Broken AOS

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04-12-2011, 10:30 AM

#31

Tom M'Guinn

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Quote:

Originally Posted by AScholtes

Oh c'mon now... no reason to take it that way. I thought this was a tech board and tech was the topic of discussion? I'm just trying to help the guy out with accurate data....

Either way, I wish it would have only been a blown headgasket in mine...

Eek, no, I wasn't being sarcastic at all. You're posts are are spot on and I was giving you props for that. Didn't mean for it to sound bitter or sarcastic -- I wasn't! I was just trying to acknowledge that all of your post made good points and were more complete than my original post so ehall wouldn't get more confused.

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04-12-2011, 10:53 AM

#32

reno808

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Location: In the garage trying to keep boost down

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Quote:

Originally Posted by JohnKoaWood

I have noticed a trend in your posts sir..

It is starting to appear you touch it.. it breaks.. you post question about it...

LMAO

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04-12-2011, 06:21 PM

#33

AScholtes

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Quote:

Originally Posted by ehall

ok no, I'm not certain either. What I'm reading is that you are saying that more air is entering the turbo than is being read at the AFm. The hole to the AOS is after the AFM but before the turbo, so why would you think that more is getting to the turbo? The air is bleeding out of the tube towards the aos and not getting to the turbo. Are you saying that the turbo is pulling air from the AOS? If so, from where? Why would that affect the fuel load? HOW would that affect the fuel load? What part of the computer is going to read that and adjust for it?
A wide open AOS is a gaping no-pressure hole, venting air away from the turbo inlet....is it not? It's a path of least resistance.
Are you saying that the turbo is creating a venturi effect across that orifice?

There is ZERO question that I'm running rich, BTW. WAY rich

Yes, air is being pulled into the turbo from the AOS. This is why the meter will read less air intake into the engine, even though there is actually the same amount. The intake behind the meter is a vacuum source when the throttle is cracked so any opening that has open access to the atmosphere will draw in air and will give an incorrect flow reading at the DME from the AFM. This will only show a problem usually under part throttle driving though, and usually not during WOT from my experience on other cars o this vintage with the use of similar controls. Basically it goes into a speed density type of situation using base fuel maps in the programming and doesn't take input measurement from the sensors. I am not positive of this, as I said, I am not fully versed in the actual strategy employed by the DME in our Pcars. The question as to how it all works needs to be answered by someone like John at Vitesse as to how the strategy is programmed from the factory, and then from how his meters actually modify the strategy on air flow readings while under boost.