Exhaust whistle when valve opens?

[RevNev]

The Baillie tip was a Holden invention

I welded the "Baillie hole" shut in my bimodal tips around the time I took off that silly induction roar tube nonsense from the air box to the firewall!

 

[Skylarking]

I welded the "Baillie hole" shut in my bimodal tips around the time I took off that silly induction roar tube nonsense from the air box to the firewall!

Like it or not, at least it was a real thing unlike the sounds some manufacturers piped throuh the vehicle's infotainment speakers

 

[RevNev]

Like it or not, at least it was a real thing unlike the sounds some manufacturers piped throuh the vehicle's infotainment speakers

My wife's BMW X3 M40i SUV has a V8 sound piped through the speakers in Sports+ mode. The exhaust is crazy loud with the bimodal valves open to the extent that you wonder how it passed ADR's and although it sounds like an inline 6 cylinder, there's plenty of exhaust noise without the need to pipe it through the speakers. I'm not a fan of fake noises and prefer to configure an exhaust to sound good in the car permanently.

 

[lmoengnr]

My wife's BMW X3 M40i SUV has a V8 sound piped through the speakers in Sports+ mode. The exhaust is crazy loud with the bimodal valves open to the extent that you wonder how it passed ADR's and although it sounds like an inline 6 cylinder, there's plenty of exhaust noise without the need to pipe it through the speakers. I'm not a fan of fake noises and prefer to configure an exhaust to sound good in the car permanently.

Mustangs are like that in Race mode, they are loud!

Not a great note, but they are loud!

 

[07GTS]

Mustangs are like that in Race mode, they are loud!

Not a great note, but they are loud!

that boat note just as they punch the pedal on takeoff

 

[RevNev]

Mustangs are like that in Race mode, they are loud!

Not a great note, but they are loud!

It's fascinating how they meet noise compliance when exhaust noise level can be increased by the flick of a switch. My wife's BMW starts up with the bimodal valves open with a high idle speed for 10 seconds and it's too loud to start up in the garage late at night or early hours of the morning without waking the Neighbours, almost sounds like a complete muffler delete on start up!

 

[RevNev]

that boat note just as they punch the pedal on takeoff

There's a couple of Mustangs around our way with the worst exhaust notes imaginable, not sure if they're modified but they're reasonably loud with seriously lousy notes and both cars sound much the same.

Speaking of exhaust notes around our way, someone screams around in this vehicle occasionally in the distance and sounds like a V8 Supercar, close ratio straight cut gearbox whine, the lot! I discovered what it is recently and it's a Ducati motorbike and sounds brilliant through the gears at high revs!

 

[Derekthetree]

Could be the airgap around the tips as the outlets in the HSV bumper are much bigger than the muffler pipes sitting inside.

I knew the fake tips might come back to bite!

There is a lot of space behind the lower bumper, leaves get stuck a lot, so I presume the airflow is not clean.

I might try mounting the camera again, and messing with speed/revs/exhaust settings to see if I can bottom some parameters.

 

[VS 5.0]

I discovered what it is recently and it's a Ducati motorbike

Best sounding bikes to my ear.

 

[Skylarking]

It's fascinating how they meet noise compliance when exhaust noise level can be increased by the flick of a switch.

Seems this was looked into by the National Transport Authority back in 2014 where they made recommendations to the states to supposedly address this. Guess either the recommendation didn’t go far enough or the states watered them down.

You’d think ADR would check sound levels throughout the rev range and with all combinations of valve settings be they bimodal, trimodal or whatever.

I really hate that new (particularly German) cars can bark and backfire so loudly when mashing the go pedal as they take off, it always makes me jump…

I really can’t understand how those manufacturers can get away with it (ok, i can imagine it’s a cheat like diesel gate) yet a nicely modded car that has a demonstrably better sounding and nowhere near as loud and penetrating a sound gets defected… Guess it’s good to be king

Bi-modal mufflers under scrutiny

The latest Regulation car news from GoAuto, Australia's most respected automotive website,

www.goauto.com.au

Victorian authorities target loud exhausts

Loud cars are in the crosshairs of Victorian authorities, with a number of drivers being fined after testing.

www.drive.com.au