It's gonna happen more and more.... people are learning as they keep on playing these trucks.

 

The ECM's fuel map takes the rail volume and injector lines' length, ID and wall thickness into account to properly time fuel delivery to the piston bowls in view of the high pressure hydrodynamic pulsing phenomena reflected by the injector solenoid seats back towards the CP3... changing any of the rail or injector line parameters without specific code in the ECM to take advantage of them would have to surrender a certain amount of fuel map resolution accuracy.

 

I realy don't think any of those issues effect the common rail injection really. The pressure is always going to be in the lines and rail or rails. If this were the case, the 2-3 different injections would mess with pulses too much and also the different durations. I think the biggest problem would be startup. It seems like it might just crank a tad longer with 2 rails.

 

I ain't gonna use the stock ECM!!!!

 

True Erick, the mean pressure inside the rail is a relative constant, but the lines' internal pulse waves do affect the actual fuel timing... at least according to Bosch engineers:

"The lines expand and contract from the high-pressure fuel pulses generated during the injection process, which can delay the injection event - ECM compensates for that based on component specs
All high-pressure fuel lines between the rail and the injectors are of the same length and inside diameter to ensure equal-duration injection events, cylinder to cylinder.
Correct high-pressure fuel line usage and installation is critical to smooth engine operation."

 

Huh..... you'd think all of that would go out the window with multiple shots and constantly changing duration. Oh well, i didn't build the stuff, i just use it.

 

I can see the advantage of two rails simply from the added benefit of increased pressurized volume. The larger volume you have pressurized, the less it will drop when an injector fires. Plus the larger volume will help maintain pressure during very short duration high fuel demand that exceeds the max output of the CP3.

All that said, I bet it would be easier and cheaper to run two cp3's to cover necessary high demand volume and a double volume custom rail to lessen instantaneous pressure drop when a shower-head sized injector fires.

 

We have a few ideas on how we will use 2 rails when it becomes neccesary. It still has not been a issue. 2 stock cp3s will do at least 1100hp on fuel. We got 1090 at 3400 rpm and ripped another boot last month. I have some floor it pumps and bigger sticks to try when Eric gets tired of being on top. ( inside joke) One think for sure the drivers side of my engine is getting full, It is a job to do anything, I have to disassenble half of my wiring and plumbing to get to anything.
Merry Christmas and Happy Holidays to all.
Tim

 

Know how you feel.... seriously.... i have to take that back off to back in there.

Don't worry, we might have your answer.....

 

Very understandable. When the injector closes it sends a fluid "shockwave" of sorts back up the line. Makes sense they would want to try to use those waves to create a sort of harmonic balance when possible so they're not fighting it for the next event. The compensation for fuel line expansion makes sense as well. GBOOST or anyone attempting this kind of modification would need custom fuel maps for sure. Although some of these kinds of problems can be reduced a "little" bit. Like for instance he could have some real heavy duty fuel lines from rail to injector to help reduce the expansion effect. There's not much to be done about the back pulses though. Those will only get worse with higher rail pressure. One thing I can say for dual rails is that you will only have the pulsing from three injectors at any given time in each rail with will downplay/change the dynamics of the pulsing compensation overall.

Wild stuff, will be interesting to see how it plays out.

 

It was closer to 1000. ;-)

But it was in Boise...where all of the secrete diesel nuts live.

Um...two rails is easy and will be done soon. If I told more I will get shot.

 

I don't think there's any question of whether multiple fuel rails would work well, it's just been intriguing to me as to how aftermarket fueling code deals with (if at all) this hydrodynamic issue.

Even though high-pressure diesel injection flow generally exhibits incompressible behavior, I believe it is accurately modeled as a compressible fluid flow in order to generate much higher resolution of the fuel map.

That magnitude of process control has a much greater effect on efficiency than power... so it's a matter of quality instead of quantity.

 

But then again greater efficiency generally leads to more power. So I vote more efficiency the better.