VW Beetle exhaust note

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Does anyone know what gives the classic Beetle it's rattly exhaust note? It has a slight rasp to it under load, somewhat similar to an opened-up Suby boxer exhaust, but the Beetle also has that very high-pitched tinny blee-blee-blee rattle to its exhaust.

Is that mechanical engine noise? I can't imagine exhaust system tuning being able to create a noise like that, but maybe...

Any suitcase engine experts in here?

Also: having been produced from the mid-1930s through the mid-2000s, is this the engine series with the longest running production date span?
 
People who race VWs try to get them to sound like normal engines.

Standing uphill at a hillclimb, you can't tell that this guy is running a dak-dak.



Funnily, the Subaru aficionados want their cars to sound like dak-daks.
 
Possibly the exhaust manifold design. If the tube for each exhaust port is a significantly different length than the others, the pulses will exit with "delays" causing that noise. It's why the Subarus have a unique note: unequal length header.
 
Bugs run and sound better with a good equal length high flow header instead of the restrictive stock exhaust and tiny resonator tips. The stock vintage Sound is mainly due to the small, restrictive resonator tips at the muffler exit.
Some subaru guys like the unequal length header sound but it is a poor tune with lost performance over a proper equal-length header design. Equal length headers can be tuned to provide two torque peaks that can coincide with low end torque for "putt around town" power and then with the upper primary resonance at the upper torque peak for excellent passing and "racing" power. Some graduated header designs can be tuned for a flatter torque curve (without a no mans land torquless valley" but with a significant loss of ultimate torque at the peak tune.
 
Thanks guys. I didn't figure the exhaust tuning could create such a high-pitched "blap", but I guess it does. Something about air-cooled bugs appeals to me. Their simplicity probably.
 
Hokiefyd, I think the exhaust note has more to do with being a horizontally opposed engine than being air cooled. Basically why old VW's and Subarus have a similar beat to them.

ARCO described it perfectly IMO.
 
Originally Posted By: ARCOgraphite
Bugs run and sound better with a good equal length high flow header instead of the restrictive stock exhaust and tiny resonator tips. The stock vintage Sound is mainly due to the small, restrictive resonator tips at the muffler exit.
Some subaru guys like the unequal length header sound but it is a poor tune with lost performance over a proper equal-length header design. Equal length headers can be tuned to provide two torque peaks that can coincide with low end torque for "putt around town" power and then with the upper primary resonance at the upper torque peak for excellent passing and "racing" power. Some graduated header designs can be tuned for a flatter torque curve (without a no mans land torquless valley" but with a significant loss of ultimate torque at the peak tune.


+1 When I put some nice headers on, the noise went away. But there was still a little valve train noise - those engines were manual valve adjust and if you couldn't hear a little noise, you had 'em too tight.
 
I love the sound of boxers and know it from Subaru, Porsche and VW.

My wife's Legacy GT with stock exhaust can rattle my house windows idling with the resonance of unequal headers.
 
Originally Posted By: Hokiefyd
Does anyone know what gives the classic Beetle it's rattly exhaust note? It has a slight rasp to it under load, somewhat similar to an opened-up Suby boxer exhaust, but the Beetle also has that very high-pitched tinny blee-blee-blee rattle to its exhaust.

Is that mechanical engine noise? I can't imagine exhaust system tuning being able to create a noise like that, but maybe...

Any suitcase engine experts in here?

Also: having been produced from the mid-1930s through the mid-2000s, is this the engine series with the longest running production date span?


The whistly part of it is just the exhaust system itself with the little dual stub pipes out a transverse muffler. The fuel injected Beetles with a larger single outlet didn't make the bleeby-bleeby-bleeby sound from the factory, and neither do any of the bigger outlet aftermarket exhausts. :)

The fact that there's an underlying burble is the same reason American V8's burble- the firing order doesn't alternate banks. The boxer 4 (ANY boxer 4) fires left-left-right-right. Some aftermarket VW headers or "extractors" have cross-cross pipes and equal length runners which eliminate the burble, too. The American (90-degree crank) v8 fires left-right-left-left-right-left-right-right, regardless of which of the 3 possible firing orders is used. The different firing orders for the v8 just change up where along the length of the crank the sequential firing pulses take place, none makes them alternate banks. That requires a flat (Ferrari, for example) style crankshaft and all the downsides that come with it such as the same inherent 2nd order imbalance that inline 4-bangers have. The flat-crank V8 IS two inline 4-bangers running 90-degrees out of phase, after all. The upside is that despite poorer NVH, the flat crank has lower rotating mass.
 
Originally Posted By: Shannow
People who race VWs try to get them to sound like normal engines.

Standing uphill at a hillclimb, you can't tell that this guy is running a dak-dak.



Funnily, the Subaru aficionados want their cars to sound like dak-daks.


It sounds decent!
 
I think 440Mag is right, it's the sound I would like when I get this current project done
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Mud, that looks like a nice, solid bug you're starting with. The exhaust tips have baffles inside them that rust loose and make that whistling noise. You used to be able to get straight through tips that clamped on the same way that sounded better and were cheaper than stock. Been 30 years since I owned a V Dubya.
 
Yes it's the baffles in the stock stingers. My mom bought a brand new super beetle in 1973, and it had the tweet sound to the exhaust. My dad bought some flared stingers at the dealer that got rid of the tweeting and gave it a deeper tone. And yes a VW and a subaru sound similar because they are both 4 cyl boxer engines. Does anybody remember when injected alcohol burning VW engines were the hot set-up in midget car racing, they did well and sounded great
 
In the stock exhaust.

My SuperBeetle had a cheap Monza exhaust (that allowed me to keep the heat exchangers that time....the stinger exhaust on my earlier Type1 did not) I don't remember hearing the chirp anymore on either.
 
Originally Posted By: Silverado12
Mud, that looks like a nice, solid bug you're starting with. The exhaust tips have baffles inside them that rust loose and make that whistling noise. You used to be able to get straight through tips that clamped on the same way that sounded better and were cheaper than stock. Been 30 years since I owned a V Dubya.

Thanks, lucky that yes it's very solid, was dad's hobby car. I've been stockpiling parts (including new stock muffler and tips)
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and researching info. I've found thesamba.com to be a great resource. I'm old school from the SBC and BBC drop-in days, but I find this to be a neat turn doing something different. I actually wanted to replicate that exhaust note lol.
 
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