Well gang... I've been playing with theories and ideas for long enough now its time to put them into a design and see if it actually works. We all know the 24V's seem to take a good tumble in MPG's as the winter sets in well ISX proved that with the 12V engines with static timing that MPG's don't change. Well if you look at it the only thing that could be tossing this out the window is the IAT sensor on the 24V is changing the VP44 performance. Most know that colder air produces better HP/TQ because colder air is denser and requires more fuel to keep balanced. Well if you reverse this and warm the air (in theory) the VP44 should retune and burn according to the manifold temp. So what I've done tonight is fished through my resistor pile and found 3 I'm going to use for test candidates. Orange - White - Red - Gold = 3.9K Ohm = 116*F IATRed - Violet - Red - Gold = 2.7K ohm = 132*F IATRed - Black - Red - Gold = 2.0K ohm = 148*F IAT So now tomorrow I'm going to pull 3 test runs on the same piece of highway... Seeing if the highier the IAT temp increases the MPG or not... I'll can give you something to think about... Grid heaters are NOT controlled directly by the IAT... With the 2.7K Ohm resistor in place before even starting the grid heater still where hitting as normal. So there is more to the grid heater that the IAT temps... ... On the cutting edge again...

When swapped from auto to manual in my 12v, i saw about a 4-5mpg increase in city, But maybe 1-2 on highway. As for the cr differences, aren't we talking TENTHS difference? That's minimal. A more measurable differenc would be realized with .5-1.0 or more in seperation. I've kicked around the whole propane injection thing for a couple yes now, just haven't pulled the trigger yet.

ppump conversion MPG thread started at CF http://www.cumminsforum.com/forum/98-5-02-24v-p-pump-conversion/352384-ppump-mpg-after-conversion.html#post3684995 will keep u posted:thumb1:

I think going from a 14 to the 12cm is going at it the wrong way. Your EGT goes up because it is more restricted so it's choking the engine (not very efficient). If your EGT went down then it had the flow you needed, rather than up because of it being too big of turbo (not spooling). I don't know how you did for boost differences but I am guessing the 12 built more, which means more heat on the intake side which in turn would mean higher EGTs which is not the way it is supposed to work. You need cold intake temps and hot EGT's. Though I guess it wouldn't make a difference since the compressor is the same, but choking the engine up wouldn't help matters I wouldn't think. Did your mileage go up or down when you changed them?

I should have that calculator done by the end of the day. It's pretty interesting. Think I will make a chart showing how compression ratios effect everything.

When I went from a 12 to a 14 turbo housing I saw EGTs drop around 100*, Didn't pay attention to the MPG so I can't say what happened there. As far as boost not much change at all. My IAT according to the SG II don't get above 95* between October and April. That's why I'm interested in Mikes IAT fooler. I will have to take the truck out and see what the IAT is reporting on the SG II when I build high boost. With the electrinics modifying the fuel delivery depending on IAT temps a CAI wouldn't seem to have a positive effect on economy unless the truck is fooled into thinking a cold air charge is above 110* or so. In the past with the truck stock except for the triple lock converter, HP valve body, and the PM3 I have had mileage numbers (hand calculated) above 20 and as high as 22.5 with an empty truck and a toneau cover on the bed at 65-70 mph. That was with the speedometer corrected for the 235/85/16E tires using a gps and the superlift calibration box. I need to add that the superlift box corrects the signal before it gets to the truck electronics so the speed as well as the transmission shift points are corrected. It was after I went to larger injectors, 4" exhaust, and BHAF that I found my mileage went to pot. With the +80 inj set to 300 bar the mileage was 14.2 - 14.5 when I changed the +80 to RV275 (don't know what they are set at) I get 14.8 to 15.2 all at 55mph straight and level on cruse control on the same stretch of highway empty. When I push up the speed to 65 - 70 the mpg drops several MPG. I don't know if the poor mileage is the result of the mods I've made in attempts to make the truck better (and except for the stalling when cold and poor mileage it runs great) or if there is a problem with the VP44. If I need to get a new VP I will make sure that the internals are all replaced and new including the delivery head before I buy it. Jim

Man this is good stuff! What were the stock injectors? You said the 300bars made everything go downhill, were the stock ones 280? I think mine are 260.

I really just need a 5.9 generator. There are so many factors to this while driving that it's incredible. Last year I went back home from NY at 80mph and got 24mpg, figure that one out.. Generally flat roads are about as good as we can all get for comparing with each other but there are still variables. It was generally flat from here to Denver but it is about 4000ft higher than here, I never noticed it. Got the same mileage there and back. The ppump thing with everyone getting less with the 24V block has me wondering though. That means it isn't the weight of the truck or anything, its something on that block, and it very well might just be compression but that doesn't explain why the HO guys don't see high mpg's either. I have a few other ideas I'm trying to find formulas on and such..

Just for reference for everyone, this is how I accelerate everywhere. I know some people wonder why they get 10mpg when they are accelerating just like the corvette they own that gets 30mpg.

There is a reason all of those cylinder deactivation things work so well once you hit the highway.. The acceleration is a big part of fuel consumption. I know a lot of us are doing just solely highway driving and still wondering about mileage, but for the city drivers, maybe this will give you an idea of how much faster your accelerating than me

http-~~-//www.youtube.com/watch?v=F8UI17nKYBs

So now I have to ask how much do we know about how our injectors work?

I've never previously heard a word about adding lift to an injector, anyone know how that works?

I was under the impression that when the fuel reached the pop pressure the injector opened until the pressure dropped below pop pressure controlled by the VP44 electronics closing the solenoid in the pump to stop the flow for that injector.

How does that relate to injector lift? I thought the hole size controlled how much fuel could flow could happen and the pop pressure when it would happen and the solenoid when it would end. Am I the only one confused over this?

Jim

That thread on injectors and your explanation really helps with my understanding of injectors and supports my previous conclusion that higher pop pressure atomizes the fuel better and supports better burn and therefor better economy. I also have suspected for a while that fuel temp plays a role here. I'm working on a heat exchanger to warm the fuel using engine coolant before being fed to the vp44. I suspect that If I can control the fuel to 100*-120* coupled with high pop pressure of the injectors 300-310 bar combustion will be improved in cold weather. This is on the premise that the timing can be fooled to be optimal (Mikes IAT fooler). However at this point it is a theory only.Jim

That thread on injectors and your explanation really helps with my understanding of injectors and supports my previous conclusion that higher pop pressure atomizes the fuel better and supports better burn and therefor better economy. I also have suspected for a while that fuel temp plays a role here. I'm working on a heat exchanger to warm the fuel using engine coolant before being fed to the vp44. I suspect that If I can control the fuel to 100*-120* coupled with high pop pressure of the injectors 300-310 bar combustion will be improved in cold weather. This is on the premise that the timing can be fooled to be optimal (Mikes IAT fooler). However at this point it is a theory only. Jim

I was told the fuel temp effected timing as well. I am not sure what warming it will do, I imagine cold fuel needs more time to combust (absorb heat) so it advances the timing, could be wrong. The only thing I see is that I thought the VP44's were prone to failure with warm fuel. What was your theory with the warm fuel? That it would burn better since it wouldn't have to absorb as much heat? I just wonder how hot the injected fuel is since it is compressed to over 4000psi, but then shot out so it would expand and the only thing I know there is that compressed air coming out is freezing, even in the summer. If the fuel were even 120F, would it really matter if it is compressed to 4000? I am just spitballing but it's something to think about. The calculators I made today show that the temperature of compression is raised 150F for every 50F raise in ambient temp. I will have to make one of injectors since that is a whole different setup.

Bought a 2000, reg cab, 2wd, 4.10s, auto a month ago. bed is empty, 245s, and drive 57 everywhere (around 1900). best I have seen so far is 16.4 mpg. I am in the flatest land in the country, NW Ohio. Was hoping for at least 20. Glad I joined the site. This is some darn good reading. Let me know if I can help.

Bought a 2000, reg cab, 2wd, 4.10s, auto a month ago. bed is empty, 245s, and drive 57 everywhere (around 1900). best I have seen so far is 16.4 mpg. I am in the flatest land in the country, NW Ohio. Was hoping for at least 20. Glad I joined the site. This is some darn good reading. Let me know if I can help.

this truck had never been tweaked in the past as far as I know. Thats what the previous owner said and it looks like it hasn't been played with. I put a Quad mileage box on it two weeks ago. I'm guessing around 1 mpg so far. yeah 245/75/16s (a mastercraft AT) on the stock rims. also went with a big line kit to help the stock in-tank pump. I know its not the best, but it will have to do for now.

this truck had never been tweaked in the past as far as I know. Thats what the previous owner said and it looks like it hasn't been played with. I put a Quad mileage box on it two weeks ago. I'm guessing around 1 mpg so far. yeah 245/75/16s (a mastercraft AT) on the stock rims.

I rigged up a gauge off of one of the schrader valves before I put the big line kit on it. had 10+ driving around. ordered a gauge for the cab few days ago, should be coming. I bought this truck, one because it was cheap, but two figured that it would be great for a fuel meiser, being reg cab 2wd. can't get any lighter. don't know if i will play with 2 cycle or not. we run b5 around here.

hello and welcome to the site!!!i have some cousins that live in southern wisc. that are steiners!!

I bought this truck, one because it was cheap, but two figured that it would be great for a fuel meiser, being reg cab 2wd. can't get any lighter. + sig looking for more mileage...

Once you get your fuel gauge - sell the EZ and get a COMP/JUICE/ADRENALINE more timing and power ......... 2-3+mpg generally

My thinking goes along the line that the hot fuel is not as viscus (thinner like hot straight weight engine oil) allowing it to flow and atomize better. My thoughts on the 4000psi fuel from the vp44 heating it up enough are that since fluid is for all practical purposes incompressible heat transfer from a pump to the fluid is less dependent on on the pressure achieved than the horse power used to pump that volume to that pressure. Work accomplished (hp) can be expressed as heat energy (btu) and pumping 3 - 4 gph at 4000 psi doesn't impart enough energy to the fluid over an hours time to raise the temp that much. I guess if one could put a temp probe on a HP injection line and insulate it well then measure the temp of the line at highway speed it would give an indication of the temp rise of the fuel by the pump. I just don't think it is enough to make an appreciable difference. Now I know that moving huge volumes of fluid rapidly will raise the fluid temp quite a bit, but it cannot raise it more than the hp converted to BTU used to pump it. Yes, the expansion of the fuel being sprayed through will lower it's temp a bit but I suspect not as much an one would think comparing it to air conditioning/refrigeration theory In AC the compressed freon changes from a compressed gas/fluid to a gas undergoing a state change (fluid to gas) thereby absorbing a lot of heat causing the cooling effect. With the injectors the fuel is atomized into vary small particles or droplets not actually undergoing a state change from a fluid to gas, just a process of dispersal to achieve more surface area. With enough surface almost any substance will become combustible with an ignition source. (that's why grain elevators and flower mills used to explode before having proper ventilation, dust in the air and an ignition source) In a diesel the compression is the ignition source for the atomized fuel. It raises the cyl pressure to the combustion point of the atomized fuel.

From what I get with this, you are trying to get the fuel to pump and flow to the injector better. You also said you don't think the injection will cool the fuel down like on an air compressor. That just proves my point a little further being that, if the fuel is cold, it will get hot when it is compressed to 4000psi so it will shoot into the engine at a hot temp. I realize it doesn't transfer that heat back to the tank or anything but that is not the thing I am concerned with. I think the heat generated by compressing it 4000psi will be very hot and the temp of the fuel, be it 0-100F, will not matter much when it probably gets to an incredibly hot temperature after it is compressed. That would mean it would autoignite by just leaving the injector. But it doesn't so that tells me it loses a lot of it's heat when it gets injected. The compression ratio for that injector would be 4000:1 (on the 24V's, my 12V actually plumbs into the fuel filter so the injector has 40psi in it constantly, making it only 100:1). But on an engine, just 17:1 raises the temp from 0F to 967F (if there were no losses). Obviously compressing air and fuel are 2 different things so I need to make another calc.

this truck had never been tweaked in the past as far as I know. Thats what the previous owner said and it looks like it hasn't been played with. I put a Quad mileage box on it two weeks ago. I'm guessing around 1 mpg so far. yeah 245/75/16s (a mastercraft AT) on the stock rims. also went with a big line kit to help the stock in-tank pump. I know its not the best, but it will have to do for now.

Hi & Welcome. My 01.5 truck is in my signature. I also have 4:10s & the best I have ever gotten is high 18's in summer... empty & babying it for mpgs. 4:10s just won't get into the 20s IMHO. I'm pure stock for now, except exhaust & I run the TCW3 2 cycle oil as an additive. Chips pretty much screw up the overhead MPG guage but mine seems to be right on because I'm stock. It's a great truck... but IMHO the 24 valves of this era were detuned for smog... the IAT fooler that the guys are working up has great promise for keeping your best mpgs year round. Best wishes, Russ

From what I get with this, you are trying to get the fuel to pump and flow to the injector better. You also said you don't think the injection will cool the fuel down like on an air compressor. That just proves my point a little further being that, if the fuel is cold, it will get hot when it is compressed to 4000psi so it will shoot into the engine at a hot temp.

I don't think that it proves your point at all, you are still making the assumption that fluid compression generates a lot of heat in the fuel. I say it does not, do not confuse compressing a gas (heat accumulation from the latent heat in a larger volume) with putting pressure on a hydraulic column of fluid (direct pressure transfer). Think hydraulic jack, does the jack get hot when you jack up a 12 ton object? If not why not, 12 ton is 24,000 lbs on the hydraulic fluid. I know this is a simple example but it is food for thought. The fuel is not compressed, it has 4000 lbs of direct pressure on it from the VP44 just like the hydraulic jack lifting 12 tons.

I realize it doesn't transfer that heat back to the tank or anything but that is not the thing I am concerned with. I think the heat generated by compressing it 4000psi will be very hot and the temp of the fuel, be it 0-100F, will not matter much when it probably gets to an incredibly hot temperature after it is compressed. That would mean it would autoignite by just leaving the injector. But it doesn't so that tells me it loses a lot of it's heat when it gets injected. The compression ratio for that injector would be 4000:1 (on the 24V's, my 12V actually plumbs into the fuel filter so the injector has 40psi in it constantly, making it only 100:1). But on an engine, just 17:1 raises the temp from 0F to

967F (if there were no losses). Obviously compressing air and fuel are 2 different things so I need to make another calc.

liquid fuel is not compressible therefor it cannot accumulate heat energy by being compressed. Gasses are compressible and therefor can accumulate the heat energy from the larger volume being compressed into a smaller volume. Just as you are putting more air in a smaller space raising the pressure you are putting the latent heat from the larger volume into that smaller space raising the temp. You point this out

"But on an engine, just 17:1 raises the temp from 0F to

967F (if there were no losses). Obviously compressing air and fuel are 2 different things".

Fuel has a flash point and an auto ignition temp. For diesel fuel in general the flash point is 62*C and the auto ignition temp is 210*C. Both are well under the 967F you calculate as a cyl temp rise from compression.

However the autoignition temperatures do change somewhat with the grade of diesel #1 is 177*C-329*C #2 is 254*C-2 and #4 is 263*C.

Source:

http://hypertextbook.com/facts/2005/EileenTang.shtml

http://en.wikipedia.org/wiki/Autoignition_temperature

http://en.wikipedia.org/wiki/Flash_point

So I believe what happens when an injector fires is:

1. The cyl compression raises the temp to above the flash point and auto ignition point of the fuel.

2. The injector fires spraying the fuel into fine droplets or mist in the cyl where the fuel absorbs heat to raise it's temp above the flash point at which time some of it becomes a gas.

3. The gas now being above the auto ignition temp begins to burn, further raising the cyl temp and flashing off and burning the remainder of the fuel being injected.

4. The injector continues to pop (chatter) injecting more fuel into the burning mass in the cyl until the injection cycle is terminated by the injection pump.

If the temp of the diesel fuel significantly raised by putting 4000 lbs of hydraulic pressure on it, it would flash inside the injector and high pressure lines and become a gas there, which would not be fun to be around. The other thing that makes me think this is the common rail injection system has fuel at a much higher pressure than 4000 lbs something on the order of 25,000 lbs I believe i have read. As far as I know there is no heat problem generated on the CR trucks by having the fuel at such high pressure.

I'm not an expert and I could be completely out in left field in my thinking, but this is what I have deducted from things I have read.

My point in thinking If the fuel were warmer going into the injection pump is it would be less viscous and atomize through the injector nozzle a little better perhaps speeding up the ignition a little. Whether or not it makes any difference in the injection and burn remains to be proven.

Jim