Engine Acceleration Noise

[rburrow87]

Nah I DIY'd a mount. Doesn't really sound like it's that though, you can vary the pitch of the sound with gas pedal.

[Ultramaroon]

Originally Posted by stevesnj

Do you have a license plate relocate kit? could be a loose tag screw

It's a pretty hard mechanical sound. Very disturbing.

[rburrow87]

Originally Posted by Ultramaroon

I experienced that exact same sound a couple times earlier this year. Both times were after hammering through some high-g turns. I had a wild-assed theory about air bubbles in the valve timing mechanism. 0.o

Originally Posted by Ultramaroon

It's a pretty hard mechanical sound. Very disturbing.

Has it come back since then? I seem to hear it pretty much every drive now. I've noticed that it only seems to do it, or least does it more easily, when it's fairly warm or hot out and the engine is good and toasty.

The only thing that has changed since noticing this sound is that I drive it a bit harder because I feel more confident ever since changing the clutch slave cylinder out. I can't imagine how that part could be related though.

Since it seems like the noise is from the intake, I'm wondering if it's just some goofy valve timing that happens when it's hot? I guess it's possible that it's detonation, but I've heard detonation from my Jeep due to a leaky intake plenum and that tends to be a more random popping/ticking/whatever you want to call it and under WOT at high RPM. The BRZ really only does it under light/medium load in the 2.5-4k -ish range.

[Ultramaroon]

It's for sure not detonation, and not related to the clutch. I haven't heard it since, I think, July. It was during a club street run and I was hammering it really hard. Once it started, it didn't matter how much I eased up.

It's a mystery to me. I hope it's not something expensive but boy, it sure sounds like it when it's happening.

The saving grace, and the reason I kept driving was because it occured in a narrow band of engine speed. About 400 RPM, IIRC.

[rburrow87]

Well it sounds like we have/had the same thing happening, only difference is yours went away! Mine only started this after I had been hammering it after the clutch slave swap because I was really enjoying it.

Maybe tomorrow, if it doesn't rain like they claim, I'll pull the airbox and all that and make sure it's not something stupid going on there. Then after that, I'll try resetting the ECU and see if that does anything. I was thinking about picking up an OFT next month to try E85, so it'd be interesting to see if that has any effect either if it's still happening then.

I'm not sure how up to date my ECU is as far as software goes considering it's a 2013 MY. It was purchased in early 2014 and you'd think they'd keep all the TSBs up to date on their inventory, but who knows. I'm kind of leery about the dealer I bought it from, and I basically just don't trust anyone else to mess with my stuff anymore, so I really don't want to go to them for anything.

[Ultramaroon]

Originally Posted by rburrow87

Well it sounds like we have/had the same thing happening, only difference is yours went away! Mine only started this after I had been hammering it after the clutch slave swap because I was really enjoying it.

Maybe tomorrow, if it doesn't rain like they claim, I'll pull the airbox and all that and make sure it's not something stupid going on there. Then after that, I'll try resetting the ECU and see if that does anything. I was thinking about picking up an OFT next month to try E85, so it'd be interesting to see if that has any effect either if it's still happening then.

Please let me know if you find anything. I need to get serious about logging.

[Ultramaroon]

Originally Posted by rburrow87

I'm not sure how up to date my ECU is as far as software goes considering it's a 2013 MY. It was purchased in early 2014 and you'd think they'd keep all the TSBs up to date on their inventory, but who knows. I'm kind of leery about the dealer I bought it from, and I basically just don't trust anyone else to mess with my stuff anymore, so I really don't want to go to them for anything.

Oh, man, I hear you loud and clear. So much to learn about the software, though. I'm new to it but will get there soon enough.

[RIP.S2000]

Weird, I've had the same problem every now and then. It's very hard to catch, but it's usually in the higher rpm range (5-7k). However, whenever I swap gears or disengage/engage the clutch, it goes away. I'm thinking it has something to do with the transmission. It's only happened about 2-3 times since I'd gotten the car. ~20000 miles on the odo and it's completely stock under the hood.

[rburrow87]

Originally Posted by Ultramaroon

Please let me know if you find anything. I need to get serious about logging.

I've been trying to figure out if the Torque app could log anything relevant to this, but all I've really done with it so far is add oil temp using one of the write-ups here. Seems like an OFT is ideal for the data logging stuff from what I've read.

Originally Posted by Ultramaroon

Oh, man, I hear you loud and clear. So much to learn about the software, though. I'm new to it but will get there soon enough.

I think I could trust a fellow enthusiast if I got to know them a bit first... but that's about it. Which is pretty sad because you should be able to trust the dealer, especially with a warranty.

And yeah I know nothing about automotive software either. Could be a fun learning experience if that's what it takes to find out what's going on.

[Packofcrows]

I found my rattle! Rear license plate vibration!

[haimichaeltran]

@rburrow87, were you able to find out what caused this noise?

[Harlock]

I had this happen to me to too long ago, same sound. But my range of occurrence was 3.5k to 4.5k rpms. After much freaking out and getting under the car, it turned out to be an exhaust leak between the midpipe and front pipe.

[Ultramaroon]

I forgot about this thread. I found mine. It turned out to be the clutch master return spring. Amazing considering how loud it gets when it's happening. I just tap/touch my foot on the clutch pedal and 'poof,' it's gone.

[Stealth15]

Originally Posted by Harlock

I had this happen to me to too long ago, same sound. But my range of occurrence was 3.5k to 4.5k rpms. After much freaking out and getting under the car, it turned out to be an exhaust leak between the midpipe and front pipe.

Sorry if I'm reviving a dead thread. Did you have any exhaust modifications? My noise started after auto x and before I had my catback installed. Not sure if it's coincidental or if something during autox caused it. Car had 1400 miles at the time. Like you it was only in certain ranges, though mine seemed to stop after 4k. Also had a honking whirring kinda noise and it still occurred when stationary while revving. Seems to only occur when the car is hot, that's not consistent either. I think it might be the TO bearing. It hasn't gotten any worse and I'm at 8k miles...

I'm thinking about doing a header and a tune soon, but I want to make sure my trans is solid first. 2nd gear is a bit knotchy and makes a bit of a thud when cold. 5th is consistently knotchy. Also had a weird sucking noise at high rpm with the AC on randomly. Sounds like a taser mixed with a vacuum. Idk how else to describe it. That only happens occasionally...