The results of static timing

[AH64ID]

So I was just thinking about that spreadsheet and I think I figured out why the mm3 is higher than expected. That's all based on 1 injection event. So with the snapshot you posted if there is a 7mm3 pilot even then the main in only 26mm3 and that's a little better and more expected.

[rancherman]

meh, no problemo on multi injection with our 12v's:whistle:DUAL PUMP'D p7100... all it takes is $$... pretty sure 'sphincters' are not required either!

[AH64ID]

So I was just thinking about that spreadsheet and I think I figured out why the mm3 is higher than expected. That's all based on 1 injection event. So with the snapshot you posted if there is a 7mm3 pilot even then the main in only 26mm3 and that's a little better and more expected.

I did a little looking at the stock tune. At 1800 rpms and 30mm3 of commanded main injection fuel the pilot injection is 4.0mm3, so 34mm3 total. At 1800 rpms and 45mm3 of commanded main injection fuel the pilot injection is 4.3mm3, so 48.3mm3 total. At 2000 rpms and 30mm3 of commanded main injection fuel the pilot injection is 4.8mm3, so 34.8mm3 total. At 2000 rpms and 45mm3 of commanded main injection fuel the pilot injection is 5.6mm3, so 50.6mm3 total.

[ISX]

I did a little looking at the stock tune. At 1800 rpms and 30mm3 of commanded main injection fuel the pilot injection is 4.0mm3, so 34mm3 total. At 1800 rpms and 45mm3 of commanded main injection fuel the pilot injection is 4.3mm3, so 48.3mm3 total. At 2000 rpms and 30mm3 of commanded main injection fuel the pilot injection is 4.8mm3, so 34.8mm3 total. At 2000 rpms and 45mm3 of commanded main injection fuel the pilot injection is 5.6mm3, so 50.6mm3 total.

I don't understand this "commanded" fuel thing. I mean you press the pedal and it gives it more fuel.. Or are you just stating snapshots at certain throttle percentages? Basically we need a reference for yours... All I can do is mpg things since I can't measure fuel flow without buying sensors. In other words, go certain speeds in the highest gear and note the RPM, mph, and mm3. It should be identical to the MPG you get. For instance, at 1800RPM and your summer tires in 6th gear you should be at 65.3mph. At 34mm3 that works out to 22.4mpg. At 48.3mm3 it works out to 15.8mpg. I just want to see how legit all this is seeing as how you can monitor the fuel rate it would be interesting to see if it works out on the calculator.

[dorkweed]

just curious, why is the cyl pressure lower, but egt higher?

Also, those mm3 aka cc's, numbers are "per 1000 events'?

Thanks

Because the later you inject the fuel in the "powerstroke of compression" or "early exhaust stroke (CR)" the hotter your exhaust will be.

In essence, the piston is pushing the flame into the exhaust manifold earlier. This reduces NOx emissions but reduces efficiency drastically!!!!! Something the EPA doesn't seem to gather................or care about.................because in our country that'd mean reduced tax revenue!!!!!!!!!!

That's the rub...............we "can" get 25mpg out of our 8000lb. Cummins if the EPA would let us. But that'd reduce the amount of fuel tax that gets paid to the various forms of government!!!!!!!!!!!!!! ALWAYS, ALWAYS, ALWAYS follow the money aspect of things when you cannot understand why things happen!!!!!

I'll start another thread here shortly about that!!!!

[ISX]

I got all the RPM values for my speeds and my MPG's are pretty consistent so here is sort of a reference for mine.

[AH64ID]

I don't understand this "commanded" fuel thing. I mean you press the pedal and it gives it more fuel.. Or are you just stating snapshots at certain throttle percentages? Basically we need a reference for yours... All I can do is mpg things since I can't measure fuel flow without buying sensors. In other words, go certain speeds in the highest gear and note the RPM, mph, and mm3. It should be identical to the MPG you get. For instance, at 1800RPM and your summer tires in 6th gear you should be at 65.3mph. At 34mm3 that works out to 22.4mpg. At 48.3mm3 it works out to 15.8mpg. I just want to see how legit all this is seeing as how you can monitor the fuel rate it would be interesting to see if it works out on the calculator.

Since there is no throttle cable hooking up to an injection pump, nor do CR injectors use pop pressure, the ECM has to determine how much fuel to spray based on many inputs, such as TPS, RPM, Boost, IAT, ECT, Load, etc... A CR engine maintains a constant, roughly but it doesn't pulse like pre-02 trucks, pressure in the rail. The injectors always have that pressure applied. The ECM then opens a solenoid on the injector for the prescribed time, at the prescribed time. There are 3 tables that play into the main injection event that I am editing/adjusting. Rail Pressure, Duration, Timing. The Rail pressure table tells the ECM to make "x" pressure at "y" rpm and "z" engine load. So say 1800 rpms and 30mm3 (~20% load) the ECM commands about 14,500 psi. The duration table tells the ECM that for the current load (~20% or 30mm3) it takes 486us to flow that fuel at that pressure. Then the timing table tells the ECM when to open the injector, 8.9° BTDC on the stock tune. So for 486us at 8.9° BTDC the ECM opens the solenoid, at 1800 rpms 486us is 5.2° of crank rotation. So that's why it's commanded fuel, the ECM does a bunch of split second math to command so much flow. What I can do with UDC is tell it to run more or less pressure at the given rpm/load, more or less timing at the given rpm/load, or that it takes longer/shorter to spray the desired fuel at a given flow/pressure. All of that plays into mileage/power/EGT's. With UDC I cannot log the commanded mm3 while driving, or at all. That's a EFI Live only feature right now, for 06-07 5.9's and 07-09 6.7's. But yes it should work out the same, but I would have to add the pilot/main and post (currently turned off) together to get that total fuel burn.

[ISX]

You said that the VP44 and P7100 both get to a max of 17,000psi or something. Well the pop pressure is 260 bar ~ 3770psi on my truck. So, the pressure is probably over 260 bar for a given amount of time, especially when floored and at redline. Does that mean that the injector stays open like a CR injector, as in no popping? Or do you think it pops at the usually million mph. I know it goes really fast on a pop tester but that's no where near the rate the engine pumps it.

[AH64ID]

With pop-style injectors the pressure will go from below pop to peak at every injection event, triggered by the compression stroke and timing in the pump or ECM/pump. If the injector was always open you would melt pistons ASAP! At 3K rpms each injector is firing 1,500 times a minute, that's 25 times a second. So if your at peak rpm and WOT the pump is going from well below 260 bar to it's peak pressure. Just because the pump is capable of 17K psi doesn't mean it will run there often, but I have no clue. But that means that at the start of your injection even the fuel is harder to ignite that a common rail that starts at the set pressure. Stock 04.5-07's cruise at about 18-19.5K. One of the reasons that you a P7100 can run 16° (or heck some of the high rpm guys with 22°+) of timing at low load is the pressure is low, so it takes a little longer to pop, the ignition delay is longer, etc.. Whereas a CR with 16° of timing has a very very low ignition delay, and super short injector delay.

[ISX]

I wonder how long the injection lasts. I have a P7100 here lol. The spill port is only closed for maybe 1/4" if that, at WOT. I just need to figure out the degree where the spill port is closed and the degree where it is opened again. It would be neat to see how many picoseconds or something it is actually injecting per stroke. Actually, do you know ahhh yes 486us. Hmmm. Did you calculate those max pressures for the P7100 or did you see them somewhere? I *think* I can calculate them......

[AH64ID]

Those pressures are for the 04.5-07 HPCR, and calibrated based on the stock nozzle. P7100 stuff is different.

Stock Duration for the Main Injection Pulse.. This is what the ECM has to determine the actual pulse width, for pressures and volumes that aren't on the map they ECM calculates it out. The pressure is in MPA.

[rancherman]

Because the later you inject the fuel in the "powerstroke of compression" or "early exhaust stroke (CR)" the hotter your exhaust will be.

In essence, the piston is pushing the flame into the exhaust manifold earlier. This reduces NOx emissions but reduces efficiency drastically!!!!! Something the EPA doesn't seem to gather................or care about.................because in our country that'd mean reduced tax revenue!!!!!!!!!!

That's the rub...............we "can" get 25mpg out of our 8000lb. Cummins if the EPA would let us. But that'd reduce the amount of fuel tax that gets paid to the various forms of government!!!!!!!!!!!!!! ALWAYS, ALWAYS, ALWAYS follow the money aspect of things when you cannot understand why things happen!!!!!

I'll start another thread here shortly about that!!!!

Remember about 10 years ago, when VW announced a diesel car (cant remember the exact model).. that was getting 70-75 mpg in Europe??

Guess what> DIDN'T MEET EPA STANDARDS ???

I fought that notion in my head for years: How can a vehicle that burns HALF the fuel per mile pollute MORE????

Then I found the reason why... The formula for figuring what a car/truck can emit is factored with expected mpg. So, basically, the VW's were 'screwed' because they got unreal fuel economy.

So, VW 'detuned' that version, which got about 40 mpg's... and sent em this way! ( I realize europe's diesel fuel is a little different recipe than ours too) and our's is/was a little dirtier..

Would this Country be better off with a little more 'junk' in the air, or use half the fuel in the first place???

Don't crucify me here... I am not a scientist... or a VW fan! Just relaying what I've read.

[Mopar1973Man]

Remember about 10 years ago, when VW announced a diesel car (cant remember the exact model).. that was getting 70-75 mpg in Europe?? Guess what> DIDN'T MEET EPA STANDARDS ??? I fought that notion in my head for years: How can a vehicle that burns HALF the fuel per mile pollute MORE???? Then I found the reason why... The formula for figuring what a car/truck can emit is factored with expected mpg. So, basically, the VW's were 'screwed' because they got unreal fuel economy. So, VW 'detuned' that version, which got about 40 mpg's... and sent em this way! ( I realize europe's diesel fuel is a little different recipe than ours too) and our's is/was a little dirtier.. Would this Country be better off with a little more 'junk' in the air, or use half the fuel in the first place??? Don't crucify me here... I am not a scientist... or a VW fan! Just relaying what I've read.

Was so much a EPA problem. But it was a tax flow problem since EU has different was of getting tax dollars than we do. So with high MPG vehicles here in US the gov't loses huge chunk of income because you don't buy as much fuel.

[ISX]

I am not sure the EPA is all bad. I don't understand the mileage bit though. However, there is a guy here from Indonesia and he said one of the biggest changes here was that he could breath. They all drive 2 stroke motorcycles over there and crappy cars and apparently the smog is unreal.

[rancherman]

Was so much a EPA problem. But it was a tax flow problem since EU has different was of getting tax dollars than we do. So with high MPG vehicles here in US the gov't loses huge chunk of income because you don't buy as much fuel.

I never thought of that!

I'll bet Big Oil might've had a say in it too...Big 3 domestics.. etc etc..

And this is yet another chapter that can be put into the thread "What is happening to US, where are we headed"

(Dance, puppets, Dance!!)... says the man behind the curtain...

- - - Updated - - -

I am not sure the EPA is all bad. I don't understand the mileage bit though.

However, there is a guy here from Indonesia and he said one of the biggest changes here was that he could breath. They all drive 2 stroke motorcycles over there and crappy cars and apparently the smog is unreal.

Off the cuff, I remember there several factors involved in figuring 'compliance' on how much 'pollution' was allowed.

intent of use.. Work or basic transportation

how many passengers

type of fuel

I'm sure there was others too...

and I am pretty sure there was some calculation based on the certified mpgs... which basically figured the amount of 'crap' expelled PER GALLON burned. Not PER MILE travelled. It probably wasn't that black and white.. maybe a ppm/gallon burned/miles traveled.. but still, I think on a per trip basis, the equation fails.

with that in mind, the VW would needed to cleaner as a similar vehicle that got 35 mpg.

[ISX]

I just got a call from a guy who was telling me his truck did the exact opposite of mine when mine was at 0* timing. Meaning, his only ran ABOVE 1300. Stuttered and coughed and whatnot below. He did my spill port method thing and eventually we got to where he marked his damper and he told me the measurement and somehow the measurement must have got doubled because he was at 27*. Obviously that's the problem. Very interesting to find out that I was that close to the edge of it running like crap when I was at 20*. I might try 25* when I get home to check. Oddly enough, mine running equally as crappy at 0* and his the opposite crappiness at 27* averages the nameplates 13.5*.