Throttle Body Spacers: The Facts!

[X E Ryder]

i have to totally disagree with all you guys you have no idea what you are talking about.

my throttle body spacer LOOKS sensational when i lift the hood, all shine and red, it has to be faster

you guys have no imagination

ok ok just kidding

hehehe that was too fuuny :roflmao:

 

[souske]

Any interest in a HHO generator?
How about a tornado?

 

[sjx40250]

What a TBS does is increase the volumn of the intake manifold. There can be change in performance if the increase is significant. Remember the ram charge manifolds with the dual quads back in the 60 and 70's that were sticking out of the hoods placing the carbs near the roof line? It is less than 1% increase in volumn for those bought for the 4.0, which is negligible. The loss in you pocket is higher.

 

[GrimmJeeper]

What a TBS does is increase the volumn of the intake manifold. There can be change in performance if the increase is significant. Remember the ram charge manifolds with the dual quads back in the 60 and 70's that were sticking out of the hoods placing the carbs near the roof line? It is less than 1% increase in volumn for those bought for the 4.0, which is negligible. The loss in you pocket is higher.

the increase in manifold volume makes no difference whatsoever because the 4.0's fuel is injected just before the air enters the cylinder.

 

[Vanimal]

i had this idea of cutting a bunch of holes in the intake hose and gluing in some computer fans to act as an electric supercharger. I also had this idea of bypassing all the extra rotating weight and constriction of a turbocharger and just plumbing the exhaust right into the intake. i do realize the problem would be heat, so i would still run an intercooler with (you guessed it) computer fans to help keep it cool. If it's still too warm, i can duckt one of the air conditioner vents to the intercooler and this is sure to work. i'm a little worried about sharing this with you guys because i was hoping to patent it first, but i trust you.

 

[souske]

Not buying the volume increase argument. If that was the case, why not use the cabin as part of the intake manifold, and have a filter sticking out the roof.

 

[Ewenm]

all jokes aside i suspect the only improvement is insulating the throttle body from the manifold as was previously mentioned,

i actually do have one fitted and back on the day i thought it made a slight improvement, is it worth the money....probably not.

for me the greatest improvement came from exhaust extractors and a 2.5 inch exhaust system, oh and 4.10 gears hehehe

 

[5-90]

the increase in manifold volume makes no difference whatsoever because the 4.0's fuel is injected just before the air enters the cylinder.

Moot.

Recall the old Chrysler "Cross Ram" RB big blocks (I think they did that with the 300-series and the RB383, in the early 1960's.)

The idea there was to achieve "resonance supercharging" - which means the acoustic pressure wave generated by the intake valve closing was used to provide a sort of forced induction at a fairly specific crankshaft speed range in order to increase VE.

This is irrespective of using a "wet" or "dry" manifold setup, since it has to do with air masses.

Problem is, you need a hugely long intake runner in order to get a benefit at low RPM - and that's using the second- or third-order pressure return (using the first-order pressure return is difficult.)

And, that has sod-all to do with "plenum volume" or any such thing - that's specifically the runner length between the intake valve and whatever provides the sharp return for the wave (usually the carburettor base. But, the far wall of a plenum can be used.)

The marketing blurb on the throttle body spacer plate recalls this, but the actual effect of a TB spacer is pretty much negligible - increasing plenum volume by a small amount doesn't help, and it doesn't do anything at all for resonant tuning (cf: "Helmholtz resonance".)

Since we're on a similar topic, let me address (over)bored throttle bodies as well. If your throttle body (an OEM unit, say, for a stroker) won't flow 90-95% of the theoretical airflow requirement, then an overbored TB can help you at WOT.

However, most production throttle bodies are good for something like 130-150% of the theoretical redline airflow for the engine it's on. Since NA VE is typically in the range of 80-90%, this means that there's significant unused capacity. You don't need a bored throttle body (even a RENIX throttle body flows enough to support most stroker configurations.) Throttle body airflow on a dry manifold engine doesn't have anywhere near the harmful effect that "overcarburetion" does in the old days.

A throttle body with an oversized bore can improve part-throttle response, but it's not going to add power. If you want to improve engine airflow throughput as a power adder, put the work where you need to - put your cylinder head on a flowbench and get to work

 

[watrousmark]

Actually the long cross ram on the letter cars was used on 413s. The runners were 27" long and had dividers inside of them to keep the fuel in suspension (i.e. small cross section in the runner). They generally fell on their faces at about 3500 rpm, but they looked super cool.