The way it was explained to me by Bill is that they don't give you 40HP, but rather the ability to be able to give you more fuel to support 40 additional HP. Really if the pop off pressure would be able to be raised then the fuel volume would be increased. On the mechanical pumps you turn them up to add more pressure thus adding more pressure to the injectors and in turn feed more volume of fuel to the chambers. On the other hand the DS4 pump does the same thing but with a re-flash. So with a slight increase of power Heath re-flashes the PCM and it raises the IP delivery pressure to add more fuel. If you wanted more fuel than that the Marine injectors would be needed as they have larger orifices. A GLE would typically use stock injectors while a GL4 would be able to use the extra volume of the marine injectors.
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Understanding Marine Injectors
- Thread starter North Maine
- Start date
Matt Bachand
Depends on the 6.5
Do you think this extra pressure makes the IP work any harder?
Sure but the IP is designed to be able to perform from a min to a max. I would think running the IP over 85-90 percent of it's operating range would be the point where it needs to be stopped. I think that is why the need for marine pumps with the larger plungers that can extend the threshold of the stock pumps volume capability. I think asking 100% from the pump leaves no room for error.
schiker
Well-Known Member
I posted this over on the page a good while back FYI.
Take a look at this...
http://public.ca.sandia.gov/ecn/orifice.php
Like was posted earlier a couple different ways I think its the timing thing.
Everything else being the same the larger the orifice the faster the penetration and larger flame front there is for a given injection event. No this is not IDI low pressure diesel but its the same injection with different orifice size and the larger orifice is slightly faster and bigger than the smaller orifice.
So I believe like others posted its all about the timing of the event. You can get factory made injectors for marine engines. Therefore in my mind they are ligitimately good injectors for thier purpose. Marine engines spend more of thier time at higher RPM, under heavier load, and with higher fuel rate than a typical truck engine. - Most big boats are like pulling a 5'er up a grade all the time.
The point being is with increased fuel rate and higher rpm the larger the injector nozzle does have a timing advantage. Do the injectors make the power no the increase in fuelrate (from the IP) and timing does. Will they make a difference in a stock on road truck engine - No probably not if they did why would GM not have gone with them. Then too with the marine engine cooling is not a problem nor fuel effeciency within reason, nor emissions, etc.
Injectors should be matched for the IP tune, engine setup, gearing, cooling, etc etc for optimal performance.
Take a look at this...
http://public.ca.sandia.gov/ecn/orifice.php
Like was posted earlier a couple different ways I think its the timing thing.
Everything else being the same the larger the orifice the faster the penetration and larger flame front there is for a given injection event. No this is not IDI low pressure diesel but its the same injection with different orifice size and the larger orifice is slightly faster and bigger than the smaller orifice.
So I believe like others posted its all about the timing of the event. You can get factory made injectors for marine engines. Therefore in my mind they are ligitimately good injectors for thier purpose. Marine engines spend more of thier time at higher RPM, under heavier load, and with higher fuel rate than a typical truck engine. - Most big boats are like pulling a 5'er up a grade all the time.
The point being is with increased fuel rate and higher rpm the larger the injector nozzle does have a timing advantage. Do the injectors make the power no the increase in fuelrate (from the IP) and timing does. Will they make a difference in a stock on road truck engine - No probably not if they did why would GM not have gone with them. Then too with the marine engine cooling is not a problem nor fuel effeciency within reason, nor emissions, etc.
Injectors should be matched for the IP tune, engine setup, gearing, cooling, etc etc for optimal performance.
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schiker
Well-Known Member
In case the link quits again.
The jist of it is this:
"The penetration rate decreases with decreasing orifice diameter (Naber SAE 960034). The momentum of the spray scales with nozzle area for sprays with the same injection pressure above ambient"
I mean its the combination of increased fuel rate and bigger orifice and this corresponding timing advantage that the marine injectors have when used in combination. Probably a decent advantage at higher steady RPM too.
You can click through some of the links on that page and see combustion chamber temperature also has a similar affect on timing. The hotter it is the faster the fuel ignites / burns.
The jist of it is this:
"The penetration rate decreases with decreasing orifice diameter (Naber SAE 960034). The momentum of the spray scales with nozzle area for sprays with the same injection pressure above ambient"
I mean its the combination of increased fuel rate and bigger orifice and this corresponding timing advantage that the marine injectors have when used in combination. Probably a decent advantage at higher steady RPM too.
You can click through some of the links on that page and see combustion chamber temperature also has a similar affect on timing. The hotter it is the faster the fuel ignites / burns.
schiker
Well-Known Member
Thinking about it further... why the line pressure might exceed cracking pressure is maybe this...
It is kind of sorta like an airplane holding its brakes and reving the engine for a short runway take off. The opening pressure of the injector is also kind of like a mechanical switch so the injection pump won't pee diesel into the cylinder with the wrong time (early) and/or without adequate pressure to produce a good spray pattern.
If the injectors did not have a "pop" pressure the IP would "slowly" build pressure with rotation and pee fuel into the cylinder early then build pressure and spray the middle and last bit. And the time would be all over the place.
In general (really always for positive displacement) pumps pump a flowrate and a nozzle makes the restriction and restriction makes the pressure. (With pumps there are relief valves/byapsses etc to control pressure but pumps don't necessarily pump a pressure its a combination of flow and restriction that makes pressure). Without a nozzle the IP would just pee fuel into the cylinder. With a smaller nozzle and more flowrate in a short burst puts higher line pressure so
MAYBE? marine injectors actually may be easier on an IP than you might think even though they POP a little higher. They just open later to insure adequate pressure/flow to produce the desired spray pattern with the bigger orifice in the nozzle.
It is kind of sorta like an airplane holding its brakes and reving the engine for a short runway take off. The opening pressure of the injector is also kind of like a mechanical switch so the injection pump won't pee diesel into the cylinder with the wrong time (early) and/or without adequate pressure to produce a good spray pattern.
If the injectors did not have a "pop" pressure the IP would "slowly" build pressure with rotation and pee fuel into the cylinder early then build pressure and spray the middle and last bit. And the time would be all over the place.
In general (really always for positive displacement) pumps pump a flowrate and a nozzle makes the restriction and restriction makes the pressure. (With pumps there are relief valves/byapsses etc to control pressure but pumps don't necessarily pump a pressure its a combination of flow and restriction that makes pressure). Without a nozzle the IP would just pee fuel into the cylinder. With a smaller nozzle and more flowrate in a short burst puts higher line pressure so
MAYBE? marine injectors actually may be easier on an IP than you might think even though they POP a little higher. They just open later to insure adequate pressure/flow to produce the desired spray pattern with the bigger orifice in the nozzle.
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buddy
Active Member
The air compressor analogy just didnt do it for you I guess 
chevyCowboy
I might be crazy but i ain't dumb
i saw a lot of discusion concerning the ds4 pump but what i want to know is when i turn my db2 pump up will marine Inj net me any better fuel milage, power, or complete fuel burn??? im pretty sure mine are getting worn not sure when they where changed last but i think the PO told me it was around 180k and its almost to 270k
chevyCowboy
I might be crazy but i ain't dumb
any one???
Goldsburg
Diesel Tinkerer
Even with a maxed-out DB2-4911 pump, I would say that marine injectors will not increase your fuel mileage over a set of new properly set "stock" injector/nozzles. In addition the extra money for marine nozzles would not be justified. Now if you were installing a DB2-5722 pump and cranking that to the max, I would say do it "most definitely"...
You could take the stock new nozzles and have the pressure all set to the top of the spec (or say 10% above) and go with just "high pops". It should be noted that the pop pressure will degrade over time, more at the early stages of life than later, as the springs work out their residual stresses. That is why I say go with 10% over high side of spec.
The "high pops" may net you some additional fuel mileage over stock nozzles, but your results may vary (void where prohibited by law; batteries not included; action figures sold separately; some assembly required; some settling may occur during shipping; pre-cooking weight referenced).
And patience, grasshopper, is a virtue...
Regards,
buddy
Active Member
I believe it would help you. Especially if you have injectors that pop at 1800-1900psi now, stock 6.5 turbos should be about 2100-2200 and the marine injectors are like 2200-2300psi. I verified that with Stanadyne.
It also may have a better spray pattern, never seen it though. But with higher pop pressure you get better atomization of the fuel for best mix with oxygen to get combustion, and in our case precombustion begins better for a more complete burn. They may also have a larger nozzle to allow more fuel to get injected, which would add some power.
When I installed them I also changed out an IP, so I cant draw any definitive conclusion, but I got rid of all black smoke at that point, and I had a ton. And I had more power and economy, noticeable but not a whole lot. Later I got the power tune for the PCM, so I dont know how much they help over stock when pushing 40% more fuel.
If you need new injectors theres no reason not to get them if similarly priced.
It also may have a better spray pattern, never seen it though. But with higher pop pressure you get better atomization of the fuel for best mix with oxygen to get combustion, and in our case precombustion begins better for a more complete burn. They may also have a larger nozzle to allow more fuel to get injected, which would add some power.
When I installed them I also changed out an IP, so I cant draw any definitive conclusion, but I got rid of all black smoke at that point, and I had a ton. And I had more power and economy, noticeable but not a whole lot. Later I got the power tune for the PCM, so I dont know how much they help over stock when pushing 40% more fuel.
If you need new injectors theres no reason not to get them if similarly priced.
Goldsburg
Diesel Tinkerer
You believe that WHAT would help?
The larger orifice of the marine injector will provide less atomization (in and of itself) than a stock nozzle, unless you provide much more fuel than the stock to the marine nozzle (IE a marine DB2-5722 pump output). That is why I am telling him to increase the pop pressure of stock nozzles for best fuel economy. The pop pressure is independent of the type of nozzle!
The marine nozzle was not designed for fuel economy!!! Regardless of what people think!!! It was designed to control the opening and PEAK injection pressures of the output of a Marine Injection pump, resulting in acceptable life for that injection system.
Regards,
Missy Good Wench
Wild Blonde from Cloud Mt
NEWS FLASH FROM THE SHOP OF MISSY GOOD WENCH 
The terms applied to these injectors is in many cases OVERUSED and MISLEADING
A Marine injector is designed to run with a higher flow rate and is assembled accordingly with a nozzle size and pintle to do this.
(USE with a DB4 or HO DB2 pump to make big power where you can keep it cool with a whole lake full of water)
Selling 40 more HP from a set of injectors is plain criminal.
Now many folks will buy these new injectors and install in the 6.5 that has 100K plus on the old ones and WOW the difference is unreal.
The truck now starts better and runs soooooooooooooo good.
Was this the result of the MARINE injectors, NO not really, a fresh set of stock injectors would have done the same thing.
Unless you are using a very high flow pump or a chip/reflash that can deliver a metric BUTTLOAD of fuel the marine injectors are not gonna do squat.
The key is to have a set of injectors that are built properly and that have the proper POP pressure and spray pattern.
I have any and all 6.5 injectors set at 2000 PSI POP maybe a tad more and specify that they all be as close to each other as is possible in POP pressure.
This nets a very smooth running engine that will see cyl to cyl timing as close as possible.
HIGH POP injectors will make starts a little better in cold weather but depending on how HIGH they are set can put extra stress on the IP that you simply dont need.
NOT TO MENTION THAT THE LITTLE CREATURE WILL RATTLE LIKE HELL
As the pop pressure exceeds stock specs the size of the rocks rattling around increases by the square of the increase
well sort of. ):h
The bottom line here is this, most people dont understand how this whole system works and they are easy prey for salesmen.
Simply put, use a good set of injectors that are assembled from top quality parts by a technician who knows what he/she is doing and set to the top of the stock POP specs and set to equal pressures over the entire set.
Choose your favorite provider of Chips/flashes (If you have a DS pump)
and the little six and a half will do all its gonna do.
Of course the proper choice of turbo and exhaust systems will help the program too.
An aftercooler is a good thing for those trying to shove every last drop of fuel into the little beast.
The DS series pump will deliver (on a good day with any luck) about 92mm3 into the engine (with the best chip/flash)
The best place for the tricked out tweeky injectors is on the shelf.
Save your $$$$ for what you need to make power.
I have built many six and a half's and never needed a set of trick injectors to get the thing to build more than enough power to break something.
If you can get black smoke out the back then you don't need anything other than MORE AIR.
Back when I rebuilt my 94 Burb, I had the injector/pump shop set the injectors at 2200 PSI.
On a cold morning this sucker will make an old Powerstroke blush.
On DaHooooley I backed the pressure down to 2000 PSI and the results are a far more pleasant running engine without the nasty rattle.
Just some observations from long term experience with these creatures.
Missy.
The terms applied to these injectors is in many cases OVERUSED and MISLEADING
A Marine injector is designed to run with a higher flow rate and is assembled accordingly with a nozzle size and pintle to do this.
(USE with a DB4 or HO DB2 pump to make big power where you can keep it cool with a whole lake full of water)
Selling 40 more HP from a set of injectors is plain criminal.
Now many folks will buy these new injectors and install in the 6.5 that has 100K plus on the old ones and WOW the difference is unreal.
The truck now starts better and runs soooooooooooooo good.
Was this the result of the MARINE injectors, NO not really, a fresh set of stock injectors would have done the same thing.
Unless you are using a very high flow pump or a chip/reflash that can deliver a metric BUTTLOAD of fuel the marine injectors are not gonna do squat.
The key is to have a set of injectors that are built properly and that have the proper POP pressure and spray pattern.
I have any and all 6.5 injectors set at 2000 PSI POP maybe a tad more and specify that they all be as close to each other as is possible in POP pressure.
This nets a very smooth running engine that will see cyl to cyl timing as close as possible.
HIGH POP injectors will make starts a little better in cold weather but depending on how HIGH they are set can put extra stress on the IP that you simply dont need.
NOT TO MENTION THAT THE LITTLE CREATURE WILL RATTLE LIKE HELL
As the pop pressure exceeds stock specs the size of the rocks rattling around increases by the square of the increase
well sort of. ):hThe bottom line here is this, most people dont understand how this whole system works and they are easy prey for salesmen.
Simply put, use a good set of injectors that are assembled from top quality parts by a technician who knows what he/she is doing and set to the top of the stock POP specs and set to equal pressures over the entire set.
Choose your favorite provider of Chips/flashes (If you have a DS pump)
and the little six and a half will do all its gonna do.
Of course the proper choice of turbo and exhaust systems will help the program too.
An aftercooler is a good thing for those trying to shove every last drop of fuel into the little beast.
The DS series pump will deliver (on a good day with any luck) about 92mm3 into the engine (with the best chip/flash)
The best place for the tricked out tweeky injectors is on the shelf.
Save your $$$$ for what you need to make power.
I have built many six and a half's and never needed a set of trick injectors to get the thing to build more than enough power to break something.
If you can get black smoke out the back then you don't need anything other than MORE AIR.
Back when I rebuilt my 94 Burb, I had the injector/pump shop set the injectors at 2200 PSI.
On a cold morning this sucker will make an old Powerstroke blush.
On DaHooooley I backed the pressure down to 2000 PSI and the results are a far more pleasant running engine without the nasty rattle.
Just some observations from long term experience with these creatures.
Missy.
buddy
Active Member
He asked about economy and power. a larger nozzle may provide more fuel, and may negate the atomization benefit from higher pressure, but it will help power. And although you may get black smoke intially, the turbo needs the extra fuel to make more boost. A larger nozzle will also reduce pressure the IP must produce when pushing 40% more fuel output.
I am running way more power than before, flying everywhere, and have noticed no loss in MPG. Little more rattle, sure, but also increased from the timing being advanced as much as it can go. I also have no issues cooling the truck with stock low flow water pump, even running a 1100 mile trip through the desert and up mountains in the same day with the A/C on the whole time, never saw even 200 degrees. I was pushing 17+ psi boost with the GM4, and I didnt have a bit of black smoke even on hard acecleration from a stop.
Down side, a little more rattle, up side some more performance and no loss in economy and lower line pressure from the IP.
My economy went up after the injectors, but also new IP, so could have been the IP. I had a Hypertech chip at that time which only increase fuel output, and not by much on the L56 tune.
I dont think its worth it unless youre getting an L65 power tune with 80+ mm3 fuel output.
I am running way more power than before, flying everywhere, and have noticed no loss in MPG. Little more rattle, sure, but also increased from the timing being advanced as much as it can go. I also have no issues cooling the truck with stock low flow water pump, even running a 1100 mile trip through the desert and up mountains in the same day with the A/C on the whole time, never saw even 200 degrees. I was pushing 17+ psi boost with the GM4, and I didnt have a bit of black smoke even on hard acecleration from a stop.
Down side, a little more rattle, up side some more performance and no loss in economy and lower line pressure from the IP.
My economy went up after the injectors, but also new IP, so could have been the IP. I had a Hypertech chip at that time which only increase fuel output, and not by much on the L56 tune.
I dont think its worth it unless youre getting an L65 power tune with 80+ mm3 fuel output.
Big T
Well-Known Member
I understand all your points made about marine diesels, as I own and maintain a diesel powered (Volvo) fishing boat. But how does this (i.e. "most big boats are like pulling a 5'er up a grade all the time") jibe with Bill Heath's advice not to use marine injectors if you're frequently pulling heavy loads up grades?
Green Machine
Truck Don't Smoke... Well...
That could have also been just because you had NEW injectors installed too. IP probably did help though.
As it has been stated before... Marine injectors were designed for marine applications. WOT for long periods of time on a nice body of water.
On my build I'm not sure which injectors I'm going to run. I'm leaning more towards marines only because I can get them for a decent price, not sure yet though.
schiker
Well-Known Member
Because a boat has nearly unlimited cooling capacity whereas a truck is marginal when chipped. Then too the RPM are generally higher under heavy fuelling in a boat. Load is more linear with rpm in a boat. Boat the faster you go the more load. Pulling a big load with the truck the load is always there independant of rpm etc. Yes, it gets heavy the faster you go by exponent of 3 but from 0-30 its probably pretty close to same big difference in a boat. I can push a big boat at the dock myself can't push a trailer.
Several nuances to this the water pump is spinning faster is the biggie which helps turbulate the water in the head. I suspect there are other things that help too.
Hold a truck to under 2000 rpm and load the fuel its going to be harder to keep the heads evenly cool (8 locallized hot spots).
schiker
Well-Known Member
Check that I am not not saying in a marine application the load is linear with speed. Its not but realitive to a truck 0-70 mph its more linear or a smoother steady increasing "sloped" curve. Comparing boat still to top speed.
Try and push a boat faster at top speed takes a whole lot more HP (or reduce drag). Same with a truck but in a truck top speed is considered 120MPH plus. So for the sake of discussion load equals speed/drag for a boat not for a truck. A truck's air drag is a factor but the weight is a bigger factor on grade than just speed for anything under what 40-50 mph??? So it can be a mixmatch of rpm and power requirement for a truck vs boat is what I am trying to say. And this figures in when real heavy load/fuel is applied vs rpm.
Try and push a boat faster at top speed takes a whole lot more HP (or reduce drag). Same with a truck but in a truck top speed is considered 120MPH plus. So for the sake of discussion load equals speed/drag for a boat not for a truck. A truck's air drag is a factor but the weight is a bigger factor on grade than just speed for anything under what 40-50 mph??? So it can be a mixmatch of rpm and power requirement for a truck vs boat is what I am trying to say. And this figures in when real heavy load/fuel is applied vs rpm.
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Big T
Well-Known Member
Well aware of the hp required to push a boat, but torque is equally important. Once a boat gets up on a plane, I'd think the linear slope of friction to overcome starts to flatten. Ahh, but I'm not a naval engineer, but a good friend is and he's now working for MTU/Detroit Diesel in their commercial engine sales division (think 2000 hp engines). Be an interesting question to ask.
What I do know is that the cooling systems on marine diesels are finely tune. Lose performance in any part of it and you'll see the heat rise rapidly. The endless heat sink posed by the ocean is not a cure all for an unhealthy cooling system.
schiker
Well-Known Member
Absolutely, drag and power requirement for speed is directly related to water displacement. On "plane" power required drops trim an outdrive up and drag drops some too as it will lift a hull slightly.
Then as you know there are all sorts of different things that have influence.
Even if you get most all the hull out of the water (but with enough for control) the drive still has drag. Typically the big drives of a diesel boat have a lot of drag vs speedy surface piecing counter rotation screws etc. I think my points are still valid considering the type of boats a typical 6.5 pushes.
The big gain you have with ocean or lake is the incoming water will be cool but true won't make up for a poor system. Circulation, flowrate, turbulence design etc is still very important...... Can't type rest of thought right now family calls.
Then as you know there are all sorts of different things that have influence.
Even if you get most all the hull out of the water (but with enough for control) the drive still has drag. Typically the big drives of a diesel boat have a lot of drag vs speedy surface piecing counter rotation screws etc. I think my points are still valid considering the type of boats a typical 6.5 pushes.
The big gain you have with ocean or lake is the incoming water will be cool but true won't make up for a poor system. Circulation, flowrate, turbulence design etc is still very important...... Can't type rest of thought right now family calls.