Knock tables with Built Motors
Dec 10, 2010, 07:41 AM
#1
Evolving Member
Thread Starter
iTrader: (14)
Join Date: Dec 2009
Location: New York
Posts: 362
Likes: 0
Received 0 Likes
on
0 Posts
Knock tables with Built Motors
To all the tuners out there, do you guys always adjust the sensitivity of the knock tables with cars with built motors in order to make power?
Dec 10, 2010, 07:55 AM
#2
Mine are still stock, however I suspect I may have a bit of phantom knock around 2800rpm. next time I'm at the pumps I'll fill up on 94 instead of 91 and see if it goes away. If it doesn't, I'll increase the 2500 and 3k rpm multipliers by one.
I would say leave them stock and see if you're getting any knock at low loads. Det cans would be a good thing to have to verify whether any knock you encounter is real or not.
I would say leave them stock and see if you're getting any knock at low loads. Det cans would be a good thing to have to verify whether any knock you encounter is real or not.
Dec 10, 2010, 08:12 AM
#4
I agree with Raptord. I had the stock tables on my car and was getting phantom knock from 2500-3000. I just slightly increased the multiplier table in this region and it solved the problem. I double checked before hand to verify it was phantom (gas test and det cans) and then edited the tables.
That being said, some built motors run a little more rough than others. Some have said that BR motors are built loose and are prone to some extra noise, I personally don't believe this and have had 0 issues with my 2.1L 4G64 and the stock knock tables. Rough cam choices can also lead to excess noise that could cause some phantom knock.
Make sure you check first that it is phantom, don't want to be ignoring real knock.
That being said, some built motors run a little more rough than others. Some have said that BR motors are built loose and are prone to some extra noise, I personally don't believe this and have had 0 issues with my 2.1L 4G64 and the stock knock tables. Rough cam choices can also lead to excess noise that could cause some phantom knock.
Make sure you check first that it is phantom, don't want to be ignoring real knock.
Dec 11, 2010, 04:08 AM
#5
Evolved Member
The best way is to check with det cans, turn off knock control by zeroing out the max knock count, then do a pull or two and have someone who knows what knock is listen while you're logging knock.
Trending Topics
Dec 11, 2010, 08:53 AM
#8
Is the added knock resistance of going from 91 to 94 octane enough to determine if it's real or not, or is race gas needed to have enough of a difference? My (suspected phantom) knock is right around 2800 rpm, and it doesn't seem to depend on the load. I can get it anywhrere from 60-70 load cruising on the highway to ~120 load entering boost.
Dec 11, 2010, 09:00 AM
#9
make sure the timing map is as smooth as humanly possible in that area, that area will cause knock if not smooth.
How much knock are we talking? If I only had access to 94octane and i was tuning with 91octane I would throw the 94 octane in and if its gone then you need to retard timing in that area, if its not gone then you need to retard timing in that area.. if it continues after you felt you retarded so much timing that its getting out of hand then you need to alter the knock MULTIPLIER table for the low load or lower the sensitivity or make it ignore knock before 159 load in that area. There are multiple ways to get rid of the knock / check if its real or fake , etc.
also wiggle around the intercooler piping and stuff, if anything hits then that can cause it also. maybe even the clicking of your grimmspeed 3 port could cause it also, depending where its mounted!
How much knock are we talking? If I only had access to 94octane and i was tuning with 91octane I would throw the 94 octane in and if its gone then you need to retard timing in that area, if its not gone then you need to retard timing in that area.. if it continues after you felt you retarded so much timing that its getting out of hand then you need to alter the knock MULTIPLIER table for the low load or lower the sensitivity or make it ignore knock before 159 load in that area. There are multiple ways to get rid of the knock / check if its real or fake , etc.
also wiggle around the intercooler piping and stuff, if anything hits then that can cause it also. maybe even the clicking of your grimmspeed 3 port could cause it also, depending where its mounted!
Dec 11, 2010, 09:51 AM
#11
make sure the timing map is as smooth as humanly possible in that area, that area will cause knock if not smooth.
How much knock are we talking? If I only had access to 94octane and i was tuning with 91octane I would throw the 94 octane in and if its gone then you need to retard timing in that area, if its not gone then you need to retard timing in that area.. if it continues after you felt you retarded so much timing that its getting out of hand then you need to alter the knock MULTIPLIER table for the low load or lower the sensitivity or make it ignore knock before 159 load in that area. There are multiple ways to get rid of the knock / check if its real or fake , etc.
also wiggle around the intercooler piping and stuff, if anything hits then that can cause it also. maybe even the clicking of your grimmspeed 3 port could cause it also, depending where its mounted!
How much knock are we talking? If I only had access to 94octane and i was tuning with 91octane I would throw the 94 octane in and if its gone then you need to retard timing in that area, if its not gone then you need to retard timing in that area.. if it continues after you felt you retarded so much timing that its getting out of hand then you need to alter the knock MULTIPLIER table for the low load or lower the sensitivity or make it ignore knock before 159 load in that area. There are multiple ways to get rid of the knock / check if its real or fake , etc.
also wiggle around the intercooler piping and stuff, if anything hits then that can cause it also. maybe even the clicking of your grimmspeed 3 port could cause it also, depending where its mounted!
Dec 11, 2010, 11:10 AM
#12
Some motors are more sensitive than others to be sure.
Since there is a table for load vs rpm I normally use this one first. Setting the car up so the knock control is inactive below let's say 100% load or 110% typically cures all phantom knock issues and leaves the rest of the knock control stock. I have logged knock voltage since it became an available channel. Comparing the 2 makes it easy, when trained to notice trends, to see if phantom knock is getting you are possibly real knock. My car is definitely not so lucky and needed a little more adjustment in the knock table, where Jake's (one of our techs) 2.4 is a little tighter motor and doesnt seem to have any issues.
I usually compare knock like this-
Timing vs boost
Knock vs boost
knock sum vs knock voltage
Then compare all 3 relative to each other. If I know the timing vs boost is "normal" then I look at how much knock vs boost I am actually seeing, if that doesnt seem normal at all I continue and look at the knock sum vs voltage to see if its most likely phantom or if there is a real voltage spike. I have been on the dyno and seen real knock at .61v and no knock at 3.94v so even then its not a 100% guarantee that you have it down pat. I try det cans occasionally and I am sure some are better than others but I have yet to hear knock on motors that I feel are safe despite what the sensor is telling me.
Since there is a table for load vs rpm I normally use this one first. Setting the car up so the knock control is inactive below let's say 100% load or 110% typically cures all phantom knock issues and leaves the rest of the knock control stock. I have logged knock voltage since it became an available channel. Comparing the 2 makes it easy, when trained to notice trends, to see if phantom knock is getting you are possibly real knock. My car is definitely not so lucky and needed a little more adjustment in the knock table, where Jake's (one of our techs) 2.4 is a little tighter motor and doesnt seem to have any issues.
I usually compare knock like this-
Timing vs boost
Knock vs boost
knock sum vs knock voltage
Then compare all 3 relative to each other. If I know the timing vs boost is "normal" then I look at how much knock vs boost I am actually seeing, if that doesnt seem normal at all I continue and look at the knock sum vs voltage to see if its most likely phantom or if there is a real voltage spike. I have been on the dyno and seen real knock at .61v and no knock at 3.94v so even then its not a 100% guarantee that you have it down pat. I try det cans occasionally and I am sure some are better than others but I have yet to hear knock on motors that I feel are safe despite what the sensor is telling me.
Last edited by JohnBradley; Dec 11, 2010 at 11:15 AM.
Dec 12, 2010, 09:36 AM
#13
Evolving Member
Thread Starter
iTrader: (14)
Join Date: Dec 2009
Location: New York
Posts: 362
Likes: 0
Received 0 Likes
on
0 Posts
Some motors are more sensitive than others to be sure.
Since there is a table for load vs rpm I normally use this one first. Setting the car up so the knock control is inactive below let's say 100% load or 110% typically cures all phantom knock issues and leaves the rest of the knock control stock. I have logged knock voltage since it became an available channel. Comparing the 2 makes it easy, when trained to notice trends, to see if phantom knock is getting you are possibly real knock. My car is definitely not so lucky and needed a little more adjustment in the knock table, where Jake's (one of our techs) 2.4 is a little tighter motor and doesnt seem to have any issues.
I usually compare knock like this-
Timing vs boost
Knock vs boost
knock sum vs knock voltage
Then compare all 3 relative to each other. If I know the timing vs boost is "normal" then I look at how much knock vs boost I am actually seeing, if that doesnt seem normal at all I continue and look at the knock sum vs voltage to see if its most likely phantom or if there is a real voltage spike. I have been on the dyno and seen real knock at .61v and no knock at 3.94v so even then its not a 100% guarantee that you have it down pat. I try det cans occasionally and I am sure some are better than others but I have yet to hear knock on motors that I feel are safe despite what the sensor is telling me.
Since there is a table for load vs rpm I normally use this one first. Setting the car up so the knock control is inactive below let's say 100% load or 110% typically cures all phantom knock issues and leaves the rest of the knock control stock. I have logged knock voltage since it became an available channel. Comparing the 2 makes it easy, when trained to notice trends, to see if phantom knock is getting you are possibly real knock. My car is definitely not so lucky and needed a little more adjustment in the knock table, where Jake's (one of our techs) 2.4 is a little tighter motor and doesnt seem to have any issues.
I usually compare knock like this-
Timing vs boost
Knock vs boost
knock sum vs knock voltage
Then compare all 3 relative to each other. If I know the timing vs boost is "normal" then I look at how much knock vs boost I am actually seeing, if that doesnt seem normal at all I continue and look at the knock sum vs voltage to see if its most likely phantom or if there is a real voltage spike. I have been on the dyno and seen real knock at .61v and no knock at 3.94v so even then its not a 100% guarantee that you have it down pat. I try det cans occasionally and I am sure some are better than others but I have yet to hear knock on motors that I feel are safe despite what the sensor is telling me.
Oct 11, 2011, 11:04 AM
#14
So as requested at KC IFO, I am going to expand on this a little and provide some reading.
Knock Voltage we are really concerned with spikes more than high voltage normally. The old rule of thumb was anything over 2.3v was getting noisy and then look for spikes above that. With the outline I have above you can normally figure it out.
Let's use this thread for "Phantom Knock" post logs, screen shots, etc. I cant promise I will be on it 100% but I think are enough gurus that we can kind of help. There is no replacement for experience. This is a pretty touchy deal and can ultimately lead to engine failure so not understanding it or not seeing it in person is a HUGE limitation. For the most part any race fuel or ethanol will not be real knock. The only condition that could cause that is the timing is WAY PAST MBT.
Aaron
Knock Voltage we are really concerned with spikes more than high voltage normally. The old rule of thumb was anything over 2.3v was getting noisy and then look for spikes above that. With the outline I have above you can normally figure it out.
Let's use this thread for "Phantom Knock" post logs, screen shots, etc. I cant promise I will be on it 100% but I think are enough gurus that we can kind of help. There is no replacement for experience. This is a pretty touchy deal and can ultimately lead to engine failure so not understanding it or not seeing it in person is a HUGE limitation. For the most part any race fuel or ethanol will not be real knock. The only condition that could cause that is the timing is WAY PAST MBT.
Aaron
