Lowering compression ratio
 

I have a MGF and wish to fit the low presure turbo from a rover 75 , it runs at about 8psi wich is fine for my needs.

My question is would I need to lower the CR? if so what would be the most cost effective way of doing this?

you shouldnt need to lower the compression for 8 psi. most stock engines can support 10 psi. make sure you use the highest octane available at the pump.

the cheapest way to lower compression is by using a thicker cylinder head gasket. this is the easiest but not recommended. a thicker head gasket is more prone to blowouts. the best way to lower compression is by replacing the pistons with lower compression dished pistons.

A means of lowering compression ratio.

http://somender-singh.com/content/view/7/31/