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edelweiss
Samba Member
Joined: June 12, 2015
Posts: 18
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 Posted: Mon Aug 03, 2015 10:57 am Post subject: Getting that signature whistling muffler sound back? |
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What part of the muffler makes that beautiful stock whistling sound?
I have a 72 Super and was assuming that the chrome tail pipes make that sound. Mine are rusted (of course) and I was going to replace them with stainless tail pipes. Do the stock tail pipes have a baffle in them that produce the whistling sound?
Thanks!
John |
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sjbartnik
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Joined: September 01, 2011
Posts: 5994
Location: Brooklyn
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| Posted: Mon Aug 03, 2015 11:09 am Post subject: |
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The pea shooters, i.e. chrome tailpipe tips are indeed what makes the whistling sound.
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edelweiss
Samba Member
Joined: June 12, 2015
Posts: 18
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| Posted: Mon Aug 03, 2015 11:58 am Post subject: |
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| sjbartnik wrote: |
| The pea shooters, i.e. chrome tailpipe tips are indeed what makes the whistling sound. |
Very cool. Thanks! |
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jlex
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Joined: January 23, 2009
Posts: 2902
Location: NW Pennsylvania
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| Posted: Mon Aug 03, 2015 6:43 pm Post subject: |
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...and it's known as FWEEM. 
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'70 std. "Elsie"
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vamram 
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Joined: March 08, 2012
Posts: 7300
Location: NOVA
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| Posted: Mon Aug 03, 2015 7:14 pm Post subject: |
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You also get the nice sound of the engine fan when using stock tailpipes. It tends to get drowned out by aftermarket headers or baffle-less tailpipes.
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'74 Super 9/16 - present, in refurb process.
'73 Super - 6/18 - Present - Daily Driver!
'75 Super Le Grande...waiting it's turn in line behind '74.
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edelweiss
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Joined: June 12, 2015
Posts: 18
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| Posted: Mon Aug 03, 2015 7:32 pm Post subject: |
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| vamram wrote: |
| You also get the nice sound of the engine fan when using stock tailpipes. It tends to get drowned out by aftermarket headers or baffle-less tailpipes. |
So the stock tail pipes do have baffles in them no? Sorry, have not attempted to take the rusty ones off yet to look at them. |
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vamram
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Joined: March 08, 2012
Posts: 7300
Location: NOVA
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| Posted: Mon Aug 03, 2015 7:37 pm Post subject: |
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| edelweiss wrote: |
| vamram wrote: |
| You also get the nice sound of the engine fan when using stock tailpipes. It tends to get drowned out by aftermarket headers or baffle-less tailpipes. |
So the stock tail pipes do have baffles in them no? Sorry, have not attempted to take the rusty ones off yet to look at them. |
Yep. Wolfsburg West and other vendors sell them.
http://www.wolfsburgwest.com/cart/DetailsList.cfm?ID=113251163C
Probably lots of pics of them in the gallery.
_________________
Eventually, "we are what we pretend to be.’”
Give peace a chance - Stop Russian-Soviet Aggression!!
'74 Super 9/16 - present, in refurb process.
'73 Super - 6/18 - Present - Daily Driver!
'75 Super Le Grande...waiting it's turn in line behind '74.
Click to view image
Save the Supers!! |
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edelweiss
Samba Member
Joined: June 12, 2015
Posts: 18
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| Posted: Mon Aug 03, 2015 7:47 pm Post subject: |
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| vamram wrote: |
| edelweiss wrote: |
| vamram wrote: |
| You also get the nice sound of the engine fan when using stock tailpipes. It tends to get drowned out by aftermarket headers or baffle-less tailpipes. |
So the stock tail pipes do have baffles in them no? Sorry, have not attempted to take the rusty ones off yet to look at them. |
Yep. Wolfsburg West and other vendors sell them.
http://www.wolfsburgwest.com/cart/DetailsList.cfm?ID=113251163C
Probably lots of pics of them in the gallery. |
Awesome! Thanks! |
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bnam
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Joined: July 02, 2006
Posts: 2936
Location: El Dorado Hills CA/ Bangalore, India
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| Posted: Tue Aug 04, 2015 6:45 am Post subject: |
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It does not appear to be that simple. I have stock replacement tail-pipes and don't have the fweem. There are some instructions on how deep they should be insterted into the muffler. The muffler on mine may have some internal differences from stock since I could not insert the tail pipes as deep as suggested in the instructions before hitting in internal pipe.
Hopefully you will have better luck. |
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ashman40
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Joined: February 16, 2007
Posts: 15982
Location: North Florida, USA
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| Posted: Tue Aug 04, 2015 6:55 am Post subject: |
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| bnam wrote: |
| It does not appear to be that simple. I have stock replacement tail-pipes and don't have the fweem. There are some instructions on how deep they should be insterted into the muffler. The muffler on mine may have some internal differences from stock since I could not insert the tail pipes as deep as suggested in the instructions before hitting in internal pipe. |
Sometimes the end of the heat riser tube that ends in the "muffler" is not centered in the exhaust opening. You may need to tweak it just a bit. That tube, which comes from the heat tube that runs below the intake manifold, should sit INSIDE the tail-pipes. This results in a vacuum that draws the exhaust through the heat riser and out the exhaust.
The adjustment for installing the tail-pipes does not specify how far they should seat into the "muffler". You bottom them out and then back them out a little (I can't recall how much you back them out??... maybe someone has their Bentley manual handy?).
BTW, I use "muffler" above to describe the resonator (what most call the muffler), but technically the tail pipes are actually the mufflers. They function the same as old glasspack mufflers.
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Luft kühl
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Joined: January 21, 2009
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Location: Allentown, PA
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| Posted: Tue Aug 04, 2015 7:47 am Post subject: |
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Adjust tail pipe length (from tip to muffler) to:
8 9/32 in. (210 mm) on 1961-1973 models
8 7/8 in. (226 mm) on 1974 models
Tail pipe length affects exhaust flow and engine back pressure. |
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Old n' slow
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Joined: October 29, 2012
Posts: 619
Location: Western Maryland
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| Posted: Tue Aug 04, 2015 9:03 am Post subject: |
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| sjbartnik wrote: |
| The pea shooters, i.e. chrome tailpipe tips are indeed what makes the whistling sound. |
. Parts place inc. in warren MI. Had original made in western Germany tail pipes, that's were I got mine. I still think they have them.........Quality chrome .
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pb_foots
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Joined: April 15, 2010
Posts: 1089
Location: Ben Lomond, CA
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| Posted: Tue Aug 04, 2015 10:32 am Post subject: |
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| Luft kühl wrote: |
Adjust tail pipe length (from tip to muffler) to:
8 9/32 in. (210 mm) on 1961-1973 models
8 7/8 in. (226 mm) on 1974 models
Tail pipe length affects exhaust flow and engine back pressure. |
Only issue with this is the various lengths sold by the aftermarket. The tip to muffler measurement is only good if the entire tailpipe is stock length.
My blue Bentley says this:
On 66-67 cars the tail pipes should not enter muffler more than 1.8 inches. On 68-69 models 3.4 inches is the limit. Obtain these fittings by first measuring total length of pipe and then subtracting the length protruding after insertion.
Orange Bentley says:
Measure the tailpipes. 3 lengths are used. depending on model, these lengths are 276 MM, 249 MM and 226MM. The last length is on 73 and 74 cars only. (However, 74 pipes have an inside diameter of 23MM, not 20MM as in 73).
On 74 cars only, install the tailpipes so that they project 155 MM from the muffler
On 70-73 cars, insert the left tailpipe. Then insert a steel tape measure through the center of the pipe until it contacts the pre heating pipe inside the muffler.
Move the pipe in and out until its outer end aligns with the correct graduation on the pipe.
The correct graduations are 270MM for 276MM pipes, 243MM for 249MM pipes, and 220MM for 226 MM pipes.
Not sure it's worth the hassle for a whistle! |
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pwmcguire
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Joined: January 30, 2011
Posts: 1108
Location: Kennesaw GA
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| Posted: Tue Aug 04, 2015 7:18 pm Post subject: |
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| If you want that sound, use an NOS muffler and NOS tips. Be careful what you buy |
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glutamodo
The Android
Joined: July 13, 2004
Posts: 26310
Location: Douglas, WY
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| Posted: Tue Aug 04, 2015 7:45 pm Post subject: |
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In my experience, new tailpipes don't really fweem very much, but as they wear and the baffles start to get loose, that's when the fweem kicks in.
About NOS muffler and pipes:
For many years I ran taper tip tailpipes (the baffled style) mostly because I was sick of fweem. Then, several years back, I on an NOS Ernst muffler and NOS Ernst brand tail pipes, and I was very happy with them NOT fweeming when I put them on there (on my big-bore 40HP engine) Eventually they started to, but not too badly. Later, that muffler died but I moved the pipes to an NOS VW-made muffler and they still sounded fairly good to me. But, they do fweem a little now and I've been meaning to try some different pipes again.
-Andy |
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Aussiebug
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Joined: June 03, 2002
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Location: Adelaide Australia
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| Posted: Wed Aug 05, 2015 12:15 am Post subject: |
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Some years ago I wrote an article on the reason for the Bug's distinctive sound.
The beat part comes about through the flat 4 arrangement coupled with the muffler design. The rear two cylinders mount direct to the muffler (which is essentially just an open box) and the front two cylinders connect via the headers/heater boxes. But inside the muffler, the two rear cylinder connections each have an internal pipe across the muffler, so the headers for all 4 cylinders are the same length (two cylinders internal and two external). This results in the pulses coming out the tail pipes as left/left/right/right, rather than left/right/left/right, and our stereo hearing hears that as a distinctive beat. But because the muffler is in fact open inside and some of each pulse can leak across to the other tail pipe, it's really LEFTrightLEFTrightRIGHTleftRIGHTleft which you hear.
The whistle sound does indeed come from the peashooter tips. It's the inner perforated tube with fibreglass packing behind the perforated pipes which does it, and incidentally THESE are the true mufflers - put plain pipes in there and hear the difference! The narrow internal diameter of the perforated pipe, resulting in a high gas speed, plus the perforations, creates the whistle sound - a bit like blowing through a snake-light perforated tube.
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edelweiss
Samba Member
Joined: June 12, 2015
Posts: 18
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| Posted: Wed Aug 05, 2015 4:00 am Post subject: |
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| Aussiebug wrote: |
Some years ago I wrote an article on the reason for the Bug's distinctive sound.
The beat part comes about through the flat 4 arrangement coupled with the muffler design. The rear two cylinders mount direct to the muffler (which is essentially just an open box) and the front two cylinders connect via the headers/heater boxes. But inside the muffler, the two rear cylinder connections each have an internal pipe across the muffler, so the headers for all 4 cylinders are the same length (two cylinders internal and two external). This results in the pulses coming out the tail pipes as left/left/right/right, rather than left/right/left/right, and our stereo hearing hears that as a distinctive beat. But because the muffler is in fact open inside and some of each pulse can leak across to the other tail pipe, it's really LEFTrightLEFTrightRIGHTleftRIGHTleft which you hear.
The whistle sound does indeed come from the peashooter tips. It's the inner perforated tube with fibreglass packing behind the perforated pipes which does it, and incidentally THESE are the true mufflers - put plain pipes in there and hear the difference! The narrow internal diameter of the perforated pipe, resulting in a high gas speed, plus the perforations, creates the whistle sound - a bit like blowing through a snake-light perforated tube. |
Thank you for sharing! Very interesting to read. |
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ROCKOROD71
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Joined: January 18, 2012
Posts: 2770
Location: Boston, MA
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| Posted: Wed Aug 05, 2015 4:47 am Post subject: |
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| pb_foots wrote: |
[
Orange Bentley says:
Measure the tailpipes. 3 lengths are used. depending on model, these lengths are 276 MM, 249 MM and 226MM. The last length is on 73 and 74 cars only. (However, 74 pipes have an inside diameter of 23MM, not 20MM as in 73).
On 74 cars only, install the tailpipes so that they project 155 MM from the muffler
On 70-73 cars, insert the left tailpipe. Then insert a steel tape measure through the center of the pipe until it contacts the pre heating pipe inside the muffler.
Move the pipe in and out until its outer end aligns with the correct graduation on the pipe.
The correct graduations are 270MM for 276MM pipes, 243MM for 249MM pipes, and 220MM for 226 MM pipes.
Not sure it's worth the hassle for a whistle! |
So...Reader's Digest version is: Jam pipe in all the way, back it out 6mm? Or are my reading skills that bad?
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jlex
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Joined: January 23, 2009
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Location: NW Pennsylvania
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| Posted: Wed Aug 05, 2015 6:08 am Post subject: |
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I've never worried much about getting the correct fweem sound, although I'm thinking if you wanted to experiment with the correct placement of the tailpipes, why not just leave the clamps loose enough to move them in & out while the engine is running? Like tuning a pipe organ, right?
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'70 std. "Elsie"
'88 Carrera |
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CarlIseminger
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Joined: May 12, 2008
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Location: Grand Forks, ND
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| Posted: Wed Aug 05, 2015 10:26 am Post subject: |
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My car had the fweem sound when I first got the car at 26,000 miles. But the muffler (or resonator) was rusting so very quickly it just got loud.
I had a new "muffler"  installed and at first, the engine was nice and quiet, but I didn't have the fweem. Slowly as I drove it more and more, it came back. But now at 46,000 miles, it is going away again. I suppose due to wear in the tips.
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