ITB Drawbacks?

[brock]

I working on designing an independent throttle body intake and I want to know anyone's experience with them and what the drawbacks are to using an ITB setup. I want to address these problems in my design. I've never driven a car with em so I need some first hand input. I've heard streetability is an issue. Let me know. Thanks

 

[cribbj]

Hard to get a good manifold pressure signal (because there is no manifold), so setting up an ECU can be a challenge. You'll need an ECU that does a hybrid load map using both TPS and MAP to get the best driveability. Make sure each ITB has a few pressure ports under the butterfly, then run small tubing from each one to a little accumulator pot in order to get an average manifold pressure signal.

Also, ITB's are not known for their stable idle. If you don't mind an idle that could vary from 1000 to 1800 RPM from stop light to stop light, then no problem. Obviously there's no ISCV, and with 8 butterflies, they're never going to close exactly in the same place each time.

Filters are an issue too. No one makes a really effective filter that doesn't take away from the looks of the ITB's.

Then there's the fun with synchronisation........

 

[ed_ma61]

get a properly machined set with an accurate/well designed linkage system, and theres no problem with syncronisation

balance pipes and accumulator is no problem. vac source issues solved.

iscv is also no problem. dont know what johns on about. just bolt one in??!

with all of the above, unless you have massif cams, youll get a perfectly good MAP signal. add big cams tho, and a blended MAP/TPS tune is a must

the key with anything like this is esuring you address all the issues before starting. design around them. dont just bolt on a set of throttles out of the box and expect to drive away. theres heaps of space under the manifold in the 'V' to assemble all of this

downside is maintenance, keeping linkages and bores clean and lubricated. it deserves more attention. filtration has nothing to do with ITB's per se and more to do with how you setup your airbox

depnd if you want bling or function i guess

 

[brock]

Thanks for the input guys. I'm going to use '05 Yamaha R1 TBs which have a well designed balancing set-up with vacuum lines connecting all barrels. Plus additional vac ports that I'll run to a reseviour in the V. Function will be the focus, I really don't care how it looks. Here's the Yamaha TBs

This one has an air box on it which I'll remove, but you can see the vac lines at the bottom.