weiscos after 2-3K. Hard to tell in the pic, but look ALOT like the above picture.

Sav., I am probably getting the Supertechs, and also do track days. Not a ton, but a few. Car will also be started on some extreme cold days. Would you suggest that kind of clearance?

Joe Perez Jul 23, 2009 07:35 PM


Originally Posted by aznDragonX (Post 433962)
Joe..are you going for 1.8L ?

Yeah, I decided that my plans for the motor will ultimately require a new manifold and turbo anyway, so if I can score a '99+ (or even '96+) motor I can take advantage of the factory crank trigger setup.

I'm dying a thousand deaths waiting for Lev to get back from the gap so I can find out if I can grab the whole drivetrain out of the 99AE that he just scored and is parting. He's close enough that I can drive out and haul it back.

ZX-Tex Jul 23, 2009 11:34 PM


Originally Posted by Joe Perez (Post 433844)
The vendor may not have them all listed, but according to the supertech catalog, 9.0:1 is available in 84mm, 85mm, and 85.5mm.

Indeed they do. That is what I have in my car.

Savington Jul 24, 2009 12:38 AM


Originally Posted by SpyHunter (Post 433989)
Would you suggest that kind of clearance?

Clearance is a discussion best left to machinists and builders. I can only share what I did - my clearances (IIRC) are in the .006" range. My motor also has maybe 75 miles on it, tops.

JasonC SBB Jul 24, 2009 11:10 AM

What do the piston manufacturers say?

JasonC SBB Jul 24, 2009 11:11 AM

Are these problematic Wisecos from FM? I though FM had some exclusive special Wisecos?

Savington Jul 24, 2009 11:49 AM

Difference between FM Weisco and Weisco:

Turbo Pistons - MX-5 Miata Forum

Full_Tilt_Boogie Jul 24, 2009 12:07 PM

Since they're so close, it seems like you would almost want to make a decision based on which design looks more resistant to forming hot spots. If one piston has less edges or softer edges on the top of the piston I would make that my deciding factor.


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