hello im looking to convert a intake to fuel injection. as doing some research i fould out that the injector should be about 1 inch up and center of the port. and 90 degrees from the ground but i can find anywhere how far the injector should be from the runner? if anyone has installed injection bungs or know where i can fine help. thanks

You're best off having it a bit up the bung, so you don't have as much of a chance to carbon the injector tip with any reversion. Just getting the bung out of the airstream, and getting the oring to seal usually does this itself.

so 1/4 inche from the runner ok or not? im a machinict by trade for 10 years so i can make it whatever i want just not sure where...lol

so 1/4 inche from the runner ok or not? im a machinict by trade for 10 years so i can make it whatever i want just not sure where...lol

just an FYI, Doug F is a Holley EFI engineer so you can run with his recommendations. We'll let him come back and give you a measurement. Most of mine have been 1 to 1.5" up the runner on the intake (as measured from the head).

Jody

just an FYI, Doug F is a Holley EFI engineer so you can run with his recommendations. We'll let him come back and give you a measurement. Most of mine have been 1 to 1.5" up the runner on the intake (as measured from the head).

Jody

Thanks Jody, but you usually just put it where it clears everything which is typically the constraints (rail to throttle body, etc).

The straighter you get the injector shooting towards the valve the better imo, but I always stick my own stuff perpendicular to the ground as that is what fits typically in a retrofitted manifold. Some people put them in perpendicular to the runner, but I can't say that would be a great idea, but they say it "works".

For super high RPM race engines they move the injector as far from the head as they can (for better atomization), but for what most people I think .5-1" from the head should be no big deal. Putting it too close to the plenum can cause another opening cylinder to start to draw from an opposing runner too possibly.

Just make sure the bung doesn't protrude into the runner, o-rings seal, everything clears, and try to get the injector perp. to the ground and I'd say you are in business.

And try to get it centered so you aren't spraying the walls of the port as you mention.