Fuel Injector placement...head vs intake manifold

m1ll10n · Feb 17, 2006

So are there any benefits between having an injector mounted inside the intake manifold vs inside the head? TIA

nismo · Feb 17, 2006

To put an injector into the head, you must have a direct-injection engine. This has shown to be the superior way of doing fuel injection, however this technology is in it's infancy and few products are even offered that can do this.

The Audi FSI engines are the only direct-injection gasoline motors I'm aware of by memory.

Eric

pkw · Feb 17, 2006

direct injection aside. what ever is easiest for you is the way to do it. either way will be fine for what you are doing....if i understand the question that is.

audifreakjim · Feb 17, 2006

No, some Audi heads have holes in the intake ports for the injectors. The MC being the most popular one. Heads like the NG have them in the manifold. I don't really see an advantage to either one, but the one cool thing about having them in the head is you can take off the IM without messing with any fuel lines.

Jonathan · Feb 19, 2006

I would guess that injectors in the IM would keep the injectors and fuel a little cooler and provide a couple more nanoseconds for atomization compared to being in the head's intake port.

quattrofrog · Feb 19, 2006

FSI is more than just the injector in the cyl head... it uses tumblers to generate precise turblence which aids in atomization of the fuel which can be injected in different pulse rates and the piston shape is designed iirc to aid in the atomization. FSI has a lean burn function which generates a combustion of varying A/F ratios at various points in the chamber.

I am not sure but mazda's DISI may be like our FSI to some degree.... really its using Diesel technology on a gasoline engine.

Krautwagen · Feb 19, 2006

Pretty much everbody will have a direct injection engine out this year. VAG is the only company with a turbo strapped to though (aside from deisels), AFAIK.

VW has also had head and intake manifold injector mount variations, both with CIS/E and digifant.

m1ll10n · Feb 19, 2006

FSI is cool, but I was just talking about the old audi heads. Jonathan brought up an interesting thought. It might not make a difference, but it deff wouldn't hurt to have the injectors in the IM.

Jonathan · Feb 25, 2006

m1ll10n said:
FSI is cool, but I was just talking about the old audi heads. Jonathan brought up an interesting thought. It might not make a difference, but it deff wouldn't hurt to have the injectors in the IM.

Definitely. You can't lose with the late-style heads. They have 40mm intake valves, too. :wink:

Jonathan · Feb 25, 2006

quattrofrog said:
.... really its using Diesel technology on a gasoline engine.

Heh--back to Bosch's original gasoline injection system--direct gasoline injection based on their diesel system, first used on MB's high-line cars and race cars. Before I get one of these :slap: let me say that I know FSI is a lot more sophisticated. Still, it's always cool to see the circle completed.

m1ll10n · Feb 25, 2006

Definitely. You can't lose with the late-style heads. They have 40mm intake valves, too. :wink:

Thats right...40mm turbo

Fuel Injector placement...head vs intake manifold

m1ll10n

nismo

pkw

audifreakjim

Jonathan

quattrofrog

Krautwagen

m1ll10n

Jonathan

Jonathan

m1ll10n

Top Contributors this Month

Recommended Communities