Can timing in 06 be adv. w/ obd II?
08-08-2006, 08:54 AM
#4
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^^ if that's the case, then I wouldn't worry too much about it Chad...i have mine advanced to 17* on my 3.5 and I really can't tell any difference...I've heard it's the 3.0 where it really makes the difference, or if you are a heavily modded 3.5
08-08-2006, 09:08 AM
#6
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Originally Posted by NmexMAX
Explain why 'heavily modified' it would make more of a difference?
08-08-2006, 10:11 AM
#9
Dealer gave me run around, said it couldnt be advanced... I find that difficult to believe.
Does the 'reset' prompt come up on obd, or just on aplicable ecu's?
Apprec.
Fujita, udp, hotshot headers, y-pipe are mods thus far... still need 06 harness to wire Apex neo
Does the 'reset' prompt come up on obd, or just on aplicable ecu's?
Apprec.
Fujita, udp, hotshot headers, y-pipe are mods thus far... still need 06 harness to wire Apex neo
08-08-2006, 10:42 AM
#12
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Originally Posted by nismology
Ehh nevermind. Carrion...(pun intended)
My previous post wasn't directed at you specifically, BTW...
My previous post wasn't directed at you specifically, BTW...
08-08-2006, 12:13 PM
#13
Collin, I see where you question is now, this is a little bit of what I know...
Take cylinder #1 and put its piston at top dead center. We go from here, when the other cylinders were sparked in their right orders, they help turn the crankshaft which connects all the pistons to move up an down--towards and away from top dead center position. This turning will draw the #1 piston downwards away from top dead center while the camshaft lobe "rounds in" to open up the intake valve for that #1 cylinder. #1 piston moving down with the open intake valve in combination will draw air into the chamber till #1 piston is about at the bottom dead center; at which point, the lobe on the camshaft is timed to "round out" causing the intake valve to close. So then the piston travels across the bottom dead center spot and comes back up towards the top dead center again. During this stroke, all valves are supposed to be closed so compression becomes. This is where advance timing comes in. Advance timing is simply to fire a spark in advance before the piston lands right on the top dead center spot. The reason we advance the timing of this spark is to eliminate the spark delay because when and if the crank is at high spin rates and piston is traveling so fast, sparking at top dead center is consider delayed because the inertia of the piston traveling up has already at or passed it's threshhold to regain the downward traveling inertia. The whole idea is to give it the "umph" before it's too late. So they calculate the degrees before the piston gets to the top dead center position and fire the spark. That's where those advance timing in degrees come from. Then after the spark, it's the expansion stroke time when the piston is pusehd away from top dead center to trun the crank. When the piston comes back up, the exhaust camshaft lobe is timed to "round in" and push open the exhaust valve open and thus, exhaust out the wasted air. At the end of this exhaust stroke, the camshafts lobes of intake can be grinded to the geometry so that before the exahust valve is fully closed, the intake valve starts to open up--this is what "overlap" is. Then all 4 strokes of the cycles starts again.
I'm typing all this in assuming you didn't know that much, yet. But You may be beyond this knowledge here. So, dont' storm me for it. lol.
Further. When timing is advanced by too many degrees, it'll spark way before the piston travels up to the top dead center, causing the expansion of air suddenly to resist the piston's stroke up. Well, then you'll get a shake, knock, shock, or whatever the knock sensor senses as an abnormal phenomenon. That's when advance timing has maxed out, we really can't go beyond that critical point.
Now, for your question, how does engine speed affect timing...It has everything to do with it. Engine spins, pulls every pulley associated with it to spin. This spins the camshafts which has their lobes grinded out to open and close the intake and exhaust valves in direct relation to the piston positions and directions. This whole system constitute the mechanical part of the timing. If of this system is aligned to be off by some degrees, the electrical controller will spark according to "don't know what" and mess up the motor. Because sparks are fired at the wrong piston positions and directions. So, implicitly, engine speed determines the timing mechanically and electrically. It's all about getting it right.
I hope I've done it pretty good for you to understand.
I guess no one wants to type this much to explain it to you.
-Peter-
Take cylinder #1 and put its piston at top dead center. We go from here, when the other cylinders were sparked in their right orders, they help turn the crankshaft which connects all the pistons to move up an down--towards and away from top dead center position. This turning will draw the #1 piston downwards away from top dead center while the camshaft lobe "rounds in" to open up the intake valve for that #1 cylinder. #1 piston moving down with the open intake valve in combination will draw air into the chamber till #1 piston is about at the bottom dead center; at which point, the lobe on the camshaft is timed to "round out" causing the intake valve to close. So then the piston travels across the bottom dead center spot and comes back up towards the top dead center again. During this stroke, all valves are supposed to be closed so compression becomes. This is where advance timing comes in. Advance timing is simply to fire a spark in advance before the piston lands right on the top dead center spot. The reason we advance the timing of this spark is to eliminate the spark delay because when and if the crank is at high spin rates and piston is traveling so fast, sparking at top dead center is consider delayed because the inertia of the piston traveling up has already at or passed it's threshhold to regain the downward traveling inertia. The whole idea is to give it the "umph" before it's too late. So they calculate the degrees before the piston gets to the top dead center position and fire the spark. That's where those advance timing in degrees come from. Then after the spark, it's the expansion stroke time when the piston is pusehd away from top dead center to trun the crank. When the piston comes back up, the exhaust camshaft lobe is timed to "round in" and push open the exhaust valve open and thus, exhaust out the wasted air. At the end of this exhaust stroke, the camshafts lobes of intake can be grinded to the geometry so that before the exahust valve is fully closed, the intake valve starts to open up--this is what "overlap" is. Then all 4 strokes of the cycles starts again.
I'm typing all this in assuming you didn't know that much, yet. But You may be beyond this knowledge here. So, dont' storm me for it. lol.
Further. When timing is advanced by too many degrees, it'll spark way before the piston travels up to the top dead center, causing the expansion of air suddenly to resist the piston's stroke up. Well, then you'll get a shake, knock, shock, or whatever the knock sensor senses as an abnormal phenomenon. That's when advance timing has maxed out, we really can't go beyond that critical point.
Now, for your question, how does engine speed affect timing...It has everything to do with it. Engine spins, pulls every pulley associated with it to spin. This spins the camshafts which has their lobes grinded out to open and close the intake and exhaust valves in direct relation to the piston positions and directions. This whole system constitute the mechanical part of the timing. If of this system is aligned to be off by some degrees, the electrical controller will spark according to "don't know what" and mess up the motor. Because sparks are fired at the wrong piston positions and directions. So, implicitly, engine speed determines the timing mechanically and electrically. It's all about getting it right.
I hope I've done it pretty good for you to understand.
I guess no one wants to type this much to explain it to you.
-Peter-
08-08-2006, 12:34 PM
#14
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Originally Posted by GodFather
Collin, I see where you question is now, this is a little bit of what I know...
Take cylinder #1 and put its piston at top dead center. We go from here, when the other cylinders were sparked in their right orders, they help turn the crankshaft which connects all the pistons to move up an down--towards and away from top dead center position. This turning will draw the #1 piston downwards away from top dead center while the camshaft lobe "rounds in" to open up the intake valve for that #1 cylinder. #1 piston moving down with the open intake valve in combination will draw air into the chamber till #1 piston is about at the bottom dead center; at which point, the lobe on the camshaft is timed to "round out" causing the intake valve to close. So then the piston travels across the bottom dead center spot and comes back up towards the top dead center again. During this stroke, all valves are supposed to be closed so compression becomes. This is where advance timing comes in. Advance timing is simply to fire a spark in advance before the piston lands right on the top dead center spot. The reason we advance the timing of this spark is to eliminate the spark delay because when and if the crank is at high spin rates and piston is traveling so fast, sparking at top dead center is consider delayed because the inertia of the piston traveling up has already at or passed it's threshhold to regain the downward traveling inertia. The whole idea is to give it the "umph" before it's too late. So they calculate the degrees before the piston gets to the top dead center position and fire the spark. That's where those advance timing in degrees come from. Then after the spark, it's the expansion stroke time when the piston is pusehd away from top dead center to trun the crank. When the piston comes back up, the exhaust camshaft lobe is timed to "round in" and push open the exhaust valve open and thus, exhaust out the wasted air. At the end of this exhaust stroke, the camshafts lobes of intake can be grinded to the geometry so that before the exahust valve is fully closed, the intake valve starts to open up--this is what "overlap" is. Then all 4 strokes of the cycles starts again.
I'm typing all this in assuming you didn't know that much, yet. But You may be beyond this knowledge here. So, dont' storm me for it. lol.
Further. When timing is advanced by too many degrees, it'll spark way before the piston travels up to the top dead center, causing the expansion of air suddenly to resist the piston's stroke up. Well, then you'll get a shake, knock, shock, or whatever the knock sensor senses as an abnormal phenomenon. That's when advance timing has maxed out, we really can't go beyond that critical point.
Now, for your question, how does engine speed affect timing...It has everything to do with it. Engine spins, pulls every pulley associated with it to spin. This spins the camshafts which has their lobes grinded out to open and close the intake and exhaust valves in direct relation to the piston positions and directions. This whole system constitute the mechanical part of the timing. If of this system is aligned to be off by some degrees, the electrical controller will spark according to "don't know what" and mess up the motor. Because sparks are fired at the wrong piston positions and directions. So, implicitly, engine speed determines the timing mechanically and electrically. It's all about getting it right.
I hope I've done it pretty good for you to understand.
I guess no one wants to type this much to explain it to you.
-Peter-
Take cylinder #1 and put its piston at top dead center. We go from here, when the other cylinders were sparked in their right orders, they help turn the crankshaft which connects all the pistons to move up an down--towards and away from top dead center position. This turning will draw the #1 piston downwards away from top dead center while the camshaft lobe "rounds in" to open up the intake valve for that #1 cylinder. #1 piston moving down with the open intake valve in combination will draw air into the chamber till #1 piston is about at the bottom dead center; at which point, the lobe on the camshaft is timed to "round out" causing the intake valve to close. So then the piston travels across the bottom dead center spot and comes back up towards the top dead center again. During this stroke, all valves are supposed to be closed so compression becomes. This is where advance timing comes in. Advance timing is simply to fire a spark in advance before the piston lands right on the top dead center spot. The reason we advance the timing of this spark is to eliminate the spark delay because when and if the crank is at high spin rates and piston is traveling so fast, sparking at top dead center is consider delayed because the inertia of the piston traveling up has already at or passed it's threshhold to regain the downward traveling inertia. The whole idea is to give it the "umph" before it's too late. So they calculate the degrees before the piston gets to the top dead center position and fire the spark. That's where those advance timing in degrees come from. Then after the spark, it's the expansion stroke time when the piston is pusehd away from top dead center to trun the crank. When the piston comes back up, the exhaust camshaft lobe is timed to "round in" and push open the exhaust valve open and thus, exhaust out the wasted air. At the end of this exhaust stroke, the camshafts lobes of intake can be grinded to the geometry so that before the exahust valve is fully closed, the intake valve starts to open up--this is what "overlap" is. Then all 4 strokes of the cycles starts again.
I'm typing all this in assuming you didn't know that much, yet. But You may be beyond this knowledge here. So, dont' storm me for it. lol.
Further. When timing is advanced by too many degrees, it'll spark way before the piston travels up to the top dead center, causing the expansion of air suddenly to resist the piston's stroke up. Well, then you'll get a shake, knock, shock, or whatever the knock sensor senses as an abnormal phenomenon. That's when advance timing has maxed out, we really can't go beyond that critical point.
Now, for your question, how does engine speed affect timing...It has everything to do with it. Engine spins, pulls every pulley associated with it to spin. This spins the camshafts which has their lobes grinded out to open and close the intake and exhaust valves in direct relation to the piston positions and directions. This whole system constitute the mechanical part of the timing. If of this system is aligned to be off by some degrees, the electrical controller will spark according to "don't know what" and mess up the motor. Because sparks are fired at the wrong piston positions and directions. So, implicitly, engine speed determines the timing mechanically and electrically. It's all about getting it right.
I hope I've done it pretty good for you to understand.
I guess no one wants to type this much to explain it to you.
-Peter-
) and I can see now how engine speed affects the timing. Thanks a lot for explaining it all in detail. Now I have another question: what does our VVT do for determining ignition timing, if anything? I know it affects when the intake valves open and close, but does it affect the actual spark as well?
08-08-2006, 12:59 PM
#16
Originally Posted by LA02MAX
Now I have another question: what does our VVT do for determining ignition timing, if anything? I know it affects when the intake valves open and close, but does it affect the actual spark as well?
08-08-2006, 01:01 PM
#17
Originally Posted by LA02MAX
Yeah I knew all about the first and second paragraphs and you did a great job a summing it up. I see what you're saying in the third paragraph (after reading it a few times ) and I can see now how engine speed affects the timing. Thanks a lot for explaining it all in detail. Now I have another question: what does our VVT do for determining ignition timing, if anything? I know it affects when the intake valves open and close, but does it affect the actual spark as well?
) and I can see now how engine speed affects the timing. Thanks a lot for explaining it all in detail. Now I have another question: what does our VVT do for determining ignition timing, if anything? I know it affects when the intake valves open and close, but does it affect the actual spark as well?Dude, so you've known much already. Well, I know how the mechanical timing works, but I have yet to fully understand the electronic's of it. I've almost got the internship with Nissan this summer, but their crew is full. But from talking with the engineers there, VVT is their new technology that they wouldn't wanna let off. They did me a good education on the valve controls with cams, but they wouldn't explain the electronic's variation to me--it's proprietary. So I really dont' know much about their sparks. VVT isn't really new, it's new after they revised their plans on intake, camshafts, and Electronic emissions. Basically, they found ways to "optimize" their mechanical efficiency by leaps. Let me know what you've found. Also, I agree with Kevlo, find his little article, it helps out alot on a deeper understanding.
-Peter-
08-08-2006, 01:06 PM
#18
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Originally Posted by Kevlo911
You guys should read my tuning thread for n00bz I posted in this forum..
http://forums.maxima.org/showthread.php?t=481540
08-08-2006, 01:12 PM
#19
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Originally Posted by GodFather
Dude, so you've known much already. Well, I know how the mechanical timing works, but I have yet to fully understand the electronic's of it. I've almost got the internship with Nissan this summer, but their crew is full. But from talking with the engineers there, VVT is their new technology that they wouldn't wanna let off. They did me a good education on the valve controls with cams, but they wouldn't explain the electronic's variation to me--it's proprietary. So I really dont' know much about their sparks. VVT isn't really new, it's new after they revised their plans on intake, camshafts, and Electronic emissions. Basically, they found ways to "optimize" their mechanical efficiency by leaps. Let me know what you've found. Also, I agree with Kevlo, find his little article, it helps out alot on a deeper understanding.
-Peter-
-Peter-
08-08-2006, 01:19 PM
#20
Originally Posted by LA02MAX
holy crap was that thread helpful! So if I'm understanding this correctly, the ECU (and many other factors) actually advance the ignition timing as the engine speed increases because there is less and less time in which the A/F has to ignite before TDC...
http://forums.maxima.org/showthread.php?t=481540
http://forums.maxima.org/showthread.php?t=481540
You are correct! ECU is used to determine the advanced spark timing. On a distributor system, they actually turn the disc ahead by which ever degrees they want, but that can only get them correct to a certain range of rpms...
We have variable valve timing because of the engine speed. Like our variable intakes--longer runner for low end torque and shorter runners for high end torque. Back in the old days, they only have one length runners, so the way them runners are made will be optimized for the economical rpms. That's why VQ's with variable runners can score so good down low and moderately good up high. VVT is the same analogy concept. They are just controlling the valves for low and high range rpms.
08-08-2006, 01:30 PM
#21
Alot of the info being posted is way oversimplified. Furthermore, i won't be posting anything else since it seems my $.02 are worthless (in this and a couple other threads in this forum).
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