Advanced Engineering Tech - Use of Carb Spacers on Carb Style Single Plane EFI intakes

Is there any value in using a carb spacer a carb style single plane port EFI intake? Particularly when using with a 4 barrel TB? You know the popular ones like the "Super Sucker" and the 1" to 3" phenolic plastic ones. Some with four holes under the TB openings or some just open space.



I know they suppose to aid in increasing the air velocity and increase the vacuum signal in carb applications but would they help us in port EFI applications??



I think of using them on a carb style single plane on intake a 396 cu LT1.

I would assume what is correct for carbs is also true for tb, the airflow shouldn't change just because the fuel is added further down the runner. that being said this isn't based upon my own experience, maybe some one with some dyno information could shed a brighter light on the subject.

I would like to know more info on this. TTT...................

The effect of spacers is much less pronounced on a dry-flow MPFI system because fuel mixing due to localized velocities is taken out of the equation.
The remaining effect would be to increase plenum space, and/or to add room for a smoother transition into the runners. The effect could be positive, negative, or not measurable, depending on what is needed by a particular combination.
I wouldn't expect a big change in a MPFI application.

MY car lost 2 rwhp on the dyno with a spacer under my TB. We were changing out three different intakes and checking dyno numbers from all of them and decided to check the spacer as well.