Big power combos under boost have always required lower compression ratios than a Naturally Aspirated combination, or at least that’s what we’ve been told. But is that true? Or is there more to it than that? I mean lower compression makes some sense if you are going to be running it on pump gas and need to control detonation, right? Well yeah, maybe. But what if you aren’t going to be running your engine on cheap pump gas when under any kind of load? Wouldn’t starting out with more compression and more horsepower make sense, since adding boost to it just adds power onto what you already have? Hmmmm
Generically speaking we always say that starting with more power before adding your power adder is a good thing, to a point. There is no reason to go crazy for another 5 horsepower if you are going to be adding boost because that 5 horsepower is ultra-easy to get back with boost. But starting with a 300 horsepower engine rather than a 500 horsepower engine, and adding the same amount of boost, will result in more power from the higher horsepower starting point.
With all other things being equal, except for compression ratio, you will typically see more power from a higher compression combination. They are more efficient, make more power, and you would think would make more power under boost also. Of course boosted applications need more ring gap, but other than that there isn’t much that needs to be different unless you are making stupid power.
What do you think?