ran itbs on my setup have a look at my thread. Very expensive to make and alot of hours trying to get it synchronized correctly. They worked very very well on offbost response. I had leaks everywhere on my itb setup as well as wet flow issue when the second injectors started coming on.

If u want to make high hp up top I think the butterflys will start causing a restriction. Alot of the gtr guys remove and go single because of this. But for na I would defenitaley do it. If I wasn't so pissed off about all the leaks I would have persevered with the setup but in the end cbf.

Good to see some decent info. I've been working on custom plenum and exhaust man. over the last 6 months or so, and read about ITB's and was curious about them. After reading what has been said, and finding some other info, I don't think I'll keep rolling down this path. Never mind, I have a few more interesting plans for the Z build.

They do improve throttle response on a turbocharged engine, but not as noticably as on a NA engine. I have a set of R1 quad TBs, with the double butterflies to improve low end torque. Quite a nice bit of engineering, but I'm not sure how suitable they'd be if used with positive pressure, as I was going to use them on a turbocharged Suzuki G13b.

Have there been any OEM turbo ITB setups since the 32 GTR and the GTiR? I reckon it's not worth the hassle.

As mentioned earlier, as soon as you add a turbo, getting every last bit of flow out of the heads & intakes is much less bang for buck.

there should be heeps on info floating around about it for hondas ... K20Z1 or B18C7 with ITB setup and TODA IM = PURE SEXUAL WIN

not that its really relevent lol