Throttle Body Spacers

Have any of you had any luck with throttle body spacers. I hear its a cheap way to get a little HP. Out of a Throttle Body. They supposably give you better MPG.

Ive Got A "helix Tower Of Power" Tbi Spacer...and I Noticed A Little Power, And I Like The Sound I Makes...people Ask Me If I Have A Supercharger....and Bout The Mpg I Didnt Notice A Differance......

I have a tb spacer and two chevy service shops have told me that is why my truck is misfiring.

I have a tb spacer and two chevy service shops have told me that is why my truck is misfiring.
that sounds like a vac. leak

when it comes to throttle bodies, just use common sense to realize that they prolly dont help at all. if they were in any way better than a stock setup why wouldnt the factory integrate a similiar design into the stock system. It wouldnt be a matter of cost. i bet they arent all that good, like the tornado inserts that claim to be some awesome increases and stuff. i dont remember where, maybe comsumer reports or popular science, but some big whig testing group has a website that shows tests of various products like the tornado and other stuff, like magnetic fuel line clips and stuff. every single tested thing either made power and mileage worse, or had no effect at all...

The basic idea of a longer vertical path for the air/fuel mixture going into the plenum is sound.

I have an Edelbrock TBI intake manifold on my '90 Suburban's 383 and one of the changes from stock is that the injector pad is 1/4" taller than stock; most spacers are about this thick.

I also have a large (about 8" diameter) aluminum velocity stack riveted to the bottom of the stock air cleaner. You have to cut a correspondingly large hole in the air cleaner bottom to mount the stack. Turbo City in Orange, California sells these to optimize the effect of a spacer on the stock intake manifold.

I didn't bother with a spacer once I saw the extra height built into the Edelbrock.

The truck also has smog-legal headers, 3" Gibson muffler leading into 4" pipe with a 5" tip.

Performance and mileage are good. I got 16 mpg at 75 mph with a one-ton load going over the Siskiyou Mountains on I-5.

I think the cam (I use a Crane RV torque model) is the biggest single factor other than gearing that affects power and mileage.