The only good throttle body spacer is made by NX, it has spray bars and take jets, lol

 

TB spacers aren't pointless on a non-TBI/carbed engine. They DO technically increase plenum volume. I would say since our plenum is already fairly large, making it a hair larger isn't going to do anything noticeable.
On other vehicles, where plenum volume is lacking, a 1 inch spacer would make a much larger difference in the overall volume, and would be more worthwile.

 

They could work on a carbed motor, but the increase in plenum volumn isn't why they don't work on EFI motor, the injectors are well below the spacer, AND the runners, so the claimed better mixing of the fuel & air is an out and out lie.

 

You completely misunderstood my post...

 

Yes the spacer increases volume but on our motors it makes no difference because fuel is not mixed with air through the intake,

 

They do increase plenum volume but even on a vehicle with a small plenum the increase in size is still very small. Plenum volume only helps high rpm power where a small increase would not be noticed. At $70 a piece I would waste my money somewhere else.

 

Your argument is the same as saying the kegger intake would be no different than a smaller plenum intake, since the fuel is mixed after the intake.
Yes it does make a difference. Percentage wise, a spacer on an already large plenum doesn't make enough difference. The same spacer on a smaller plenum would be more noticeable.
I am not defending the products, but the theory. It is not snake oil, they do have their place on some FI engines.

 

Thank you for understanding what I was saying. Agreed that I wouldn't waste the money (or the effort to make one for free) on our engines.
Just didn't want people to be completely closed minded to them when they are applying what they learned to a different engine. People have realized gains on engines such as the LS4 in my grand prix GXP (5.3L).
On another note, I thought larger volume plenum was for better low end...?

 

The whole idea behind throttle body spacers was to induce turbulence in the air flow, such that the fuel vapors would be more evenly distributed. Plenum volume has little/nothing to do with it. On 99.99% of port injected engines, you would see zero difference in performance, and on the .01% that might get some, a dyno might notice it, but, the driver certainly won't.

Where you make your power is determined by runner length. (all else being equal.) Throttle body spacers ARE snake oil for most cars on the road today.

 

Smaller the plenum size generally more torque. Shorter distance for air to travel to the runner=higher air velocity threw the ports at lower RPM'S. Looking at the M1 2BBL alot of guys add a turtle to decrease volume to gain back the low end loss.

EDIT....Agreed that theres more effect with a smaller plenum vs larger. X2 To small of an increase.