EFI Injector Location

[FortescueTech]

What does everyone know about injector location in relation to the intake valves? is it a closer the better situation or perhaps further away the better? I see locations on Japanese OEM engines put them right at the mating face of the cylinder head with minimal intake runner distance while some aftermarket companies move the locations on their manifolds back a touch, if anyone has any knowledge they would like to share that would be much appreciated.

[andyf]

Depends if you are trying to make power or are interested in economy and emissions. Also depends on the type of fuel that you are burning. Some fuels want more time to vaporize so they'll want to be injected higher up the runner. I've played around with this just enough to learn what I don't know. I'm sure there are a few guys in NASCAR and Pro Stock who know a lot by now. Those guys have been playing with injector placement since the EFI rules came out. The little bit I've seen tells me that they both want the injectors as far up the runner as they can go. I suppose they are trying to duplicate the vaporization time that a carb has.