OK, for a 150 shot, I needed to run a 62/41 in order to keep from leaning out at the top. NX Express recommends a 62/33 though.

So what should I run for a 75 shot? They say a 41/22 but should I run a 41/24? 41/26? 28? Don't have a wideband.. so need to make an educated guess.

 

Bump... going to make a few test passes tomorrow and would like a second opinion on this. I figure since I went up one step at 150, I should go up one step at 75. However, the jump in "steps" is different obviously.

 

trial and error

 

Why is it leaning out up top? Fuel pump unable to keep up?

With a smaller shot, it may not lean out as much up top.

How do you know it's leaning out up top? How are you monitoring it?

 

Did some dyno pulls at Speed Inc and it does have an upgraded 255l fuel pump.