[The HACK]

Really? I'm used to dealing with rodders and the common knowledge/understanding is stroking an engine decreases compression ratio. I've always thought that compression ratio is calculated as the volume at the bottom of piston travel divided by volume at the top of piston travel, therefore if you simply increase the stroke of the engine, compression ratio decreases since you're not changing the amount of movement of the piston.

Say, for example, the S54 has a bore of 87mm and a stroke of 91mm, with a compression ratio of 11.5:1. To stroke it to a 3.4L, you would add a 4mm spacer on the cylinder head to get to a 95mm bore. That 11.5:1 compression ratio means, the piston travels from fully extended to fully compressed is 91mm-(91mm/11.5)=83.1mm. At a 95mm stroke, the compression ratio is now (fully extended)/(fully compressed) which is 95mm/(95mm-83.1mm)=7.9*

I'm using the formula of volume = Pi*r^2*h, since Pi*r^2 stays constant in this instance, compression ratio can be calculated straight from the change in height.

If my math is correct, a small increase in displacement from 3.2 to 3.4L would yield quite a significant decrease in compression ratio, at nearly 8:1 it's PERFECT for a supercharging application.

Like I said. EPIC.

EDIT: Huh. Maybe I should start hanging out with people who mod newer engines...Apparently it's far more common to increase the stroke of the engine by actually increasing the movement of the piston vs. spacer plates on top of blocks. Guess I was WRONG.