Engine breaking sound - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

Lakitu · 03-22-2018, 08:24 PM

What is the very audible (from cabin at least) and distinct rubbing sound that you hear while engine breaking? What part is rubbing against what part to slow the car down?

I always wonder if people can hear this rubbing from outside the car. It's pretty loud. Sounds like me dragging my mouse around on my wooden desk.

bcj · 03-22-2018, 08:27 PM

Braking

Cylinders and piston rings. And air passages. Unless it really did break.

Jordanwolf · 03-22-2018, 08:37 PM

Quote:

Originally Posted by Lakitu

What is the very audible (from cabin at least) and distinct rubbing sound that you hear while engine breaking? What part is rubbing against what part to slow the car down?

I always wonder if people can hear this rubbing from outside the car. It's pretty loud. Sounds like me dragging my mouse around on my wooden desk.

Old video, but these are the components you're probably hearing, as well as a combination of transmission sounds..

Going off of your "rubbing" description

[ame="https://www.youtube.com/watch?v=pJj8NvDUSFs"]Clutches - Explained - YouTube[/ame]

Lakitu · 03-22-2018, 09:45 PM

H...hmm.... Getting the feeling you guys don't experience this sound...

Starting to feel like something is terribly wrong.

Lakitu · 03-22-2018, 09:49 PM

Yep. Have just confirmed via youtube there should not be a sound. Hm...

humfrz · 03-22-2018, 10:24 PM

If it sounds like a diesel compression release braking ...... I'm ah feared there is something wrong with your car.......

If it sounds like just an uaaaaaaaa..... then I figure it's just normal compression/decompression sound.

humfrz

Mr.ac · 03-23-2018, 02:20 AM

Why would you engine brake?
It's not a truck.
Use your brakes. Cheaper, faster to replace than a clutch, and engine stress/gear box problems that you may ....uh.... wait....never mind.

HKz · 03-23-2018, 07:57 AM

we can't trust OP's judgement, he never figured out where the smell came from.

I'm betting the OP is being paranoid again. This car makes sounds for days, unless the car actually mechanically functions poorly then there probably isn't anything wrong..

Quote:

Originally Posted by Mr.ac

Why would you engine brake?
It's not a truck.
Use your brakes. Cheaper, faster to replace than a clutch, and engine stress/gear box problems that you may ....uh.... wait....never mind.

...there is nothing wrong with engine braking unless you're one of those folks that claim driving up to the redline is "bad" for a car too.

Tcoat · 03-23-2018, 08:40 AM

No part is "rubbing" against another part to slow the car. At least no parts that are not rubbing against each other when you accelerate. When you engine brake the compression from the engine is what is slowing you down. The engine cuts fuel so the cylinders are no longer firing and creating power or torque. The existing torque in the wheels and drivetrain is used up by turning the engine against the compression. There is a minimal speed reduction just due to the mechanical resistance of the drive train but the compression is doing the bulk of the work. This is why the exhaust note changes dramatically when engine braking since there is no firing occurring and no actual exhaust being generated. You will hear things that you normally don't simply because they are no the louder sounds to cover them up. It doesn't help that these cars have the tranny sitting almost in your lap and it is covered by the soundproofing equivalent of tinfoil and Kleenex. There is nothing wrong with the car.

Oh and as pointed out it is very important to understand the difference between "breaking" and "braking" since they are not the same thing!

extrashaky · 03-23-2018, 08:54 AM

Quote:

Originally Posted by Tcoat

No part is "rubbing" against another part to slow the car.

Unless he doesn't rev match and is slipping the clutch like a brake pad.

PetrolioBenzina · 03-23-2018, 10:27 AM

Slammillionaire · 03-23-2018, 10:29 AM

Quote:

Originally Posted by Mr.ac

Why would you engine brake?
It's not a truck.
Use your brakes. Cheaper, faster to replace than a clutch, and engine stress/gear box problems that you may ....uh.... wait....never mind.

...wut

This is giving me flashbacks to ludwig double clutching up-shifts

Jordanwolf · 03-23-2018, 10:34 AM

Quote:

Originally Posted by Slammillionaire

...wut

This is giving me flashbacks to ludwig double clutching up-shifts

Truck master race.

PetrolioBenzina · 03-23-2018, 10:35 AM

Quote:

Originally Posted by Tcoat

It doesn't help that these cars have the tranny sitting almost in your lap and it is covered by the soundproofing equivalent of tinfoil and Kleenex. There is nothing wrong with the car.

Tranny's ride in the trunk, sorry.

03-22-2018, 08:24 PM	#1
Lakitu Senior Member Join Date: Jan 2017 Drives: 2017 Halo 86 Location: USA Posts: 383 Thanks: 104 Thanked 136 Times in 87 Posts Mentioned: 3 Post(s)	Engine breaking sound What is the very audible (from cabin at least) and distinct rubbing sound that you hear while engine breaking? What part is rubbing against what part to slow the car down? I always wonder if people can hear this rubbing from outside the car. It's pretty loud. Sounds like me dragging my mouse around on my wooden desk. __________________ Build Thread / Daily Driver OFT Stage 2+, GrimmSpeed CAI, JDL Ultra Quiet FP, Perrin 2.5" Resonated CBE, Enkei 18x8.5 +45, 245/35 Continental ExtremeContact

03-22-2018, 08:27 PM	#2
bcj Geo Tyrebighter Esq Join Date: Mar 2013 Drives: '13 scion fr-s Location: pnw Posts: 4,324 Thanks: 6,780 Thanked 5,270 Times in 2,296 Posts Mentioned: 43 Post(s)	Braking Cylinders and piston rings. And air passages. Unless it really did break. __________________ -- "I gotta rock." -- Charley Brown

03-22-2018, 09:45 PM	#4
Lakitu Senior Member Join Date: Jan 2017 Drives: 2017 Halo 86 Location: USA Posts: 383 Thanks: 104 Thanked 136 Times in 87 Posts Mentioned: 3 Post(s)	H...hmm.... Getting the feeling you guys don't experience this sound... Starting to feel like something is terribly wrong. __________________ Build Thread / Daily Driver OFT Stage 2+, GrimmSpeed CAI, JDL Ultra Quiet FP, Perrin 2.5" Resonated CBE, Enkei 18x8.5 +45, 245/35 Continental ExtremeContact

03-22-2018, 09:49 PM	#5
Lakitu Senior Member Join Date: Jan 2017 Drives: 2017 Halo 86 Location: USA Posts: 383 Thanks: 104 Thanked 136 Times in 87 Posts Mentioned: 3 Post(s)	Yep. Have just confirmed via youtube there should not be a sound. Hm... __________________ Build Thread / Daily Driver OFT Stage 2+, GrimmSpeed CAI, JDL Ultra Quiet FP, Perrin 2.5" Resonated CBE, Enkei 18x8.5 +45, 245/35 Continental ExtremeContact

03-23-2018, 02:20 AM	#7
Mr.ac [insert cool phrase here] Join Date: Aug 2015 Drives: BRZ Premium Location: Central Coast CA Posts: 2,368 Thanks: 709 Thanked 1,559 Times in 930 Posts Mentioned: 30 Post(s)	Why would you engine brake? It's not a truck. Use your brakes. Cheaper, faster to replace than a clutch, and engine stress/gear box problems that you may ....uh.... wait....never mind. __________________ New daily driver - Subaru BRZ Premium Weekend fun/track car - '91 MR2 Turbo Gen3 Old daily driver - '88 MR2 Supercharged

03-22-2018, 10:24 PM	#6
humfrz Senior Member Join Date: May 2013 Drives: 2013 FR-S, white, MT Location: Puyallup, WA Posts: 30,436 Thanks: 29,833 Thanked 32,866 Times in 16,849 Posts Mentioned: 717 Post(s)	If it sounds like a diesel compression release braking ...... I'm ah feared there is something wrong with your car....... If it sounds like just an uaaaaaaaa..... then I figure it's just normal compression/decompression sound. humfrz

03-23-2018, 08:40 AM	#9
Tcoat Senior Member Join Date: Jul 2014 Drives: 2020 Hakone Location: London, Ont Posts: 69,838 Thanks: 61,656 Thanked 108,295 Times in 46,456 Posts Mentioned: 2499 Post(s)	No part is "rubbing" against another part to slow the car. At least no parts that are not rubbing against each other when you accelerate. When you engine brake the compression from the engine is what is slowing you down. The engine cuts fuel so the cylinders are no longer firing and creating power or torque. The existing torque in the wheels and drivetrain is used up by turning the engine against the compression. There is a minimal speed reduction just due to the mechanical resistance of the drive train but the compression is doing the bulk of the work. This is why the exhaust note changes dramatically when engine braking since there is no firing occurring and no actual exhaust being generated. You will hear things that you normally don't simply because they are no the louder sounds to cover them up. It doesn't help that these cars have the tranny sitting almost in your lap and it is covered by the soundproofing equivalent of tinfoil and Kleenex. There is nothing wrong with the car. Oh and as pointed out it is very important to understand the difference between "breaking" and "braking" since they are not the same thing! __________________ Racecar spelled backwards is Racecar, because Racecar.

03-23-2018, 10:27 AM	#11
PetrolioBenzina Senior Member Join Date: Sep 2016 Drives: 17 86 Location: Oregon Posts: 1,671 Thanks: 75 Thanked 1,133 Times in 647 Posts Mentioned: 10 Post(s)

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