Quote:
Originally Posted by arghx7
I can't think of an aftermarket racing-type ECU that can drive two electronic throttle valves on their own, without some kind of piggyback setup. If you find one under $5000, let us all know.
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As my car is still 3 months away from delivery i haven't really researched this, so i bow to your greater knowledge. I was under the impression Motec and Autronic had electronic throttle capabilities. Although they may not fall under your $5k threshold.
Quote:
Originally Posted by arghx7
They're actually very similar to ITB's in terms of the way they are physically driven. On ITB's for electronic throttle, you have all the throttle valves for a bank driven on a common shaft. There has to be software learning to calculate and compensate for differences in airflow between cylinders. So if you have two banks with ITB's, you have two electronic throttles essentially. In one sense that's the same as two upstream throttle valves.
Never say never I guess, but you do realize that each electronic throttle module has two throttle position sensors on it used for feedback? So how is the computer going to compensate for variations in throttle valve deposits if you are feeding it a dummy signal to drive the DC motor? The electronic throttle learning won't be accurate for the other throttle. I suppose that matters a lot less in a racing environment with very little part-throttle driving, but I just don't see it being feasible on a street car.
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With a twin throttle body setup you could us a balance tube between the manifolds to over come any part throttle imbalance. Or just position the throttles in such a way that you could run them off the one electronic motor.
I hadn't thought about the feedback loop that ETB must run. It certainly kills my idea of splicing the signal.
Quote:
Originally Posted by arghx7
Nobody has addressed my point about the lack of variable valve lift. On Celica 2ZZ or basically any Honda engine, you have more than one lift profile. That allows you to have some semblence of low speed torque. If you can succeed in going with a very aggressive camshaft design you will lose a lot of your low-end torque on this engine.
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The simple answer is that changing the cams is a compromise of greater performance at the expense of easy drivability. However a properly set up engine won't lose too much drivability as long as you don't go too insane with your cam choice. 304* will be much harder to drive in the low range than 272* but the variable timing will make both cams far more livable then and engine without variable timing.
If you are worried about low end torque then keeping the FA20 NA probably isn't for you.