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Discussion Starter · #1 ·
Everybody always talks about turning up the power on their motor. However I had an idea (maybe its been discussed before not sure). Would it be possible to "de-tune" the engine to produce less power and possibly increase mileage when not towing and just crusing around town empty.

My questions are...

1. Is this possible / feasable?
2. Can you run a diesel motor too "Lean" like a gas motor and burn up the valves?
3. Can you compensate by using less fuel and more boost to achieve this or does it go hand and hand (more boost = more fuel)?

I am not sure what effects would be on the motor if the air / fuel mixture was modified moderatly to significatly.

I have heard of tuner cars that are running low 7:1 compression ratios and running high amounts of boost and getting lots of power out of a motor when it was needed type deal. Yet still streetable / efficient. (not saying I want to change the internals of the diesel motor!).
 

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On gassers you use low compression to control heat. You can cool boost but you can’t cool static mechanical compression. It has nothing to do with mileage. You end up with a gutless engine off boost that may be less efficent than a normal compression motor.
 

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Yea, the engine detuner is your right foot!!:D But seriously, the higher the output of programmer I use the better the fuel economy is assuming I drive sanely :driver:
 

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If I understand how railroads and trucking companies do it, basically it takes the basic equation of more fuel = more power. On a diesel, the more fuel you pump into more air, the more power you generate (within reason). I'm sure injection timing is factored in there as well, but in general, the less fuel you put in, the less power, and less fuel is used overall. Now, if you need to stomp on it more, you will use more fuel than if you hadn't done the 'detune".
 

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The best MPG in my van is 21 mpg , average 17 , 16 in the winter , I don't think the detune would help.
 

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Everybody always talks about turning up the power on their motor. However I had an idea (maybe its been discussed before not sure). Would it be possible to "de-tune" the engine to produce less power and possibly increase mileage when not towing and just crusing around town empty.

My questions are...

1. Is this possible / feasable?
2. Can you run a diesel motor too "Lean" like a gas motor and burn up the valves?
3. Can you compensate by using less fuel and more boost to achieve this or does it go hand and hand (more boost = more fuel)?

I am not sure what effects would be on the motor if the air / fuel mixture was modified moderatly to significatly.

I have heard of tuner cars that are running low 7:1 compression ratios and running high amounts of boost and getting lots of power out of a motor when it was needed type deal. Yet still streetable / efficient. (not saying I want to change the internals of the diesel motor!).
1. it is possible, but not feasable
2. no. you cant run a diesel lean, you have it backwards. More fuel= more boost. A gas motor runs hot on the least amount of fuel with max amount of air. A diesel always has max air , then you add fuel. The more fuel you put in the cylinder the more power and heat it makes. Use the least amount of fuel, like taking off from stop and drive 55 mph and you will see an improvement in economy
 

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drive 55 mph and you will see an improvement in economy
Also make certain you are in 6th gear at highway speed, and try and not let vehicle downshift out of overdrive too often. Use your cruise control if you have. Accelerate with a light foot, and watch your rpm's.

Keep oil clean & fresh, use good lubricity additive, and keep tires at least 65psi cold, or more if your carrying load.
 

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booo!!! no fun......
 

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Our Mechs at work thought this was a great idea and detuned all our Cat powered line trucks. It failed. You had to start off in lower gears, which ment more shifting, thus more times the engine revs up. Plus the engine is run harder because we are trying to make it do the job it used to do in higher gears riding the governor in the lower gears. If the engine spins less RPM the less fuel it will burn no matter how much power it makes.
 

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There is a de-tuner on the market. It is made by PPE. I'm not sure if it works on the LBZ and up engines though. It was designed for use by mining companies and others that have to deal with confined areas with low oxygen levels.
 

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The '06 LLY is detuned, wretched mileage here.
 

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Very high tune, VERRY light right foot, no cruise = 26-30 MPG.
 

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These truck do not have EPA MPG ratings, so why are you concerned with MPG? Its a HD Pickup.
 

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Our Mechs at work thought this was a great idea and detuned all our Cat powered line trucks. It failed. You had to start off in lower gears, which ment more shifting, thus more times the engine revs up. Plus the engine is run harder because we are trying to make it do the job it used to do in higher gears riding the governor in the lower gears. If the engine spins less RPM the less fuel it will burn no matter how much power it makes.
That is my half understanding also. You're used to driving with power level x. Detune it to x-1 and you have to drive it even harder just to keep up with traffic.
 

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These truck do not have EPA MPG ratings, so why are you concerned with MPG? Its a HD Pickup.
Because we have to buy fuel.
 

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It's simple it is called "law of physics". As mentioned before these are HD trucks which are roughly 7000+ lb trucks. I am getting 16-20 which I think is pretty good for a 7000+ lb. Believe me I am also concerned every time I fill up and do hope for 20+. The only way I have truly figured out how to bypass the fuel stations more is to buy a Toyota Prius or a VW Jetta diesel that gets 50+ mpg's...but I am not about to do that!
 

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Discussion Starter · #20 ·
So if that is the case (which makes sense). If the vehicle is detuned the engine would have to spin faster to compensate for the loss of power (think of a 4 banger going up a mountain).

Are you saying that a high tune (IE more power) would actaully increase mileage due to it being able to run at a lower RPM. I know that the laws of physics states that the slower the RPM on a motor the less fuel it consumes ( higher rpm = more fuel / more air).

so, if we could increase the power at lower RPMs and use a light foot, theoretically it should be able to produce better mileage. But at what point would it be a diminishing return? (IE: engine longevity, etc)
 
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