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

[Brett W]

Staged injectors actually came from turbo cars that have to use huge injectors. Try trying to get 1200cc injectors to idle on a 1.6 or 1.8 litre engine. If you can get it to idle at all you won't have a clean idle. But with staged injectors you can use the smaller injectors at mild throttle openings and engine loads, then bring in the big guns to supply fuel for massive levels of boost and HP.

You will see an improvement on a "low revving stock" engine with high mount butterfly throttle bodies. We saw that on some smaller restrictor engines we built to run in FSAE. You don't gain anything by turning 15-17K when you restrictor goes supersonic at 10k, so you look for anything you can to get on the low end.