So I removed the Vac Rac, but was curious when the original VDI would have had pressure. (when would the solenoid open). If I put a pressure to the solenoid, can I hookup the solenoid and hace the cpu drive the VDI?

Otherwise all emmisions is gone. using an eletric air pump to supply pressure to the 6ports and VDI.

 

On my 91NA I picked up the ground signal from the Aux port solenoid connector to close a relay & turn on the air pump. The pneumatic rack tee's to both the 6PI & VDI so when the VDI solenoid opens ~5800 the pressure is already there. I bleed off the excess pressure with a spring & ball check made from generic brass fittings.

By the way the ECU will not open either solenoid if the boost sensor sees high vac, or the tranny is in neutral.

 

ahh so, you don't have aux's open at ~3800 But rather open both auxs, and VDI at 5800?

This is what i was looking to do. I just wanted to make it with 1 rpm switch instead of two...

http://webpages.sdsmt.edu/~4392494/a...iondiagram.htm

 

Here is the diagragm of my S5 NA e-pump setup.

 

So you're using both solenoid leads from the ECU? It makes sense and looks pretty good, but are the systems only activated underload?

Whats the determination to when the ECU decides weather or not to ground at 3.8 and 5.8?

 

I looked them up in the FSM.
Page 76 - fuel & emissions section. The O's indicate a relation.

Air flow meter
Crank angle sensor
transmission neutral switch
clutch switch

 

awesome, that helps alot. Thanks

 

Hmmm,

VDI opens at 5200 RPM according to page F1-80 of the S5 FSM, not 5800 (wire 2M).

 

Either mine came in late, or my tach was off.

Two years ago, when testing the VDI, it would open at half throttle ~5500.
Last year it tripped at ~5800, and only at nearly WOT?

Anyway - I sold the NA when I got the turbo. (A whole new set of challanges)

 

I am actually opening mine at 46-4800 on mine, which I think is a touch low (there really is not much of a noticeable kick in, unlike what others with the S5 conversion report).

Your air pump may have been getting old, or the solenoid valve was clogged (common if a decent air filter was not used for the air pump when a cone filter conversion was done).

 

You should use the ECU to operate both the stock 6PI and VDI solenoids, and trigger the compressor relay from the 6PI signal (since it operates first).

As I've said before, leaving the whole thing stock would've been a helluva lot easier, and would work better than anything to put together yourself. All this effort just to remove the air pump and solenoid rack, only to require another air pump and the same solenoids. Where are the gains from doing this?

 

I dunno, I feel like i did something, gain some experience I guess. Like the person that makes a telephone out of a coffeepot. Sure, it was a perfectly good phone before... but now its a phone that looks like a coffeepot. And who can say that have one of those?