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ISX

Timing Effects

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I took the P7100 out a while back and I got in a hurry and messed up the timing but it ran fine so I said heck with it. I noticed it started up basically instantly, but quickly fell on it's face. When I pulled our trailer the same place (Branson), instead of the usual 15-20psi max, I was now getting into the 30's and it still didn't have the same power. I found it interesting so I drove it some more, pulled some more and now I got a chance to see exactly what the timing was. Believe it or not, it was at 3.8* :stuned:This was actually good because it really made the effects show. Starting is a lot quicker of course, because the piston gets a chance to go up farther, building more heat before the fuel gets shot in. It was 44F a couple days ago and it was still starting insanely fast and my grids are not hooked up. It actually seemed to be doggier at low RPM driving than usual. You would think it would be better off but it really didn't show that effect at all. Higher in the RPM it was a piece of crap. It still had power I suppose but it was nothing to brag about and definitely didn't snap your neck. Boost has just been wayyyy up there trying to compensate for the crappy fuel burn. Mileage was somewhat worse, but I still got 15mpg pulling the trailer 70mph, which is 2100 RPM. It was very obvious that I was stepping on the pedal a lot more. When you floored it, it really was a junker. Mine being a 215 pump means it has retarding notches to allow more fuel in, which I am told allow up to 4* retarding. Which means it was dumping the fuel in right at TDC. It smoked a lot more at all RPM's.

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You certainly put your truck thru the settings dont you!

[TABLE=align: center]

[TR]

[TD=bgcolor: #FFFFFF]Engine parameter:[/TD]

[TD=bgcolor: #FFFFFF, colspan: 2]

TIMING is:

[/TD]

[/TR]

[TR]

[TD=bgcolor: #FFFFFF]RETARDED ( - )[/TD]

[TD=bgcolor: #FFFFFF]ADVANCED ( + )[/TD]

[/TR]

[TR]

[TD]EXHAUST TEMP[/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[TR]

[TD]CYLINDER PRESSURE[/TD]

[TD]decreases[/TD]

[TD]increases[/TD]

[/TR]

[TR]

[TD]INTAKE MANIFOLD PRESSURE

(BELOW P-TORQUE) WASTEGATED [/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[TR]

[TD]BSFC (brake specific fuel consumption) [/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[TR]

[TD]NOX (oxides of nitrogen)[/TD]

[TD]decreases[/TD]

[TD]increases[/TD]

[/TR]

[TR]

[TD]HEAT REJECTION[/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[TR]

[TD]HYDROCARBONS (HC) [/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[TR]

[TD]BLACK SMOKE: 1000RPM[/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[TR]

[TD]BLACK SMOKE: PEAK TORQUE[/TD]

[TD]decreases[/TD]

[TD]increases[/TD]

[/TR]

[TR]

[TD]BLACK SMOKE: RATED[/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[TR]

[TD]WHITE SMOKE: < 1000RPM[/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[TR]

[TD]WHITE SMOKE: > 1000RPM[/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[/TABLE]

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You certainly put your truck thru the settings dont you!

[TABLE=align: center]

[TR]

[TD=bgcolor: #FFFFFF]Engine parameter:[/TD]

[TD=bgcolor: #FFFFFF, colspan: 2]

TIMING is:

[/TD]

[/TR]

[TR]

[TD=bgcolor: #FFFFFF]RETARDED ( - )[/TD]

[TD=bgcolor: #FFFFFF]ADVANCED ( + )[/TD]

[/TR]

[TR]

[TD]EXHAUST TEMP[/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[TR]

[TD]CYLINDER PRESSURE[/TD]

[TD]decreases[/TD]

[TD]increases[/TD]

[/TR]

[TR]

[TD]INTAKE MANIFOLD PRESSURE

(BELOW P-TORQUE) WASTEGATED[/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[TR]

[TD]BSFC (brake specific fuel consumption)[/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[TR]

[TD]NOX (oxides of nitrogen)[/TD]

[TD]decreases[/TD]

[TD]increases[/TD]

[/TR]

[TR]

[TD]HEAT REJECTION[/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[TR]

[TD]HYDROCARBONS (HC)[/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[TR]

[TD]BLACK SMOKE: 1000RPM[/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[TR]

[TD]BLACK SMOKE: PEAK TORQUE[/TD]

[TD]decreases[/TD]

[TD]increases[/TD]

[/TR]

[TR]

[TD]BLACK SMOKE: RATED[/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[TR]

[TD]WHITE SMOKE: < 1000RPM[/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[TR]

[TD]WHITE SMOKE: > 1000RPM[/TD]

[TD]increases[/TD]

[TD]decreases[/TD]

[/TR]

[/TABLE]

I never understood that chart until now. I see everything as being a chain reaction. First off the thing isn't burning very efficient at cruising RPM, this means less power per fuel. The way a 12 valve is, or mine anyways, the pedal is your fuel amount, literally. If I am going 20mph and want to go 30 at a set acceleration, I push on the pedal a set amount and it gives it that much more fuel IRREGARDLESS of ANYTHING. If I change injectors or mess with timing or anything like that, it still gives it the exact same amount of fuel. Since the same amount of fuel now produces less power, I have to step on it a little more to get the same acceleration. Because I have to step on it more, I put in more fuel which raises EGT's while also creating more boost (intake manifold pressure). Cylinder pressure is down because the inefficient operation isn't creating as much of a "boom".

EGT's actually were the same if you compare apples to apples. As in a slight haze and 30psi would be the same EGT as before, difference is that the power was a lot less. So the heat output is pretty linear whether the engine uses it for work or just blows it out the exhaust.

I just set my timing to 14.5* and my power is back lol. EGT's are down but there again, I drive the same and since it's much more efficient it doesn't take as much fuel to get the same acceleration, so less fuel = cooler EGT.

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Timing has a huge effect on EGT's, not because you make more power per gallon but becuase there is more work being done in the cylinder (same reason power goes up). With timing that retarded you should have seen a huge increase in EGT's. With timing alone I can see a 200° drop in my EGT's, or more.

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Isx, I'm pulling my pump this week to have it tested and re calibrated, I purchased a Snap on / blue point timming kit. What are you setting yours at.. I was thinking 15.5-16..

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Timing has a huge effect on EGT's, not because you make more power per gallon but becuase there is more work being done in the cylinder (same reason power goes up). With timing that retarded you should have seen a huge increase in EGT's. With timing alone I can see a 200° drop in my EGT's, or more.

Yeah I really didn't see much of a change. If it was at 30psi it was at the same EGT as when the right timing was at 30psi. I do question how you do just timing, I mean if it's a chip I kinda doubt it messes with timing and absolutely nothing else. I bet it changes a few other parameters, though I have no clue. Seeing the timing maps for the VP44 which are all over the place really tells me that it could be a whole different map as well. Could be less timing here but more there and less here and.... Nobody ever has a chart to show what they actually are. 12 valves have the same exact timing throughout so they show the principles of timing a lot better since all of the variables are not variable at all. It's definitely not a benefit of the 12 valve but in this case it does have a better reputation since we know for sure what my timing is and a new truck just has "more or less timing", which is still highly variable and very questionable unless we saw another vp44 looking map thing.

Isx, I'm pulling my pump this week to have it tested and re calibrated, I purchased a Snap on / blue point timming kit. What are you setting yours at.. I was thinking 15.5-16..

I had mine at 13.5 and loved it there. I bumped it up to 14.5 since I spend a lot of time at 2000RPM with the trailer lately. If it wasn't for the trailer I would be back around 1600RPM and would set it back at 13.5, maybe 12. The thing is that you lose power down low when you advance it a lot and I doubt you would care with an automatic but I don't like having to rev higher in gears to try and make up for the loss in power the next gear will have. Many people say 16 is the sweet spot but that seems a little high to me. If you pull trailers a lot (run higher RPM), then 16 would be good, but I like to keep a good average between startability, low RPM driving and trailer driving. Startability needs probably around 0-5* advance, low RPM driving (1500-2000) is probably in the 10-14 range, and over 2000 is 16-20. I wouldn't go much over 18 because it will start like crap in the winter, more like autumn. Basically it's all up to how you drive.

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Yeah I really didn't see much of a change. If it was at 30psi it was at the same EGT as when the right timing was at 30psi. I do question how you do just timing, I mean if it's a chip I kinda doubt it messes with timing and absolutely nothing else. I bet it changes a few other parameters, though I have no clue. Seeing the timing maps for the VP44 which are all over the place really tells me that it could be a whole different map as well. Could be less timing here but more there and less here and.... Nobody ever has a chart to show what they actually are. 12 valves have the same exact timing throughout so they show the principles of timing a lot better since all of the variables are not variable at all. It's definitely not a benefit of the 12 valve but in this case it does have a better reputation since we know for sure what my timing is and a new truck just has "more or less timing", which is still highly variable and very questionable unless we saw another vp44 looking map thing.

If I run my Smarty Jr on SW1 it's stock fueling with only advanced timing. It is dynamic, but advanced across the board. Reading many posts on the P pump timing effects EGT's pretty noticeably. I really wonder why yours didn't. It also should have taken a lot less fuel to make 30 psi. If you look at fuel to make 30 psi on advanced timing its a bit more than fuel to make 30 psi on retarded timing. On my model motor its quite easy to hit 40 psi on the stock turbo if you disabled the WG, but advance the timing and run the same fueling and you peak at 33-35, but the EGT's are 200-250° cooler.

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As far as I know my timing is stock. I'm interested in the 1800-2000 rpm power. I have a 5 speed. It takes a lot for me to push the EGT to the limit with my setup. I'm interested in more mpg and lower EGT. Before i pull my pump I will check the timming. So I will know a baseline.

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If I run my Smarty Jr on SW1 it's stock fueling with only advanced timing. It is dynamic, but advanced across the board.

Reading many posts on the P pump timing effects EGT's pretty noticeably. I really wonder why yours didn't. It also should have taken a lot less fuel to make 30 psi. If you look at fuel to make 30 psi on advanced timing its a bit more than fuel to make 30 psi on retarded timing. On my model motor its quite easy to hit 40 psi on the stock turbo if you disabled the WG, but advance the timing and run the same fueling and you peak at 33-35, but the EGT's are 200-250° cooler.

My timing used to be really advanced and my max boost actually went up by 5psi. This was with the wastegate hooked up but outflowing it, as in I was hitting 30psi with stock timing and 35 with advanced. Notice it says manifold pressure decreases below peak torque, that leads me to believe it increases above it, especially since I have seen it first hand.

I have heard mixed things on timing effecting EGT's. Guys who have sled pulling trucks tell me their EGT's go up when they advance it, yet nonpullers say the opposite. There are some other factors in the equation apparently though sled pullers are advancing it into the 20's. I think the degree of advance has a lot to do with it. You get to a certain sweet spot which will help EGT, but keep going and you eventually have reversed effects. There is also just the fact that people say the EGT is higher but they are still not telling the whole truth, yes it is higher but only because it takes more fuel because of the inefficient burn, if they compared results with boost psi they would see EGT is the same, as in 10psi egt with advanced timing is the same as 10psi egt with retarded timing, people on forums are comparing 10psi advanced egt with 15psi retarded egt. I am saying if boost is equal, EGT is the same as well. It is only higher because you have to step on it more to get the same power. I am talking about pure engine operation EGT where the fuel going in is the same amount no matter the timing, and with that, EGT will always be the same. This is not a model of any sort, it is what I have seen personally from doing it.

--- Update to the previous post...

As far as I know my timing is stock. I'm interested in the 1800-2000 rpm power. I have a 5 speed. It takes a lot for me to push the EGT to the limit with my setup. I'm interested in more mpg and lower EGT. Before i pull my pump I will check the timming. So I will know a baseline.

I would set it to 14.5. That should put the timing in the best spot. As for EGT's, set your valves at 6 intake and 15 exhaust, makes a big difference. If you haven't straight piped it yet, that would help, or at least have a see through muffler. 4"+ exhaust is best, even says they need that in the cummins manual so I don't know how they ended up with 3".

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My timing used to be really advanced and my max boost actually went up by 5psi. This was with the wastegate hooked up but outflowing it, as in I was hitting 30psi with stock timing and 35 with advanced. Notice it says manifold pressure decreases below peak torque, that leads me to believe it increases above it, especially since I have seen it first hand.

It says below peak torque becuase its a wastegated scenario. Above peak torque you get into wastegate operation and the wastegate controls boost, not timing. To see the effects of timing on boost in the upper rpms you have to remove the wastegate from the scenario.

I have heard mixed things on timing effecting EGT's. Guys who have sled pulling trucks tell me their EGT's go up when they advance it, yet nonpullers say the opposite. There are some other factors in the equation apparently though sled pullers are advancing it into the 20's. I think the degree of advance has a lot to do with it. You get to a certain sweet spot which will help EGT, but keep going and you eventually have reversed effects. There is also just the fact that people say the EGT is higher but they are still not telling the whole truth, yes it is higher but only because it takes more fuel because of the inefficient burn, if they compared results with boost psi they would see EGT is the same, as in 10psi egt with advanced timing is the same as 10psi egt with retarded timing, people on forums are comparing 10psi advanced egt with 15psi retarded egt. I am saying if boost is equal, EGT is the same as well. It is only higher because you have to step on it more to get the same power. I am talking about pure engine operation EGT where the fuel going in is the same amount no matter the timing, and with that, EGT will always be the same. This is not a model of any sort, it is what I have seen personally from doing it.

I would not say the burn is inefficient, it's actually very efficient in terms of emissions if its retarded a little. That is the reason the 04.5+ motors run retarded timing, it improves the emissions. EGT's go up because the burn happens later and the combustion is much hotter when the exhaust valve opens.

To make 10 psi with advanced timing takes more fuel than 10 psi with retarded timing.

You keep talking about the same amount of fuel being equal. But if you inject 100 mm3 of fuel at 14° it will have lower EGT's, lower boost, and more hp than injecting 100 mm3 of fuel at 12°.

EGT is not related to boost, not 100%. I am running 30 more hp at 3-7 psi less boost with my new turbo and run 50-100° cooler.

I have run several different timings on my truck over the years, they all made very noticeable differences in EGT's, so much that max continuous EGT and max EGT's vary with each timing setting. As the EGT drops for the same amount of fuel you put more heat into the cylinder, and will melt a piston sooner.

It's hard to quantify as I don't know timing number, but here is what I use. TM1 is stock, TM4 is the most advanced. In order of retarded to advanced is TM1, 3, 2, 4. IMO this creates similar piston temps.

TM1: 1400 max cont, 1450 momentary

TM2: 1300 max cont, 1350 momentary

TM3: 1350 max cont, 1400 momentary

TM4: 1250 max cont, 1300 momentary

--- Update to the previous post...

Take a look at the points/dyno about timing in this..

http://www.madselectronics.com/downloadfiles/SSR_Tuning_Instructions.pdf

--- Update to the previous post...

I spent some more time thinking about this topic this morning..

I know Mike believes that dynamic timing was a function of emissions but I don't beleive so. It is also a big factor in the very flat torque curve that 98.5+ trucks have. With dynamic timing you can vary the timing based on fuel flow and boost to get the most power out of the motor. Now as emissions have evolved timing has been used to manipulate emissions along with power.

As boost increases you need to back off the timing, one of the reasons the useful rpms vary so much on the P7100 trucks, you are timed for a certain rpm and/or load.

Consider the 06-07 trucks that can utilize EFI Live. In low rpm, low boost, high power demand instances the timing can be retarded to help spool the turbo. As boost and rpms increase the timing is advanced to get the most power out of the motor thru efficiency. At cruise boost, rpm, and load the timing can be advanced to improve economy becuase we are not worried about acceleration spool.

What Mike did with his fixed IAT sensor would be a good basis for proving the EGT, power, efficiency change. If there were a potentiometer in the system, vs a resistor, you could watch everything change using a boost, EGT, and Scan Gauge.

Set the cruise at 75 mph on a long straight stretch of highway, or 55 while towing. You want the speed and/or trailer to put a load on the motor so the changes are more drastic.

Once you have a stable med-high load adjust the potentiometer. At IAT increases the timing is advanced, this would generally make less boost, lower EGT's, lower GPH, but the power output is unchanged as the truck still requires "x" hp to move the weight at the set speed. Start decreasing the IAT and timing is retarded, more boost, more EGT's, higher GPH for the same rwhp.

I really couldn't think of a better way to test it..

--- Update to the previous post...

The way a 12 valve is, or mine anyways, the pedal is your fuel amount, literally. If I am going 20mph and want to go 30 at a set acceleration, I push on the pedal a set amount and it gives it that much more fuel IRREGARDLESS of ANYTHING. If I change injectors or mess with timing or anything like that, it still gives it the exact same amount of fuel.

This is not quite how the mechanical pumped engines I have messed with work. Not saying it's not how the P7100 works, just not how I have seen it.

The engine I have the most experience with is a 3406C marine motor. It's a good example as prop demand is pretty constant per rpm. 1" of throttle lever movement would produce the same rpm in neutral as in gear, thus the throttle doesn't apply "x" fuel, but looks for a specific govern point.

Now in a truck it would still apply to a point. If "y" throttle is looking for "x" rpm but the load it too great for the amount of fuel at "y" throttle you will end up with lower rpms. My HPCR still works this way, it takes a TPS near 70-80% to get to 3000 in N, and the same in lower gears, in higher gears it fully depends on the load as now your torque demand exceeds what your pedal position can call for.

Hopefully that makes sense and you could test it very easy. If the pedal position only dictates fuel flow (like a carbed gas motor) then it takes very little pedal to hit rated rpm, but if its like the other mechanical and electronic diesels I have experience with then it will take a lot of pedal to get to rated rpm. Ever drive a skid steer? You can go WOT without moving the skid or hydraulics and not over rev the motor, you couldn't do that on a gasser you would go well above redline. Diesel pumps govern fuel differently.

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What Mike did with his fixed IAT sensor would be a good basis for proving the EGT, power, efficiency change. If there were a potentiometer in the system, vs a resistor, you could watch everything change using a boost, EGT, and Scan Gauge.

I'm currently setup with rheostat next to my transfer case lever and I can adjust IAT temps while on the fly.

As for changes there don't seem to be any huge changes in EGT's or boost... I'm not saying there isn't any change at all but it most likely very slight changes. My 55 MPH mark seem to stay fairly constant 2-3 PSI of boost and 550-600*F EGT's. But what does change is the MPG's warmer the temp the better the MPG number.

As boost increases you need to back off the timing, one of the reasons the useful rpms vary so much on the P7100 trucks, you are timed for a certain rpm and/or load.

Which follows the Autoignition Temperature

The autoignition temperature or kindling point of a substance is the lowest temperature at which it will spontaneously ignite in a normal atmosphere without an external source of ignition, such as a flame or spark. This temperature is required to supply the activation energy needed for combustion. The temperature at which a chemical will ignite decreases as the pressure increases (Boost pressure) or oxygen concentration increases. It is usually applied to a combustible fuel mixture.

Autoignition temperatures of liquid chemicals are typically measured using a 500 mL flask placed in a temperature controlled oven in accordance with the procedure described in ASTM E659.

Also under normal engine configuration and 40 cetane diesel fuel it takes roughly 13* of crank travel before diesel ignites normally hence why the initial timing typically is right around 12-13* BTDC

But the tabling for the dynamic timing was designed more so around the emission controls more so than driviblity/performance. Why else did all the proformance boxes (Edge, Quadzilla, etc) come out with with more aggressive timing curves? (Gotcha!)

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As for changes there don't seem to be any huge changes in EGT's or boost... I'm not saying there isn't any change at all but it most likely very slight changes. My 55 MPH mark seem to stay fairly constant 2-3 PSI of boost and 550-600*F EGT's. But what does change is the MPG's warmer the temp the better the MPG number.

Which is why you need to load the motor more to see the effects easier. Under normal driving the changes will be slight, but that increase in economy is from advanced timing which does the things I have stated.

But the tabling for the dynamic timing was designed more so around the emission controls more so than driviblity/performance. Why else did all the proformance boxes (Edge, Quadzilla, etc) come out with with more aggressive timing curves? (Gotcha!)

They are just that.. more aggressive. They are not making it static they are simply advanceing it for performance. Emissions does play a role in timing, but not the only role. The driveablilty and performance are huge in dynamic timing, its the main reason 98.5+ trucks are smoother. I am not saying it doesn't effect emissions, just that emissions is not the sole reason. Making a VP44 or CP3 have static timing is a step in the wrong direction.

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If I were still a member of CF, I could get you in touch with a fellow I've met a few times. He had a "BAD ___" 12valver............that IIRC, at the dyno day we had, he put down just about 450HP and over 900FT LBS torque !!!!!!!!!After the dyno day, we drove over to a restaurant close by. I was following him, and had to wait at several lights for the smoke to clear............both diesel and rubber!!!!! Twas pretty cool actually!!!!:cool:I sure wish I could get in touch with him. Before I got banned from the other site, we used to get e-mails back and forth thru another CF member.Let me do some phoning and see if I can contact him for y'all. He's a 60+ guy that knows his diesel stuff.:smart:

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Which is why you need to load the motor more to see the effects easier. Under normal driving the changes will be slight, but that increase in economy is from advanced timing which does the things I have stated.

Well that's what the Jayco Travel Trailer and the 8x8 Utility Trailer are for too.. Load... But even then there is very little change from the normal. Even with my last trip I scaled the truck and trailer GCW 16,080# and pulled 14.13 MPG hand calc'd. But that was with my stock injectors but still using the IAT fooler locked at 143*F.

They are just that.. more aggressive. They are not making it static they are simply advanceing it for performance. Emissions does play a role in timing, but not the only role. The driveablilty and performance are huge in dynamic timing, its the main reason 98.5+ trucks are smoother. I am not saying it doesn't effect emissions, just that emissions is not the sole reason. Making a VP44 or CP3 have static timing is a step in the wrong direction.

No kidding I know I'm not going to be able to lock down the timing to a single place. Because I know there is load, boost, manifold temp, fuel temp, engine coolant temp, and throttle position that play a role in how the timing curve is created by the ECM then the Edge Comp will modify it again. But like Quadzilla told me that the idea of locking the IAT down to a signle spot is a good thing then on top the warm temp will retard the timing but since the ECM & VP44 are talking the Edge Comp can bump the timing up even quicker. But there is only so quick the timing can forced because if it forced too early the VP44 can and will shut it down. (Timing). As for the emissions part that always the main reason of the stock tune. Cleanest burn reduces NOX oxides of nitrogen. Because if it was all about performance then timing curve would already be bumped. But lets say the 60% of the stock tune is emmisions and the other 40% is performance.

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I gotta read over all of this some more for a while. I wonder if that timing table is right on the 20 degree thing. Why else would VP44 trucks knock like crazy at idle when they have basically the same everything as mine except the injector is moved to the center. I don't see that causing a huge knock at idle. Every time I park by one unknowingly idling I pop my hood and check the oil, until I figure out it's that truck. With mine advanced a lot it still didn't knock as bad as them so I'm really thinking they have a very advanced idle timing. I think i have been explaining what I saw in a point of view only I understand but you are right AH. Without a trailer the differences are pretty subtle. If you floor it then it shows the effect pretty good. I noticed I get more of a grey haze now than the soot I got before when I floored it. Pulling a trailer the differences really show. I was still getting decent mileage with the trailer though, I woulda thought it would be a lot worse. Most people on the net claim huge mileage differences with timing but I saw maybe 2 less if that going from 13.5 to 4. That was trailer mileage, didn't check it without it. Eh let me read over this some more and add more in a bit, I'm hungry and thirsty and you guys wrote a book while I was gone :lol:

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I can quite easily see the difference in boost/EGT when I change my timing parameters. It's most noticeable to me in acceleration, but cruise/towing is also noticeable. But what I don't know is the difference in timing from stock to max advance on my tuner, maybe its more than 5-7° and that's why the effects are more noticed.

--- Update to the previous post...

This is from the H&S 5.9 tuner, a tuner I have zero experience or knowledge about.. But as you can see the timing changes are not small!

0 - 18 degrees

1 - 24 degrees

2 - 26 degrees (Default)

3 - 28 degrees

4 - 32 degrees

--- Update to the previous post...

I have heard the stock tune refereed to as 12° max, but that EFI Live table disagrees. But I did some reading and think I run about 6° advanced, but that's on the 12° scale so it's really hard to say!

--- Update to the previous post...

I wonder if that timing table is right on the 20 degree thing. Why else would VP44 trucks knock like crazy at idle when they have basically the same everything as mine except the injector is moved to the center. I don't see that causing a huge knock at idle. Every time I park by one unknowingly idling I pop my hood and check the oil, until I figure out it's that truck. With mine advanced a lot it still didn't knock as bad as them so I'm really thinking they have a very advanced idle timing.

That table I posted is a HPCR table, not a VP table. I can't read numbers on Mikes. Also those very advance numbers are above idle rpms...

--- Update to the previous post...

Even more reading show that this is what is thought to be factual on a stock tune. VERY retarded numbers, but there is a pre-event before this so it's not apples to apples... Testing is still being done to confirm/deny the theory.

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I still frequent that site, :nono:, what's his name?

His call name is WAYNES WORLD. He hangs out mostly on the Illinois forum of the site.

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Alright I read AH64's stuff some more and looked at that link. That dyno was very interesting. I guess what I don't understand is why 12V's get better mileage with static timing than VP's or CP3's with dynamic timing. They claim emissions and weight differences but I can throw 1000lbs in the bed of mine and still get 25mpg. There is more to this than just timing but for the sake of the thread I will just focus on timing. To me it's almost like mileage doesn't really change, even though boost and power are all different. It's like something is making up for the differences which causes the mileage to be the same. I admit it was a little less but hardly enough to say a few degrees timing will wreck havoc on your fuel tank. I read a huge article once on timing, not really what it does but what effects the degrees, like pop pressure and spray pattern and stuff. What I would like to see is a chart showing exactly where the timing needs to be for most efficient operation at each rpm and power percentile (which I would assume to be most powerful at that rpm as well) with emissions thrown completely out.

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Your 3.54's and 4x2 make a HUGE difference, that and the weight.. even if you add 1K to your bed I bet I am still heavier, more wind resistant, and despite all my efforts still have a more emissions minded motor... and that doesn't even get into the terrain! I bet I could get 22ish out of my truck at 60 mph in your part of the country, if not more. You also have to consider the CP3 trucks have 2 or 3 injection events and based on EFI Live testing removing and reducing them makes a big difference, up to 3 mpg is reported.. thats a real world 3 mpg not a marketing ploy. 12V's are very efficient motors, any way you cut it. They don't turn the rpms that newer trucks do, which has an effect on mileage when accelerating. I have heard 15-15.5° is about optimal for economy, power, and driveability on a 12V manual trans truck. Timing does play a decent role in my economy. The setting I have now I see at least .75 mpg better when cruising at 75-80, and on more advanced see 1-1.25 mpg better.

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Your 3.54's and 4x2 make a HUGE difference, that and the weight.. even if you add 1K to your bed I bet I am still heavier, more wind resistant, and despite all my efforts still have a more emissions minded motor... and that doesn't even get into the terrain! I bet I could get 22ish out of my truck at 60 mph in your part of the country, if not more. You also have to consider the CP3 trucks have 2 or 3 injection events and based on EFI Live testing removing and reducing them makes a big difference, up to 3 mpg is reported.. thats a real world 3 mpg not a marketing ploy. 12V's are very efficient motors, any way you cut it. They don't turn the rpms that newer trucks do, which has an effect on mileage when accelerating. I have heard 15-15.5° is about optimal for economy, power, and driveability on a 12V manual trans truck. Timing does play a decent role in my economy. The setting I have now I see at least .75 mpg better when cruising at 75-80, and on more advanced see 1-1.25 mpg better.

But a 2wd truck the same as mine gets 3mpg worse be it a CP3 or VP44. I know there are emissions things, but for a truck that is most efficient at all RPM's I would think they should be getting 30, as I know if my timing was dynamic I would probably have no problem hitting 30. At 55 I get 27.. I just see all these benefits on the newer trucks but it's like the thought process of having the benefits itself costs you mpg.

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But a 2wd truck the same as mine gets 3mpg worse be it a CP3 or VP44. I know there are emissions things, but for a truck that is most efficient at all RPM's I would think they should be getting 30, as I know if my timing was dynamic I would probably have no problem hitting 30. At 55 I get 27.. I just see all these benefits on the newer trucks but it's like the thought process of having the benefits itself costs you mpg.

Unfortunately emissions has taken a lot of the efficiency away, any way you look at. The P7100 runs lower injection pressure, less fuel at less pressure takes less horsepower to pump. The CP3 pumping up to 23K takes a bit of hp to make. Unfortunately there are far more variables than just the timing. I do agree that a dynamic P7100 would be pretty cool and probably yield great results.

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