Numpty question but..........Is there any technical reason - neglecting any ancilliary equipment clearance issues - why injectors cannot be fitted on the underside of an inlet manifold, instead of on top?

[Edited on 29/12/09 by Confused but excited.]

As long as you're spraying into the air stream at the right angle, no

I had similar thoughts regarding the Fireblade 929 installation in our Phoenix.
We wanted to turn the standard airbox upside down but the airbox / trumpet/ throttle body interface suggested that we turn the bodies upside down as well.
This, of course, means that the injectors point upwards, as per your post.
I can report that the engine starts, ticks over, and runs nicely to the redline through the gears and seems to have suffered no ill effects from the exercise.
Geoff.

The general idea is that they spray onto the back of the inlet valve, not the side walls, so geometry permitting no reason why not.

i would have thought it was just easyer to get access to them, for testing and removel....

The reason, is that I want to make an inlet manifold with the injectors underneath. This is to basically hide them from view, so that the twin 40 carbs that I am using to make throttle bodies, will look more like a carb set up, to go with the 'retro' look that I am after for my build.
Purely cosmetic and yes it will make more work maintenance wise, I know, but don't care about that.
I couldn't think of any reason it wouldn't work but wanted confirmation of you guys who are much more knowlegeable on this subject that me.
Cheers for the input guys.
Excellent comments as usual.
Much appreciated.

Just got to make a mock-up/pattern now and see if it will all fit.

[Edited on 29/12/09 by Confused but excited.]

Only drawback i can think of, is crap getting into the injector and blocking it over time???

Other than that, Fuel is Fuel.

Would have thought that they would be self cleaning, at least as far as any muck coming down the inlet tract.

Mines upside down as well to keep things low under the bonnet, only issue has been a little rubbish collecting in the pressure regulator which I could easily blow out, would have stuffed the injectors so I recon its the better way now on the basis they are top side for easier servicing.

Mark, don't quite follow that, but there again not called 'Confused' for nothing.
Surely crap in the regulator would be caused buy a dodgy fuel filter. So the position of the injectors is irrelevant to that.
Or have I missed something?

regulator needs a vent, so dirt may lead to malfunction/failure?