HOW TURBOS AND ITBS COEXIST
All this time you’ve been thinking individual throttle bodies and boost ought to remain exclusive to one another and you’ve pretty much been wrong. It turns out that multiple throttle bodies and forced induction get along just fine, too, thank you. Ask the turbo and it’ll tell you all it wants to do is compress a whole bunch of air—it doesn’t care where it goes after that. Unlike naturally aspirated layouts where that pile of throttle bodies can individually suck up the oxygen right in front of them, having a turbo in their way means some sort of manifold’s got to be there to tie it all together. The manifold doesn’t just send air from the turbo’s compressor outlet to the throttle bodies, it does so in an evenly distributed sort of way and with the sort of crisp and immediate throttle response you’ve come to expect from a multiplethrottle body layout. But there are drawbacks. Tuning can be more of a challenge, for instance, since both manifold pressure and throttle position now have to be considered when configuring engine management fuel tables. Get it right, though, and you could end up with the best of both worlds.