ok i have heard some goods and some bads lol. i just dont see how that 1 inch can make that much of a difference. but he did make a good point on how certain parts of your intake help you more than others, my mass air flow sensor gain was twice what my intake was. Has anybody with an 07 and up 6.0 used a throttle body spacer because that year and up uses a Drive by wire T.B. and it is 90mm. thats what i have and thats what i want to know???

 

DBW started in '03 in the trucks I believe...

 

Drive by wire was introduced in 01. Not many trucks got them, none had a 6.0 and drive by wire. At least I never found any while I searched for a bin file for a 4l80e conversion..
In 03 ALL trucks had drive by wire.....

 

First let's get one thing strait. Throttle body spacers do not change, straiten, or swirl the air. That is IMO, a sells gimmick. I feel the throttle body manufactures think it would be easier to "con" people into believing Throttle body spacers change the way air flows into the engine, rather than trying to marked the throttle body spacer for what it is... A Plenum volume adder.... Plus if the manufacture sold it as a volume adder, not everyone would need one. But EVERYONE needs better atomized air, or "straiten air flow". No market limitations.

Then you have people that actually try a throttle body spacer. If it is a poorly designed one (with swirls) it may actually restrict incoming air. If by chance the person that tries a throttle body space does get one that does not hinder air flow, what are the chances his engine actually needs a larger plenum?

SO, not everyone needs a larger plenum, the spacer could hurt performance, and they are marketed all wrong.... I wonder why most people feel they suck? Throw on top of that forums where one person post-up of have good luck with a spacer...... well you see what happened here....

On top of all that, by changing the plenum volume, runner length, runner volume etc. You change the why the manifold works at certain rpm ranges. So if you had two trucks both having a 5.3 and a junk *** 4l60e, and 30" tall tires. but one had 4.10 gears, the other had 3.73 gears. Cruising rpm would be different area, changing the plenum volume in both trucks may not affect the same way.....

The bottom line is this, Throttle body spacers DO work. They wont improve everyone's engine performance. And the only way to know if one would help you, is to bust out a math book, or try one.... It is easier to just buy a nice turbo or Radix kit....



Take a Look at this table. Notice how G.M has increased the plenum volume as well as the runner volume for the ls1 engines?
Notice how ALL the truck manifolds have the same plenum, runner length, and volume? That intake has perform on three different sized engines.. The ls1 only on one engine size...

A few links... If you are that board....

Pulse Ram link
Manifold tuning
A bit about Helmholtz

 

Damn Dusty, you did some homework on this one!

 

hey where can i go to research my plenum volume? and i appreciate all your info!! and i am having a difficult time finding spacers that DONT have the swirls or some design. so why would every company make their spacers with the swirls in them if they dont work?

 

because making people think that the air swirls around and creates more power is what sells these things to people that dont know better...

on a side note, everyone says the tornado thing sucks, but i used one on my 03 sierra and it actually slightly improved gas mileage and throttle response...
key word, 'slightly'... i only bought it cause i found it on ebay for like 10 bucks, and i said what the hell.
but, i tried it on my 07, and it robbed me of power and mpg for some reason... needless to say, it is now sitting somewhere in a distant landfill

 

i have put one on my 07 vmax and my wifes truck and not going to say i picked up hp but i did pick up fuel mileage