what would be an acceptable knock count that could be detected by evoscan? some of my DSM buddies say that they dont worry about 1-2 counts that get detected by DSMLink. when i log sometimes i get 2-3 counts. now i know that i should tune for 0 knock but i dont wanna go lowering my timing if the knock is engine noise or something like that. any help is appreciated.

 

My fastest pulls have no more than 1 count for each of no more than 2 - 3 samples

 

I would say 4 counts is acceptable. It will vary depending on daily changing variables. That is just the ecus way of adjusting itself. With 2-3 you should be fine. One day you could see 0 knock next day you may see 4 counts especially if you tuned on a hotday and then you do a log on a cold day. Long as your not getting something outrageous like 10 counts throughout the rpm band.

 

exactly what i was lookin for. thanx guys.

 

I'm working on no more than 1 occaisionally. If you have regular knock at a specific rpm / load cell you should fix it.

 

another question. does it read in "knock Sum" or "knock Count"
i heard there is a difference, will someone who knows about this elaborate for me.
Thank You!

 

How is the ECU adjusting its self if you are not decrementing the octane number? The octane number is the only way the ECU will change the way it deals with timing and fuel in open loop over a long term. Knock count will pull timing, but that is not really adjustment, because unless you reach the point where the octane number is changed the car will keep knocking. You can adjust the barometric compensation if there are significant changes in the way your car behave due to tempreture change.

You should also look at the timing in the load cells above and below those you calculate to hit on a given run. 2-3 counts might be ok if you only get that ocasionaly, but if you see that on every run or accross alarge part of the rev range then you need to re tune.

MB

 

So let me ask you this, why is it that a stock evo off the showroom floor shows slight knock throughout some parts of the rpm range, seen various times on this forum? This is knock occurring with very rich maps, low 10's afrs and very low timing, since most factory cars are tuned conservatively. The reason I say 3-4 is acceptable is because if you live in an always changing climate like HOUSTON, TX then you know that you can go tune during the day while it is hot and dry and perfect the tune showing no knock, then 3hrs pass it rains for 10 minutes(happens in houston all the time) and then all of a sudden it is humid and hot outside. Then you go log again and you see about 3-4 counts of knock in some parts of the boosted part of the map, so you go tune again to get rid of that knock, now guess what 3hrs later it is night time and it is cool and dry now and you log again and see some knock again even though when it was hot and humid you had the map perfected with 0 knock after several pulls. This is all on the same tank of gas. You think I am going to sit there and keep tuning all day since the weather keeps changing. Not I. So to me that 2 - 3 counts of knock is acceptable. Now if it jumps to like 6 - 8 counts all of a sudden or 8 - 10 counts, then you know something is wrong and you need a retune. Also what about those who do not tune their own car but do datalog. They were tuned on a hot day by their tuner who flew in from florida on a hot dry day, and that tuner perfected the tune no knock at all for that day after several passes. 2 weeks later it is cold, but they are broke and have no money for another tune at this time, but are noticing on their daily datalogs they have 3 counts of knock in various parts of the boosted portion of the map. How can they over come that. No map will stay perfect all the time for every condition that you drive in. There are too many changing variables on a daily basis to keep a map perfect and for those who dont tune their own car, there is no ability to keep changing it if your tuner only comes once every six months. On the other hand if you see some abnormal knocking like a spike to like 8 or 10 or something random like that and it is consistent, then that is something that needs to be looked at.

 

so staying below 5knock counts is ok?

 

You want it as close to possible as 0 but like already stated it will vary day to day. If you are constantly seeing 5+ at a certain RPM you should fix it, but if you are only on occasion seeing 2-4 counts of knock that is fine.

 

I live in the same climate as Houston (Rio Grande Valley), you can tune your knock out. I'll tell you this, when my car was custom tuned it didnt knock and it had block timing (custom tuned in Houston). Later the car started knocking and I decided to go with a different tuner, while working with him I decided.. I can do this myself and then I did. My tune looks more conservative than both of the professional tuners tunes that I tried but when I look at the logs I know my non knocking tune is faster than theirs (LogSeconds and no knock). Now, just to be fair I didnt work with the second tuner long enough to allow him to get it perfect and the first tuner spent a grand total of 2hrs with my car where I've spent countless hours reviewing logs and making changes to my image for it to run with very little knock (occaisional 1's with equal amounts of totally knock free runs) and yes it knocks less than it does on the stock map.

 

I'd add that it depends on what you use your evo for. I'm tuning for zero knock becuase I track the car also and dont' change my tune for the track. If the car was my daily driver only, 2-3 counts here and there are ok.

 

I was testing this yesterday....by 1-4 does this mean that 1.5634 is like 1 and 1/2 counts of knock thanks! How will I link my zeitronix to this program when I install it?

 

1. As close to 0 as possible
2. 4 and below is mild to nothing at all
3. Above 4 and consistant, look at ignition timing, fuel, type of plug, boost, air temp, gear, and most importantly early rpm A/F

 

I've noticed that anything past 4 counts of knock the ecu pulls like 5 degrees of timing. I'm around 2-3 in a couple spaces. If you don't have any knock that means your not really pushing your car to the limits.