How much of a HP gain? (guesstimated)

[Jerith]

I know you guys probably hate this question, but for anyone who wants to give it a shot.........Ported Head, .30 bore, oversized pistons (same compression), Injen Intake, Turbo XS type H RFL BOV, and of course free mods. The reason I'm asking is because a guy from my work said "at best I would gain 30hp", I personally think more, but thats what I'm asking the pros for.
Thanks

 

[doug]

Is this going from bone stock to the list you posted? If so, I can only comment on the BOV-- going from the stock 2G POS BOV to one that can actually hold boost, I think you can get 14-15 psi out of the stock BCS with the free mod. From what I've read, you get about 6-8 HP from each PSI, so figure 7 (let's use the median) times 3 (stock BOV leaks around 12) = 21 HP. This is all just bench racing, but for the sake of argument.....

OK, I'm totally speaking out of my arse about the ported head, but I'd guess only 4-5 HP. And intake should add 5-10. So depending on the oversize pistons (I have NO idea about those), 30 HP does seem ballparkish.

These HP numbers may in fact not be that high considering you're still running the restrictive stock exhaust-- I'm not sure of the impact there since mods seem to have a cumulative effect.