new custom inatake mani watcha think

[kandyflip445]

Originally Posted by JeffMilano

I like it. Of course, I've got a gsxr750 ITB setup sitting in my garage, and actually need a plenum like that to use em.

As far as runner length, it looks very close to ideal, but yes technically longer runners improve midrange, shorter runners improve top end. With an engine as relatively large and untuned as the KA (as opposed to a sportbike engine), you could double the length of the runners and probably not see an improvement on the dyno.

In regards to atomization, the injectors atomize almost perfectly - it's the trip from the injector to the combustion chamber where you have problems. What happens if you have a long, smooth runner is the fuel starts to puddle together (think how water drops on your windshield pool together), and that makes for a slower, more uneven detonation. Again, we're talking about a KA truck motor here, not a gsxr1000 superbike motor, so the difference is small, but still.

Good luck getting him to install the old mani again before hittin the dyno lol.

But isn't the injector almost a straight shot into the head? If it's that close and it's timed correctly then why would it have a chance of starting to puddle. It would make sense on a carbed engine where the fuel is introduced much earlier in the intake path but not in a fuel injected engine like the KA.

[GSXRJJordan]

Originally Posted by kandyflip445

But isn't the injector almost a straight shot into the head? If it's that close and it's timed correctly then why would it have a chance of starting to puddle. It would make sense on a carbed engine where the fuel is introduced much earlier in the intake path but not in a fuel injected engine like the KA.

Without straying too far here, the injector is placed as close as it can be, but you still want that nicely-atomized spray from the injector to swirl and mix as evenly as possible, so that's why the injector isnt actually "on" the head/closer/etc. Anyway, the point is, it doesn't truely matter until you get waaaaaay closer to the "edge" of tuning (aka Superbikes).

The KA/truck motor thing isn't so much saying that the KA out of a car could have been in a truck in a past life, etc... it's more of a comment about how de-tuned it comes from the factory, compared to something that's tuned to the absolute legal limit, like a bike. Do with it what you will ~ this thread reminded me to re-download solidworks for my laptop btw