[Jason]

We do not close threads simply because someone demands it. If a thread is generally on-topic, civil, constructive, and does not violate forum rules, it should remain open.

The scope of this entire thread is beyond Sevak's situation. There are discussions continuing in this thread which do not relate specifically to Sevak's situation, but N54 technical discussions in general. It remains on-topic to the subforum, discussions remain constructive, and is covering topics which members are interested in discussing further (of course it could have done with less of the tuner vs. tuner drama).

However, Sevak's response to the situation has been added to the OP for easy reference by readers. Further off-topic posts will be deleted.

[klipseracer]

Originally Posted by Jason

We do not close threads simply because someone demands it. If a thread is generally on-topic, civil, constructive, and does not violate forum rules, it should remain open.

The scope of this entire thread is beyond Sevak's situation. There are discussions continuing in this thread which do not relate specifically to Sevak's situation, but N54 technical discussions in general. It remains on-topic to the subforum, discussions remain constructive, and is covering topics which members are interested in discussing further (of course it could have done with less of the tuner vs. tuner drama).

However, Sevak's response to the situation has been added to the OP for easy reference by readers. Further off-topic posts will be deleted.

nice!

[Mr. 5]

Originally Posted by Jason

We do not close threads simply because someone demands it. If a thread is generally on-topic, civil, constructive, and does not violate forum rules, it should remain open.

The scope of this entire thread is beyond Sevak's situation. There are discussions continuing in this thread which do not relate specifically to Sevak's situation, but N54 technical discussions in general. It remains on-topic to the subforum, discussions remain constructive, and is covering topics which members are interested in discussing further (of course it could have done with less of the tuner vs. tuner drama).

However, Sevak's response to the situation has been added to the OP for easy reference by readers. Further off-topic posts will be deleted.

True. I have been following this thread and although I have not seen every single post, I have found that this thread has had some very good discussions.

[shifterboy45]

Originally Posted by Ilma

Don't believe the DME is seeing the spike, but if the AF ratio is going lean for a split second then I can see the logic in a knock event occuring.....especially if the DME is riding along the inception of knock.

this is a very good discussion of some of the basics required to accurately tune a car. but there is something i would like to add as food for thought...

to get maximum drivabilty, factors other than boost, timing, octane, cylinder environment, etc.. have a substantial effect on the outcome. one factor this is commonly overlooked is road speed and actual load. if these elements are not a part of your equation nothing will make sense. the road is not a static environment, nor is every street the same.

road simulation on a dyno is required, the operators' ability to induce incremental loads through the power absorbsion unit can make a big differnce is locating (isolating) less than optimal performance.

unless you find the optimal road conditions, and use them for every test, every run.. your documented results will vary from a little to a whole hell of a lot. this includes ambient temp, generated road heat, traction, or lack of it ...

thats only if you want to be accurate and reproducible

[CBR335]

Originally Posted by shifterboy45

this is a very good discussion of some of the basics required to accurately tune a car. but there is something i would like to add as food for thought...

to get maximum drivabilty, factors other than boost, timing, octane, cylinder environment, etc.. have a substantial effect on the outcome. one factor this is commonly overlooked is road speed and actual load. if these elements are not a part of your equation nothing will make sense. the road is not a static environment, nor is every street the same.

road simulation on a dyno is required, the operators' ability to induce incremental loads through the power absorbsion unit can make a big differnce is locating (isolating) less than optimal performance.

unless you find the optimal road conditions, and use them for every test, every run.. your documented results will vary from a little to a whole hell of a lot. this includes ambient temp, generated road heat, traction, or lack of it ...

thats only if you want to be accurate and reproducible

I agree. You can really see this manifest itself when data logging on the flat vs an uphill road in a single or multi-gear pull. Timing curves alone behave very differently with varying degrees of load in my experience as does the propensity to knock. A road simulating load-bearing dyno would really aid in developing dynamic mapping.

[Ilma]

Originally Posted by shifterboy45

this is a very good discussion of some of the basics required to accurately tune a car. but there is something i would like to add as food for thought...

unless you find the optimal road conditions, and use them for every test, every run.. your documented results will vary from a little to a whole hell of a lot. this includes ambient temp, generated road heat, traction, or lack of it ...

thats only if you want to be accurate and reproducible

Glad you piped in shifterboy......

I do use the exact same stretch of (safe) road each time I datalog so I try to keep as many of the variables as constant as I can control.

But it's hard to control the weather.

I have tried......but failed!

In any case, the timing logs do vary a bit from run to run so what I shoot for in dialing in is to see whether the majority of my timing logs for identical boost and ignition correction tend to be smooth, spike free and upward sloping to 11+ degrees by around 6K rpm.

So if one out of three logs has a single 3 degree dip, but the other two logs are knock-free then I feel pretty good that my settings are close enough to make me comfortable for how I drive on the street.

I generally will not do more than a 3rd to 4th gear WOT on the highway in daily driving....so that is what I log.

A single gear log is not enough as CBR335 pointed out......heat is cummulative, so you need a couple of gears, or a long 4th gear pull.

I try to use the worst-case scenario by heat-soaking the engine with a couple of prliminary pulls before I do my datalog, because generally I find you get less knock on a cool engine than one that has been thermally challenged.

Of course weather changes all the time, so the case is made for autotune here.

But because no one has really answered the question as to how much knock is considered "normal" and acceptable, I prefer to get as little of it as possible.

Even autotune averages the number of knock events before adjusting the tuning parameters, so in some sense it is initially reactive before becoming proactive.

Does that make any sense?

[vasillalov]

Originally Posted by Mike@N54Tuning.com

1) The JB3 G3 box can't itself monitor knock activity or air/fuel ratio. So it is up to the high HP user pushing the boundaries to monitor this via an external tool like the CT to display them on dash or the BT for logging to a laptop.

Mike

You've got to be kidding me! Seriously, now...

How does this method help prevent damage when the user is doing a WOT pull down the drag strip and the engine is running at max rpms? Knock events are fast and NO HUMAN is capable of making adjustments fast enough to address the issue. The tune must be smart and capable to be able to PREDICT, not REACT to such events. That's called proper tuning.

Reacting to a knock event is like mopping up after you spill a glass of water on floor. You are much better of to be careful and not spill the water in the first place.

[Mike@N54Tuning.com]

Originally Posted by vasillalov

You've got to be kidding me! Seriously, now...

How does this method help prevent damage when the user is doing a WOT pull down the drag strip and the engine is running at max rpms? Knock events are fast and NO HUMAN is capable of making adjustments fast enough to address the issue. The tune must be smart and capable to be able to PREDICT, not REACT to such events. That's called proper tuning.

Reacting to a knock event is like mopping up after you spill a glass of water on floor. You are much better of to be careful and not spill the water in the first place.

Knock monitoring is inherent to tuning and much of tuning is inherently reactive. You just need to look for subtle clues before you push things too far. If you don't want or know how to monitor engine parameters you should not be making your own maps or using existing maps outside of their suggested guidelines. With the G4 knock monitoring is automatic so a big step forward in that regard but if someone wants to turn the autotuning off and misuse the progressive methanol input that is on them.

Mike

[Ilma]

Originally Posted by Mike@N54Tuning.com

Knock monitoring is inherent to tuning and much of tuning is inherently reactive. You just need to look for subtle clues before you push things too far. If you don't want or know how to monitor engine parameters you should not be making your own maps or using existing maps outside of their suggested guidelines. Mike

Speaks to using products as designed, but instead of arguing about it why don't we just answer the question below?

Originally Posted by Ilma

But because no one has really answered the question as to how much knock is considered "normal" and acceptable, I prefer to get as little of it as possible.

[Mike@N54Tuning.com]

Originally Posted by Ilma

Speaks to using products as designed, but instead of arguing about it why don't we just answer the question below?

The only method we have to measure knock is the DME's short term timing trims. That the DME puts timing back in quickly off these short term trims and that they often occur on stock tuning as well tells us that level of activity isn't overly detremenal. If the designers considered them detrimental they would have made the long term trims more aggressive meaning timing would be added back much more slowly off dips. That short term system in general is a great gauge for how aggressive you're running.

Mike

[OpenFlash]

Originally Posted by Mike@N54Tuning.com

The only method we have to measure knock is the DME's short term timing trims. That the DME puts timing back in quickly off these short term trims and that they often occur on stock tuning as well tells us that level of activity isn't overly detremenal. If the designers considered them detrimental they would have made the long term trims more aggressive meaning timing would be added back much more slowly off dips. That short term system in general is a great gauge for how aggressive you're running.

Mike

The designers calibrated the knock control system to support 5-9psi of boost. The effects of knock (cylinder pressure spike) are more severe at higher boost pressures. This means knocking at 5psi is far less damaging than knocking at 15psi.

If the designers were to re-calibrate the knock control system to support 15psi, you can bet that it would be mapped to respond differently. If you ever tuned a knock control system on a good standalone computer, you'd already know this. And would never post such a ridiculous response. Then again, this is the first turbo engine that Terry ever tuned. With boost controllers no less.

Shiv

[Ilma]

Originally Posted by shiv@vishnu

The designers calibrated the knock control system to support 5-9psi of boost. The effects of knock (cylinder pressure spike) are more severe at higher boost pressures. This means knocking at 5psi is far less damaging than knocking at 15psi.

If the designers were to re-calibrate the knock control system to support 15psi, you can bet that it would be mapped to respond differently. If you ever tuned a knock control system on a good standalone computer, you'd already know this. And would never post such a ridiculous response. Then again, this is the first turbo engine that Terry ever tuned. With boost controllers no less.

Shiv

There is some cross-validation to what you are saying in that link that I posted about detonation earlier in this thread.

Some detonation can be tolerated in low power engines for a long time.....but the higher the output, the less tolerance to knock.......

Here is the excerpt:

"Detonation is not necessarily destructive. It's not an optimum situation but it is not a guaranteed instant failure. The higher the specific output (HP/in3) of the engine, the greater the sensitivity to detonation. An engine that is making 0.5 HP/in3 or less can sustain moderate levels of detonation without any damage; but an engine that is making 1.5 HP/in3, if it detonates, it will probably be damaged fairly quickly, here I mean within minutes.

Detonation causes three types of failure:

1. Mechanical damage (broken ring lands)

2. Abrasion (pitting of the piston crown)

3. Overheating (scuffed piston skirts due to excess heat input or high coolant
temperatures)"


So detonation would seem more relevant/critical as you push more power.....as the tunes do.

[OpenFlash]

Originally Posted by Ilma

There is some cross-validation to what you are saying in that link that I posted about detonation earlier in this thread.

Some detonation can be tolerated in low power engines for a long time.....but the higher the output, the less tolerance to knock.......

Here is the excerpt:

"Detonation is not necessarily destructive. It's not an optimum situation but it is not a guaranteed instant failure. The higher the specific output (HP/in3) of the engine, the greater the sensitivity to detonation. An engine that is making 0.5 HP/in3 or less can sustain moderate levels of detonation without any damage; but an engine that is making 1.5 HP/in3, if it detonates, it will probably be damaged fairly quickly, here I mean within minutes.

Detonation causes three types of failure:

1. Mechanical damage (broken ring lands)

2. Abrasion (pitting of the piston crown)

3. Overheating (scuffed piston skirts due to excess heat input or high coolant
temperatures)"


So detonation would seem more relevant/critical as you push more power.....as the tunes do.

Exactly!

[Ilma]

So in some sense......given that tunes push power and heat higher than stock levels....there will be more and more susceptibility to knock events, and these knock events will be even more of an issue due to the higher boost pressures.

I wonder if the resulting pressure spikes from detonation amplify with more boost....or is the higher boost pressure just a faster trigger?

[Ilma]

Originally Posted by Mike@N54Tuning.com

That the DME puts timing back in quickly off these short term trims and that they often occur on stock tuning as well tells us that level of activity isn't overly detremenal.

Mike

Yes...I think shifterboy has alluded to that.

If you have a knock event due to heat, then you have to reduce heat and the DME does this by pulling out some timing.

The next step should be to stabilize the unfavourable conditions (if they truly do exist).

If the combustion chamber was overheating, I would imagine that adding timing back in would just recreate the heat and result in another knock event in short order.

If however, your timing curve keeps rising after the knock event, then I get the impression this was just a DME induced adjustment for some reason other than knock.......at least that's what I like to believe.

I have also seen where the timing curve stays flat after the knock event.....neither rising nor dropping - so I am not sure what to make of this one.

[shifterboy45]

Originally Posted by Ilma

There is some cross-validation to what you are saying in that link that I posted about detonation earlier in this thread.

Some detonation can be tolerated in low power engines for a long time.....but the higher the output, the less tolerance to knock.......

Here is the excerpt:

"Detonation is not necessarily destructive. It's not an optimum situation but it is not a guaranteed instant failure. The higher the specific output (HP/in3) of the engine, the greater the sensitivity to detonation. An engine that is making 0.5 HP/in3 or less can sustain moderate levels of detonation without any damage; but an engine that is making 1.5 HP/in3, if it detonates, it will probably be damaged fairly quickly, here I mean within minutes.

Detonation causes three types of failure:

1. Mechanical damage (broken ring lands)

2. Abrasion (pitting of the piston crown)

3. Overheating (scuffed piston skirts due to excess heat input or high coolant
temperatures)"


So detonation would seem more relevant/critical as you push more power.....as the tunes do.

normally aspirated cars can endure a lot more knock related incidents due to the lower compression ratios. the power translation is lower and geared toward economy.

if you ever want to see the actual power of detonation, look for a AA fueler that detonated. its clear that the event is destructive... instanteously --

as for timing control, its just like an umbrella, you take one out even if its just misting, right.. it not as though you can eliminate every drop from hitting you.. but its purpose is shield you -- so keeping the timing at optimal is not done by waiting for the knock to happen, but provide variable below the threshold. try this for an example, if you have a 6MT -- from a stand still give it a little less gas than normal, allow it to bog and ping a little -- the service engine soon light will come on almost immediately.

now remember that the knock event occured at a lower rpm, little or no boost, and barely moving. the system will sense the knock and switch maps to prevent engine damage. now this "detected" knock wtih DME intervention based on given parameters -- what is the result when there is substantially more boost, and a heck of a lot of rpms involved. how many knock events will occur at that speed, and how well will the system control them?

riding the knock sensor for optimal power gains have the result of lessening engine longevitiy ... working under the knock umbrella is always the best way to make power

[Mike@N54Tuning.com]

Originally Posted by shiv@vishnu

The designers calibrated the knock control system to support 5-9psi of boost. The effects of knock (cylinder pressure spike) are more severe at higher boost pressures. This means knocking at 5psi is far less damaging than knocking at 15psi.

If the designers were to re-calibrate the knock control system to support 15psi, you can bet that it would be mapped to respond differently. If you ever tuned a knock control system on a good standalone computer, you'd already know this. And would never post such a ridiculous response. Then again, this is the first turbo engine that Terry ever tuned. With boost controllers no less.

Shiv

Nothing but the normal insults out of you. I've never claimed to be a tuner but Terry has tuned plenty of forced induction applications prior to the N54. Including the first to tune a turbo LT1 motor using a standalone system back in 1997. Around 630whp on 9.8:1 compression with mostly pump gas if I remember the story.

As I said looking at the short term drops is the only method currently viable for determining how close to the knock threshold you are. Fewer drops are probably better but its an inherently reactive method. Now that BMS has full CAN they're exploring a few new options. Among them reading the knock sensors directly to catch occurrences sooner in the cycle. Also turns out there are a few CAN commands that influence the OEM timing set points directly. Things are going to get interesting soon.

Mike

[infinitekidM2C]

This is the guy's version of a soap opera..i likes it actually lol

[Jeff@TopGearSolutions]

We can complain or remark about the bickering, but this is what makes our tunes better... so its good for us at the end of the day.

[infinitekidM2C]

im not complaining, just enjoying lol..and i agree competition creates better products most of time..definitely here...

[Mark313]

Originally Posted by infinitekid2002

This is the guy's version of a soap opera..i likes it actually lol

Me too.

[Belarus]

Originally Posted by shiv@vishnu

The designers calibrated the knock control system to support 5-9psi of boost. The effects of knock (cylinder pressure spike) are more severe at higher boost pressures. This means knocking at 5psi is far less damaging than knocking at 15psi.

If the designers were to re-calibrate the knock control system to support 15psi, you can bet that it would be mapped to respond differently. If you ever tuned a knock control system on a good standalone computer, you'd already know this. And would never post such a ridiculous response. Then again, this is the first turbo engine that Terry ever tuned. With boost controllers no less.

Shiv

+1 agree 100%