Increasing Compression Ratio

mrx · Post by **mrx** » Sat Dec 25, 2004 7:58 am

OK. Just throwing it out there.

Obviously there are benefits, but what is required, cost etc to achieve this? I have been reading on the web that for every .1 increase, you can expect a 2% increase. Increase by .5 = 10% more power.

So, over to you. Thoughts?

Black_FTOGPX · Post by **Black_FTOGPX** » Sat Dec 25, 2004 10:41 am

Just remember that the 6A12 mivec already has a high compression ratio and was designed to run on 100 octane fuel.

If you are going to run a higher compression ratio you will need to run good fuel and try to keep intake temperatures to a minimum. If you use crappy fuel you will get a case of the "knocks" big time. Which will stunt the power more and could be bery bad for your engine.

spetz · Post by **spetz** » Sat Dec 25, 2004 9:51 pm

It might just be possible to use a thinner gasket otherwise custom pistons.

But yeah, they run high enoughy compression as it is.

dannyboyau · Post by **dannyboyau** » Sat Dec 25, 2004 11:28 pm

personally i would not use any type of head gasket except for the original mitsubishi one, we have run my engine at 26 lb boost and not a problem, it screamed like a banshi but didnt loose a drop of coolant and purrs like a kitten under normal driving. The metal shim type of head gasket that mitsubishi use is exactly the same type of gasket you get if you buy a expensive HKS gasket for a high boost application on the nissian motors ( SR20, RB20, RB25, RB26, ETC )

I would change the pistons to custom made pistons or do some work to the combustion chamber or a combination ( weld up the combustion chamber on the heads so it is smaller ).

with these type of mods you would also have to remap the fuel map.

I also would recommend using ARP head studs