Side by side

SUPERTECH:
https://www.miataturbo.net/forum/att...0-piston-1.jpg

FACTORY: Notice the cutout
https://www.miataturbo.net/forum/att...ton-cutout.jpg

I just bought a set of JE 84mm 9:1 pistons for my '02. What do you guys think? am I going to be in trouble? they just went with the block to the machine shop. The head did not go with them as I am doing a mild pocket & relieve job here in my shop. the '02 has stock VVT cams. Does anyone run this setup?

so is there any conclusions here? are bel-fab and supertech the same pistons? should i be scared of supertech pistons? stick with je or weiscos?

Belfab SELLS Supertech pistons. IIRC there was never any question about this.

I still suspect that the cause of my #1 failure was uneven distribution of WI. But, that thin web area on the piston certainly does not help as it could create a hotspot that would lead to local detonation and more heat, leading to more detonation, etc. The rest of the piston looked fine, just that one spot.

So my motor has been reassembled for some time now with the FM Wiseco pistons and is waiting to go back in the car. If I could do it over again I would probably research it to be sure it is OK, then have that web around the intake pocket removed a-la the pictures JasonC shows above. They would have to be rebalanced but this is all no big deal for a good engine shop.

I hate that this happened to you, but thanks for documenting the situation. If the same situation happens to someone else, hopefully supertech will due the right thing and offer parts/labor compensation.

I guess the other question is how much boost do you plan to run, i have the 9.5:1 supertechs & so far they are fine, i wanted to run stock compression so i had good low down torque, i dont think i will ever see more then 18 psi though

I have this concern now as well. I was planning to have diyautotune tune my car to the limit of the MS MAP sensor ~ 22psi. I wonder how much this weak point can withstand with no detonation problems?

I've had 2 machinists tell me it won't be a problem in the absence of detonation.
I'd asked them if they thought it would be a good idea to mod the pistons to look like the factory ones.
I didn't bother then - however, I don't plan to run ludicrous boost.

Keep in mind I was running up to 18 psi with a GT2871 with an aggressive tune so I was well over 300 HP based on other data here. If you do not plan on pushing your engine as hard it may not be as big a deal.

without having to go back & read your thread over again, how aggressive was your tune? did you have it dyno'd? how much timing did you pull out of it?

What are you fueling with? Are you low comp? With even stock comp, I wouldn't think you could run 22 psi on that turbo on street gas. Maybe I'm wrong, but watch for det carefully.

Any updates?

I finally got the engine back in the car. I should have it running again pretty soon.

It's about time! I've been real interested in your build.