How does this Injector Flow Base table work?

[67SS509]

Can someone explain the basics on this type of table. It's not like any other years 2007 & up that I have seen in trucks.

[Taz]

Hello 67SS509,

Take a look at the thread attached below ...

http://forum.efilive.com/showthread....-Delta-MAP-Kpa...

From about post #18 onward it should help understanding the relationship between Delta Map kPa, MANVAC, BARO, and injector flow rate.

With Gen III controllers (LS1-B) the OEM parameters generally had small variations in injector flow (B4001) - year to year - platform to platform. That trend does not seem to be true for the Gen IV controllers (E38 / E67). Visually, Gen IV B4001 parameters may:

• slope in an upward curve from the lower left to the upper right
• look as they do in the tune you posted - a backward "Z" type pattern
• or as in some GMPP E-Rod tunes - an "N" canted forward at 45 degrees

In a NA (naturally aspirated) application as long as the B4001 Delta MAP kPa values are accurate in the 400 to 480 range of cells - with respect to the injectors being used in the specific application - the tune should work fine.


Regards,
Taz

[67SS509]

Thanks, this was a big help but I'm still a little short to fully understanding what I read. On this tune I posted what would the injector size be? I'm guessing 38lbs/hr based on what I just read. I have no idea what GM says for 2008 Chevy truck with a 5.3 but with "Flex Fuel" it probably could be that big.

[Taz]

Working in Delta MAP kPa does not come naturally to me either - I always have to double check my thinking. To convert from lbs/hr to g/s multiply by 0.1259. To convert from g/s to lb/hr divide by 0.1259. These conversions will yield an approximate result.

Your 38 lb/hr example above - loosely equates to 4.7842 g/s.

In the tune you posted:

• the 400 Delta MAP kPa value was 4.5861 - or loosely 36 lb/hr
• the 480 Delta MAP kPa value was 4.9520 - or loosely 39 lb/hr

When comparing injector flow rates, always remember to compare them at the same fuel pressure - the Gen III / IV operate at 58 PSI of fuel pressure - or "4 bar" (4 times standard barometric pressure).


Regards,
Taz