tip in knock with turbo

[wparsons]

I think James is on the right track with "fixing" it... the knock doesn't seem to be detrimental down low, except to the IAM so removing the advance so it doesn't hurt the IAM is a good enough solution for me. It doesn't happen very often for me, so I'm not too concerned about it.

[welllam]

Originally Posted by wparsons

I don't have any logs, but I've heard tip in knock on the stock tune on heel toe downshifts many times. Zero load on the engine, just a blip while in neutral and you can hear it ping.

I'm also finding that city driving (or getting stuck in traffic) kills my IAM in a hurry, but beating on it doesn't effect it.

I tried mine revving at idle and fail to see knock detected, but at driving and have detected at sudden change in throttle at 2-5krpm. What you have heard might be the sound of our two piece drive shaft going from relax to load.



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[jamesm]

Originally Posted by wparsons

I think James is on the right track with "fixing" it... the knock doesn't seem to be detrimental down low, except to the IAM so removing the advance so it doesn't hurt the IAM is a good enough solution for me. It doesn't happen very often for me, so I'm not too concerned about it.

you can keep it from dropping the IAM just by disabling coarse correction in the areas most proned to tip-in knock... always low load so not much of a concern to disable it there. this is done by ensuring the value in the advance map in that cell is less than 3.9 degrees.

[s2d4]

Originally Posted by jamesm

disabling coarse correction in the areas most proned to tip-in knock.. this is done by ensuring the value in the advance map in that cell is less than 3.9 degrees.

Does this mean that everything under 3.9 in the following map means coarse correction is disabled?



Do you mean total advance?

I also found this which says coarse correction is enabled when advance is above 0.

[wparsons]

Originally Posted by welllam

I tried mine revving at idle and fail to see knock detected, but at driving and have detected at sudden change in throttle at 2-5krpm. What you have heard might be the sound of our two piece drive shaft going from relax to load.



Sent from my SM-N9005 using Tapatalk

It's definitely knock, hard for the drive shaft to make a noise like that when the clutch is still in.

Revving from idle behaves differently because you're going from an idle state (injectors on) instead of a deceleration state (injectors off).

It doesn't happen all the time, but it has definitely happened more often than I would like.

[jamesm]

Originally Posted by s2d4

Does this mean that everything under 3.9 in the following map means coarse correction is disabled?



Do you mean total advance?

I also found this which says coarse correction is enabled when advance is above 0.

yes it does. i mean the currently applied value from the advance map. bad noodle's doc suggests 3.9 degrees as the value, which my own testing seems to confirm. it's likely that map definition is wrong or isn't scaled properly or something, as a value of 1 or 2 degrees will definitely disable coarse correction. this is really easy to test, just go induce some tip-in knock with it normal and watch it drop, then reflash with lower advance values (but same total timing) and watch it stay put. works every time lol.

[s2d4]

Originally Posted by jamesm

yes it does. i mean the currently applied value from the advance map. bad noodle's doc suggests 3.9 degrees as the value, which my own testing seems to confirm. it's likely that map definition is wrong or isn't scaled properly or something, as a value of 1 or 2 degrees will definitely disable coarse correction. this is really easy to test, just go induce some tip-in knock with it normal and watch it drop, then reflash with lower advance values (but same total timing) and watch it stay put. works every time lol.

Interesting, maybe @Td-d would know some history behind this.

[steve99]

I
Below is modified advance table I am using to reduce knock. Has not completely eliminated it in 1500-3000 PRM range but is less frequent and less severe and now does not result in IAM dropping below 1, when driving in that range in traffic for long periods.

However I am using 100 octane fuel. Will try it out on 98 once tank is run down.

[wparsons]

Originally Posted by steve99

I
Below is modified advance table I am using to reduce knock. Has not completely eliminated it in 1500-3000 PRM range but is less frequent and less severe and now does not result in IAM dropping below 1, when driving in that range in traffic for long periods.

However I am using 100 octane fuel. Will try it out on 98 once tank is run down.

Australia is RON octane ratings, right? So your 100 octane is about the same as our 93-94 octane?

[steve99]

Originally Posted by wparsons

Australia is RON octane ratings, right? So your 100 octane is about the same as our 93-94 octane?

AFAIK yes

98 RON 93 AKI
100 94
95 91
91 87
However I believe the "test" procedure is different for the different ratings so its not an exact equivalence . It does appear that our 98 RON is not quite as good as your 93 AKI for real world knock resistance.

[jamesm]

octane shouldn't make any difference to the tip-in knock. i get it even on e85, just the same as on pump gas (which led to my pekc theory that i've yet to prove lol).

[steve99]

Originally Posted by jamesm

octane shouldn't make any difference to the tip-in knock. i get it even on e85, just the same as on pump gas (which led to my pekc theory that i've yet to prove lol).

If thats the case I will be happy as it should be reduced on 98RON as well.

What is the cause of tip in knock , Fueling error ??

[OrbitalEllipses]

Originally Posted by steve99

What the cause of tip in knock , Fueling error ??

Don't forget type I error.

[jamesm]

Originally Posted by steve99

If thats the case I will be happy as it should be reduced on 98RON as well.

What the cause of tip in knock , Fueling error ??

that's the million $ question... i can say what makes it worse (too much advance in low load areas, bad tip-in tuning), but i can't say what is causing it because i haven't been able to completely eliminate it 100%.