BRZ Knock/Rattle
 

I have a 2017 Subaru BRZ 6MT Performance Package with approximately 3,000 miles. I ordered the car from Subaru and picked it up with 5 miles on the odometer. When I drove it for the first time, it was making a knock/rattle/ping noise when applying the throttle below 3,000RPMs in any gear. The dealer stated that all cars from their dealership were filled with 85 octane gas from a pump on the dealership property so the noise may have been a pinging, but this was the first time they had heard the noise on a new BRZ sold from their dealership. They added some 'octane booster' and the noise disappeared. However, I have been hearing the noise again on and off. It does not appear to be caused by any set of specific conditions such as high temperature, A/C on, sitting at idle for a long time, or going up or down a steep gradient. The car has no modifications and has been filled with 91 octane (California) fuel. I am going to take the car into the dealer later in the week but I don't believe they will be able to recreate the noise to be able to diagnose it, so I'm looking to see if anyone here has an idea what is causing it:
[ame="https://www.youtube.com/watch?v=9Hidfpp5nNo"]BRZ Rattle - YouTube[/ame]

I'm no mechanic, but I'm sure an engine with a 12.5/1 compression ratio would not do well with this peasant gas.

lol... peasant.

Yeah I always thought the twins has to take premium gas.

Learned this the hard way with my first e36. These things really do need 91+ to run correctly.

Agreed, the manual does call for 91.
I've been filling it with 91 since the first tank of 85 and it continues to make the noise randomly.

How many tanks have you gone through since you started hearing it?

Welcome to our happy forum ......:clap:

In addition to the question about how many miles driven since you started hearing the sound ....... how many total miles on your car so far ...??

BTW ...... I can't hear what sound you are referring to in your video ..... :iono:


humfrz

The dealer filled mine with 85 as well but I never noticed any knock. Burned through it in a day though so maybe it never had a chance.

That clicking sound? It's happening when you step on the gas?

That sounds like the electric throttle body snapping open as you stomp on the pedal, nothing wrong.
You don't hear it at higher rpms because induction/exhaust noise drowns it out.
And I bet if you ease on the throttle there's no noise at all.

You're not the first and you won't be the last.
http://www.ft86club.com/forums/showp...20&postcount=3

http://www.ft86club.com/forums/showthread.php?p=1776903

there's more but I'm lazy

I'm at 3,000 miles so far so figuring 25mpg and 12 gallons per tank, about 10.
About 3,000 miles on the car total so far. Sound occurs at 3 seconds and 7 seconds in video.

I can hear it in the second post you linked. I'll definitely try easing on the throttle next time I hear it. It's a very weird sound. Really sounds like knock/ping.

Does anybody else hear this noise driving normally or is my throttle body defective?
Noise is at 3 seconds, 7 seconds, 11 seconds in video when i apply the throttle. I am applying throttle to about 20% and I am in 6th gear.

Well, I reckon you could take it back into the dealer, if that would make you feel better. I figure they will just tell you it's "normal".

While you're at the dealership, you might consider driving another BRZ to see if it sounds differently.


humfrz

I have this exact same noise on my 2017 Halo manual toyota 86 as well. when i step on gas kinda fast and sort of aggressive acceleration i hear a brief 1 second chirp click whatver you call it but it is the sound on the video you posted. my car is bone stock as well it was doing it the day i pick it up from the dealer brand new. i belive it is normal.