I have to ask this, as I am in the process of building an ITB setup for my engine now, and just want to know exactly the in's and out's of using this system.

First off, I'm hearing from all sorts of different people, all sorts of different things and would like to clarify a few of these speculations before proceeding with the build.

So, one thing that has me really confused is the statement that ITB's are very difficult to tune; and once tuned, they need to be constantly retuned? I'm understanding that these ITB's somehow get out of tune by themselves. This makes no sense to me as there are only stop screws and air bleed screws on the unit that could vibrate out of adjustment. -But, if you have them really tight or use locktite to ensure they don't rattle loose, then what's to come out of tune here? The ECU? I've never had my Hondata just drop out of tune like this just by itself, so I am totally baffled.

Now, the MAP sensor issue is one for the books, I hear. Supposedly, what happens here is the reason they are so hard to get tuned in the first place. Honda's have MAP's instead of MAF's. So, when moving to a ITB setup, you have a small runner instead of a plenum that doesn't allow vacuum to build up, throwing off false signals, making it a bitch to adjust. I'm understanding that at an idle and low rpm's up to 3k or so, they create a vacuum that's in the normal range, but as soon as you floor it and get the engine into the high range, the vacuum drops next to nill. I assume this is the case with homebuilt systems. If this is the case, then surely something can be done to increase vacuum with chambers or something? Like the TWM ones that have "vacuum accumulators".

Also, I've been hearing that there's an unusually strong odor of gasoline when using this setup. Is this the case? I really don't care as the car is going to be a track vehicle anyways. I highly doubt that it would be allowing that much atomized fuel into the atmosphere to be prompted to relocate the fuse box and other such electronics, or else the juice going to the injectors would be close enough to ignite it. I haven't heard of this happening, so I'm not worried about the smell. I assume this is all stuff from people that put these on their daily drivers that still have all the interior pieces in to absorb the fumes; so they're just warning you what to expect.

 

I am still in the middle of my ITB build and have read and dismissed most of these rumors.

No personal experience with the out of tune delema. I'm not sure about it myself. I have read that it has something to do with Intake Air Temperatures fluctuating drastically. Well I live in Canada and if my stock ECU can go from +30 to -30 and adjust. I don't see how ITB's will make any difference.

Map..what is that. You can get these up and running using TPS voltage reference only now. It's not quite as accurate but I had my stock F22B2 running a chipped P72 with TPS vs MAP. As well with Crome you can do a MAP to TPS crossover, where after the map falls off the TPS is then used.

I could see there being a slight odor but no more than what you would smell around a street bike or carb'd car. Unless you are running your injectors high on the runner and the angle of injection is directed strait at the back wall of your runner. This would allow fuel to stick to the sides of your runner and smell a bit. Injectors should be directed at the back of the intake valve. If your running secondary injectors directed at the mouth of the runner then yes it will smell of fuel.

 

Cool, yea after some time had passed, I decided to post this same question in the All Motor forum and got some good feedback. https://honda-tech.com/zero...75667