There you go... and that is called "Hot Rodding" !! Kudos to ya!! Just a bit more Hot Rod stuff... you can increase the dynamic compression ( more torque- better low power and MPG) by advancing the OEM camshaft. might want to look into that also. The ECU will still accept that new cam phase with no CEL's Just me................................ Thumper
Remember, he's not trying to wring the most from a boosted engine on the cheap. Because of the restrictions of the rally series he runs in he's trying to get all he can from the W10 without straying too far (in any noticeable / testable way) from R50 stock. When it comes to the R50/W10, small improvements matter and you take every small improvement you can find so they add up to tangible gain.
If that's the case I would contact Ian Stewart, he knows his way around the track and can tell you what will help you get the best times. Mrsideways.com Ian Stewart Racing
Thanks Steve for clearing that matter up. good MPG is not on my agender LOL but beating all the cars in my class is! So any visible mods I'm keeping away from. Basically a better than JCW spec with a 2028LBS overall weight. Also next year will be an all gravel championship so the Mini/Subaru suspension has to do the job.
I have not built one of these motors, but if Thumper is correct and the motor has .145 thousands of an inch piston to head clearance, you will have significantly more of a performance increase by decking the block as opposed to removing material from the head. You will need to determine the compression ratio for the amount of deck removed, but there will be an improvement beyond just raising the compression. You can run the piston to deck clearance down to about .040 before you need to worry about the piston hitting the head, and the closer the better. The affect is twofold. The combustion chamber in the squish area does not start to burn until the piston starts to move down the cylinder. The second effect is that the gases in the confined space are forced out as the piston rises. This has the effect of causing the gases to swirl around more. The more swirl the more homogeneous the gas air mixture and the more complete the combustion. The original or Classic Mini engine had a plate attached to the valve cover that listed all the patents covered in the design. The most significant was from Harvey Westlake, and dealt with squish.