Topic: double stacked tbs

[Tall Boy]

Anybody ever heard or done a double stacked throttle body spacer. I ain't too sure if it wasn't sarcasm but somebody said if it were double stacked it's like double-mint gum.

[YJmechanic]

that would be hard to rig up with the cables and if it ran properly which may or may not you would have no torrque left.  that is like running a giant single plain intake on an old street rod.  I wouldn't suggest it unless you just want to waste time playing around.

[Jeffy]

You can stack the smaller ones.  They are more like 1/4" shims then spacers.  You would not want to stack 1" spacers though.  The reason for using the smaller spacers is to fine tune the pulse wave and get optimal induction.  It's the pulse wave that is important so just adding more and more spacers will not help.  You need to time the pulse wave so it comes into the intake and hits the top of the valves right when they open. Then the valve closes the wave heads back out.

BTW: the pulse wave also occures at the exhaust which is why you cna tune the exhaust to optimise the pulse wave.

[wrangler387]

If the jeeps intake manifold was equal length then tuning for pulse wave would probably work. And its more to do with runner length then plenum size that determines about what small RPM the X wave will be effective (X being whichever degree wave your looking to utilize [the less times it bounces back and forth the stronger the pulse]). Helmholtz resonator formulas might not have even went into play designing the jeep manifold... although timing it right does provide a decent boost in efficiency, its only for a small section of rpm and is somtimes ignored.  Most people don't look into tuning the exaust either, if they did we wouldn't have short runner'd exaust manifolds on our jeeps. most of the exaust benefits come from creating a "scavenging" effect, which is also kind've neglected in jeeps.

[YJmechanic]

WOW this went way further than I expected for a little question but that's what's great here is everybody comes together adds info.

[John Do Daddy-O]

I saw the same thread where somebody thought that if a 1" spacer is good, two should be twice as good. Being mechanically illiterate, I thought "Makes sense to me!" I found some cheap ones on e-bay (had to replace my original because I tried to grind it outmyself .. sad..very, very sad) I bought two and installed them.

I can't say I found any substantial increase in performance, but it works at least as well as it did before. But i would say that knowing what I know now, I wouldn't do it again.

[Tall Boy]

Right on.