compression ratio

mik_str · Post by **mik_str** » Tue Apr 18, 2006 5:22 am

Hello

I have a few quick questions regarding the possibility of raising the compression ratio on the VTR. Has anyone tried to accomplish this via the old head milling technique? If so, how much did you take off and what were your results?

I realize that J.E. and Moriwaki make pistons that will up the comp ratio. Can an engine equipped with these run on (R+M/2) 91 octane (at sea level)? What kind of performance increase can one expect from installing these?

thanks again

Mikstr

Stormin Ben · Post by **Stormin Ben** » Tue Apr 18, 2006 11:48 am

Err - woosh - over my head there I'm afraid

You're very best bet is to drop an email directly to Roger at Revolution racing. He is the Godfather of VTR tuning and a really helpful, genuinely nice bloke too

His address is
enquiries@revolutionuk.co.uk

Ben
PS be sure to post the answers though

Post by **sirch345** » Wed Apr 19, 2006 8:38 am

In the past I've raised compression ratio's, not on a Firestorm though, but in my experience it does give more crispness to the engine, but at a pay off, of more vibration

Probably your best bet as Ben said, email Roger at Revolution

Jaglifter · Post by **Jaglifter** » Wed Apr 19, 2006 10:40 pm

Two things spring to mind............... Watch the valve clearance to the piston (usually you can check this by putting something like soft plasticine on the head of the valve, assembling and turning the engine over) and.......it may slacken the cam chain too much (but this is unlikely I'd have thought).

I've done this on a bike before (but not a modern one) and on many jaguar engines.