Knock Knock
 

Hi All

I have taken the time to read some post on here and im trying to get to the bottom of some knock

car is stock motor and turbo, full exhaust, pump, injectors, 1.5 bar actuator, filter and head studs. Im running tephra V7 96260709

My Knock light values are 3 low and 6 high
Knock multiplier setting are 1000 rpm - 4000 rpm 18 and 4500 rpm - 7500 rpm 19

I have retarded my whole timing map 5 deg to make sure its not real knock. i am still seeing 4 counts of knock at 2500 - 3500 rpm and 80 - 140 load when taking off and changing up through the gears with normal driving. i am also seeing knock count of 4 on a hard pull in 4th gear when i back off and get back on it.

So i want to try an eliminate this but do not want to just keep increasing the multiplier values as i do not want to miss real knock when i put the timing back into it.

So can anyone please give me some guidance. is it ok to keep increasing these values till it goes away?? or is there another way to filter the noise the sensor is seeing.

Also i have just installed a new knock sensor, timing belt and all associtaed bearings seals, and new clutch (hpi coppermix)

Any help would be great

Regards,
Neal

What is the timing value at there, boost level, and octane?

Free revving it neutral still shows these knock levels?

Thanks for taking the time to reply.

Car is running on 98 ron and 1.5 bar boost. i have also attached the timing map which has been set to 5 deg less to make sure it is false knock.

Sorry to be a pain but can anyone help with this issue i am having.

Happy to provide more info if needed.

What is your afr where you are seeing knock? Have you tried adding fuel in those areas as well as reducing timing?

Hi

I have not yet tried adding fuel. i will try doing this today.

As mentioned before i don't believe this to be real knock. i have attached the ignition map the car has been driving around on for 4 years and i was seeing the same amount of knock on this. i then decided that i wanted to stop the knock flashing my check light on the dash. i then reduced the whole ignition map by 5deg (second map) to make sure i was not going to get real knock whilst increasing the knock multiplier map to try and eliminate this knock. After reducing the ignition i did not see any changes in the knock i was seeing. i have increased the filter slightly and have seen a reduction but it is still there on occasion.

So i will try adding fuel to eliminate that but my main question was how far can you increase the multipliers before the knock sensor will stop picking up real knock

Thanks
Neal

Post a log.

BTW, every 8 ROM I have seen has 3 knock multipliers, while you only list 2. The other one should have a stock value of 13 and controls the low rpm range. You might need to adjust this one along with the rpm table for load at which knock control is enabled.

As for your question, nobody can really say how high you can increase the values. The higher you increase them, the more likely it is that you will miss real knock events, so it is best to keep them as low as possible.

I do have the low mid and high multipliers but from my understanding the are not used when you have the rpm multiplier table.

Also added fuel today and no change

What do you call the rpm multiplier?

this is what i have been using to adjust the knock filter

I was having a problem with phantom knock at cruise idle but not under full throttle so I simply changed the load values under 3000 RPM...car was knocking 22,34,40 under cruising but under full throttle it never knocks

Nemini,

Your knock multi table is set more aggressive (as in hears better) than stock. In the 80-140 range between 2500-3500 take another 5* out. I would set the multiplier to 19 across the board and retest. You arent going to blow it up at the low of boost.

drop your multiplier down and let us see some AFRs

All good now.

I cleaned up the AFR's and reduced the timing heaps then dialled out the phantom knock by increasing the multiplier table. Also used DET cans to listen for real knock. once i removed the phantom knock i added timing till i heard real knock and the knock sensor picked it up at the same time. i reduced the timing a little from there and ended up with the below outcome.

this is tuned on 98ron and running 25psi and dropping to 23 up top

I didn't previously know that there were any 8 ROMs that had the knock multiplier vs. rpm table like this. I thought only the 9s had this table while the 8s used the three separate values for low, mid and high.

Having this same issue with my tephra flash.

Hi VRP

I was able to sort this out.
first thing i would do is pull at least 5 deg of timing out of the whole Hi ignition map. once you have done this drive around and see if knock is still present. if you are increase the knock filter by only 1 point at the load you are seeing the knock and test again.

also you need to make sure that you fuel map is good and i would do this on a low boost setting too.

i was also able to make some DIY det cans to listen for real knock.