Exhaust whistle when valve opens?

[Ryan_044]

I remember this vid and noticed it so seems fairly standard! (Skip to approx 2mins and then again at 3mins)

 

[VS 5.0]

I remember this vid and noticed it so seems fairly standard! (Skip to approx 2mins and then again at 3mins)

It's quite loud in that one.

 

[Commo64]

Was standard fit on most VF V8s?

Yes, I think they were called Bi-modal mufflers

 

[Derekthetree]

I remember this vid and noticed it so seems fairly standard! (Skip to approx 2mins and then again at 3mins)

Cheers for the vid, yep identical sound.

Mine are always open, but no whistling.

No other exhaust mods on yours? Did you do the vacuum tubes to get permanently open? (Gen-f was this, and F2 was the relays)

 

[Skylarking]

Some pure speculation on my part but wouldn‘t a Bailie tip behave like a musical instrument where the ideal note would depend on the hole size and exhaust flow rate much like the sound of a flute would depend on the mouth shape and how hard one was blowing?

If that’s true, then maybe the ideal sound would change somewhat if engine mods were made which increased exhaust flow rates or the upper parts of the exhaust system were modded changing other aspects of the exhaust flow and thus the “flute”?

Baillie tip, which is part of the bimodal exhaust muffler, is show below:

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A quick test to see/hear if its the Baillie tip is causing the whistle is to grab some gaffer tape and cover/seal the stainless cover to the inner exhaust pipe proper (between the pipe and the valve in the pic above).

If by doing the gaffer tape test it doesn’t whistle any more, then you’ve found the cause and it’s just tune your flute to get the sound your after

 

[lmoengnr]

Did Gen-F HSV's get the Ballie tip? I thought they had different mufflers?

 

[lmoengnr]

No other exhaust mods on yours? Did you do the vacuum tubes to get permanently open? (Gen-f was this, and F2 was the relays)

No mods on the Magnum exhaust, apart from the override relay to keep the electric valves always open.
Full exhaust on the Maloo, with DPE vacuum bimodals on the mufflers. Installed a switch in the power line from the EDI module to the vacuum solenoid to override the EDI control.

No whistles on either ute.

 

[panhead]

I asked my mate who's an exhaust fitter and Ford tragic what he thought the sound was, and he said it reminded him of his girlfriend when she goes parachuting.
He believes it's something Holden owners have to accept and learn to live with.







.

 

[Skylarking]

Did Gen-F HSV's get the Ballie tip? I thought they had different mufflers?

Yeah, you're probably correct

The Baillie tip was a Holden invention so probably not part of the HSV exhaust system which IIRC was a basic system installed at the Holden plant and changed out by HSV during their fettling of the car at Clayton... And as is, the first HSV bimodal exhausts had vacuum operated valves though I'm not sure when/if they moved to electic valves and whether they indeed scored the "flute"

But then again the majority of what was used to build a HSV came from GM/Holden so I've always classed them as a Holden (to the dismay of HSV owners everywhere)

 

[RevNev]

@RevNev ,I think your expert opinion is wanted, needed?

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