Injector duty cycle question

[Mike T]

My 60's are running 85% @ WOT, How far can you safely push the DC ?

 

[Chuck Leeper]

I try to stop at 85% when doing size calculations....

 

[Mike T]

I try to stop at 85% when doing size calculations....

So I would guess that according to screen shot I'm almost out of injector?

 

[87-WE2]

Don't know the answer to your question for sure, so I'll keep my mouth shut on that, but I notice your a/f ratio is super fat at 7.3. (Unless you have no wbo2 hooked up and that's the default reading with no signal.)

 

[earlbrown]

narrow band 02's are .760. that's not 7.3 on the wideband

 

[Mike T]

No wideband yet (soon), but the tune seems to be very close according to the plugs. I want to see how far pump gas will go, I don't have alcohol and only rely on the injectors for fuel

 

[Chuck Leeper]

I assume you are running the fuel psi @ 43?? If so, that's about at the recommended max.
Or, you could run the injs at 4 bar, [58psi], recalculate the flow, and drop the duty cycle down.
AT 58psi, the inj flow would be 69.7#/hr.
As for how far you can go on pump gas.......I'd get the wb in there, asap.
Reading the plugs is fine...............As long as you aren't too late.

 

[Mike T]

Yes the WB is a must. I bumped the FP a little to 46 on the posted run. Later in that run, in 4th gear duty cycle was around 81% @ 21 psi.

 

[Slow91z]

Just speeking of duty cycle 80's aren't scary at all to me, I've run well into the 90's with no adverse effects.

Just be sure it's the injectors are the limiting factor and not the fuel system feeding them.

 

[87-WE2]

narrow band 02's are .760. that's not 7.3 on the wideband

I was pointing out that the AFR shows 7.36. That must be the default when there's no signal sine he gots no wbo2!!

 

[Mike T]

Just speeking of duty cycle 80's aren't scary at all to me, I've run well into the 90's with no adverse effects.

Just be sure it's the injectors are the limiting factor and not the fuel system feeding them.

I think the pump will be ok it's the new Aeromotive in tank. I do believe you about running in the over 90% range but I did find that most injector application formulas were in line with what chuck said 85%. The general thought seems to be that spray pattern get a little funky after 90%?? IDK that's why I'm asking for input. I thought that 60s would fuel a car into the 10 second range my car pulls really hard but it's not 10 seconds hard and to think the injectors do not have a lot left with what I think is a fairly close tune does not add up for me. Thank you for responding to my question.

 

[Slow91z]

I think there is more left than you think...5% on a big injector is a lot of fuel.

And since you have one of the 340 lph pumps I would not be scared to run the pressure higher either.

 

[Mike T]

The car in general may run better than I think, a club member with a 10.30 car drove mine because he wanted to see how the 70 spooled he said it felt like a 10.90 car to him. Seems like 12.0 to me.