I did alot of research on inlet manifolds for EVO's recently, also on the actual port sizes and head differences.
From my findings, I'm sure some people will try and say otherwise, but hey, I ask you to prove me wrong.
EVO small port heads, have more hp potential, and better torque spread than the big port VR4 heads.
The Inlet manifold on the EVO, is much better suited to making torque at all rpm due to the simple issue of air velocity.
Not going to go into specifics, but lets just say, new evo's run identical port sizes, with near identical inlet manifold(reversed side for throttle body). People have been able to achieve huge hp with the stock head/manifold on both the early and late model EVO's.
While saying that, there is alot to gain by a well designed custom inlet manifold. The only thing to decide is if this is worth the cost vs performance gain, or are there better alternatives to making hp.
I recently witnessed a friends EVO 2, with forged internals, headwork, cams, stock inlet manifold, stock turbo with 20g comp wheel, standard cooler, upgraded pipework, 3" exhaust and autronic pull just under 250kw@wheels(on pump fuel and 21psi). This car and engine setup to me, is probably the best street setup I've ever driven. Almost stock boost response, yet the power to spin all 4 wheels through 1st, 2nd and 3rd gear. I actually thought it had more power til it was on the dyno, where it actually is just a torque monster, and drops off a lil in the top end, but hey, like I said, perfect street engine.
Sorry for going off topic there a bit Jon, but yeah, just pointing out what I think would be better mods in order to gain hp.
