Mallory boost referenced adj fuel reg

[ZR8ED]

Ok here is a question.

 

I have a mallory adjustable fuel pressure regulator with a vacuum port on it. I am running it on a boosted VG30ET engine. I notice a slight lean condition when transitioning from cruising to WOT. I am running rich at cruising 12.5:1, and 11.5 at WOT. It leans to about 14:1 as the throttle transitions.

 

Here is the question. my regulator has about 24" of hose for the vacuum signal. The factory unit was on the manifold, and used about 4" of vacuum line.

 

I was thinking that the extra distance is causing a delay effect. Kinda like the difference of using stock brake flex lines, and using the ss braided stuff.

 

Anyone ever see this happen? I plan to test this with some copper pipe if i can find some and see if i get a quicker response for additional fuel.

 

BTW fuel pump is high pressure mallory unit, with enough capacity for my needs.

 

Any ideas?

Thanks,

Scott.

[Nigel]

Hey Scott!

 

I think the throttle position switch will tell the ECU to dump in more fuel at full throttle. Have you confirmed that the switch is operating at the correct throttle positions? A brief spike to 14:1 doesn't sound too bad though for the big gulp of air it's taking in, so long as it's not hesitating. But I don't know what's normal for the Z31's.

 

Nigel

'73 240ZT