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Originally Posted by carbuff
This touches on a subject that I need some education on, so anyone who can help, I would appreciate it!
My car currently has 39# injectors. As best I can tell, that rating is at 3 BAR, or 43.5PSI. I'm running my system at 58PSI (at least when it keeps up), so using the formula which I've found online, that converts to about 45# equivalent.
So your statement above, that I need 45# injectors, does that mean that I have them? Or are you saying that I need 45# injectors, rated at 3 BAR?
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That statement was you need 45# worth of fuel coming out of the injectors to be in the 80% duty cycle range. I know the whole nominal flow vs. actual flow thing can be a little confusing.
I think your injectors are spot on as most injectors are controllable up to 92-3%, so you do have some headroom available.
Quote:
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Originally Posted by carbuff
I attempted some math to determine if I am going static or not. What I came up with is this. At 6500 RPM, each revolution takes about 9.2 mS, and 2 revolutions takes 18.4 mS. I'll paste another screenshot from the Holley Datalogger below. It's telling me that the Injector Pulse width is running consistently in the range of 16.0 - 16.3mS. If that, and the above 18.4mS at 6500RPM is correct, that would be about 87% duty cycle at 6500rpm.
Also note in the new picture below that my actual AFR is hanging at almost exactly what my Target AFR is (after recovering from Acceleration Enrichment, caused by the rate-of-change in my TPS and MAP), which was set to 12.5:1 for this run. This is also the run which shows the rail fuel pressure dropped to 44PSI.
I find several things about this interesting. First, the Injector Pulse width stays almost constant throughout the RPM range. Maybe that makes sense if I'm requesting the same AFR at all times (which I believe I am, and the Target AFR line appears to show).
So... Do I need to increase my injector size? Based on AFR, they seem to be keeping up. And do I need to keep worrying about this, if my AFR is keeping on target?
I have decided to install one of Carl's Vaporworx PWM controllers, if for no other reason than to get a clean voltage to the pump that isn't limited by my ECU. I'll be curious to see what differences that makes on my readings!
Thanx!
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I think the speculation comes back to the fuel pump. I measured flow at the outlet of the pump. There will be some flow/pressure loss as fuel travels through the system, but shouldn't be too significant. The question I have is if the fuel pump assembly itself has any kind of internal restriction that may decrease the numbers I was measuring.
Are you using the complete LS3 fuel pump assembly, with the bucket and fuel pressure regulator?
Also, if you'd like, you can check out the fuel system calculators available on our site >
http://www.deatschwerks.com/resources/fuel-calculators/