Squeal/squeak/chirp sound during shift at WOT?

[Eric Arroyo]

Hey guys, I did a launch control pull the other day on a 2.6 degree downward slope (on-ramp off a bridge). When the car shifted from 2nd to 3rd there was a brief (half second) squeal/chirp/squeak sound. The sound occurred between shifts and stopped when 3rd gear engaged.

I have a stock GT2 AWD and it was a dry day at about 75 degrees F so it definitely wasn't tire spin, but it did sound a bit like that.

My only thought is that it was boost releasing out of the diverter valve between shifts. I've just never heard it before under hard acceleration. That said, it was my hardest/fastest acceleration yet in the car. 4.6 to 60 according to the Torque app reading the speed through my OBD2 port. My usual times range between 4.8 and 5 depending on slope.

Any thoughts on what the sound could be? And has anyone else heard this (without aftermarket intakes)? I'm concerned it was something like a belt slipping.

 

[Eric Arroyo]

No takers on this one? I'm guessing this is not normal then?

 

[Rynil2000]

Sorry, WOT?

But yeah, I’ve seen a few others mention it as being normal. @nhcowboy28 maybe? I haven’t noticed it yet.

 

[MerlintheMad]

Wide Open Throttle.

Sorry, WOT?

 

[Eric Arroyo]

Sorry, WOT?

But yeah, I’ve seen a few others mention it as being normal. @nhcowboy28 maybe? I haven’t noticed it yet.

Wide Open Throttle. And good to hear that you've seen other people post about it. I'll keep logging any time I do 0-60 pulls and see if I can catch a log of it happening. That'll probably go a long way in figuring out what's going on.

Thanks!

 

[jasheppard84]

First thing I thought of was belt slip.

 

[Eric Arroyo]

First thing I thought of was belt slip.

Same here, which is what concerned me haha.

 

[MerlintheMad]

First thing I thought of was belt slip.

Same here, which is what concerned me haha.

But on a brand new car? What are the chances?

 

[jasheppard84]

But on a brand new car? What are the chances?

I agree... But if Eric's flogging it (based on "best 0-60 time yet" comment), I'd say it's also at least a little more likely. A little bit of slip right at the shift point, under high load... Those would be just about ideal conditions for it to occur.

 

[Eric Arroyo]

I agree... But if Eric's flogging it (based on "best 0-60 time yet" comment), I'd say it's also at least a little more likely. A little bit of slip right at the shift point, under high load... Those would be just about ideal conditions for it to occur.

I do drive it hard occasionally. I probably average 5 hard accelerations a week (rolling start of ~20mph getting onto the highway) with a launch control maybe once every two to three weeks. The pedal was to the floor with launch control when the chirp sound occurred. I've never heard it during normal driving or any of my other launch control runs.

I did some more reading on other cars online and it looks like it could be the serpentine belt slipping. Other cars (not Stingers) have had this happen under high load while the AC was on. I'm wondering if mine is ever so slightly loose, such that it may slip under extreme load.

Either way, I haven't heard it since, which is a good thing. If anyone else has any other ideas, I'm all ears

 

[jasheppard84]

I do drive it hard occasionally. I probably average 5 hard accelerations a week (rolling start of ~20mph getting onto the highway) with a launch control maybe once every two to three weeks. The pedal was to the floor with launch control when the chirp sound occurred. I've never heard it during normal driving or any of my other launch control runs.

I did some more reading on other cars online and it looks like it could be the serpentine belt slipping. Other cars (not Stingers) have had this happen under high load while the AC was on. I'm wondering if mine is ever so slightly loose, such that it may slip under extreme load.

Either way, I haven't heard it since, which is a good thing. If anyone else has any other ideas, I'm all ears

Yep, honestly not the most "unheard of" thing... See what I did there? ;-)

Doesn't even necessarily need to be a tension issue with the belt. A couple insanely well-placed drops of any liquid, whether they be water, oil, soap... Could cause it. Since it hasn't recurred, probably not a huge issue. As for the 0-60, maybe the momentary reduction of pulley load from the slip itself actually helped get you there!

And of course, this is all hypothetical nerdy nonsense until/unless we actually ever figure out what happened, but it seems like recurrence is the only chance of that, and we don't want it to happen again, so... Yeah, lol.