Twin or Single Round Throttle Body for better throttle response?

[dgf2003]

Hi all,

I have been looking for an answer to this and I cannot find one. So here is my question...

The surface area of 57mm twin round throttle body set-up is 31 in.^3 and the surface area of a 75mm single round throttle body set-up is 28 in.^3.

Now to the actual question...

Does smaller (twin) throttle bodies allow the gas pedal to be less "touchy" under part throttle conditions.

In other words, assuming both throttle bodys (twin and single) have the same surface area on the blade, would the twin be more manageable under part throttle conditions.

This seems automotive, but I figured you professionals would better be able to help me.

I hope this made sense. Thank you guys and gals.

 

[jonnycowboy]

Throttle response, keeping everything in the engine the same (interial effects such as flywheel), is a function of 'throttled air', ie the volume of air between the throttle plate and the valve. This is reason that individual throttle bodies have better throttle responses when compared to a single throttle body setup. You should never, however, have 2 different throttle bodies feeding the same valve inlet.

Hope that helps.

 

[samplesecond]

I disagree with johnny cowboy-"You should never, however, have 2 different throttle bodies feeding the same valve inlet"

There are a multitude of factory setups which utilise two tb's feeding a common plenum.

I think what you are looking for has merit (throttle response and control)-however, if you match the effective cross sectional area twin, or single, you will find the throttle response will be similar. The advantage of a twin tb setup is that you can stage the butterflies for very controllable throttle response. Something else that you can do if you want to keep it simple with a single tb is to actuate the throttle plate with a 'cam', so you get increasing throttle plate rotation rate.

 

[dgf2003]

Thanks for the reply!

Can you explain to me how the "cam" works for the single throttle body, and reason for it? I have heard of them discussed before.

Also, what do you mean that a two-blade throttle body set-up can be better "staged"?

 

[thruthefence]

The Toyota ( I think Yamaha consulted ) 20valve 4AGE engine has one butterfly per cylinder.