Max cruise timing
- Thread starter arinkuddy
- Start date
tylerltr450
Wanna Be Hacker
Did you try an testing yourself?
arinkuddy
New member
This was between 1200 - 2000 RPM and 0 - 45mm3
I am running around 8 - 11 deg of main timing in this area. I think 11 is about as high as I want to go. I am using about 8 deg of pilot timing in the same area which will make pilot start around 16 - 19 degrees BTDC. The pilot qty is low here at 2mm3.
Keeping the pilot timing and qty the same and changing tunes between the 8 - 11 degrees I see a improvement in mileage the higher main timing I use. My theory is that I reduce fuel consumption by reducing pilot qty and compensating by raising the main timing. I wanted to be able to change this timing using the CSP5 and in the winter use the higher timing to compensate for thinner fuel. I am still testing but the best mileage touched into the 20s. Thats with 35" tires, and a leveling kit too.
Thats all I got and anywhere not in that cruising range I have a lot less timing.
Edit: Fuel pressure is not really increased in this range.
I am running around 8 - 11 deg of main timing in this area. I think 11 is about as high as I want to go. I am using about 8 deg of pilot timing in the same area which will make pilot start around 16 - 19 degrees BTDC. The pilot qty is low here at 2mm3.
Keeping the pilot timing and qty the same and changing tunes between the 8 - 11 degrees I see a improvement in mileage the higher main timing I use. My theory is that I reduce fuel consumption by reducing pilot qty and compensating by raising the main timing. I wanted to be able to change this timing using the CSP5 and in the winter use the higher timing to compensate for thinner fuel. I am still testing but the best mileage touched into the 20s. Thats with 35" tires, and a leveling kit too.
Thats all I got and anywhere not in that cruising range I have a lot less timing.
Edit: Fuel pressure is not really increased in this range.
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JWhite
Trained monkey
I'd try putting the pilot further ahead, like 16 or 17. Then drop main to under 8.
Try increasing fuel pressure too on a couple files, pushing up to 100-130 depending on load. At 2000 rpm I'd try and be full pressure by 60-70% throttle.
This is based on what I've seen, and how mine is set up, so FWIW
Try increasing fuel pressure too on a couple files, pushing up to 100-130 depending on load. At 2000 rpm I'd try and be full pressure by 60-70% throttle.
This is based on what I've seen, and how mine is set up, so FWIW
arinkuddy
New member
When you increase pilot qty you essentially shorten the time between end of pilot and beginning of main. I've done this and yes it works, but you can do the same thing by decreasing pilot timing, and use less fuel at the same time. Thats what I'm doing and there is no rattle at all.
2007 5.9
West Coast Dyno Modifier
Partially right but mostly incorrect...
Unless you modify the pilot to main "limiter" your not changing anything in regards to "shortening" the time between pilot and main...your mentioned way is simply giving pilot less time to fully burn. While it may reduce your rattle, the way I mention is much simpler and adding 25uS is hardly increasing your fuel consumption.
Two different ways of doing things.
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arinkuddy
New member
Ok say you are running at 1800 RPM, 7º of pilot timing, and 2mm3 of pilot qty which is from 270-160µS depending on fuel pressure, I'll use 215µS.
Using
[(DegOfPilot*60)/(RPM*360)]-PilotDuration=TimeFromEndPilotToMain
-OR-
[(7*60)/(1800*360)]-0.000215=0.000433=443µS
So there is 433µS between end of pilot and start of main. The Limit is 250µS. So there is plenty of time between pilot and main still, and no need to adjust the limiter. This allows you to decrease the pilot qty and get rid of rattle at the same time. You don't need a complete pilot burn you just need it to heat the cylinder up enough to get rid of rattle. Why put more fuel in way advanced then you need to when you can get the same effect by doing this. I actually used excel and interpolated the pilot pulse table and compared it to logs and they agree.
If you don't think its right thats cool, I just wanted to show off a little of my research. I really think pilot is a contributor to poorer mileage. Why else would no pilot tunes produce pretty decent mileage numbers?
JWhite
Trained monkey
I could be misreading, but I think Les is saying your low pilot qty might not actually be burning. And THAT is wasted fuel.
Have you tried doing it his way? Or just don't think it'll work?
And if turning pilot off gets so much better MPG, why not kill it and deal with the noise?
Have you tried doing it his way? Or just don't think it'll work?
And if turning pilot off gets so much better MPG, why not kill it and deal with the noise?
phale
Comp Diesel Sponsor
no pilot tunes produce pretty good mileage because you have to run a minimum positive timing value. On a multi injection tune timing is often negative except for the actual cruising area. Get off of the cruising part of the table and you can go from 8* to -5* pretty quick depending on how you build the table which hurts economy but is useful for other things. The minimum 5-8* needed for a single event tune to run properly ensures you are always running timing conducive to economy while it may not deliver the best results in other areas.
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phale
Comp Diesel Sponsor
On a second note, when you remove pilot the ecm will automatically increase commanded main duration to compensate and maintain desired rpm. You really do not save much if any fuel by removing the pilot pulse. Shortening the time between shots can actually be detrimental to economy as it shortens the dwell time. In general more timing of either event will give more time for the air/fuel mixture to develop and results in a more economical burn. This of course has its limits as you can put too much dwell time between shots and advance the total injection event too far and reach the desired mixture rate before the point of auto ignition which in turn can cause fuel droplets to form on the piston and cylinder walls resulting in poor combustion known as "wet stacking" or early detonation (high cylinder pressures).
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2007 5.9
West Coast Dyno Modifier
arinkuddy
New member
I've ran a tune the way Les mentioned for a long time. I got ok mileage, no problems really. Then I started playing around with no pilot and I got about 2-3 mpg better. Not crazy good, ehh worth looking into. I really get tired of the loud rattle so I wanted to use pilot. I don't care if the pilot isn't getting burnt all before the main because the main will finish it off. I mean its not like its smoking white or even black. Keep in mind I'm only talking about cruise region here.
arinkuddy
New member
Curious but did you ever look closely at the logs between pilot and no pilot. On mine I would run in the 45-55mm3 with pilot and with no pilot I was consistently between 30-45mm3. That looks to me like less fuel/duration. I don't think the ECM cares, it is just commanding what ever is in the tables that keeps you at 60mph. I can make some more logs to prove this again because I don't have the files anymore.
I agree with you on your timing logic. There is a limit to the amount of timing you can add before it starts hurting you. I think 10˚ of pilot added to about 9˚ of main might be a little too much at cruise RPM. That pilot shot is way out there early and the cylinder probably isn't going to be hot enough for it to start burning. If anything too much pilot timing would cause droplets of fuel hitting the piston and cylinder. I actually think stock pilot timing on the 5.9 overall is ridiculously advanced.
On your previous comment on no pilot yeah I agree the spooling takes a hit because you have to run higher timing all over. I get better low end performance using pilot no disagreements there.
I'm not saying you guys are wrong theres more then one way to skin a cat.