How much timing under boost?
11-30-2009, 07:18 PM
#21
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Ok.
Pinging, or pinking: This is a light metallic clinking sound. It is caused by the ignition being too far advanced. What happens is the pressure rise in the cylinder happens too early and the piston rattles against the bore as it goes over TDC. This is a mechanical rattle and it has nothing to do with combustion.
Knock: Inside the combustion chamber as the flame front spreads out from the spark plug a series of reactions take place in the gases ahead of the flame front. We call the gases furthest away from the spark plug the end gases, and under certain conditions they can auto ignite. Instead of a smooth burn, we now have two flame front's colliding with each other producing a knocking sound. This noise is much heavier than the light pinking sound.
Pre-ignition, or detonation: Pre-ignition will kill an engine stone dead very quickly. This is where the air fuel mixture burns before the spark arrives. This is caused by something in the combustion chamber getting hot enough to ignite the fuel mixture, usually the spark plug overheats. Spark plug overheating can be caused by using the wrong plug grade for your application, but it is more commonly caused by ignition timing which is too far advanced and/or a weak mixture. The increased combustion temperature caused by advanced ignition or a weak mixture causes the plug to overheat and pre-ignition takes place. The plug is almost always the source, even if it isn't the cause.
To describe the different levels of pinking/knock/detonation you could say, pinking will make you concerned, knock will make you wince, and detonation will make you cringe.
Pinging, or pinking: This is a light metallic clinking sound. It is caused by the ignition being too far advanced. What happens is the pressure rise in the cylinder happens too early and the piston rattles against the bore as it goes over TDC. This is a mechanical rattle and it has nothing to do with combustion.
Knock: Inside the combustion chamber as the flame front spreads out from the spark plug a series of reactions take place in the gases ahead of the flame front. We call the gases furthest away from the spark plug the end gases, and under certain conditions they can auto ignite. Instead of a smooth burn, we now have two flame front's colliding with each other producing a knocking sound. This noise is much heavier than the light pinking sound.
Pre-ignition, or detonation: Pre-ignition will kill an engine stone dead very quickly. This is where the air fuel mixture burns before the spark arrives. This is caused by something in the combustion chamber getting hot enough to ignite the fuel mixture, usually the spark plug overheats. Spark plug overheating can be caused by using the wrong plug grade for your application, but it is more commonly caused by ignition timing which is too far advanced and/or a weak mixture. The increased combustion temperature caused by advanced ignition or a weak mixture causes the plug to overheat and pre-ignition takes place. The plug is almost always the source, even if it isn't the cause.
To describe the different levels of pinking/knock/detonation you could say, pinking will make you concerned, knock will make you wince, and detonation will make you cringe.
11-30-2009, 07:27 PM
#22
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Just for the record...
I never asked for a magic number. I'm not an idiot, I understand the basics of the project. I kept a stock 2003 @ 9psi w/ a stock lower end together for 10k very hard driven miles before it popped. Total miles on ODO were 16k at ground zero. It was my toy, not my daily driver. Road tuned with a WBO2 and my ear. I got a few 12.1's out of it with my crude tune according to the accelerometer I had at the time. I suppose I should have just asked what others are running for timing under boost. I would never attempt a borderline/risky tune on a fresh motor w/o some place to start. That's all I needed. By the way if you read the entire thread you'll notice that I sold the car to a friend and am trying to help him out with a base setup before he goes to the dyno after break in. I hope he can find someone qualified and trustworthy here in Vegas to tune the thing. See a lot of horror stories about tuners on the forum. Have not heard about any really great shops here in Vegas.
Thanks again...bon voyage....no more Z's for me
09 CTS-V sounds like a fun next project though
I never asked for a magic number. I'm not an idiot, I understand the basics of the project. I kept a stock 2003 @ 9psi w/ a stock lower end together for 10k very hard driven miles before it popped. Total miles on ODO were 16k at ground zero. It was my toy, not my daily driver. Road tuned with a WBO2 and my ear. I got a few 12.1's out of it with my crude tune according to the accelerometer I had at the time. I suppose I should have just asked what others are running for timing under boost. I would never attempt a borderline/risky tune on a fresh motor w/o some place to start. That's all I needed. By the way if you read the entire thread you'll notice that I sold the car to a friend and am trying to help him out with a base setup before he goes to the dyno after break in. I hope he can find someone qualified and trustworthy here in Vegas to tune the thing. See a lot of horror stories about tuners on the forum. Have not heard about any really great shops here in Vegas.
Thanks again...bon voyage....no more Z's for me
09 CTS-V sounds like a fun next project though
At least you get to the point!
12-01-2009, 09:16 AM
#24
I was also wondering what kind of timing other people are running on their boosted setups. I am using the UTEC APS base map on my HKS GTRS TT, but shifted the columns to match my 0-10 psi open loop range. In the 70% load column (6-7 psi) my timing is between 19 and 23 BTDC. Seems like it might be a little high...but then again I have yet to record a knock when logging with the UTEC.
12-01-2009, 12:41 PM
#26
Well the UTEC uses MAP as the "load" reference, so what I was saying is that at full boost (~6.5 psi) and WOT my timing is between 19 and 23 degrees. These numbers were derived from the APS TT base map that TurboXS provides for the UTEC. Looking at other TurboXS base maps, such as the Turbonetics and the GReddy base map, these numbers seem high (although it is hard to tell without knowing the minimum and maximum mapping values for each base map, which are found in the parameter files and they don't make much sense looking at them in text editor).
12-01-2009, 01:04 PM
#27
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Well the UTEC uses MAP as the "load" reference, so what I was saying is that at full boost (~6.5 psi) and WOT my timing is between 19 and 23 degrees. These numbers were derived from the APS TT base map that TurboXS provides for the UTEC. Looking at other TurboXS base maps, such as the Turbonetics and the GReddy base map, these numbers seem high (although it is hard to tell without knowing the minimum and maximum mapping values for each base map, which are found in the parameter files and they don't make much sense looking at them in text editor).
12-01-2009, 01:05 PM
#28
Well the UTEC uses MAP as the "load" reference, so what I was saying is that at full boost (~6.5 psi) and WOT my timing is between 19 and 23 degrees. These numbers were derived from the APS TT base map that TurboXS provides for the UTEC. Looking at other TurboXS base maps, such as the Turbonetics and the GReddy base map, these numbers seem high (although it is hard to tell without knowing the minimum and maximum mapping values for each base map, which are found in the parameter files and they don't make much sense looking at them in text editor).
12-01-2009, 01:07 PM
#29
I haz da turbos
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It depends also on how they tuned it. Maybe they run there tune richer with more timing advance, whereas others may run it a bit leaner with less timing.
12-01-2009, 02:01 PM
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You guys hit it on the head about the number of variables. You can take the same car and run 15 psig or 13 psig, and have vastly different timing maps that might actually make similar power depending on how efficent the forced induction is at the various pressure ratios. If the setup is super-efficient at 6.5 psig and the tune is fairly rich, no reason not to run a lot of timing so long as the engine make sbetter power with it.
12-01-2009, 08:02 PM
#31
Octane is 93, intake temps are low because I live in Michigan. I just recently finished the turbo install about 6 weeks ago, and I don't think it has gotten above 65 degrees outside since then. IIRC, my air intake temps have been in the 15-20 C range which I realize is quite cool. Also, at 6 psi I doubt the turbos are working very hard or making very much heat. That is probably why I haven't seen any knock with the timing values I have been running. My A/F is about 13.5:1 at 0 psi and goes down into the high 11's at 6 psi. I must say though, the car is a beast! There is no point in me making any more power until I get wider tires. The stock size tires spin like crazy in 2nd gear when the boost hits!
One thing that comforts me a little (just a little) is looking at the stock timing numbers in the logs vs. the UTEC numbers. The UTEC numbers are generally retarded several degrees from what the stock ECU is trying to do, so at least I know that I am going in the right direction
.
One thing that comforts me a little (just a little) is looking at the stock timing numbers in the logs vs. the UTEC numbers. The UTEC numbers are generally retarded several degrees from what the stock ECU is trying to do, so at least I know that I am going in the right direction
.
12-02-2009, 08:40 AM
#32
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/\ it is not that simple. First how do you know your Utec Knock settings are calibrated right? Knock setting should be calibrated on the dyno. Post your knock settings so we can take a look but even then every car is different. Since our ECU dont monitor knock past 5000rpm, just look at what the ECU is doing below that. If you see the ECU is pulling timing below 5000rpm then most likely you are knocking.
12-06-2009, 09:56 AM
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Dv8, it is not quite that simple (they can knock before tq drops) - but you've got the idea. And no, assuming all things constant it is not going to quit making power and then start again as you continue to advance timing.
Regarding your utec, are you sure it is not just knocking and cutting back a lot on timing to protect? Have you tried reducing timing rather than reducing sensitivity? You may want to visit a tuner as well - it does not take a lot of error to blow a VQ with regards to timing.
Regarding your utec, are you sure it is not just knocking and cutting back a lot on timing to protect? Have you tried reducing timing rather than reducing sensitivity? You may want to visit a tuner as well - it does not take a lot of error to blow a VQ with regards to timing.
The f'ed up thing is that timing is pretty mild on my setup. Since then we've increased the threshold thinking its just vibration and tuned timing until there wasnt anymore power to be gained. at that point we pull 1 degree back from the last decent gain for saftey. Ive been driving like that for over a year now and alls been good.
The low mustang numbers (298whp@9.5psi) so its always got me thinking that the car should be making more power than it really is.
Thanks.
~Dv8
12-06-2009, 10:32 AM
#34
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It's not an opinion it's facts. Ping is another name for detonation, knock is also another name for detonation. Pre-ignition is NOT another name for detonation.
That said, ping or knock are usually used to describe very light detonation. A little light knock won't usually hurt a built motor. Heavy detonation could definitely hurt any motor.
Just because you don't think ping and knock are forms of detonation doesn't change the fact that they are.
Read up
http://en.wikipedia.org/wiki/Engine_knocking
Pre-ignition is NOT detonation.
12-08-2009, 11:26 AM
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So glad to see this information being put out!
Pre-ignition is more or less when you get the air/fuel mix igniting before ignition and often when the piston is still going up. It will kill any piston/rod. Rod bearings will look nasty to, just like they can with detonation.
Detonation is essentially when the mix ignites far too rapidly after the sprak plug fires and has characteristics more like an explosion than an orderly progressive flame front.
Detonation occurs when temperatures and pressures in the chamber exceed the levels that a given air/fuel mix can handle. In other (perhaps over-simplified) words, it happens when you run out of octane.
Pre-ignition often happens when you have a really hot spark plug electrode or exhaust valve that ignites the air/fuel mix before the plug even fires.
12-08-2009, 12:40 PM
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So glad to see this information being put out!
Pre-ignition is more or less when you get the air/fuel mix igniting before ignition and often when the piston is still going up. It will kill any piston/rod. Rod bearings will look nasty to, just like they can with detonation.
Detonation is essentially when the mix ignites far too rapidly after the sprak plug fires and has characteristics more like an explosion than an orderly progressive flame front.
Detonation occurs when temperatures and pressures in the chamber exceed the levels that a given air/fuel mix can handle. In other (perhaps over-simplified) words, it happens when you run out of octane.
Pre-ignition often happens when you have a really hot spark plug electrode or exhaust valve that ignites the air/fuel mix before the plug even fires.
12-10-2009, 10:03 PM
#38
I haz da turbos
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It's not an opinion it's facts. Ping is another name for detonation, knock is also another name for detonation. Pre-ignition is NOT another name for detonation.
That said, ping or knock are usually used to describe very light detonation. A little light knock won't usually hurt a built motor. Heavy detonation could definitely hurt any motor.
Just because you don't think ping and knock are forms of detonation doesn't change the fact that they are.
Read up
http://en.wikipedia.org/wiki/Engine_knocking
Pre-ignition is NOT detonation.
That said, ping or knock are usually used to describe very light detonation. A little light knock won't usually hurt a built motor. Heavy detonation could definitely hurt any motor.
Just because you don't think ping and knock are forms of detonation doesn't change the fact that they are.
Read up
http://en.wikipedia.org/wiki/Engine_knocking
Pre-ignition is NOT detonation.
You didn't read my post properly then, because i am describing three different levels of knock/detonation, just as you said. I've read that artical on wikipedia before, and i've also done some other research on my own. My source comes from 2 pro tuners, one of which is a retired tuner for the subaru world rally team, plus a couple of books on tuning.
Yes the article on wikipedia, along with a few other people say it's not the same, but then other people will say it is the same, so who do you believe? I've just done some research and come to my own conclusion.
So yes. Everyone has their opinion, wether you and half the world think so or not.
Last edited by ReV2Red; 12-10-2009 at 10:37 PM.
12-11-2009, 10:57 AM
#39
on my old utec tune with a greddy tt 11.5psi 91 octane we were running roughly 12* initially but I would pick up slight knock counts inconsistently and eventually turned the timing way down to 9 degrees to have it fully smooth regardless of temperature (100 degree to 10 degrees - lovely colorado). I could of gone with more timing yea but I wasn't too concerned about massive power, the power was good regardless at roughly 490whp at that time after pulling timing. IIRC the midrange was roughly 14-18* 18* being in the lower rpm and timing sliding off down to 14ish range* as the rpm's picked up in the load sites. Of course the timing varied all over but usually mid range it was below 19*, and redline was below 13* on the high load cells and rpm's.
Once you get your redline smooth, pay attention to your mid as that's the PITA part as your load will always vary and it will take some time and miles to data log the hell out of a UTEC and drive off boost, slow roll into boost etc with normal daily driving.
Be careful and if you feel your car hesitate its pulling timing so let off and re-adjust those rpm/load sites with LESS timing (this assume your fuel ratio is good to begin with).
Good luck street tuning till you can get it on a proper dyno.
Once you get your redline smooth, pay attention to your mid as that's the PITA part as your load will always vary and it will take some time and miles to data log the hell out of a UTEC and drive off boost, slow roll into boost etc with normal daily driving.
Be careful and if you feel your car hesitate its pulling timing so let off and re-adjust those rpm/load sites with LESS timing (this assume your fuel ratio is good to begin with).
Good luck street tuning till you can get it on a proper dyno.
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12-11-2009, 06:33 PM
#40
Hal didn't you used to tune your Maxima on the street, not the dyno 
We all have to start some where, certainly you've progressed well past that. Guys like this could possibly tune their cars, possibly blow it up, but good for them for trying. You've got to blow up one or two to figure it our, right? For sure with out using the dyno he will more than likely leave some power on the table.
I do find that in the 350Z world or maybe just on this forum that their is a very odd propensity for beginners to be quickly directed to a shop, rather than encouraged to try it themselves and give the information they request. Perhaps this is the capitalistic marketing machine in action? The Nissan stuff is not any more complex than Honda or Chevy, its just fuel and air, metal and oil.
I salute the DIY folks who have the guts, to try it. It takes an investment of time and determination to get the skill set to work on cars at this level. Some folks don't have the time, don't have the location, or they just have enough money to not care, shops are good for these folks. For some of the folks who start off DIY it turns in to a lifetime career, but they to started out DIY for a time...
We all have to start some where, certainly you've progressed well past that. Guys like this could possibly tune their cars, possibly blow it up, but good for them for trying. You've got to blow up one or two to figure it our, right? For sure with out using the dyno he will more than likely leave some power on the table. I do find that in the 350Z world or maybe just on this forum that their is a very odd propensity for beginners to be quickly directed to a shop, rather than encouraged to try it themselves and give the information they request. Perhaps this is the capitalistic marketing machine in action? The Nissan stuff is not any more complex than Honda or Chevy, its just fuel and air, metal and oil.
I salute the DIY folks who have the guts, to try it. It takes an investment of time and determination to get the skill set to work on cars at this level. Some folks don't have the time, don't have the location, or they just have enough money to not care, shops are good for these folks. For some of the folks who start off DIY it turns in to a lifetime career, but they to started out DIY for a time...
Last edited by MardiGrasMax; 12-11-2009 at 06:35 PM.
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