M50b30 Pistons

[ByrdmikalE36]

So have a spare engine that I'm building I have the m54b30 crank that's getting thrown in. The pistons I decided to go with weisco 8:8:1 84.5mm pistons for the m54b30 engine. Everyone says just to go ahead and bore to 86mm and run s52 low comp pistons. What would be the issue of running 84.5mm pistons vs 86mm pistons. Just wanting some insight and knowledge.

[rajicase]

Nothing, just less displacement. Less power out of boost and slower spool.

[ByrdmikalE36]

Nothing, just less displacement. Less power out of boost and slower spool.

So still can make high hp just not as efficient as a bigger bore since it has a bigger area to detonate if that makes any sense lol

[someguy2800]

It's pretty much free displacement if your already buying pistons and getting the block bored anyway. Bores bigger than 85mm used to be a real challenge to keep a head gasket in it at really high power but the cut ring gaskets have solved that. The 86mm and larger bores have a tendency to crack in the 1000hp range as well.

[ByrdmikalE36]

It's pretty much free displacement if your already buying pistons and getting the block bored anyway. Bores bigger than 85mm used to be a real challenge to keep a head gasket in it at really high power but the cut ring gaskets have solved that. The 86mm and larger bores have a tendency to crack in the 1000hp range as well.

So would you say 85mm bore is a sweet spot between good displacement and not cracking the bore or no? Or go 86mm or go home lol. I have the Ces cutring already for m50/52.

[someguy2800]

If you have the m50 head gasket set I think the biggest you can go is 85 due to the head gasket bore. With the cut ring gaskets I don't think there is any reason not to do 86+ mm bore unless your going for 1000 whp