Carb spacer questions

[FE3X CLONE]

Okay, I know that the rule of thumb is that a 4 hole carb spacer will typically boost low to mid-range torque and an open spacer will boost upper end HP.

Now, will the same hold true for a vehicle with a 4bbl EFI throttle body since there is no fuel being introduced before the spacer?

I'm just wondering if a 4 hole spacer would help increase my intake port velocity considering I have a large dominator flange single plane intake and a 1600cfm throttle body to give it a bit more part throttle response.

 

[drogg1]

Yes I believe it would work the same regardless of the fuel being introduced before or after. As you said, I think a four hole spacer increases intake port velocity due to the decrease in area which leads to an increase in velocity. This has to do with the air not the fuel similar to a cold air intake affecting the density of the air. More velocity makes it easier for the cylinder to be filled.

 

[Minion1186]

I agree, you are still shaping the air with the 4 hole and i would assume that with an open spacer you are still creating a mini tunnel ram effect. I guess the only way to tell if it works is by trial and error. I think I'd go with the 4 hole spacer or a tapered 4 hole.