Duallydog

I know this has been covered before but hey.
#1 (for Quad) How advanced can timing be and stay safe? How much timing can be added before getting into trouble when set on 100hp and 130hp on the Xzill? (305hp engine).
#2 How to manually advance timing
#3 Have those who have done the manual timing advance seen an increase in mileage?
#4 I heard a Ford 6.0L start on a cold morning and it had a really loud knock to it. Was the timing set pretty aggressive on it (high horse box/programmer) or is more likely pressure?
For some reason timing is on my mind.

qzilla

Well #1 is sort of a trick question. You can go 18-21 degrees on a stock truck and be safe. When you start adding extra fuel and boost to the mixture then the whole equation changes based on how much fuel and how much boost you want to run. The problem with timing is that it increses cyliner pressures which is what you want. That increases efficiency as well as makes more power. The downside is at somepoint you can blow headgaskets and even break wrist pins or pistons if the pressure get out of control.

So normally on a modified truck around 12 degress should be sufficient. The more you add the more power you will make but, the greater the risk in hurting something.

#2- You can monkey with the Cam and Crank Sensors. IF you go much over a couple of degrees on one you must do the other or you will get codes. You could also monkey with the Gears on the Cam and Crank but I don't know anyone who has ever done that?

#3- Some swear by it and some say it made no difference? I would have to think that 1-2degrees by itself would help only minimally.

#4- He probably had the pilot injection turned off or the timing was way out of whack when it was cold. The 6L's are way different than these trucks as the injectors are run off of oil pressure. Typically raising the oil pressure does not really make them rattle. Now there are plenty of people out there that have no regard to timing on those trucks because they respond so well to timing that they keep cranking on it. Then you can read the posts about how they are blowing headgaskets and blowing coolant everywhere.

Duallydog

Thanks Quad. The first one was just for you, I figured the others would chime in on the other 3. 12 Degrees including what would be added by the 100 and the 130hp Xzill? Am I thinking of one of the earlier generations (ISB, 12V) on the manual timing? You can turn the pilot injection off on a 6.0? Mileage gains are usually off of timing and pressure since there is more power being gained at XXXX rpm with less fuel correct?

v8440

In a gasoline engine, it is entirely possible (under some circumstances) to advance timing to the point that power is decreased, without encountering preignition and detonation. Of course, in a diesel preignition can't happen since there's no fuel to burn until the injection event.

What I'm leading up to is this: You can't simply say that more timing equals more power. There's a point of diminishing returns, then no gain, then a loss as you keep advancing timing. Look at this example for a minute-let's say you take the cylinder head off a motor, and you put a 200 lb weight on the piston in a cylinder. Now, you have a constant downward "pressure" on that piston of 200 lbs. As the piston is pushed down the bore by that pressure, you might think the twisting force imparted to the crankshaft by the rod would be constant, from TDC to BDC. If so, you'd be wrong. This is because of the changing rod angle as the piston travels. There is a point during that travel at which the twisting force on the crank will be at its maximum. The exact placement of that point is determined by rod length, or rod/stroke ratio to be exact.

Now, to further complicate things, the burn does not happen instantaneously. There is a gradual rise in pressure, a peak, then a decrease in pressure. To FURTHER complicate this, valve timing events play a role in this. So, you have a burn of not-zero length pushing down on pistons that have not-steady mechanical advantage against the crankshaft. As the engine revs, the burn has less and less time to push down on the piston.

Now, out of all this, we want to time the burn so as to impart maximum energy to the crankshaft. Remember, the piston has more leverage to turn the crank at some places than others. The leverage is 0 at TDC and BDC-think of how things are arranged (relationship of connecting rod to crankshaft) at those points and it will be obvious why. This fact is important because it means that not all cylinder pressure is created equal-at some points in piston travel, cylinder pressure is useless or even counterproductive. Therein lies the real reason why endlessly advancing timing won't help. Even if it wouldn't break stuff, it does no good to have cylinder pressure at TDC, and will actually cost power to start developing it before TDC.

All of these variables can be solved mathematically. In practice, it's probably easier to just experiment and see what the engine likes.

dodgezilla04

well dang, that was well thought out and worded very clearly. thank you v8440. a most professional and accurate post.

RamWheelsBy4

Duh, what he said . I just change settings, see if it starts, see if it will move, get in staging lane, see if it will build boost quick enough, go, see if it pops, blows or EGTs go over 1700*. If not perfect then change something and start all over again. Only way I know .

And with triple stack, TST with mulitple programs and TIMING CONTROL, EZ adjustments, 9 different Smarty programs the combinations are many. Will take a lot of time and hopefully find the best one before I find the WURST one.

Duallydog

Wow now that's detailed.