With the datalogger all wired up, we're almost ready for the dyno, but there are still a few things to hook up. Remember the carbon fiber intake manifold we started building waaaaay back in Oct 2010? (no wonder you guys are demanding donuts!) Well, we still had to finish it.
Last time we showed this thing, it was a solid block of styrofoam taped to a carbon fiber air horn. Now, obviously, it's a lumpy looking piece of gen-you-ine carbon fiber. Alex did most of the work on this plenum at his house, away from my camera, so there will be few details about how it happened. Just know that it's a wet layup, making it much heavier than it needs to be, but even so, the whole thing weighs less than a pound.
The giant hole in the front is for this air filter cover. Alex bonded a piece of carbon tube (which he made by simply wrapping some carbon around a piece of aluminum tube) into the lid with a generous length of tube sticking out both sides.
On the inside, that lip is used to hold an AEM dryflow filter, which will be hidden inside the plenum. We're actually running the filter reverse flow, with air flowing from inside to outside. This might make cleaning the filter a little more complicated, but it makes the packaging really compact. This is the same way the factory Suzuki airbox works.
The lip on the outside can be used to attach a duct to pipe in cool air, so it doesn't have to breathe off the hot crap coming off the back of the radiator.
The next challenge is hood clearance. We designed this plenum to (barely) clear the hood, but the final engine mounts (especially after the final addition of the retaining ring) sit a fraction of an inch higher than expected. The minimal clearance shown here turned into no clearance at all.
We had anticipated this possibility, and our backup plan was to add 45-degree elbow hoses to tilt the plenum down out of the way a bit.
We got 4, 2-inch 45-degree silicone elbows from Vibrant Performance to do the job. You can see some of the test fits, above, were done with a single Vibrant hose to prove the concept before trimming all four hoses to length. With the clearance established, I then trimmed the hoses, installed them all on the throttle bodies, and spent two days trying to jam the manifold into all four hoses at once. Then I tried installing the hoses one at a time on the plenum and jamming the whole thing onto the throttle bodies.
Still no. The Hayabusa hoses, it turns out, were 54mm, which, if you're good with the arithmetic, you'll recognize is not 2″, but 3mm bigger than 2″. Stretching a hose 3mm to install it is no big deal at all. Stretching four hoses 3mm simultaneously, it turns out, is a HUGE deal. Completely impossible, in fact.
Vibrant Performance has nothing between 2″ (50.8mm) and 2.25″ (57mm), and neither does almost anybody else. After an extensive search, I finally ended up with no-name Chinese 2.125″ (53.9mm) silicone elbows in not-subtle-enough-for-me blue. Fashion aside, the blue hoses finally make it possible to actually install the manifold.
(It turns out HPS does have 2.125″ hoses, but I failed to figure this out at the time…)
At this point, I was checking hood clearance by spray painting a taped patch of the the underside of the hood, closing it, and seeing where the paint ended up. The rubbing on the silicone hose will just have to be something we live with. The little black patch on the carbon plenum will be fixed by cutting the plenum down there and sticking a little carbon patch over the hole.