effects of fueling characteristics of gov spring

[ellis93]

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So by changing springs I go from this

800rpm/idle 7cc
1500rpm wot 180cc
2000rpm wot 200cc
2200rpm wot 200cc
2500rpm wot 190cc
2600rpm wot 180cc
3000rpm wot 45cc
To getting 200cc of fuel to3000rpm where it then tapers off, right?

[RCCUMMINS89]

Wow, this all reads as being more complicated than it actually is.
Unsubscribing before my head explodes.

Mark.

I know,

I need help in explaining this.

[ellis93]

Wow, this all reads as being more complicated than it actually is.
Unsubscribing before my head explodes.

Mark.

I'm just trying to find out how this spring "can't" effect anything but rpm in our pumps and how it could "not" effect things like mileage

[ellis93]

Maybe my foot is the cause,I use the extra rpm,whatever doesn't matter. You all go take a smoke break and I'll go ram my head against the shop wall till it makes sense

[RCCUMMINS89]

It can affect fueling and rpm and mileage.

But your foot is in control of that. Just like deleting an afc will not affect sustained speed mileage. However, 99% of people see worse fuel economy because of their foot.

[m880cummins]

You mentioned a statement earlier about throwing more fuel at the same RPM. The only way you can throw more fuel at the same RPM is by injectors, the cam plate lift and the head size. Correct me if I am wrong but a pump is set to deliver the same amount of fuel at a given RPM no matter the size of the governor spring or the hill you are trying drive up.

Also, if you're truck is loaded down and you hit the pedal, you are technically delivering more fuel at the same RPM but engine speed will increase to meet the amount of fuel being given. That's where RCCUMMINS was right about the governor spring not affecting your fuel economy unless you accelerate.

Buy a junk pump, take it apart and then you can avoid banging your head against the wall. That won't help anything at this point.

[Tacoclaw]

He's saying that your pedal isn't hooked directly to the fueling device, there's a spring in between them. The spring is being pulled in separate directions by the two things it's attached to.

Now then, if you're going up a hill at 2400 and the engine starts to defuel, you'll have to give it a bit of throttle to maintain speed. With a heavier spring your pedal can stay in the same spot because it will take that more RPMs to actually pull the spring apart.

You'll still be using the same amount of fuel since the truck will be maintains the same speed, it will just require less pedal input.

[cmann250]

How's this for a simple explaination? You have to relearn how to drive your truck. The 3200 spring makes it accelerate differently. The majority of fuel is burnt up accelerating as opposed to maintaining speed, true? Until you get used to it, your mileage will not be the same. In fact it's almost always worse until you learn to make the truck behave like it did before.

I can't really say a modification has changed my fuel economy until I've ran 4 or 5 tanks through it. That being said, up until I installed the intercooler and HX35, my fuel economy was within 1 mpg of my best stock mpg. I think my best of 20.8 was a fluke, but I have backed it up with half a dozen or more 20+ mpg tanks at various levels of modification. Since the intercooler and HX35, I've had one 20+ mpg tank. That's not an apples to apples comparison at all because the truck idles a ton in this cold weather and that reading came from an interstate trip (as did all my other good numbers).

Fair?

[ellis93]

Called up a friend in Texas last night and he emailed me a couple of breakdowns and some test/calibration sheets. I got it figured now
I can say that it is simple and I was making it harder than it actually is.
Sad deal is....I can take apart and understand the inner workings of any automatic trans or manual but I couldn't wrap my head around what rc and the rest of you were saying stupid stupid stupid

RC if I pissed you off my apologies sir

[RCCUMMINS89]

NO, you didn't piss me off. It is my fault that I couldn't explain it in a correct way.

[Remps]

Gonna try and confuse everyone again... Iirc, a 3200 spring will make more power with a 14 mm pump than a 4200 spring.. Am i wrong? I thought this was because the heavier 4200 spring fueled harder down low, where a 14 mm is already putting out a crapton of fuel.. Just trying to get the facts perfectly straight here, obviously 14 mm pumps dont like that much rpm, but if going from a 4200 to a 3200 increases power, there must be a difference in fueling throughout the entire rpm range, no? I know i read at least one post where a member switched from a 3200 to a 4200 on a 12 mm pump and noticed a difference in low end fueling..

[RCCUMMINS89]

It has the same affect on fueling as adjusting your afc.

[D-dog357]

Please correct me it I'm wrong.
The governor spring in diesel engines achieve 2 things at the same time. It helps ensure a steady RPM at a given throttle setting under varying loads while preventing a run-away engine.

The governor sets the max RPM you can run the engine with or without a load and not run-away. As opposed to most gassers that will grenade at full throttle with no load.

It's a dynamic controller. You can very the load on the engine and the governor will change the fuel flow to maintain that RPM within the springs parameters. Just like when you go up a hill as the engine slows it will allow flow more fuel. If your against the governor it will try to keep you at that speed.

Since we rarely drive at full throttle it acts more like a dampener. The higher the RPM the more it affects fuel flow up to the point where it won't allow any more fuel/RPMs. The stronger the spring - the higher the RPMs it will allow the engine to rev to. Also the less peddle movement is needed to increase RPMs as the spring stretches less so it maintains more fuel over a longer amount of peddle travel.

If you replaced the spring with a rod, it would still try to limit the max RPMs the engine could turn but it would have to fight the peddle pressure directly. I suppose you could remove the whole assembly with some mods. You wouldn't need a spring and it would act more like a gasser - can you say runaway ?

For me it as clear as mud

[mhuppertz]

I can add this, the throttle is a lot more touchy (which I love) but it can sometimes make cruise control really twitchy and spastic (which I hate). I was actually thinking of putting an accumulator in the vacuum like to the cruise to calm it down a bit. Making sure all the linkage is tight also helps.
All that being said, there has not been one second that I have regretted springing my pump!

[oldestof11]

Please correct me it I'm wrong.
The governor spring in diesel engines achieve 2 things at the same time. It helps ensure a steady RPM at a given throttle setting under varying loads while preventing a run-away engine.

The governor sets the max RPM you can run the engine with or without a load and not run-away. As opposed to most gassers that will grenade at full throttle with no load.

It's a dynamic controller. You can very the load on the engine and the governor will change the fuel flow to maintain that RPM within the springs parameters. Just like when you go up a hill as the engine slows it will allow flow more fuel. If your against the governor it will try to keep you at that speed.

Since we rarely drive at full throttle it acts more like a dampener. The higher the RPM the more it affects fuel flow up to the point where it won't allow any more fuel/RPMs. The stronger the spring - the higher the RPMs it will allow the engine to rev to. Also the less peddle movement is needed to increase RPMs as the spring stretches less so it maintains more fuel over a longer amount of peddle travel.

If you replaced the spring with a rod, it would still try to limit the max RPMs the engine could turn but it would have to fight the peddle pressure directly. I suppose you could remove the whole assembly with some mods. You wouldn't need a spring and it would act more like a gasser - can you say runaway ?

For me it as clear as mud

Clear but no.

That would be a tractor/AG gov. You set the throttle by RPMs and it changes fueling to keep those RPMs. Static governor. Reactive: IE, go up a hill, loose RPMs, it adds more fuel.

Our trucks have a dynamic input governor. When you set the fueling with the gas pedal and varying loads change your RPMs. Proactive: You see a hill and adjust your fueling to keep the same speed (RPMs).

Until the governor weights overcome the spring tension, you basically have a rod stuck in there.