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-   Engine Performance (https://www.miataturbo.net/engine-performance-56/)
-   -   First Look SuperTech Pistons (1.8l Dohc) (https://www.miataturbo.net/engine-performance-56/first-look-supertech-pistons-1-8l-dohc-65235/)

JasonC SBB 04-19-2012 06:52 PM


Originally Posted by Savington (Post 866474)
I am the proud owner of that piston.
...
Complaining about how that piston failed at the sharp edges near the valve reliefs is like regretting the flammability of your polyester shirt while standing a few feet from the center of a military nuclear strike.

Impressive.

Weren't there other Supertech pistons that also failed at the valve relief edge?

BogusSVO 04-19-2012 07:18 PM

Any piston can fail under the right (wrong) conditions.

Go lean, too much advance, wrong tune, wrong octane, wrong PTW clearance,faulty sensor, the list can go on and on.

But to blame the edge of the piston to cause the failure is a bit out there.
What that shows is the weak point of the piston to fail.

Any piston will have a melting point.

Savington did say he had a small ebay IC when this happened, so being an armchair quaterback, the IC got heat soaked, the IAT went up, and that inturn brings up the combustion chamber temps, and that brings up EGT.

With the raised combustion chamber temps, that was just enough to cause the piston to fail.

Remember for every 1* IAT go up, EGT go up 3*

so even a 10* increase in IAT will cause a 30* in EGT, I do not know how much that would raise combustion temps.

JasonC SBB 04-19-2012 07:54 PM

I think the high IAT's didn't cause the failure in and of itself; it led to detonation.

falcon 04-20-2012 01:48 AM

Voodoo magic inside a motor, that's all I know.

Sav, do you remember what size that egay IC was? I think it's time for me to upgrade and I'm contemplating the Precision one you seem to like.

Savington 04-20-2012 02:14 AM


Originally Posted by falcon (Post 867279)
Voodoo magic inside a motor, that's all I know.

Sav, do you remember what size that egay IC was? I think it's time for me to upgrade and I'm contemplating the Precision one you seem to like.

28x6x2.5 rings a bell, but it was mounted at a steep angle and not shrouded very well. The new one is 31x8x3.5, fully shrouded, stood straight up against the airflow. The 600hp core doesn't really fit in the car unless you've removed all of the stock plastics/shrouding, so buyer beware.

Our turbo kits will get the 350hp core, which is a 27x6x3.5. Should do the trick nicely.

falcon 04-21-2012 02:02 AM

I was going to say, the 350whp core should be alright for someone like myself with a mainly track day only car with a few TT's here and there? I will be doing some full shrouding. And coupled with the fact it's a Rotrex'd car I think the slightly smaller one should be ok?


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