At what duty cicle does fuel cut come in ?

[Ricardo]

Just wondering when does fuel cut come in, is it if injectors reach over 100% or ...? I dynoed today and its running rich. I got under 10.0 a/f w/ the walbro 255 and stock injectors. Turned the boost up to compensate... fuel cut. Wondering what duty cycle I get fuel cut. Anyone?

 

[Defiant]

It's determined off air mass, not duty cycles:

http://members.shaw.ca/costall/ECUprimer/ECU_ch7.html

 

[Ricardo]

Originally posted by Defiant
It's determined off air mass, not duty cycles:

http://members.shaw.ca/costall/ECUprimer/ECU_ch7.html

ok, i see. Thanks! I dynoed 230hp/254tq. Had to turn the boost up coz it was running rich as hell... after turning up still rich. Then I went to the street on that setting and fuel cut, but it's only coz a stupid spike. I get 21psi briefly then it drops. I need ebc i guess

 

[brads]

Originally posted by Ricardo
Then I went to the street on that setting and fuel cut, but it's only coz a stupid spike. I get 21psi briefly then it drops. I need ebc i guess

An EBC might allow you to run right up to the edge of fuel cut by avoiding the spike. But they aren't cheap, and that doesn't buy you a lot of headroom for the $$$. A set of larger injectors, and corresponding adjustments to your AFC would move fuel cut up so that you wouldn't be as likely to hit it. Or better yet, a reprogrammed ECU could eliminate fuel cut altogether. I'd look at these instead of a boost controller.

Brad