Tip in knock?
 

Hi all. I've searched this forum and couldn't find any specific info but I did find someone on youtube that posted the same symptoms that I'm experiencing. It happens on 1-2 shifts and 2-3 shifts at standard rpm shifts(3-4k). If anything it seems to happen less frequently at high rpm. Car is a 2014 purchased late December 2013 and currently has 10k miles. Happens on all different brands of 91 gasoline in Southern California. No modifications.

[ame="https://www.youtube.com/watch?v=g8nnFeP7ib0"]Frs/Subaru Brz "tip in knock"? and VVT sound - YouTube[/ame]

Any help would be appreciated.

Yep stock tune requires 93 octane (usa) for best result and minimum knock, on 91 it going to knock .

especially in areas you quote even on 93 it will get tip in knock occasionally no where near what it will be on 91

If you on older rom series eg 700 900 or A00 its worth getting dealer to update to at least A01 or preferably B01 series rom as these have transient ignition retard enabled, they will reduce that type of knock which was apparently the cause of some DI seal failures. If your not on the later series rom get dealer to update.

however if your car is fairly new it likely to be on the later rom.

Unless your going to modify tune your only option is to run better fuel
see below for further info (for tip in knock)

You rearly need to log the knock parameters to be sure its knock though.

http://www.ft86club.com/forums/showthread.php?t=61820

That sound is completely normal, its related to throttle.
Take a listen to my under the hood audio on track its very very loud. And this is completely logged, zero knock etc.

[ame="http://www.youtube.com/watch?v=wGcv6SKj858"]Vortech FR-S Track Testing | Audio and Video Testing - YouTube[/ame]

LOL at that Mustang clogging up the turns.

Thanks for all the replies! I will keep an eye on it.

it's my video

at first i thought it was knock
but my datalogs has showed no sign of knock

like Dezoris said im sure it's related to throttle
Ive tried a lot of frs/brz and all of them do that

I'd just like to point out that 93 octane is not available in several states, you are insinuating that Toyota is selling a car with an engine that damages itself if owned and operated in certain locations of the country.

The manual specifically states that 91 octane is perfectly acceptable for the vehicle and will cause no damage.

it is normal

Not saying it will cause damage but it will not perform to it optimum level as the ecu will retard timing due knock.

The ecu works by detecting knock then retarding timing, then it waits a bit and starts advancing timing till it either get to the maxium values or it detect knock again. On 91 it will generally start to detect knock before it gets to the max advance values so it drops advance again. So its in a cycle of knock detect retard advance knock detect, the knock it detects is reliativly minor but its still knock.

The older roms it appears they forgot to enable the transient ingnition timing retard feature in the ecu to its definitly worth getting the newer roms flashed by dealer it often refered to as the DI seal fix as some cars driven hard were getting damage to DI seals due knock:)

Good explanation for those that aren't in the know, this was all I was looking for.

:cheers:

Hey there, would you mind explaining more on how it's related to the throttle? I have a similar issue and from my experience with engines, it sounds very very much like some quick knock, which goes away immediately since the knock sensor will cause the ECU to pull timing.

What part of the throttle is making this noise?

Thanks!

mine has a part throttle tip in knock when its above 95*... i've been making sure i run pure 93 octane and not abusing it when its so hot now.

When logging we could see the throttle go to max everytime the sound was made, could be induction noise or throttle sharply opening causing quick surge.

Does the log include knock sensor activity? And there was absolutely no sign of it?

I'm not saying I'm an expert on the matter but I'm not ready to just start ignoring it as normal sound without a bit more evidence. I drive 'around' it so that it doesn't happen in case it is pinging.

Edit: For the record, this only started happening a few months ago. From when I completed the break-in (mid January) up until ~May, it did not make this noise at all.

I know there were some ECU updates surrounding some of this, so I'm going to have the dealer take a look at my version (Its a 2014, but I bought it on December 31st, 2013).

I would like to get to the bottom of it since it keeps me from having as much fun in the car.