Fuel pressure question? AFPR, with Walbro 255 pump, TBI 60 pound injectors.

It's really nice to know things like that, but you can have all the numbers and calculations you want, and you can usually get very close, provided you did all the math correctly, but when it comes to actually do the thing you calculated for, there is usually something that will change what the final number will need to be to act the way you want it or need it to.

Quote:

---

Originally Posted by EagleMark

What PSI do you run?

---

not to hijack his thread, but I am running 13psi on 4 61lb injectors. And I was thinking about running 4 4.3L injectors at a higher pressure in order to get the same flow but slow down the opening with the higher pressure.

Quote:

---

Originally Posted by 907 Chevy

As I understand it, injector offset times increase at lower voltages and vice versa, but offset times are also affected by fuel pressure... yes?
So if an injector takes say ~700 usec to open at 14V and 12psi fuel pressure...how much longer does that same injector take to open if you increase fuel pressure 50% or 100% or 150%? It seems that this value is very important to have correct as the PCM adds it to injector pulse width, even more so at idle.

Or am I completely over thinking this? Lol

I'm just trying to mitigate Murphy's law for when it comes time to tune this thing...

---

Yes,...there is not a formula for conversion, you can use the percentage of pressure increase as a starting value for the change, really it's just an idle/low rpm concern you may need to fine tune to your taste of afr vs smoothness.

Determining latency is not a service normally offered by injector servicing outfits.

Quote:

---

Originally Posted by Six_Shooter

It's really nice to know things like that, but you can have all the numbers and calculations you want, and you can usually get very close, provided you did all the math correctly, but when it comes to actually do the thing you calculated for, there is usually something that will change what the final number will need to be to act the way you want it or need it to.

---

I'm just trying to take some of the guesswork outta the equation this time around. I see what you're saying though.
I'm going to send the big block injectors off to WitchHunter and will post the latency numbers when I have them. I'm really curious how much they'll change with the increase in fuel pressure.