Injector sizing question...

[Birddog]

Trying to get fuel worked out on the Dakota and just wanted to get some advise from the people I trust.
Basics: 2001 Dak R/T 5.9, Vortech V1 7# boost, home ported intake, 53mm tb, MP PCM, Hi6R with boost referenced timing retard and returnless fuel system.
Current setup is stock 19lb/hr injectors, stock pump (190lph) with two 42lb/hr "extra" injectors driven by a SS box..(Vortech says this is a solid setup:rolleyes: )
I run out of fuel at 5200rpm, pressure rolls down from 45#@35xx rpm to 25#@5200 and the rappitatappita begins.
SO... I got a deal on an FMU(thanks Heath), a killer deal on 24# injectors, and will be calling one of our vendors for a rail mounted 255 pump. I'm hoping this will help supply the fuel I need for the time being...

Any input on this?? Advice?? Warnings??

(I did do the math and going by factory HP of 245 and .50 BSFC, 24# injectors should have been stock.
If I use .65 BSFC and Vortech's claimed power levels (345hp/405tq) I come up with the need for 33lb/hr injectors. Obviously I can't do that with the OBD2 computer without doing a MS piggyback but it is the next step when the juice comes:D )

ANY ADVICE OR INFO IS WELCOME

[Frank]

Well .65BSFC is not realistic. You need to roll with 0.51 BFSC. Here is what I have come up with over the years....


Assume/Estimate

* .36 BSFC - Turbocharged Intercooled Diesel
* .38 BSFC - Turbocharged Non-Intercooled Diesel
* .42 BSFC - Race Engine or Older Diesel Engine *
* .47 BSFC - Hi Performance Engine *
* .51 BSFC - Modern Stock Engine or Light Modifications Engine *
* .55 BSFC - Supercharged / Turbocharged Non intercooled Engine

* - These include N/A Engines or Supercharged/Turbocharged Intercool

If you only want to use 8 injectors, you would need 43-45 lb/hr injectors of course as you said... you need MS for that. Honestly with the SS/42 setup you have, I would just roll with that and just change your pump for now. I honestly think that the 255 pump is a bad choice.... you will be running out of that if you expand beyond what you got now. You need more....


Just my 2 cents.

[Birddog]

I have to go back to the drawing board now and change the math... I 've discussed the fmu/2nd pump idea with JT too and he wasn't too fond of the idea either(overrunning the injectors).. But for now it will be better than the stock system.

I know I need more and juice will double that. First I have to go back and recalculate a few things, I always thought it was .50-.55 N/A and .60-.65 boosted... MS may be coming sooner than I thought;)
Now I need to size a pump since the heads, rockers, TB, WBO and cell will be here by June(some earlier than others..)
Learning as I go;) Thanks!:thumb:

[Birddog]

O.K I swapped in a 255 in tank, and Cobra injectors today. It's MUCH better and pressure stays within reason. Stock pump may have been going.
Still not right though, I'm going to use a second in line 255 and FMU temporarily. But when I do the heads and M1 intake vs. my home hogged unit I'll need a lot more so I think a return style system and the fuel cell may be the answer(sized up already!).. The stock pump cartrige won't handle another manhandling anyway..

Is there a pump size calculator or formula somewhere??

EDIT: I found out the dealer I gor it from performed the "death" flash on it... So now I have built in mega retard on top of the Crane retard.... I need a spare computer now.