ITB, Dual throttle bodies - when does it help

[turbogrill]

Hi,

 

I am a little confused in how ITB/DTB can give MORE horse power. I understand that it improves response since there is a short path for the air to travel once you hit WOT.

So to me it seems like it only helps with the respons when opening and closing the throttle.

 

Once the pedal is open air should flow anyhow?

 

Or does it improve flow as well, so it makes up for a restrictive intake?

 

[supernova_6969]

from what I understand, I think you are right about less restriction, allowing more air to come in faster (on top of having a shorter and straighter route to travel)

 

I think it also has to do with the fact that with more carbs (unless you are talking about injection), you can fine tune your AFR better ( think of it as having two small hammers instead of a sledge hammer.  more precision)

 

One of the things about ITB is that you can tune the stacks so that they are just the right length to encourage the air to go in faster (I'm not clear on how that works, but that's why i'm not a car engineer)

 

but i'm certain there is more to be said about it. 

 

don't forget there are also some relative downside, like not having any vacuum since there is no plenum from where the pictons would suck up the air. it's more expensive and harder to tune.  there are more moving parts...

 

 

PS: also I think that the way they look adds more horsepower.  I mean seriously, ITBs, or even duals, are so cool....

[Derek]

Well the noise gives me a massive chub every time I stomp the gas so there's that:)

 

Seriously for a street car looks and sound need to play into your decision process because ITB's make literally everything induction related much harder. 

[JelmerPatrol]

I ran my BMW M5 3.8 with open stacks once....the noice was breath taking at 7000 rpm!

[jacky4566]

Man there is whole books on this topic but generally ITB are better mainly for response but also benefit because you no longer need a plenum to distribute air. In the world of intake design its all about laminar flow. A short ITB with no curves will flow better than a twisty manifold.