nGauge Datalogging - Knock Explanation?

[3beeps]

I took a 3rd gear datalog of my car and I'm just curious if someone can explain the "Knock" parameter. I come from Subaru land where knock is the main thing you're worrying about and it should always be 0 and never below -1.4 degree during WOT.

In my datalog, the knock column has both positive and negative numbers during WOT in 3rd gear and I don't really know what they mean in this case. Can someone explain it to me?

My mods are JLT intake, MBRP street catback, Lund tune w/ nGauge (93 octane). The car feels very strong and doesn't feel like it's pulling timing or anything, but I'm also new to this car so I have no idea what I'm talking about.

:cheers:

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[Major League Infidel]

If you car is showing a negative number then the car is adding timing. if it shows a positive number then that means the sensors are detecting knock and that it is pulling a small amount of timing to keep the knock in check.

 

[markmurfie]

The rules for all engines are the same as far as knock. You want your ignition timing to be on the knock threshold. This means spark happening any sooner would cause the engine to produce knock. This is referred to as borderline ignition timing. If you have positive knock that means your ecu was told to use ignition values too aggressive for the fuel you had in your tank. Some tuners richen up the afr to remedy this. The better way is to lower the ignition values in the ecu and leave the afr alone. When the ecu receives positive numbers it holds the ignition timing back for a period of time after which reduces the power of the engine. This is done to protect and ensure the engine operates safety in case you get some very bad gas. This brings us to the negative knock values. Sometimes the fuel you have is a little more resistant to knock(higher octane). The knock sensors can determine this by not sensing knock. The ecu will then add ignition values until they do and back off a little. This ensures you get the most out of the quality of fuel you are getting. Letting the ecu manage the ignition timing in this way can give inconsistent power as knock sensors are not perfect. It is safer than positive knock, but done to aggressively can less to a very bad situation.

 

[3beeps]

Appreciate the info guys.

I saw +/- 2 towards the top part of the powerband so I was worried. I sent the log to my tuner but I've been waiting for a reply for a few days and really want to get to the bottom of it since it's scary when knock isn't 0.

 

[markmurfie]

I wouldn't worry to much. You definitely want to sort it out to get the most power out of your tune. Engines can live a very long time with a small amount of knock. It's when it gets excessive that they don't last long.

I would pay attention to your lambda value before and after and make sure your tuner isn't just adding more fuel to correct the problem. You want the ecu to be happy with the ignition numbers and not a bandaid of too much fuel for bad numbers.

 

[3beeps]

I wouldn't worry to much. You definitely want to sort it out to get the most power out of your tune. Engines can live a very long time with a small amount of knock. It's when it gets excessive that they don't last long.

I would pay attention to your lambda value before and after and make sure your tuner isn't just adding more fuel to correct the problem. You want the ecu to be happy with the ignition numbers and not a bandaid of too much fuel for bad numbers.

Lund is tuning the car so I'd imagine I'm in great hands. Awaiting a reply though..

 

[markmurfie]

I'm sure you're in good hands.

Just giving you info to look out for to get the most out of your tune. Just know is easier to tell the car to add some fuel than it is to go over the numerous ignition timing tables and correct them. Both will correct the problem, one will result in more power than the other. Most customers will be happy either way and not even know the difference.

 

[GSLSE20B]

My 91 base FF tune adds 10 on mine . Never gets +knock

 

[markmurfie]

My 91 base FF tune adds 10 on mine . Never gets +knock

The FF tunes are designed to be dynamic. This applies to tunes for a single fuel. OP said he had a 93 tune.

 

[MyFirst5.0]

I took a 3rd gear datalog of my car and I'm just curious if someone can explain the "Knock" parameter. I come from Subaru land where knock is the main thing you're worrying about and it should always be 0 and never below -1.4 degree during WOT.

:

lol..i come from subaru land as well..how good did you sleep the day you got your mustang and didnt have to worry about cracking a ringland? :lol: i just got my ngauge today, will flash this weekend, what are you viewing as gauges on your ngauge? i know for subaru, the feedback knock, fine knock learning and DAM were all important, i have no idea what to monitor on the mustang..im just a 3" catback, stock intake, i learned on the intakes from subaru..

 

[3beeps]

lol..i come from subaru land as well..how good did you sleep the day you got your mustang and didnt have to worry about cracking a ringland? :lol: i just got my ngauge today, will flash this weekend, what are you viewing as gauges on your ngauge? i know for subaru, the feedback knock, fine knock learning and DAM were all important, i have no idea what to monitor on the mustang..im just a 3" catback, stock intake, i learned on the intakes from subaru..

Man I got the Mustang so I didn't have to monitor anything. I'm extremely far from the limits so I don't wanna be monitoring every single time I hit the gas. I keep the Gauge off most of the time.

 

[MyFirst5.0]

Man I got the Mustang so I didn't have to monitor anything. I'm extremely far from the limits so I don't wanna be monitoring every single time I hit the gas. I keep the Gauge off most of the time.

i was told just flash it and not worry, but coming from a subaru i just cant do that..:frusty: im sure lunds tune is like cobbs stage 1, good power and its safe..

 

[markmurfie]

For the most part the mustang while still N/A will be safe with any reputable tuner. You probably could just flash and enjoy. If you want the most you can get out if it then you should data log and get revisions.

 

[MyFirst5.0]

For the most part the mustang while still N/A will be safe with any reputable tuner. You probably could just flash and enjoy. If you want the most you can get out if it then you should data log and get revisions.

i will probably do a few logs, however i dont know what lund is looking for. with my wrx, it was 3 pulls in 3rd gear from 3k to redline, (around 80 or so mph) . i emailed lund to see what they require

 

[markmurfie]

i will probably do a few logs, however i dont know what lund is looking for. with my wrx, it was 3 pulls in 3rd gear from 3k to redline, (around 80 or so mph) . i emailed lund to see what they require

I'm not sure I've never directly worked with them.
With your mods I'm sure they will tell you everything is fine you don't need logs which is probably true seeing as they have tuned so many cars with your combo and have no problems. From what I gather they are very busy so if you are willing to wait I'm sure you will eventually get any problems you have with your tune sorted out. In the mean time you have nothing to worry about enjoy the additional fun it brought to your car.

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