Tip In Knock?!

[Teseo]

Originally Posted by Ultramaroon

I can reproduce tip-in knock at will in the same way that OP describes. I don't know much about what the ECU is doing except that it's waking up from fuel cut.

1. Drive for a good long period a steady highway speed.

2. Lift completely for long enough to go into fuel cut.

3. Stab at it. Doesn't take much.

Like @ermax describes, it can be avoided by applying throttle in two stages. First crack it open to wake up the injectors. Then go ham-fisted (footed?) with confidence.

Bravo!! I thought i got paranoic and filled the car with "race gas" (95 oct) because knock. Thanks mate, i feel like rubbish for spend 40 dollars at that pump.

[ermax]

The TB is almost silent. Go out to your car and turn on the ignition but don’t start the car. Now go all nuts on the throttle. You will hear the TB moving but it’s very faint. Definitely not loud enough to hear over the engine. You will sometimes hear air rush into the intake but this isn’t the ping/knock sound as heard in the video.

[DaBoBo21]

Originally Posted by ermax

The TB is almost silent. Go out to your car and turn on the ignition but don’t start the car. Now go all nuts on the throttle. You will hear the TB moving but it’s very faint. Definitely not loud enough to hear over the engine. You will sometimes hear air rush into the intake but this isn’t the ping/knock sound as heard in the video.

Right, I know that the air induction noise isn't related, but I have heard on numerous accounts what the OP is describing. Though, it only happens on WOT shifts for me.

[ermax]

Originally Posted by DaBoBo21

Right, I know that the air induction noise isn't related, but I have heard on numerous accounts what the OP is describing. Though, it only happens on WOT shifts for me.

Okay, I was just clarifying. I firmly believe the sound we are all hearing is knock. I just can't believe a modern car would knock right from the factory the way our cars do.

[DaBoBo21]

Originally Posted by ermax

Okay, I was just clarifying. I firmly believe the sound we are all hearing is knock. I just can't believe a modern car would knock right from the factory the way our cars do.

You're good! It is interesting, though. Has there been any reports where this leaded to serious damage (specific to our cars)?

[ermax]

So we all know about the early 2013 having the messed up transient retard table which was blowing injector seals. They fixed this in mid 2014. Well this table was updated again on the 2017 to pull even more timing.

Tor talks about tip in knock in this thread:
http://www.ft86club.com/forums/showthread.php?t=118629

He seems to have solved the knock by dropping the 2017 table into his rom. I think I am going to try this tonight and see how it goes. It does impact throttle response a little though. Hopefully it isn't unbearable. I am real picky about laggy throttle response. But if it prevents knock I will suck it up.

[Ultramaroon]

Originally Posted by Teseo

Bravo!! I thought i got paranoic and filled the car with "race gas" (95 oct) because knock. Thanks mate, i feel like rubbish for spend 40 dollars at that pump.

Bah! Nothing wrong with mixing in some good stuff. I bet you noticed the difference.

[steve99]

Stock tune in 2012-2016 cars will knock even on 93 fuel in 2000-4000 rpm under high load

2017 stock tune is better

[Teseo]

Originally Posted by Ultramaroon

Bah! Nothing wrong with mixing in some good stuff. I bet you noticed the difference.

Yup, at 6k rpm vvti kicked in yo

[strat61caster]

Originally Posted by ermax

I think a data log of the throttle position in sync with an audio recording may be handy.

Agreed, watch the car's knock sensors.

http://www.ft86club.com/forums/showp...20&postcount=3


60k on stock early tune, almost 5k on the OFT tune, noise is exactly the same before and after.
Oh but now with added VVT noise as with the video in the OP.

[ermax]

Originally Posted by strat61caster

Agreed, watch the car's knock sensors.

http://www.ft86club.com/forums/showp...20&postcount=3


60k on stock early tune, almost 5k on the OFT tune, noise is exactly the same before and after.
Oh but now with added VVT noise as with the video in the OP.

I have recreated the sound while logging and there are no signs of knock in the data. But knock sensors aren’t 100% definitive one way or another. You can bog this car in 2nd from a dig and it will ping like a bitch and still not show in the data. I just can’t imagine what else the sound could be if it isn’t knock.

I will report back what impact the K00C transient retard table has.

[guybo]

A knock sensor will pick up a knock WAY before you can hear it. By the time you hear a knock your engine is pretty much fucked, which is why the piezo speakers that are knock sensors pick up any knock well before your ears can.

That noise isn't knock.

[ermax]

Why does it go away when pulling timing then? If it isn’t knock, what to you think it is?

[Ultramaroon]

Originally Posted by steve99

Stock tune in 2012-2016 cars will knock even on 93 fuel in 2000-4000 rpm under high load

2017 stock tune is better

I understand from speaking with more learned friends that the stock tune, at least for the zenki, is actually optimized for 94 octane.

And before this devolves into a panic, let's remember what the owner's manual says about it. On this page alone, the owner is reassured four times that a little pinging is normal. The system is designed to constantly look for the knock threshold and keep timing right up against it.