ColinRX7

it is? you sure?





Theres no dynamic chamber really when you do that.. There is a whole different dynamic in tuning boosted engines over naturally aspirated



ITBs are an n/a thing, looking to maintain velocity and even flow for each rotor, as opposed to having the pulses combine at one throttle body..



it's about tuning runner lengths and sizing, velocty, etc.. it's a different ballgame when you are running forced induction, you want a big section to have boost "stored", as where n/a you don't.. I can't even really compare the two, I have no real versing in tuning boosted intake manifolds.. But ITBs from what I understand are mainly an n/a thing



in which case ITBs (from what I understand) are NOT ideal for boost, which is why nobody does it.. I could be wrong, but the dynamics of boosted over n/a are completely different.. Throwing boost at something is, yes, a bandaid, but it doesn't mean any given design + boost is the most ideal design.. Everybody wants an ideal design for their application

Tessai

Saw a big turbo 1st gen this weekend with ITBs... I don't know much about tuning, but it seemed to work.



~460whp on a big turbo REW motor, I think.

rfreeman27

thats not that much power.



Plentium tunning is crutial, you loose that with ITB's unless you have a collector, which defeats the purpose anyways.

sidewayz7s

hmm..yah i guess that tru. I think it can work both ways for NA or Turbo, but i never really took into consideration of the plenumn design and length. maybe i will stick to single throttle body, this is very helpful advice guys thanks again and keep the info/experience and knowledge coming.

75 Repu

it will work for boost.. tunin like with any engine is what will determine alot of it.. that and experience.. runnin ITBs on a boosted car would require a setup similar to a blow thru carb setup.. the question is are the ITB sealed to take the boost? i know you have to get the carbs sealed up a certain way to take boost so they dont leak.. I think the engine in that crazy *** pink beamer with the rotary had ITBs

One320B

I went with ITBs for a few reasons. I'll try to justify myself the best I can...



1. All parts are brand new, clean and easy to setup and repair.

2. The ITBs setup utilizes a "top-hat" design similar to what you would find on older FI carb cars. The top-hat acts as the holding place for the boost before it enters the TBs and runners to the ports.

3. The design of the ports is more direct, adding better throttle response and reduced boost lag.

4. The top hat I'm utilizing is tuned for the amount of boost I plan to run (16 pump and 24 c16)

5. The larger diameter TBs offer better flow than the stock FC or FD TB.

6. ITBs are not intended for stock or midly modified engines..it should only be utilized when the modifications justify the need.



Vehicles such as the Skyline GTR use ITBs w/ FI from the factory. ITBs are not just for NA.



I've seen ITBs FI cars at numerous drag events, rally and open-wheel cars...we'll see how it works out. I don't personally know anybody running ITB boosted FC though

One320B

Yea...sealing the ITBs is my only real big concern. Since this is my first ITB FI setup, it'll be a learning curve for me too



I'll put pics up of my plenum if anybody is interested...

sidewayz7s

hell yah, I am gonna weld me up a custom mani to make the ITB's work, be one of the few to have turbo 13b with itb's. one morw question. wuts the best way to setup the throttle position sensor? can i use the factory yamaha one that is allreadu on the itb's by anychance?

jefraney

You can use the factory yamaha sensor as long as it has the same outputs as the stock one

One320B

I saw a website with a honda guy that used GSXR ITBs and made his stock TPS work. You'll need to use your stock one (or go standalone and use a different one) You would probably need to fab up a bracket to mount your stock one. The one off of the bike won't work...there TPS sensor usually have way more range than us....



My ITB setup has the TPS sensor mounted to the throttle shaft already, but it was intended for a rotary, not a bike...and I'm using a standalone which helps... you will probably have to go standalone as a stock ECU setup probably wont be able to control, or even understand ITBs