Technical: Why increase fuel rail pressure?

[rbattelle]

No, wait... I meant :-laf

 

[BillGotthelf]

I was all set to argue with you but then I read post #2,3 & 4. Man you need to seek professional help. Better yet take the last 3 issues of the TDR and reread them.

 

[JHardwick]

Okay Ryan ... ... I knew you were ate up with this Cummins, but after just seeing the on-board diagnostics and single sided conversation ... ... ... ... ... ... ... ... . I'm convinced that it's time to seek professional help



I’m sure this is waaay off base, but here goes.



On our sprints motors set’s a constant flow injection system, 60’s technology and not streetable. This system rains alcohol at the valve constantly if the motor is running. The way you tune the system is by adjusting the bypass of alcohol back to the tank in a series of bypasses reliant on engine RPM and pump pressure. There is a main, secondary and high speed bypass all with different weight springs and “pills” or orifices. These are a basic poppit valve.



Now to my point ……. these 410 inch motors have only slightly increased from 800 to 800 and maybe 30 HP in the last few years, before that power was being found by leaps and bounds due the new found ability to CNC machine the ports and combustion chambers. Also leading the way were the CNC ground camshafts and the ability to achieve greater valve speeds. Why did it stall? It would appear that peak flow efficiency (remember this is a big air pump) had been found, but the fuel pump industry was lagging and relying on old flow numbers. They couldn't produce a pump that could handle the flow numbers of these head/cam combinations.



The recent 30 or 40 horse was found in a stronger, higher flowing pump. System pressures have almost doubled!



In the port lays a nozzle or orifice (injector). The more pressure you throw at the same sized hole, the greater atomization you achieve on the other side. More efficient burn. And hence a leaner burn ……. more power until melt down. So, you have to increase pressure even more to achieve the same efficiency of burn and still be rich enough to not melt a piston. In order for that highly atomized mixture to become rich, it has to have a higher volume of fuel ..... through the same sized nozzle, or orifice.



Okay, I’ve had way too many beers, lol, yes you can increase volume by increasing pressures …………… in laymen’s terms

 

[Torque King Jay]

LMAO

Ryan... we're getting worried You haven't answered yourself in quite a while :-{}



With confidence and reasoning like that you could run for public office... :-laf

 

[rbattelle]

I think this post is one of those that will come back to haunt me later in life. :-{}



-Ryan