Technical Injector Question

We all talk about 30#, 36# 42# etc. injectors. Is that a measure of how much fuel it can flow, in a given amount of time? If that is the case, is there a "standard" fuel used to rate the injectors? It would have to be a exact specific gravity to be a "standard" fuel. Why aren't injectors rated in lph, like fuel pumps are. Of course, lph would also have to specify duty cycle of the injector.

Curious 68COUGAR

Uhhh...They are measured in liters per hour I think. I believe they have a specific duty cycle and are supposed to be measured at 38psi (not sure on that one) BUT the duty cycle should not change AND they should be able to flow close to that.

Chris

the 30 or 42 lb injectors refers to 30lb/hr. Technically this is called a weight flow rate, or "W" from a fluid mechanics standpoint.

Weight flow rate is determined by multiplying the SG of the fluid by the volume flow rate "Q". In tern, the volume flow rate is the area of the piping multiplied by the velocity of flow.

Q=A*v
W=SG*Q

And for those of you who aren't engineers out there... SG stands for specific gravity... which is 1/density if i remember correctly.

I believe you are correct. Where did I put my carburator?

Chris

If you really want to get technical about it...you can figure out the volume flow rate.

If its a 42lb/hr injector then the "W" is 42lb/hr. The Specific weight of gas is 42.40 lb/ft^3. This yeilds .99ft^3/hr...or .000275 ft^3/s. This can be converted to gal/min which is .1234 gal/min. This results to .467 L/min or 28.04 L/hour

I hope my math is correct....