Port Injector Bung Mount Configuration

[flatbill]

I have been running a throttle body setup and now want to step up to full port injection. I will be using an aluminum log intake on my '56 Desoto motor. It is set up to use 6 small 2 barrell carbs. I will be using 4 with 2 of the carb flanges capped off. I want to install the injectors on the inner sides of the manifold halves. The manifold has pretty much vertical runners dumping right into the head ports. With the clearance that I have I will have to install the bungs at a pretty good angle to the flow in the runners, just barely angled towards the direction of air flow. Will this be a problem? Also, how far into the runner should the injector tip/bung protrude? I would think that I should cut off the excess of the end of the bung to match the inner wall of the runner. Should the injector tip protrude into the runner? Thanks for any advice you can give. Billk

[Matt Cramer]

I have been running a throttle body setup and now want to step up to full port injection. I will be using an aluminum log intake on my '56 Desoto motor. It is set up to use 6 small 2 barrell carbs. I will be using 4 with 2 of the carb flanges capped off. I want to install the injectors on the inner sides of the manifold halves. The manifold has pretty much vertical runners dumping right into the head ports. With the clearance that I have I will have to install the bungs at a pretty good angle to the flow in the runners, just barely angled towards the direction of air flow. Will this be a problem?

While not ideal, I've seen setups that had the injectors at a ninety degree angle to the airflow still work decently well. It may need a bit more acceleration enrichment and such but it'll still run fine.

Also, how far into the runner should the injector tip/bung protrude? I would think that I should cut off the excess of the end of the bung to match the inner wall of the runner. Should the injector tip protrude into the runner? Thanks for any advice you can give. Billk

Theoretically, it would be best to have the tip flush with the inner wall of the runner.

[flatbill]

Matt, Thanks again for your help. Billk

[fury fan]

Good info from Matt (as usual).

To minimize issues with shooting almost directly at the other wall of the manifold runner, I’ll recommend using a wide-pattern injector, probably a disc-style, that atomizes the fuel more. You don’t want a pencil-stream bouncing off the opposing wall.

Here's a good page with pics.
http://www.witchhunter.com/spraypattern1.php4