The Diesel Garage banner

1 - 20 of 53 Posts

·
Senior Member
Joined
·
925 Posts
Discussion Starter #1
If, infact the new 6.4 will be a common rail, what do you members see as the advantage to the HEUI system of the past?
 

·
Registered
Joined
·
208 Posts
Well, the Dmax(Common-Rail) Makes 500HP with stock injection system and turbo...

I would think that the new 6.4 will have enought air to support that stock.
 

·
'Ol Builder guy
Joined
·
7,051 Posts
maxxis_mudder said:
If, infact the new 6.4 will be a common rail, what do you members see as the advantage to the HUEI system of the past?
Your question might be better put like this:

"Is there any disadvantage to the common rail fuel system in the new 6.4L compared to the HEUI system" LOL

You know, I think common rail has HEUI beat 6 ways to Sunday. Maybe the only way HEUI is better is that there's no lift pump failures. Give the new CR system a high quality, well placed pump and there's really no advantage to HEUI. :blah:

$5,000 to get both fuel & oil to match C/R fuel is eliminated, too. LOL

To me, it's a win-win-win with CR.
 

·
Registered
Joined
·
125 Posts
Dmax doesnt have a lift pump... it just relies on suction from the low pressure side of the CP3.
 

·
'Ol Builder guy
Joined
·
7,051 Posts
I didn't say it did. I just meant that if the 6.4 does have one, it's a potential achilles heel.
 

·
Senior Member
Joined
·
281 Posts
It sucks to think they design a high tech piece of equipment (HP Pump) and not design a reliable supply system. At least one that if it should fail, fuel will still flow without damaging the pump but a code would be set.

GM has gotten away without a lift pump because they use large supply lines and a well designed sealed supply line to the tank. Any airleaks cause hard or no-starts.

The Bosch CP3 has it's own integral geared lift pump so it's possible for any of the manufacturers to design a no-external lift pump system if they use the CP3.

I haven't figure out why Dodge decided to keep a lift pump when they went common rail. It's possible the location of the tanks and the plumbing restrictions are the reason.
 

·
Registered
Joined
·
2,838 Posts
well one advantage of the CR is that wont suck like the HEUI system:popcorn:
 

·
Registered
Joined
·
208 Posts
As many know there are advantages to running a lift pump in higher HP situations with the Dmax.

If you are concerned about perfomance, chances are you will be adding a lift-pump, or replacing the stock one anyway. I would say the lift pump is a moot point, as there are options out there that are far superior to the pumps that have been proned to fail in the past. They are flow-through as well, so if they did crap the bed you could still get home.
 

·
Registered
Joined
·
2,600 Posts
Major advantage to common rail is that you can have like 4 injection events. 2 pre injection, Injetion, and post injection. Lets see you try that reliably with heui. Not gonna happen. Probably the biggest advantage to common rail will be diagnosis. Gone will be the days of trying to figure out if you don't have fuel or don't have oil in there. And then if you didn't have oil, OK which head has the stupid leak.
 

·
Registered
Joined
·
208 Posts
maxxis_mudder said:
I believe a dual lift pump kit is available from TTS as well.
That's the setup I run. It works really well.
 

·
Senior Member
Joined
·
2,655 Posts
.....the only advantage to the HEUI that I could see would be a goof of sorts. If you 'forgot' the oil plug or poped the pan (lost your oil) the truck should not run.


.........It's now time for one of Hoots famous posts!

Play it again Sam........



Let's see it HOOT! :Thumbup:
 

·
Registered
Joined
·
125 Posts
BASICALLY (a very simple explanation)

is that HEUI (hydro electric unit injection) supplies fuel to injectors on a common rail at about 100 psi I think...then the fuel reaches the injectors where there, very high pressure oil compounds the fuel pressure to reach 25,000 PSI or so, where it is then injected into the cylinders.

HPCR (high press common rail) is where the 23,000 PSI of fuel is always stored on the fuel rail and is availble to all injectors at any given time. The injectors are basically simple electric solenoid valves that open and close when the ECM tells them to, and can inject high pressure fuel at anytime, because the high press fuel is always availble on the rail to each injector. The advantge I can see is infinite control over injection duration, how many injection events, and when they occur. IMO its the most versatile injection method, and really the simplest in theory (maybe not in operation) if you think about it.

--Ben
 

·
Senior Member
Joined
·
281 Posts
Here's a good explanation of the idiosyncrocies of the HEUI system.
thepowershop.com

The biggest drawback of the HUEI system is it's use of engine oil and the additional high pressure oil pump required to run the injectors. The Powerstroke draws unfiltered engine oil for use as hydraulic oil to run the injectors. They did a great job in the design of the system but the real world exposed many of it's limitations. You gotta keep your oil changed if you plan on having a good running engine past the 100,000 miles mark. Foaming of engine oil also effects injector performance.
In the HUEI system, there is no injector pump at all. Each injector is it's own single shot, high pressure intensifier pump injector. They did devise an ingenious method of adding a preinjection shot at the nozzle with a secondary port. The injectors are also effected by hydraulic pressure variations and pulses from adjacent injectors.



The HPCR system is inherently, mechanically simpler from a system point of view. Controlling the supplied 26,000 PSI fuel was and still is the achillies heal of this system. It's why they have injector failures at a higher than normal rate. Fuel under those pressures becomes hot and is abrasive, especially when impurites and dirt reside in it. With conventional injection systems, the fuel is under up to 21,000 psi only at the very tip of the injector nozzle. The HPCR has to deal with the high pressure fuel from the pump on down the rest of the system.
 

·
'Ol Builder guy
Joined
·
7,051 Posts
Don't the older (or maybe the new) HPCR systems have the potential for a catastrophic loss of fuel under the hood?

In other words, one of the HP fuel lines could blow, spewing fuel everywhere?

If my DT466 loses a fuel line, it would be a real mess, maybe even a fire.

That's about the only disadvantage I can think of.

I'm all for CR. It'll be nice when (if) IH really does this for Ford's new diesel.
 

·
Senior Member
Joined
·
281 Posts
Duke said:
Don't the older (or maybe the new) HPCR systems have the potential for a catastrophic loss of fuel under the hood?

In other words, one of the HP fuel lines could blow, spewing fuel everywhere?

If my DT466 loses a fuel line, it would be a real mess, maybe even a fire.

That's about the only disadvantage I can think of.

I'm all for CR. It'll be nice when (if) IH really does this for Ford's new diesel.
What was happening in early systems on the Duramax was leaks developing in the return lines under the valve covers. The return lines are very low pressure. This would literally fill the crankcase with fuel, spewing fuel/oil mix out of the breather and all over the underside of the truck. GM redesigned the heads so all of these lines are external. Dodge uses integral galleys cast in the head for returning fuel to the tank.

In this image of a 600 Cummins you see the fuel supply as a long tapered fitting. The return in the picture is the chrome banjo fitting/line on the end of the head.


High pressure lines don't blow. Never heard of it. They are fabricated out of very heavy wall tubing and overkill steel compression fittings.
This is a 2001 Duramax supply line. It's about 1/4 OD and 1/8" ID steel.
 

·
Super Moderator
Joined
·
4,247 Posts
maxxis_mudder said:
If, infact the new 6.4 will be a common rail, what do you members see as the advantage to the HEUI system of the past?
What is common rail?

- HEUI but using FUEL (and piezo-electric injectors) instead of HP oil to allow ultra high injection pressures.

CR:

Adv: One pump (fuel), BOSCH designed system (none better), has been in use EXTENSIVELY in Europe and USA for many years, some mechanical parts commanility with other brands.

DisAdv: If it leaks, fuel in oil and engine destroyed quickly, external leaks possible and at very high pressures, elevated fuel temperatures.

HEUI:

Adv: Very good operational understanding, current systems leak internally, VERY good pressure and timing control, common system with a good track record, easy to repair.

DisAdv: HPOP life tied to good service of basic engine, ECMs subject to foolish interventions, oil/fuel contaminations, external leaks (older units), CMP issues (older units).

HEUI is a VERY good system, it is well understood and the current models have numerous advantages over the previous engines. There are currently more HEUI engines (CAT, International, Ford) running than Common Rail.

CR was developed by the World's leader in EFI/DFI, the Robert J Bosch corporation, and they have a reputation for excellance (and expensive systems). It is widly accepted world-wide, and has very good support from the mfgr.

Which is "better"? In my opinion, it is a draw.
 

·
'Ol Builder guy
Joined
·
7,051 Posts
John_G said:
What is common rail?

- HEUI but using FUEL (and piezo-electric injectors) instead of HP oil to allow ultra high injection pressures.

CR:

Adv: One pump (fuel), BOSCH designed system (none better), has been in use EXTENSIVELY in Europe and USA for many years, some mechanical parts commanility with other brands.

DisAdv: If it leaks, fuel in oil and engine destroyed quickly, external leaks possible and at very high pressures, elevated fuel temperatures.
I have seen the result of an under hood fire from an external line leak at a truck yard I go to-not pretty. From what I heard, driver barely had time to get out of the cab.

Too rare to really get concerned over, though.
 

·
Ol Dirt Contractor
Joined
·
2,803 Posts
They refined the HEUI system on the 6.0 so that performance wise it works MUCH better. The Fuel Injector Control Module (FICM) is networked with the computer. Unlike our 7.3's the extra solenoid closes the spool valve faster for better burn control.

I wish we could adapt that to our 7.3's but it probably won't happen. Think we're stuck with the "slush box".. :shrug:
 
1 - 20 of 53 Posts
Top