yes, the issue is that the bottom end of the k20a3 is not built to handle rpms that high.Hyaboosta said:But by swapping an a2 head on an a3 and swapping out new aftermarket a2 pistons and rods what would keep the new motor from reving to 8k? since it does have the a2 ecu? is it a blance issue?
With the lower cpr of the a2/a3 wouldn't it be perfect for a turbo or sc?Schwebel said:I just saw that someone figured out how to make A2 cams(or really any K-series true-vtec cam) work in an A3 head. I' d say change the A3 head over to whatever cams you want and of course drop in a s2k valvetrain. Buy a CRV/TSX bottom end, put some high comp pistons and nice rods in it plus KPRO and for the price (maybe less since you already have the head) of an A2 swap you'll have a beast of a motor that you can beat the piss out of. The thing about just swaping an A2 is that after you've dumped the money on the swap, you are starting at square one with an engine again, you'lal either want to turbo/supercharge/NA build-up on it since for the $3500 youre spending, you have a stock motor. Putting an A2 head on a A3 is pretty much a waste of time if you are really looking for serious power.
Correct, the CR is very boost friendly. However, the a3 rods are supposedly weaker than the a2 rods, so the bottom end could still be a limiting factor.mozze said:With the lower cpr of the a2/a3 wouldn't it be perfect for a turbo or sc?
Alot of peeps have turbo'd the A3 with great success, but realibilty is def an issue with daily driven boost levels greater than 7psi. A general rule of thumb is that a stock motor can accept about 7psi of boost and be reliable, not saying that you can't run more boost, but I like to keep my motors around awhile. With the mods I have suggested you can make the same amount of reliable power as a turbo'd A3 can and also for about the same price as a turbo kit, without the high maitenece. You also won't have the thought in the back of your head as you hit WOT of "Is my motor going to explode this run?". Also your motor would be lighter weight than a turbo'd A3. But yea you could just as well put low CR pistons in a frankenstein and turbo it. The problem I see with the A3 is that trying to build-up the bottom end is kinda pointless, I'm sure there are lots of threads on here to the differences in the A3 and A2 bottom ends so I won't go into that. I've built a crapload of frankenstein turbo'd VW engines (kinda new to hondas) and came to realize that reliability is 50% of the power equation.mozze said:With the lower cpr of the a2/a3 wouldn't it be perfect for a turbo or sc?