I have spent hours researching frm sleeves with forged pistons, i know that the best way to go is to get it over with and sleeve the block to accept forged pistons, and i have read about these mahle pistons for frm sleeves and people i have talked to say the only difference is that they put a coating on their pistons that wears off. My problem is that i want to run about 10-12 psi without sleeveing, is this in any way attainable?? even on stock internals, maybe shot-peened rods or something?? any experienced thoughts are greatly appriciated!

 

I'm definitely not an expert on this, but isn't the general rule to keep it <U>under</U> 10psi on stock internals (ideally about 5-7psi)?

Like you said though, the best way is sleeved & forged.

EDIT: If you're pulling everything out to possibly change the pistons anyway, I think you'd be ahead to go ahead w/sleeving.

 

Check in the FI forum for the "monthly Mahle piston thread" or something like that from what I understand the Mahle pistons are working fine with the FMR sleeves, and people are boosting 15lbs. I think they rate the mahles at 125hp per piston max.

 

Save your money and buy something else.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by M3BimmerBilly &raquo;</TD></TR><TR><TD CLASS="quote">Save your money and buy something else. </TD></TR></TABLE>

Uh...no.

Mahle makes a piston - the Goldseries piston - that is compatible with the FRM sleeves of our engines and the s2000. The pistons aer being used by many people - and I will be using them myself. There's actually someone in the for sale section up top selling some right now. They're proven to work - and they're ideal for 10-12 psi. I would say the max would be 14 or so psi assuming you're using rods also. Good luck researching.

 

At the same time, I've seen plenty of people running 12+ PSI on stock internals. I believe there was a guy on here (can't think of his sreename) who had been running something like 18psi for more than a year.

IMO, the prelude's stock internals are fine for the amount of boost that a lot of people want to run. Not a lot of people want to spend the money on good management, and lots of tuning.
Its more about how you TUNE the engine and less about the amount of boost (there are limits to this statement of course). I can make 12psi with a bike pump, surely the h22 could handle that right?