Originally Posted by
Niburu
yes and no
with the air pump disconnected the ports stay closed unless wired open
the air being pumped into the cat does heat it up but more importantly it does this by providing the exhaust gasses with some air to further combust
also the VDI system is very very very important to performance for this car - think of it being like variable valve timing only not really
norachelhere I don't want you to think I'm bashing on you please, (cuz I'm not, you've asked some really good questions)
these are interesting little engines and it's not just the spinning triangle that you have to wrap your head around to understand
they have alot of strengths and some definite weaknesses
so have some fun and keep readin
oh no, not at all, you've been rather helpful.
I just have a general working knowledge on engines, so using that, I was trying to apply it to these. I've seen these motors at the track stripped down to nothing (basically) so it just clicked in my head that most of the crap bolted to it was emissions, or otherwise related.
Then I saw the air pump and i knew that I could make that do something else more "productive" I've been working it out on paper to try and get a model of what it all does using the FSM the ensencorp hooked me up with. It almost seems like a lot of it can be turned into electronic controled, instead of just vacuum/pressure controled. Maybe not the best for a dialy driven car, but might be advantageous to a track car. I don't know, maybe I just get crazy ideas and have a hard time with the "its not worth it" excuse... either way, is a hell of a learning curve...
do the older s4 motors have that same VDI system? or is it just controled differently? It seems that taking things like the air pump off of those motors doesn't really damage anything...