Side feed port injector in TBI

[paulsco]

Hi,

Assuming the flow rate is adequate, is there any reason why a port injector cannot be used in a TBI application?
I am planing to convert my SU carbs by possibly using Subaru side feed fuel injectors mounted in an adapter in the carbs.

Also I have seen injectors with the flow rates advertised at say 3 bar; how would I work out the rate at 1 bar (not divide by 3 surely) and is it relevant when selecting sizes?

Thank you,
Paul

[Matt Cramer]

It's doable, but you will probably want to feed it 3 bar of pressure; port injectors normally don't work too well at the 15 psi of pressure some TBIs run at.

[fury fan]

I'm sure you've probably considered this, but keep in mind that *generally speaking* TBI injectors are higher lb/hr than a port injector, although there are injectors of either type at either end of the spectrum...

[paulsco]

Hi, Thanks for your responses.
I was thinking in terms of boost pressure when I was referring to 3bar, I hadn’t realised it was fuel line pressure that was being referred to.
I’m beginning to think that using port injectors is a non starter.
Can you tell me why TBI injectors require less fuel pressure than port injectors?

Thanks,
Paul

[fury fan]

You are running 45PSI of boost??? 3bar is generally the rated pressure for port injectors, so that's why us responders went down the path of fuel pressure ILO boost pressure.

Don't know why the pressures are different, just seems to be the standard of port vs TBI. If I were to guess, the barrel of the TBI injectors is typically larger and therefore the lower pressure over a larger area gives a similar force at the pintle for making a fuel spray? Or maybe I'm completely off-base...