Head & Cams.

[carl0s]

If aftermarket heads (V engine) and cam on a 5.7L yanky LS1 engine can increase power by ~40%, and the heads only cost $2,500 each per pair, then why is nobody offering an aftermarket head for the 2JZGE engine? Is there some reason why the LS1 can go up from 350hp to ~500hp with just heads and a cam change, yet the best NA Supra owners can hope for is ~15hp from HKS cams?

Edited June 27, 2009 by carl0s (see edit history)

[jevansio]

They are not tuned as highly from factory. Compare the bhp per litre and you'll see a 500bhp vette is approx the same as a 250bhp supe

[carl0s]

Well, there's a bit in that I suppose, but not much. The 2JZGE makes 73.4hp/L whereas the LS1 makes 61.4, so if the 350hp LS1 was as factory tuned as the 2JZ, it'd be making 418hp. Hmm, actually I suppose you're not too far off really. I guess it's just that and the fact that the Supra market tends to focus on the turbo cars while the yank market focuses on NA.

[paul mac]

The reason the SBC can see big gains from the head is simple, its a 2 valve pushrod single cam design that goes back to the dawn of automotive history (even with the new generation LS series) so there is a lot of room for improvement. The Supra however has a very well designed modern pent roof 4 valve twin ohc head (Cosworth influenced ), there really are no "golden bullets" with the Supra head as its pretty damm good straight out of the factory, it would stack up reasonably well against any modern head, with only the high BHP per litre N/A engines such as the BMW M3 or Honda's being markedly superior.