Timing Effects

[AH64ID]

Without knowing how long the injector is open (above pop pressure) for I don't think you can fill that spreadsheet out, but maybe you could. A CR at high pressure will inject 100mm3 of fuel much faster than a p-pump will, so the CR needs less timing to get a 50% split (or whatever you want). So 16° of timing on a p-pump may be like 13° of timing on a CR (arbitrary numbers). Timing on a p-pump is best set to where you normally spend your time, rpm/load wise. If you lived empty on the highway then a more retarded timing would be good, but load the truck up with a big trailer and it wouldn't be as efficient. Just like you can time it for towing up 8% grades at 2300 rpms, and it will be a little louder and less efficient at 1800. It's still a guess on a CR, but it's easier to change and predict since all the variables of injection are known. We still don't know ignition delay, but can take a conservative guess.

[ISX]

I think I can figure out how long the injector is open. Yes timing is set where you spend the most time but we have NOTHING to go by. 13-16 is good but I want exact numbers. Shouldn't be a guessing game. I know being static that you just have to set it somewhere close but still, this guessing game is a bunch of crap. Basically I can measure the distance the plunger goes up and the distance it is actually pressurizing and then do a bunch of fancy math to calculate the time it takes to push all that fuel in using the profile of the cam in the pump. It might not be the exact duration that the injector is firing but I think it would be close [enough]. Actually timing on mine is retarded at high load. It has these retarding notches in the plunger to get more fuel in at the cost of timing which supposedly retards it 2*. I need to test it to see exactly how much. It is only on the 215 pumps.

[AH64ID]

Even with all the control of a CR it's still a guessing game, unless you have a way to measure peak cylinder pressure and relate it exactly to rpms. Ignition delay isn't exact, timing has delays, IAT's, ECT's, Cetane, altitude, boost, rpms, and amount of fuel all have an effect.Does the 215 motor run more boost than the lower hp motors?

[Mopar1973Man]

Depends on the turbo... Like the 1st gen with a HX35W turbo will boost 30-35 PSI without thinking. But stock it barely makes 15 PSI H1C Turbo.

[ISX]

Even with all the control of a CR it's still a guessing game, unless you have a way to measure peak cylinder pressure and relate it exactly to rpms. Ignition delay isn't exact, timing has delays, IAT's, ECT's, Cetane, altitude, boost, rpms, and amount of fuel all have an effect. Does the 215 motor run more boost than the lower hp motors?

So you're saying your calculator is a guess.. We need a genset with all the sensors and crap on it to test everything to get exact figures. I can get pretty exact readings on all of that except cetane, ignition delay, and cylinder pressure. I know there is a lot more to it than just that. So again, genset with dynamic timing p7100 (they did make those) and then a fuel rate thing and see which timing has the lowest fuel rate for a number of loads/rpms. I've been wanting to do that so bad for years. I think you mean in stock form on the boost and yes it is wastegated at 23ish and the lower HP ones were more like 18-20. I have a thread on some forum (no clue as I once ran around on a bunch) and I actually tracked the mm3 of all the different pumps even the VP44 ones. There are a lot of them with the same number but different HP ratings. This even applied to the 12V with the same stock timings. The injector sizes are all different though so I guess even though the pump could do whatever mm3/stroke, the injector could only get so much out.

[ISX]

Depends on the turbo... Like the 1st gen with a HX35W turbo will boost 30-35 PSI without thinking. But stock it barely makes 15 PSI H1C Turbo.

The 1st gens had all sorts of exhaust housing sizes on them, from 12 to 21. They sure didn't have the power to push a 21 and only the later ones finally got down to 12 like they have been ever since. The 2nd gens have all been 12cm from 94-02. Except for the HY turbos.

[AH64ID]

So you're saying your calculator is a guess.. We need a genset with all the sensors and crap on it to test everything to get exact figures. I can get pretty exact readings on all of that except cetane, ignition delay, and cylinder pressure. I know there is a lot more to it than just that. So again, genset with dynamic timing p7100 (they did make those) and then a fuel rate thing and see which timing has the lowest fuel rate for a number of loads/rpms. I've been wanting to do that so bad for years.

No, the calculator is exact in terms of when you inject. But I am still guessing on ignition delay, and what injection point is optimal for peak pressure at 12-15° ATDC. I don't worry too much about ignition delay, as the pilot greatly reduces it. As far as boost, ECT, and IAT the ECM adjusts timing properly (well I think, not a parameter of UDC). Yeah, fuel burn per hp is the easiest way to measure optimal timing. Dynamic timing should have been on the trucks, and static on the genset.

I think you mean in stock form on the boost and yes it is wastegated at 23ish and the lower HP ones were more like 18-20.

That could be the reason for the timing retard, and emissions. And possibly why the 180 pump is preferred for big power.

I have a thread on some forum (no clue as I once ran around on a bunch) and I actually tracked the mm3 of all the different pumps even the VP44 ones. There are a lot of them with the same number but different HP ratings. This even applied to the 12V with the same stock timings. The injector sizes are all different though so I guess even though the pump could do whatever mm3/stroke, the injector could only get so much out.

Well just like on a CR, you can get a variety of hp out of the same mm3. Timing and rpms play a big role in that.

The 1st gens had all sorts of exhaust housing sizes on them, from 12 to 21. They sure didn't have the power to push a 21 and only the later ones finally got down to 12 like they have been ever since. The 2nd gens have all been 12cm from 94-02. Except for the HY turbos.

IMHO emissions and drivers (wanting diesel engines with gas response) has caused diesels to run more boost than needed. A 21cm housing 12V ran like a true diesel. My 18cm Garrett runs more like a true diesel, still spools and accelerates crazy fast (bb baby!), but it cruises with lower boost and lower backpressure.

[ISX]

Well I'll throw something out there to rock your world. MAN diesel (the biggest diesel company out there and the company that rudolph himself worked with) created a diesel said to be the most efficient in its class. What it did was had some sort of dual stage turbo that created incredibly high boost (80psi) and well those big engines always end up in some static RPM application, so it was designed to be running WOT at this 80psi. The reason for this high boost pressure was to get the air in the combustion chamber as fast as possible because they had the valve lash set so loose that the valves would barely open, meaning there was less power lost by a valve opening. For example, the exhaust valve opens nearing the end of the power stroke, but not after, so some power is lost, not much I'm sure, but some. Then you have the intake valve staying open into the compression stroke, so the air doesn't get compressed as much. So they said if we had a ton of boost, we could make the exhaust valve open later and the intake valve close sooner since the boost would drive the exhaust out quicker and replenish the combustion chamber with fresh air faster. I will have to find the article and more details on it but that was the gist of it.

[AH64ID]

Diesels in general have such high boost per lb/min because of the low valve lift, unlike a gasser. A gasser at 8 psi may be moving more air than a diesel at 30 psi. So I could see that, but the 80 psi is a result of high resistance, not high flow, at least thats what it sounds like. We are after flow, just like I now run less boost and more air with my current cam/turbo setup and more hp at lower EGT's.