guys, this stuff is gold.
my mehc eng final year project is coming along - im developing the performance potential of the idi 1.5 engine ('cos i have one spare) and i'm DEFINATELY going to try this.
my current goal is to look at modifying the injector system to improve its efficiency at higher rpm.... but the project will go further.
as someone noted in another thread, optimum CR for the vw idi is around 17:1. VW also note that they would have preferred to use a longer duration higher lift camshaft.
i would like to turn down the piston crowns, machine the groove and the "flowers" back in to the piston to get a 17:1 CR and then use a standard petrol 1.6 camshaft for the extra duration and lift on the intake.
with the use of a thin head gasket and good studs, the reduction in compression ratio and extra clearance should be more than enough to allow easy application of a supercharger setup.
did anyone get around to machining grooves in their pistons?