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9.5:1 Pistons In Rb25det Neo

aaron1259

By aaron1259,
in Engines & Forced Induction

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aaron1259 Explorer

aaron1259

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My parts provider has been trying to sort me out with some forged pistons for my build, however he said the best he could do was a set of forged pistons matched with a 1.8mm MLS head gasket, he said I would be getting around 9.5:1, is this too high? Will I be increasing the risk of det by much compared to something lower? I will only be running 98 pump.

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https://www.sau.com.au/forums/topic/460189-951-pistons-in-rb25det-neo/
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GTSBoy Grand Master

GTSBoy

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I don't think JE understand that there is a difference between the old 25 and the Neo. They list that piston as suiting both. It can't. They have a 14cc dome on them.

If you go to JE's site and separately search for pistons for a 33 and for a 34 (on two different tabs) you can flick back and forth and see the exact same list. It can't be right. Have a search around on SAU for threads discussing the CR difference you get with a NEO head on 33 pistons. I can't remember the exact numbers, but they're not good (for boost). Might be good for E85, so long as there aren't valve-piston clearance issues.

Edited by GTSBoy
  • 3 months later...
aaron1259 Explorer

aaron1259

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Just an update, yeah the pistons still had a high compression even with the 1.8 MLS gasket, so he decked the pistons he worked the comp to be 9.2:1

Is this still quite high, I have decided to use e85. Turbo is a Garrett gtx3076r, what would be the highest, safest boost I can run, I have all supporting mods.

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