IR vs. Plenum?, Bonafide dyno tests anyone? Options

[jhadler]

Hey all,

I realise that this may have been hammered at before, but I was currious if, on a stock 2.0L, there was any distinct advantage of going to IR throttles over the stock plenum (or some other single throttle plenum).

I know that the stock cam will limit the amount of air the engine can ingest, and that IR throttles will definitely NOT be the limiting factor on the top end, but with tall manifolds, and IR throttles, can a stock 2.0L run better than it could with the stock intake plenum. Assuming that both are running a programable fuel injection system that has been optimized.

Thought? Experiences? Test data? Dyno results? (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

-Josh2

[jhadler]

QUOTE (Bleyseng @ Jan 17 2006, 07:19 PM)

I thought that only mattered at wide open throttle. I thought one of the benefits of a plenum was the other cylinders were keeping the air flow into the plenum so it is "forced into" past the valve some. You don't get that with IR so you lose some torque. (IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif)

Right, but there's the other side of it too...

With an IR setup, you develop a "stack" of air fuel mixture above the intake valve before it opens (the injector has sprayed two squirts of fuel into the manifold), and the air has a straight shot down to the valve instead of having to turn throgh the manifold. Gravity assist if you will...

I really don't know however if the IR is any better than the plenum with a STOCK motor.

Jake, I have no doubt that the IR setep is better with a hot motor and more aggressive cam. My question is regarding a stock motor with a stock cam.

The plenum intake can generate intake pulses that can help draw in more air, but the IR can drive it into the combustion chamber better. So, what's better with the weak-ass stock cam in the 2.0L motor?

So, given that, will an IR intake be any better than a plenum under those conditions?

-Josh2