maybe the longish one that'* below the coolant there?

which in turn would come out on the lower at:

nice detective work, Kaake. But what the heck does it go to? You've already got two coolant passages - don't think you'd need three. You don't need oil in the TB, so it'* not an oil passage... So that leaves air, right? But for what purpose?

a very good question indeed.

what'* more disturbing?

the l26 mani has that same hole going to the lower, but directs it somewhere other than the TB. need to do some serious staring at pictures today to determine where it actually leads to on the new manifold. if we're lucky, it'll take care of itself somewhere in there. if not, then things will be a little more complicated.

when we pull that TB, we should check where it goes on the TB and on the lower, so we can get an idea of what it'* trying to do...

Well does any one know what that ports function is?

nope


i took a look at a series III today at work (thanks linda!), and saw what i could see...

and assuming we're right about where it ends up on the lower intake, than it'* just some sort of a fresh air intake for the lower manifold. no idea why, but that'* what it is. on the new aluminum upper (series III), instead of making it'* way to the TB, it just shoots straight up to the top of the plenum, into a vacuum line, and then to the air intake tubing, just in front of the throttle body. Made a lot more sense that way than carrying over the series II design. If you get the chance to look at a series III tb, i do recommend it - it'* very slick. and small. it'* an electronic TB, so there'* no IAC, so they were able to package it just slightly larger than the diameter of the neck on the upper intake. very cool. and because of that, putting this passage through the TB would have made it more complicated (and expensive to make), as well as more complicated and expensive on the new upper intake.

so that'* what we've got. i'm pretty sure.

Hi Mkaake looked at a lower intake at the junk- yard today and the oval port goes to crankcase air. The port comes out between intake runner 4 & 6 on the lower intake, the teardrop shaped opening.

PS: Motor at the junk yard died because of lower intake gasket failure.