Oppo, I need your help.

"K-Roll-PorscheTamer" (k-roll390)
07/30/2014 at 13:52 • Filed to: Exhaust

In determining a sound. Do you ever notice how some cars have a two-tone exhaust note? Sometimes I think it's some kinda fan sound or something like that, but does anyone know?

Here are two cars that have this two-tone:

Lamborghini Aventador LP720-4 50 Aniversario

It's pretty obvious with this car. Kinda like a high pitch wining(Like a supercharger!)

Porsche 911SC

You can obviously here the sound over the engine!

What is making that sound and how??

DISCUSSION (23)

TwinCharged - Is Now UK Opponaut > K-Roll-PorscheTamer
07/30/2014 at 14:04

A belt or a pump of some sort?

cabarne4 > K-Roll-PorscheTamer
07/30/2014 at 14:07

Belt whine.

K-Roll-PorscheTamer > cabarne4
07/30/2014 at 14:09

That's it?? Just belt whine? If that's the case, I would've imagined that whatever belt it is would be too tight? Or do certain belts make that sound??

K-Roll-PorscheTamer > TwinCharged - Is Now UK Opponaut
07/30/2014 at 14:09

That's what I thought about.

TwinCharged - Is Now UK Opponaut > K-Roll-PorscheTamer
07/30/2014 at 14:10

You'll hear this pretty clearly on the 1st gen BMW MINI - a high pitched whine that comes from the power steering pump.

cabarne4 > K-Roll-PorscheTamer
07/30/2014 at 14:11

Well, the Lambo is supercharger whine. Superchargers are belt driven, so basically the same concept.

There's a lot of things that can cause belt noise. Basically anywhere the belt finds resistance. This could mean a bad tensioner or pulley, or just a bad belt. The 911 video has a normal amount of belt whine for an older car — keep in mind newer cars are better insulated, especially under the hood. So pesky belt noises aren't heard. The 911 has a flimsy metal hood over the engine, with slots in it to let all that glorious belt noise out.

Party-vi > cabarne4
07/30/2014 at 14:13

Funny how the Lambo has supercharger whine with no supercharger...

K-Roll-PorscheTamer > cabarne4
07/30/2014 at 14:16

I don't think the Lambo is supercharged....I was just comparing the sound.

I like me some belt noises! :)

K-Roll-PorscheTamer > Party-vi
07/30/2014 at 14:16

I know, I was just making a sound comparison.

cabarne4 > Party-vi
07/30/2014 at 14:19

I thought the Aventador was?

Either way, lots of things that can whine under the hood. Worn out belts whine. Bad pulleys and tensioners whine. worn power steering pumps and water pumps whine.

If you're trying to ID a whine on your car, ask yourself when it's making the noise, and what makes it louder. Power steering whine is common when the fluid is low, or the pump is on its last leg. Steering will feel heavier than normal, and the sound will be louder with the wheel at full lock than dead center (because the pump / hydraulic system is more stressed). Water pumps are belt driven, so the whine will get louder with engine revs, but steering has no effect. Belt whine can be anything from an annoyingly high-pitched squeal or chirp, to a bit of a whine. Also engine-speed dependent. Worn pulleys and tensioners make noise when the bearings inside them start to fail. Usually it'll make a noise every time the pulley comes across the bad bearing, so the sound won't be constant. Hard to explain, so I'll post this:

Party-vi > K-Roll-PorscheTamer
07/30/2014 at 14:22

cabarnett said the Lambo was supercharged - it ain't. Also belt whine doesn't make that noise. it's probably timing chain whine. The Lambo and Porsche have chains on them.

Party-vi > cabarne4
07/30/2014 at 14:23

It's more than likely timing chain whine. A new Lamborghini isn't going to have any bad pulleys, and the Porsche whine is part of the engine.

cabarne4 > Party-vi
07/30/2014 at 14:31

True story: Once had a kid in a V6 auto Mustang try to convince me his car was supercharged. Major belt whine. He refused to pop the hood, and couldn't even tell me how a supercharger works, what he was running, or how much power it was putting down.

CAR_IS_MI > K-Roll-PorscheTamer
07/30/2014 at 14:32

Well I have no sound at work to listen to your videos but my first guess based on your description would be noise from a balancer. My Daytona used to make a high pitched SC-like sound and people would always ask and I would lie and say it was a supercharged bike (it wasn't). The noise was being created by components related to the harmonic balancer and was normal. I would presume it to be the same or similar on something like this where high performance is the end game and a high performance balancer is required to keep the engine running properly.