I believe that ECS carries the SuperTech 4032 forged piston sets.

RMW... carries the Mahle in a High Silicon content forged pistons ... though their reputation and order time has taken hit on this forum.
https://store-revolutionmini-com.3dc...ton_p_227.html

OutMotoring... Mahle forged silicon alloy (M142)
https://www.outmotoring.com/piston-s...930067351.html



There are quite a few top brands out there that offer pistons... but finding the appropriate alloy offering... that is in stock or short order can be challenging.
The CP-Carillo for the Gen2 engines are all 2618 from what I can find...

And yes.. it does matter for longevity and engine noise... a 2618 piston will require a lot more piston/wall clearance... and unless you are building an all out race motor... stay with the more appropriate alloy IMO.


You can google 4032 vs 2618 and come up with a lot of info.... but make sure you are differentiating between RACE applications and those that are expecting to get a lot of service life from a performance STREET engine.

"MAHLE
These pistons are specially made using Mahle’s proprietary M142 Forging Alloy. Other alloys require larger piston-to-bore clearances (like the 2618 alloy) or end up sacrificing strength (like the 4032 alloy). This alloy combines the strength of the 2618 alloy with the lower required piston-to-bore clearances needed with the 4032. The M142 alloy is used on several high-performance OEM applications"

https://www.us.mahle.com/media/usa/m...er-webpage.pdf

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I recall reading about the differences in alloys a while back - where my take away was: For most “street” applications and engines with lighter upgrades, low boost applications, 4032 alloy is a good choice. For track, race of high boost ( performance ) 2618 is used. For the Mini - what is the cross over to 2618 ? 400 hp ( 100 hp/piston for a 1.6 ), or 26 psi or ??? I believe what was high performance/high boost 10 years ago might be considered moderate or even low today.

Observing piston slap was quite common when boosting miata's using CP ( 20 yeas ago ). People just warmed their car up for 5 mins LOL