KR, timing retard and knock counts
Thread Starter
On The Tree
Joined: Nov 2002
Posts: 168
Likes: 0
From: Crestview, FL
KR, timing retard and knock counts was wondering what the max KR is on the ls1.
Usually knock sensors have a table the work on 0 being the lowest and "X" being the highest. They usually base timing from these levels also, respectively when a KR count goes up the ECU will back off timing to safeguard your car.
Im under the assumption from my previous tuning experiences with other cars, if you are seeing ZERO KR, that means more than likely the car is rich and you could use some leaning out. All previous setups I have had on other cars I tuned until I got knock "low counts of KR" and just fine tuned. I like a car to run on the edge where i know it isnt drowning in fuel if you know what I mean.
What is the acceptable amount of KR????
Im fairly new to tuning ls1's so excuse me if my terminology is off.
I may be confused with other systems. I know on Talon and Eclipse you had a actual KNOCK COUNT on a 1-40 scale 10 being acceptable which usually led to maybe 2-5 degrees of retard. I usually tuned for 8 counts of knock
Usually knock sensors have a table the work on 0 being the lowest and "X" being the highest. They usually base timing from these levels also, respectively when a KR count goes up the ECU will back off timing to safeguard your car.
Im under the assumption from my previous tuning experiences with other cars, if you are seeing ZERO KR, that means more than likely the car is rich and you could use some leaning out. All previous setups I have had on other cars I tuned until I got knock "low counts of KR" and just fine tuned. I like a car to run on the edge where i know it isnt drowning in fuel if you know what I mean.
What is the acceptable amount of KR????
Im fairly new to tuning ls1's so excuse me if my terminology is off.
I may be confused with other systems. I know on Talon and Eclipse you had a actual KNOCK COUNT on a 1-40 scale 10 being acceptable which usually led to maybe 2-5 degrees of retard. I usually tuned for 8 counts of knock
TECH Senior Member
Joined: Nov 2001
Posts: 9,246
Likes: 3
From: Troy, AL
Re: KR, timing retard and knock counts "if you are seeing ZERO KR, that means more than likely the car is rich and you could use some leaning out."
It's quite possible to run on the mixture on the lean side AND have no KR even with high timing advance. Point being, you want no KR at all for best results. KR is also cause be other things than detonation. Oftentimes it's caused by something hitting the exhaust system or a faulty crank pulley. We call that false KR. It of course has the same detrimental effect on timing advance that real KR has and should be eliminated.
It's quite possible to run on the mixture on the lean side AND have no KR even with high timing advance. Point being, you want no KR at all for best results. KR is also cause be other things than detonation. Oftentimes it's caused by something hitting the exhaust system or a faulty crank pulley. We call that false KR. It of course has the same detrimental effect on timing advance that real KR has and should be eliminated.
TECH Apprentice
Joined: Apr 2002
Posts: 308
Likes: 0
From: Austin, TX
Re: KR, timing retard and knock counts You really don’t want any KR on an ls1.Not that a little would kill you, but you would never want to tune your car to purposefully have a little. A wideband a/f meter will tell you your mixture at WOT and that is what you should tune against.
As far as KR and counts go, it is rather complicated, but here is how I basically understand it.
Every knock event that is observed goes against a few tables to determine how much retard will be applied. There are also decay tables that determine how much timing will be added back in during subsequent engine revolutions. There are occasions where 1 knock event will not really count for any retard, but they quickly add up.
Example: at 4k rmps 1 knock count = .40 degrees of timing. That value then would decrease by about 50% after 2 revolutions without any knock counts.
In addition, there is a knock learn capability that will actually retard timing to avoid KR before the knock is read.
As far as KR and counts go, it is rather complicated, but here is how I basically understand it.
Every knock event that is observed goes against a few tables to determine how much retard will be applied. There are also decay tables that determine how much timing will be added back in during subsequent engine revolutions. There are occasions where 1 knock event will not really count for any retard, but they quickly add up.
Example: at 4k rmps 1 knock count = .40 degrees of timing. That value then would decrease by about 50% after 2 revolutions without any knock counts.
In addition, there is a knock learn capability that will actually retard timing to avoid KR before the knock is read.
Thread Starter
On The Tree
Joined: Nov 2002
Posts: 168
Likes: 0
From: Crestview, FL
Re: KR, timing retard and knock counts Thanks for the response...
That pretty much is what I was looking for, didnt know how these cars used KR and how it was determined.
Thanks
That pretty much is what I was looking for, didnt know how these cars used KR and how it was determined.
Thanks
