Why does a VW flat-four sound so different from an inline-four? Don't they both get a power-stroke (spark plug fires) every 180 degrees of crankshaft rotation? The air-cooled flat-four also has some kind of "whistling" sound to it that's very unique. Just curious.

Alfred

cooling fan and cam gear whine

exhaust system.
inline /4 usually have 4in1 headers and then a muffler (with very short individual tube for each cylinder).

the flat /4 has a separate pipe for each cylinder and they all get dumped into the muffler individually and then 1 out.

same for type1 engines, that's why our flat /4s sound so much like a bug

Andy

Also remember that water-cooled engines are much more isolated and therefore you can hear less mechanical "noise"

cheers,

Jeroen

hey, i'm qouting myself! first time for everything ...

just wanted to add, the really high pitch annoying sound bugs sometimes make is actually the mesh in the exhaust pipes which is only pressed in and comes loose after a while. it then starts vibrating and makes this typical bug-noise ...
remove it and you have a MUCH better sound

Andy

So, If I got a 4 to one header and a supertrapp or Flowmaster, I ill not sound like a bug-ish?

i thought bugs sounded like that because they had lil pea-shooter exhausts...

I actually like the way the flat-four sounds - but then again, I also like the way the 914 looks.

Alfred

i'm sure a flat four- four cam carrera engine sounds cooler!!!!

I've got a 4 into 1 collector and a Flowmaster. It does not sound like a bug.

Demick
'74 2.0

I just had stock H/E's with a Bursch and I thought my car sounded decent thru the exhaust, it's all the other "noise" that the 914 /4 motor emits that I don't care for

I belive this extra "noise" is due to the lack of a sound barrier (water jackets) and the mechanical tappets.

The engine sheetmetal cannot be helping as well. I've thought that if small strips of dynomat or something similar are attached to the engine sheetmetal, it would help.

I also think that the valve covers could use something to help dampen the noise, but maybe it's just me

yes...i agree mueller , ther eis lots of valvetrain noise... hydrolic lifters would help aleviate the noise...

POP POP POP POP POP POP POP POP POP POP POP

I like the metallic note of the factory 2.0 setup, I wish I could get rid of some of the intake noise, it's annoying if you drive very far, maybe I should run a hose to my intake.



M

I would have to say that my sons 2.0L does not sound bug like. Having owned two 74 supers no comparision. one was really hopped up sounded like a top fuel dragster till it warmed up. Nieghbors hated me.

914 just seems to have more authority to the exhaust note. 2.0L stainless heat exhangers thru Bursch muffler. Web 86B cam and 40 IDF's The 44IDF's would really howl over 3500 RPM.

Now close the door with a blind fold on and I dare you tell the difference.

Just BTW my 928 sounds exactly like a 944 when the doors close. turning the key is a whole different story.

The best description of the stock bug exhaust I have heard is that it sounds like the car is "dragging a chain". Does that fit or what?

Coffee Can full of nickles.....

I thought the shrill whistling commonly heard with bug engines was due to the carb -there was a kit like a rubber gasket that fitted twix carb and manifold to eliminate this.

Swivel feet can help somewhat with the valvetrain noise

Two of my neighbors have Miatas and they have a terrible exhaust note. I much prefer the sound of the flat-four. Here's a page from Road & Track where they briefly talk about the 2.0's sound.

Alfred

My Type 1 has had both a 1600cc 912 engine, Dual Dellorto DLRA 40's, Busrch Exhaust, and the current engine, a stock 1600cc dual port, with the stock exhaust and carb.

The main difference between the two engines is valve geometry. (IMO).

The 912 gave me much more power, and a much wider range of RPM. The carbs were noisy! There was the constant sucking sound. Then there was the whine of the cooling fan - almost turbine-like (gave me chills) - and the exhaust note . . . buhwaaaaaaah! Absolutely in stark contrast to the VW engine.

About the only thing in common was the valve-train noise, which is a component that sounds much like a battery of a dozen sewing machines in a Panamanian sweatshop. Both engines had this sound, and it was very similar - and would even change audibly as valve-lash drifted out of spec over the miles. (I'm fairly anal about valves - I adjust them every 1000 miles religiously, and I record how far out of spec each one is).

The VW engine's carb has a sucking sound (which varies by how far out you adjust the bypass screw), but it's a lot different, it's a single voice, the 912's Dellortos was a barbershop quartet. That's even running a bad aftermarket aircleaner. The stock oil-bath aircleaner does a great job at muffling noise from the stock 34-PICT carb.
But the big difference was the exhaust note, IMO - the VW has the pea-shooters, and it "fweems". Chirps like a bug, and I'm told this was done on purpose for the US market, a decision made back in the late 1940's or early 1950's, that went along with calling the car a "Beetle". There are inserts in the pea-shooter tailpipes that cause the moving gasses to whistle. And those inserts do wear out over time - and can be removed as well.

the inserts are supposed to be fixed. on new pipes they are, but they're just pressed in and hold by 3 notches (IIRR).
they come loose over time and the vibration is what makes that strage sound. either get new pipes or remove the inserts.
both will improve the sound

Andy

I leave them in. The kids love the "fweem".

Though, someday, I'll sell it, and buy a 914, then they'll love the BUHWAAAAAAAAAAH!

Yeah I've noticed too that the 912 engine sounds nothing like a beetle engine (not 912E).
There's a guy who races his 356 engined 912 and it flies round the track and sounds really beefy too.
He reckons it has a handling advantage over the 911 too due to the lighter engine being situated slightly further forward.