now ive read that ITBs arent a simple bolt on. smooth air in, means it needs to be just as smooth coming out. which means custom header...
Ok guys I'm back so i can answer this sort of stuff...(was dragged into helping Twilightprotege out at melboune (2 days drive away) at the last minute, literally... 20mins before he left, i packed my bags....anyway, we went drag racing, andy's not technically NA anymore....i'll explain all later or something).
You don't need "smooth air in, smooth air out" etc... you need to TUNE the intake, and TUNE the exhaust. Custom header is an ABSOLUTE MUST to achieve any sort of big NA numbers on these engines, nothing decent exists off the shelf - and i mean NOTHING...what you can buy is great for a bit of extra pep on the street, but will not support the kind of power that is needed for big power...
anyway...You tune up the runner length on your throttles to work where you want them to work, and tune up the exhaust primaries to provide max scavenging at your desired RPM point, and thats that....all done.
nothing too difficult about it....
setting IRTB's up isn't a walk in the park though.... tuning them can be a bastard, because you need to tune for TPS not MAP, and getting each throttle to flow the same amount of air to prevent leaning on a particular cylinder etc will do your head in. Any IRTB questions should be directed at flat_black - he's done the deed on the FS already, and knows quite a bit about the ins and outs of this sort of intake manifold set up, and is a font of knowledge when it comes to head porting etc as well....
