What are your opinions for a trottle body spacer on the new xb? Does anyone have one on theirs? How did it effect MPG/Performance?

someone out there knows about this part... I know the only thing that people have talked about are the snorkel removal, silencer removal, and CAI installation. Any help with research for this part would be great!

I don't notice the whistle on the Jeep

true lol it's a soft top TJ so not very quiet inside

alright now we are geting somewhere... Thanks for the great info. I didn't feel that they work all that well since now days there is no carb to fuly atomize air and gas right at the initial start of the intake, but it still might work beter than nothing since the fuel is port injected. I have had several race cars but all carbed and they seemed to work decently on those and i didnt want to waste my money until i did come research and found out what others have done with theirs. I will check out the TC forums to see how they work on their cars. Whisle part of the trotle body spacer doesn't bother me... superchargers whisle when you have them so it is about the same just without the GO

As you point out, the vortex TB spacer is most obviously suited for carburetor and TB injector applications, not ours where the injection takes place at the end of the intake runners (a lusty distance and at right angles from any TB spacer).  Regarding the whistle -- a supercharger whistle occurs whenever the engine is pressed (acceleration), however a TB vortex whistle occurs purely due to air flow, and that can be at fairly low speeds from what I'm told by one owner.  He seemed to consider it a little embarassing to have a whistle when street cruising at roughly 25 mph (for my Eclipse, that would be third gear)!

As said, I'm very interested in learning what others conclude from trying TB spacers.  Personally, I suspect the only style that really makes any sense for our engines is a smooth bore, not vortex.  It provides less restriction and more room for flow stabilization (reduced turbulence) following the throttle plate before hitting the air plenum (effectively increasing plenum size).  From there to the intake ports, I suspect it really doesn't make any difference.