timing and nitrous

Exactly if you run CATCHER #9 with timing #3 that puts you at 18* +RP about 5* and NO2 your at 25-28* timing.

I ran timing #2 and the 12* on the TST plus the RP box. The truck liked it, I would never run it for and extended amout of time though.
 
full pull said:
Exactly if you run CATCHER #9 with timing #3 that puts you at 18* +RP about 5* and NO2 your at 25-28* timing.

I ran timing #2 and the 12* on the TST plus the RP box. The truck liked it, I would never run it for and extended amout of time though.
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When you guys are talking about RP "adding timing" I assume you're talking about the additional rail putting more fuel in faster with the same start of injection point right?

Cause obviously rail doesn't actually effect timing. It effects start of combustion and flame front propagation.

So when you guys say like above, RP adds ~5* of timing, that just means with the added rail the net effect is the same as if you had left the rail alone and just added 5* in terms of cylinder pressure?
 
Extreme Engines said:
18-19* of static timing is the most i would go, because when you factor in the added 27,000+ psi RP you are "really" getting about 24-26* of timing. RP has alot to do with timing.

Something to think about.:poke:
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I had heard this said before and I do not agree with it. Timing in a diesel is not the same as timing in a gasser. If you have 25* of timing in diesel that is the point before TDC that the injector is commanded to open. Rail pressure does not change that. Timing in a gasser is when the ignition lights the spark plug which in turn lights the fuel that is already in the cylinder.

Heat from compression lights the charge in a diesel not timing. Adding rail pressure gets more fuel in before TDC at the same timing then it would with a lower pressure. But the commanded open is the commanded open.

One giaint thing missing from this discussion is RPM. Timing numbers are great and all But CR timing is not static. 25* timing at 2000 rpm is to much IMHO but at 3000 or 4000?????. You need to think about timing in more than just Crank Angle Degrees. You need to think of as time. Time as in microseconds. You need so much time to get a given amount of fuel in before TDC. As the RPM goes up you need the same amount of time to get the same amount of fuel in. So you need to open the injector farther from TDC but your actual time is the same. 10* of timing at 2000rpm takes the same amount of time as 20* at 4000rpm. See where I am going here? Just looking at peak timing is not enough. You need to plot the entire curve of the timing vs RPM Then your getting somewhere.$.02
 
JOHNBOY said:
I had heard this said before and I do not agree with it. Timing in a diesel is not the same as timing in a gasser. If you have 25* of timing in diesel that is the point before TDC that the injector is commanded to open. Rail pressure does not change that. Timing in a gasser is when the ignition lights the spark plug which in turn lights the fuel that is already in the cylinder.

Heat from compression lights the charge in a diesel not timing. Adding rail pressure gets more fuel in before TDC at the same timing then it would with a lower pressure. But the commanded open is the commanded open.

One giaint thing missing from this discussion is RPM. Timing numbers are great and all But CR timing is not static. 25* timing at 2000 rpm is to much IMHO but at 3000 or 4000?????. You need to think about timing in more than just Crank Angle Degrees. You need to think of as time. Time as in microseconds. You need so much time to get a given amount of fuel in before TDC. As the RPM goes up you need the same amount of time to get the same amount of fuel in. So you need to open the injector farther from TDC but your actual time is the same. 10* of timing at 2000rpm takes the same amount of time as 20* at 4000rpm. See where I am going here? Just looking at peak timing is not enough. You need to plot the entire curve of the timing vs RPM Then your getting somewhere.$.02
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Here's something to think about when you're thinking about rail pressure and timing in the same discussion.

Overly advanced timing on a diesel will eventually become evident as an audible "rattle", if the bottom end does not undergo rapid disassembly before-hand. That sound is rapid combustion of a large "pocket" of diesel fuel. When the start of injection is continually pushed farther and farther in advance of TDC, the environment in that cylinder is (as you mentioned) cooler and cooler the farther you progress in advance of TDC. The pressure and temperature are lower. The result is that the burn rate of diesel fuel is slower and slower, and with increasing injection advance you run into a situation where the injection rate of the injector exceeds the burn rate of the diesel fuel at these points BTDC. In these cases, the fuel mass is building in the cylinder at a rate faster than it is igniting and burning off. The result is a large pocket of unburned fuel forming that instead of uniformly burning at a constant rate, will instead have a portion of the entire injection mass pooling and collecting as the injection event progresses. Then as the pressure/temperature in the cylinder continues to build and increase, the burn rate keeps increasing and increasing until at some point near TDC this large pocket of fuel will "flash" off rapidly, and uncontrollably. The result is a harsh increase in cylinder pressure, resulting from the wasting of good diesel fuel that could have worked to increase the BMEP ATDC nicely, but instead merely slammed the piston/CR like hell right near TDC, made the audible "rattle" for all to hear, and left the BMEP relatively unaffected.

The takeaway is, excessive timing advance produces a situation where you have too much fuel, too soon. It actually drops cylinder pressure/temperature as the fuel mass sucks heat out of the cylinder charge, and then flashes off spiking cylinder pressure.

Increasing rail pressure? Well, that increases injection rate. Making it that much easier to inject more fuel faster. Producing the exact same scenario of fuel amassing in the chamber instead of burning uniformly.

Having tuned injection pressure and timing separately, I can say that the net effect is very similar for each when the state of tune in use is practical.
 
Charles said:
Having tuned injection pressure and timing separately, I can say that the net effect is very similar for each when the state of tune in use is practical.
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X2,
Even the same quantity of fuel faster with the same begining point of injection = more timing. And is most deadly when there is oxygen.

For the most simple demonstration, pull the fca at idle, rail jumps to 20k or better, timing stays the same, duration drops to nothing. And "timing" rattle through the roof.

.....Kinda like the sound...more mechanical than that mushy CR idle.....
 
Charles said:
Here's something to think about when you're thinking about rail pressure and timing in the same discussion.

Overly advanced timing on a diesel will eventually become evident as an audible "rattle", if the bottom end does not undergo rapid disassembly before-hand. That sound is rapid combustion of a large "pocket" of diesel fuel. When the start of injection is continually pushed farther and farther in advance of TDC, the environment in that cylinder is (as you mentioned) cooler and cooler the farther you progress in advance of TDC. The pressure and temperature are lower. The result is that the burn rate of diesel fuel is slower and slower, and with increasing injection advance you run into a situation where the injection rate of the injector exceeds the burn rate of the diesel fuel at these points BTDC. In these cases, the fuel mass is building in the cylinder at a rate faster than it is igniting and burning off. The result is a large pocket of unburned fuel forming that instead of uniformly burning at a constant rate, will instead have a portion of the entire injection mass pooling and collecting as the injection event progresses. Then as the pressure/temperature in the cylinder continues to build and increase, the burn rate keeps increasing and increasing until at some point near TDC this large pocket of fuel will "flash" off rapidly, and uncontrollably. The result is a harsh increase in cylinder pressure, resulting from the wasting of good diesel fuel that could have worked to increase the BMEP ATDC nicely, but instead merely slammed the piston/CR like hell right near TDC, made the audible "rattle" for all to hear, and left the BMEP relatively unaffected.

The takeaway is, excessive timing advance produces a situation where you have too much fuel, too soon. It actually drops cylinder pressure/temperature as the fuel mass sucks heat out of the cylinder charge, and then flashes off spiking cylinder pressure.

Again this is all well and good but we are not dealing with static timing. Being to far advance can cause a quench that will result in a sudden Spike in CP. Bad. the rattle you describe. But saying that X* is to much without referencing that value to rpm is BS as we are not dealing with static timing It varys with RPM among other things. Back to the shape of the curve again. To much or to little is relative to time. More RPM means less time. Not timing.

Increasing rail pressure? Well, that increases injection rate. Making it that much easier to inject more fuel faster. Producing the exact same scenario of fuel amassing in the chamber instead of burning uniformly.

More pressure put more fuel in over a set peroid of time. The timing does not change. Command open is command open. Period.

Having tuned injection pressure and timing separately, I can say that the net effect is very similar for each when the state of tune in use is practical.
I have had the abilty to tune with both for over 3 years now similar yes but not the same. so saying that RP adds timing is not correct it does not. In increses the fuel load that can be deliver over a set peroid of time.
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Joesixpack said:
X2,
Even the same quantity of fuel faster with the same begining point of injection = more timing. And is most deadly when there is oxygen.

For the most simple demonstration, pull the fca at idle, rail jumps to 20k or better, timing stays the same, duration drops to nothing. And "timing" rattle through the roof.

.....Kinda like the sound...more mechanical than that mushy CR idle.....
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Take that same 20000psi, fuel shot, timing, and move it to 2000 rpm what happens? The rattle goes away. Why? Because even with the same timing the actual time before TDC is less than 1/2 what it was at idle. So the Cylinder pressure ramps up later as compared to TDC than it does at idle. The noise you here in that example. Is not a timing issue it is an overfuel is. Similar but not the same.
 
Timing

I run over 30K pressure with LOT'S of timing compared to what you guys talk about. I also run higher rpm than the dodge's i'm guessing. At around 4800 is my shift points in the upper gears and 4600 on the 1/2 shift. Very interesting talk and very civil I like that. Jeff
 
Timing

I slao agree with Johnboy as the rpm goes up so should the timing. Bigger injectors will help. Jeff
 
JOHNBOY said:
Take that same 20000psi, fuel shot, timing, and move it to 2000 rpm what happens? The rattle goes away. Why? Because even with the same timing the actual time before TDC is less than 1/2 what it was at idle. So the Cylinder pressure ramps up later as compared to TDC than it does at idle. The noise you here in that example. Is not a timing issue it is an overfuel is. Similar but not the same.
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I don't think anybody is talking about running __ degrees of timing from idle to redline. We aren't all running a P7100...

I think most people assume it's common knowledge that appropriate timing advance varies with rpm (at a minimum). Do you often encounter people that argue that point? I can't understand why you keep harping on that.

It doesn't matter what rpm you're at, what power adder you're running or anything else. Whatever the situation, there will be an appropriate range of timing advance for that situation. Being that most times changes of a single degree or so become significant, it is usually sufficient to speak in terms of a single value. And most times, that value is the maximum found anywhere in the rev range. I think most assume it to be understood that if you were running say, 30 degrees total advance, that you wouldn't be running 30 degrees at idle...

Unless of course you were working with a P7100 or similar.
 
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And I think it would be of benefit if people altered their conception of "timing" a bit. Timing is often times seen as synonymous with Injection Timing. But the over-riding concept is fuel timing. At what point BTDC do you inject __cc of fuel. If you picked any point BTDC and at any rpm/boost/everything else and you did nothing but calculate or measure the actual fuel injected at that point, you would literally have a value for fuel timing. You could vary injection timing and injection pressure wildly and still have the same value for cc per degree advance, and the engine would sound nearly identical in each case. And the cylinder pressure would be very similar in each case.

The over-riding concept is fuel per time. Too much fuel, too soon and you upset the cylinder. You can call it timing or rail if you wish. Doesn't matter what you call it, it's too much, too soon.
 
Well I think the OP may have found the too much point, he posted on another board that he split the block this weekend. :doh:
 
Im not sure how the SMARTY adds the timing I would assume that it would ramp up with boost or RPM... I know that the TST comes on at or around 20psi.

I understand that RP doesnt change the time the of the injector opening, but with more pressure it gets there faster. Think of a garden hose, if you only open the valve a little (lower RP) the water isnt going to come out of the hose very fast. now open the valve all the way (high RP) you will get more water faster. To me thats more fuel in the same amount of time, inturn your geting the same amount of fuel as if you had injected it earlier. To much of either and you will get fuel or timing knock whatever you want to call it, there both caused from to much fuel to early.
 
morkable said:
I want to get everyones opinion on how much timing I should be able to get away with while running nitrous. Right now I have my smarty on level 8 no additional timing,,,
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Heard you've joined the window'd block club.....:poke: I take it you found out how much timing you can get away with?
 
Yeah I did it big too,, both sides, have some pics up on my face book,, as soon as i get a moment I will upload the ones off of the camera
 
Hey Kevin, what year motor are you running? I think my failure was a split pistion first then the rest of the carnage.

Malcolm
 
It sure is John, it sure is. LOL

Malcolm it is a 03. From prelim observation it looks like possibly the #4 con rod let go, taking everything close to it with it.. I will pull the engine out and fully diagnose it when I get back home.. I hope it didnt destroy the head, but we will see.. truck was still running which blows me away
 
full pull said:
Exactly if you run CATCHER #9 with timing #3 that puts you at 18* +RP about 5* and NO2 your at 25-28* timing.

I ran timing #2 and the 12* on the TST plus the RP box. The truck liked it, I would never run it for and extended amout of time though.
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timeing 2 on tnt is 21* ive seen some bad stuff come from tst and tnt stacked were both are increasing timeing. what sticks are you running?
 
I don't know if this will help or hurt kevin ?? In the words of my late grandfather..... "tuition is expensive no matter which college you attended". Words of wisdom that still ring true.
 
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