Slotted rotors noise

[TFSI]

I posted this thread in technical brake/suspension section, but looks like hardly anybody goes in there...

Anyways, when I purchased S4, the previous owner had installed stoptech slotted rotors on all corners. After driving for few months and track events, I noticed a loud humming noise during hard braking. Is this normal? It doesn't feel the rotor is warped, there's a slight pulsation during hard braking, but nothing during normal driving condition.

I'm going try resurfacing these at local pep boys.

[jimrobbington]

I posted this thread in technical brake/suspension section, but looks like hardly anybody goes in there...

Anyways, when I purchased S4, the previous owner had installed stoptech slotted rotors on all corners. After driving for few months and track events, I noticed a loud humming noise during hard braking. Is this normal? It doesn't feel the rotor is warped, there's a slight pulsation during hard braking, but nothing during normal driving condition.

I'm going try resurfacing these at local pep boys.

This is completely normal. Upgraded my brakes on my b7 a4 to slotted rotors and was like wtf is that noise? It's the hot air escaping through the slots, totally normal. I feel like it quieted down after some wear, maybe I just got used to it.

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[TFSI]

Thanks for quick response. Yea I guess I need to get used to this noise.

[MME1122]

I have dimpled and slotted rotors from Adams, they make a bit bit of a hissing sound as well. I think it's normal.
I'm wondering if rotors like this still make noise with something like 4 piston or 6 piston caliper. With out single piston sliding calipers, the inner pad is is closer to the disc when not braking. With a non sliding caliper it might be more even.

[jimrobbington]

Thanks for quick response. Yea I guess I need to get used to this noise.

I started to enjoy the sound when you drive close to a wall and can hear it really well.

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[Michigan_Rings]

Thanks for quick response. Yea I guess I need to get used to this noise.

This happens to me as well, when i replaced my OEM rotors for the ECS slotted rotors. Mostly when it's wet outside. I'm glad someone else is experiencing this because I was worried as well.

[TFSI]

I have dimpled and slotted rotors from Adams, they make a bit bit of a hissing sound as well. I think it's normal.
I'm wondering if rotors like this still make noise with something like 4 piston or 6 piston caliper. With out single piston sliding calipers, the inner pad is is closer to the disc when not braking. With a non sliding caliper it might be more even.

Interesting. Because on my previous FR-S, I had 4-piston calipers up front and it never made humming noise.
Sliding caliper is simple design to maintain, but I don't like how inner rotors wears faster than outer. Caliper pins move freely.

[MME1122]

Interesting. Because on my previous FR-S, I had 4-piston calipers up front and it never made humming noise.
Sliding caliper is simple design to maintain, but I don't like how inner rotors wears faster than outer. Caliper pins move freely.

Upgrade to the Q5 brembos

[blackfunk]

Whats weird is that I've encountered this before on different platforms so I know exactly what it is. Yet on my current setup which is drilled and slotted I don't actually ever hear any of the whirring noise that's typical. Could be I can't hear it over the charger whine and exhaust.

[TFSI]

Q5 calipers would be nice, but still on tight budget :(

Whats weird is that I've encountered this before on different platforms so I know exactly what it is. Yet on my current setup which is drilled and slotted I don't actually ever hear any of the whirring noise that's typical. Could be I can't hear it over the charger whine and exhaust.

That's weird. Have you tried braking really hard, like from 100mph to 40mph? (on a closed road of course )


Does anyone have experience with PowerStop slotted/drilled rotors?

[blackfunk]

I've beat on it. I mean really beat on it. Been on a couple runs with the local Mustang club (insert oversteering joke here LMAO) I get the customary ticking on cooling etc but just none of the whirring.

I should also point out that this is AP 370 mm semi floating rotors.

[chilort]

I don't like the sound and I don't like the feel on mountain runs when hard breaking down hill. I run solid face rotors. Also, additional surface to surface contact area.