Thoughts of fast injection
Thoughts of fast injection
I have a Mercedes GD290 with a SsangYong OM662LA engine. It's the mechanical 2.9L IDI 5 cyl engine that Mercedes build for their heavy vehicles. SsangYong made a few adaptations to the cooling system and put on a small Garett turbo, as well as Bosch inline pump with ALDA.
My G is for traveling, thus any engine modification I make is for torque and increased range on fuel.
I need to get my pump to Dieselmeken anyways.
So while it's there I'm thinking about a slight modification.
Have the 5,5mm elements replaced with 7,5mm, and reducing the fuel on the 7,5mm elements to only 10% above stock settings.
Thereby take advantage of faster injection time, to burn the fuel more efficiently.
Am I correct in thinking that this will increase my torque when there is no boost, as well as make my turbo spool faster from low rpm?
The ALDA should keep the extra 10% max flow, from being aplied until the boost pressure is up, thus I should avoid any significant black smoke.
As this is a vehicle for long distance traveling, I'm not fond of black smoke or high EGT's.
For a racecar - that is a different matter.
But what about the drawback of faster injection?
Faster injection will mean faster pressure buildup in the cylinders. Obviously this will change how "harsh" the engine will sound. But my question is for you guys that made the jump to 7,5mm elements (or bigger).
Did your engine sound change significantly? Is it still worth using as a comfortable vehicle - day in and day out?
Do the requirements for fuel quality change? Will it tolerate 3rd. world country fuel?
What drawbacks is there to faster injection, other than the two I questioned?
If it was all good, the OEM would have fitted larger elements from the beginning. What am I missing?
Hoping that some of you experienced tuners out there, could enlighten me a bit on the subject.
Regards
Johnny
First and foremost, let me describe the situation:
I have a Mercedes GD290 with a SsangYong OM662LA engine. It's the mechanical 2.9L IDI 5 cyl engine that Mercedes build for their heavy vehicles. SsangYong made a few adaptations to the cooling system and put on a small Garett turbo, as well as Bosch inline pump with ALDA.
My G is for traveling, thus any engine modification I make is for torque and increased range on fuel.
I need to get my pump to Dieselmeken anyways.
So while it's there I'm thinking about a slight modification.
Have the 5,5mm elements replaced with 7,5mm, and reducing the fuel on the 7,5mm elements to only 10% above stock settings.
Thereby take advantage of faster injection time, to burn the fuel more efficiently.
Am I correct in thinking that this will increase my torque when there is no boost, as well as make my turbo spool faster from low rpm?
The ALDA should keep the extra 10% max flow, from being aplied until the boost pressure is up, thus I should avoid any significant black smoke.
As this is a vehicle for long distance traveling, I'm not fond of black smoke or high EGT's.
For a racecar - that is a different matter.
But what about the drawback of faster injection?
Faster injection will mean faster pressure buildup in the cylinders. Obviously this will change how "harsh" the engine will sound. But my question is for you guys that made the jump to 7,5mm elements (or bigger).
Did your engine sound change significantly? Is it still worth using as a comfortable vehicle - day in and day out?
Do the requirements for fuel quality change? Will it tolerate 3rd. world country fuel?
What drawbacks is there to faster injection, other than the two I questioned?
If it was all good, the OEM would have fitted larger elements from the beginning. What am I missing?
Hoping that some of you experienced tuners out there, could enlighten me a bit on the subject.
Regards
Johnny
NOx emissions should increase. Possibly an increase in upper cylinder wear, ring land wear on the piston. Is it the difference between 500k miles between rebuilds or 400k miles? Don't know. In my case, I don't care. I use the 603 engine because it's plentiful here, so I don't expect to ever pay for a rebuild.
I've wondered about how well a stock ALDA would work with larger elements. Since X amount of pressure change in the ALDA = Y amount of rack travel, once larger elements are installed, Y might be too much rack movement. Dieselmeken would be the guy to ask about this.
raysorenson
09-07-2014, 08:38 AM #2Johnny, my 7.5 pump has yet to be installed so I cannot give first hand experience. There are a couple of good threads here regarding injection duration and the benefits of shortening it, but discussion of the drawbacks are few and far between. Rose colored glasses, I suppose.
NOx emissions should increase. Possibly an increase in upper cylinder wear, ring land wear on the piston. Is it the difference between 500k miles between rebuilds or 400k miles? Don't know. In my case, I don't care. I use the 603 engine because it's plentiful here, so I don't expect to ever pay for a rebuild.
I've wondered about how well a stock ALDA would work with larger elements. Since X amount of pressure change in the ALDA = Y amount of rack travel, once larger elements are installed, Y might be too much rack movement. Dieselmeken would be the guy to ask about this.
For a guy like me, that has the interest in making my adventure vehicle perform at it's best, then STD has a lot of interesting reading.
There is a lot of videos floating about, of how well their large pump elements perform at full power... but no one shoots a video to show how the car is performing in ordinary driving.
Thanks. I know that these questions are a bit odd, given that this forum has it's focus on making the cars fast as hell. But there is a lot of really good knowledge that comes from going far beyond the factory specs.
For a guy like me, that has the interest in making my adventure vehicle perform at it's best, then STD has a lot of interesting reading.
There is a lot of videos floating about, of how well their large pump elements perform at full power... but no one shoots a video to show how the car is performing in ordinary driving.
Much of the same holds truth in petrol engines. A pro stock naturally aspirated drag racing engine with its compression ratio in the mid teens has a far lower brake specific fuel consumption than any economy street car engine.
The thermodynamics tell us that to make the most power out of each drop of fuel we need quick combustion to make the most of the expansion ratio available to us. Fuel that still hasn't burnt 25-30 degrees after top dead centre is pretty much wasted, makes no impressionable impact on mechanical power at the crankshaft, or rather, there's a curve of diminishing returns in terms of BSFC for every degree after the piston starts accelerating down the bore. Too quick of a combustion is a problem too as it presents a big shock on the mechanical components.
In the case of SSangYong, you will find that when the engine was converted from naturally aspirated to turbocharged, no considerable changes were done to the engine. Same fuel pump spec and everything so surely there was something sub-optimal about the spec in either application (N/A or turbo). In any case, the factory power rating of the turbocharged OM662 is barely any higher than the naturally aspirated version, only about 25% greater (going from 95hp to 120hp).
In general, you will also find that the car manufacturer is not only interested in maximum efficiency, they're juggling a lot of balls, the heaviest of which is emissions requirements (NOx and soot quantities).
Baldur Gislason
More often than not the quest for maximum power is also the quest for maximum fuel efficiency. The guys who make the absolute most power from diesel engines don't spew any considerable amount of black smoke because they're burning all of the fuel and turning it into horsepower. Black smoke is bad because it's fuel that did not contribute at all to making horsepower.
Much of the same holds truth in petrol engines. A pro stock naturally aspirated drag racing engine with its compression ratio in the mid teens has a far lower brake specific fuel consumption than any economy street car engine.
The thermodynamics tell us that to make the most power out of each drop of fuel we need quick combustion to make the most of the expansion ratio available to us. Fuel that still hasn't burnt 25-30 degrees after top dead centre is pretty much wasted, makes no impressionable impact on mechanical power at the crankshaft, or rather, there's a curve of diminishing returns in terms of BSFC for every degree after the piston starts accelerating down the bore. Too quick of a combustion is a problem too as it presents a big shock on the mechanical components.
In the case of SSangYong, you will find that when the engine was converted from naturally aspirated to turbocharged, no considerable changes were done to the engine. Same fuel pump spec and everything so surely there was something sub-optimal about the spec in either application (N/A or turbo). In any case, the factory power rating of the turbocharged OM662 is barely any higher than the naturally aspirated version, only about 25% greater (going from 95hp to 120hp).
In general, you will also find that the car manufacturer is not only interested in maximum efficiency, they're juggling a lot of balls, the heaviest of which is emissions requirements (NOx and soot quantities).
Baldur Gislason
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