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MsTaboo
Samba Member
Joined: June 02, 2006
Posts: 4082
Location: East Kootenay, British Columbia
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 Posted: Tue Jun 23, 2015 1:19 pm Post subject: |
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OK, thanks for the update! So the main reason you changed from the Magnaflow SS unit was because it was too loud?
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Currently:
'90 Syncro Westy 3 knob w/Zetec
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LemonCove
Samba Member
Joined: July 29, 2010
Posts: 324
Location: Henderson, NV
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| Posted: Tue Jun 23, 2015 3:36 pm Post subject: |
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| MsTaboo wrote: |
| So the main reason you changed from the Magnaflow SS unit was because it was too loud? |
Yep. Especially under acceleration; the maganaflow sounded great, but hey, this is no sports car. I really notice the difference now with the Walker on long drives at highway speeds . . . now we can have a normal conversation, listen to the stereo, less stress from the constant din. The Walker still announces you're coming . . . . my cat is always at the door to greet me. 
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'88 Bostig Westy |
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shizzon
Samba Member
Joined: July 25, 2006
Posts: 596
Location: Boulder, CO
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| Posted: Tue Jun 23, 2015 3:39 pm Post subject: |
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Do you know how the walker 17904 compares to the bostig-spec quiet-flow in terms of volume?
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1989 Bostig Syncro Westy |
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LemonCove
Samba Member
Joined: July 29, 2010
Posts: 324
Location: Henderson, NV
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| Posted: Tue Jun 23, 2015 7:59 pm Post subject: |
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| shizzon wrote: |
| Do you know how the walker 17904 compares to the bostig-spec quiet-flow in terms of volume? |
Using the dimensions from the table on the previous page it compues to appx:
17904 = 383 ci
Bostig Spec = 570 ci
As I indicated earlier, I spoke to Walker tech support to ask about the "quietest" muffler. The Walker tech rep indicated that the noise level for all the Walker mufflers in the table (except the megaflows) would be equivalent (tone and volume) on the Zetec. All have similar internal construction. None of them should create any significant back pressure concerns.
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'88 Bostig Westy |
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shizzon
Samba Member
Joined: July 25, 2006
Posts: 596
Location: Boulder, CO
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| Posted: Tue Jun 23, 2015 8:56 pm Post subject: |
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Oops. By volume I meant noise, not mass divided by density 
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1989 Bostig Syncro Westy |
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LemonCove
Samba Member
Joined: July 29, 2010
Posts: 324
Location: Henderson, NV
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| Posted: Wed Jun 24, 2015 10:02 am Post subject: |
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| shizzon wrote: |
| Oops. By volume I meant noise, not mass divided by density |
Thanks for that. I was wondering how you were going to make a decision based upon the internal capacity of the mufflers . . . . I should have figured that out  . I guess it was a good math exercise for me.
I use a research grade sound level meter for doing environmental assessments, and actually attempted to evaluate mufflers using that. Trouble is it's real hard to do this . . . what's the proper methodology? My tailpipe and van interior tests proved inconclusive . . . the Magnaflow was somewhat louder based on those measurements, but the 2 Walkers were essentially the same. Honestly, the measurements did not agree with my subjective evaluation. The sound level meter (as I recall) measures at 3 distinct frequencies, while the human ear hears full spectrum.
https://picasaweb.google.com/13VelosdeRemi/BostigMufflerUpgrade#6001992353038131842
The van interior sound level (volume if you will) is what counts; I went from relatively quiet (Bostig spec), to agressive, throaty, louder (Magnaflow), to relative quiet again (17904). I couldn't honestly notice a "volume" difference between the 2 Walkers.
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'88 Bostig Westy |
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shizzon
Samba Member
Joined: July 25, 2006
Posts: 596
Location: Boulder, CO
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| Posted: Wed Jun 24, 2015 9:12 pm Post subject: |
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To be clear... is the fitting the same with both the bostig-spec and the 17904? Do you still use the same shim and clamp?
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1989 Bostig Syncro Westy |
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LemonCove
Samba Member
Joined: July 29, 2010
Posts: 324
Location: Henderson, NV
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| Posted: Wed Jun 24, 2015 9:43 pm Post subject: |
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| Quote: |
| is the fitting the same with both the bostig-spec and the 17904? Do you still use the same shim and clamp? |
it can be, and others have done so. PM Kourt to see how he did his.
Because the offset design moves the "centerline" of the muffler outward, the Bostig hangers are too far "inward." The inboard rubber isolators are now pretty much centered on the 17904 case. I decided to use modified Walker 36273 hangers ($5/ea). I took off the rubber strap, and shortened the hanger to one hole from 2. I still used 2 of the the Bostig rubber isolators (inboard) and S/S screw clamps.
This is all detailed in a picasa album "Bostig Muffler Upgrade":
https://picasaweb.google.com/13VelosdeRemi/BostigMufflerUpgrade#
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'88 Bostig Westy |
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shizzon
Samba Member
Joined: July 25, 2006
Posts: 596
Location: Boulder, CO
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| Posted: Wed Jun 24, 2015 10:03 pm Post subject: |
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The hanger connection looks slick, but I meant the part that connects the muffler to the exhaust. Is that part of the muffler the same diameter as the bostig-spec muffler? I.e., no welding or funny business required at that connection?
thanks!
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1989 Bostig Syncro Westy |
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LemonCove
Samba Member
Joined: July 29, 2010
Posts: 324
Location: Henderson, NV
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| Posted: Thu Jun 25, 2015 11:00 am Post subject: |
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| shizzon wrote: |
| Is that part of the muffler the same diameter as the bostig-spec muffler? I.e., no welding or funny business required at that connection? |
Same diameter, Same slot cuts in the muffler pipe, Same overlap on the cat pipe, Same clamp for the 17904. I don't recall using a shim, but did use the AcoustiSeal.
No welding.
I found it immensely fun
If you get stuck PM me.
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'88 Bostig Westy |
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shizzon
Samba Member
Joined: July 25, 2006
Posts: 596
Location: Boulder, CO
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| Posted: Fri Jul 03, 2015 2:07 pm Post subject: |
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I got some of the walker exhaust sealing compound. is it necessary to let it cure before using the engine and having it get really hot.. .i'm surprised there are no instructions on the bottle!
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1989 Bostig Syncro Westy |
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LemonCove
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Joined: July 29, 2010
Posts: 324
Location: Henderson, NV
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| Posted: Fri Jul 03, 2015 10:32 pm Post subject: |
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I didn't do any special "curing."
Applied it to the joint, drove the van.
No leaks, has remained leak free.
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'88 Bostig Westy |
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shizzon
Samba Member
Joined: July 25, 2006
Posts: 596
Location: Boulder, CO
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| Posted: Thu Jul 09, 2015 5:06 pm Post subject: |
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| kourt wrote: |
| I've put the Walker 17904 on my Bostig, with a 9" down curve tip, and it's roomier and quiet, and gives more clearance from the AC compressor. |
Kourt, do you have the part number for the 9" curve down? Does it stick out?
Does anyone know whether a tip really makes a difference in quieting things down?
I did this install and my initial impressions are that it is pretty much the same or maybe quieter than the stock bostig setup. I'd be stoked if i can quiet it even more!
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1989 Bostig Syncro Westy |
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kourt
Samba Member
Joined: August 13, 2013
Posts: 1931
Location: Austin, TX
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| Posted: Thu Jul 09, 2015 5:11 pm Post subject: |
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I just used a cheap tip from the local auto parts store--I think it was 2 1/4" inlet. The inlet side was widened slightly, and tapered to a standard 2" output.
kourt |
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shizzon
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Joined: July 25, 2006
Posts: 596
Location: Boulder, CO
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| Posted: Fri Jul 10, 2015 8:20 am Post subject: |
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Did that cheap tip seem to quiet it down, kourt?
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1989 Bostig Syncro Westy |
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kourt
Samba Member
Joined: August 13, 2013
Posts: 1931
Location: Austin, TX
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| Posted: Fri Jul 10, 2015 8:27 am Post subject: |
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It could be the placebo effect, but it seemed to help keep things quieter back there. It's hard to say--what with "sooting in" (as Bostig calls it) and other factors.
kourt |
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LemonCove
Samba Member
Joined: July 29, 2010
Posts: 324
Location: Henderson, NV
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| Posted: Thu Dec 01, 2016 6:08 pm Post subject: Re: Bostig Muffler Upgrade |
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Updated link for "Muffler Upgrade" photo album (picasa link is dead):
https://goo.gl/photos/CFk44jXnuQQkiXHS6
For each photo, clicking on "i" (info) icon will open sidebar with notes.
EDIT: Ooops, I guess I'm the only one who can see the comments/notes, and only while I'm signed in (thanks, Google). Vid links don't work either.. Can still see photos though.
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'88 Bostig Westy |
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vwcampin
Samba Member
Joined: November 19, 2002
Posts: 392
Location: Omaha
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| Posted: Thu Dec 01, 2016 9:34 pm Post subject: Re: Bostig Muffler Upgrade |
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I just wanted to say thanks for this thread. Helped me make the leap and definitely happy with results!
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1986 Vanagon Syncro Westfalia Weekender |
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Microbusdeluxe 
Samba Member
Joined: July 26, 2003
Posts: 980
Location: Bellingham, WA
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| Posted: Wed Jun 28, 2017 1:40 pm Post subject: Re: Bostig Muffler Upgrade |
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Wanted to add my thanks for this thread. I wasn't happy at all with the original muffler set-up and the fitment of the suggested muffler.
Everything seemed to be loosey-goosey and definitely hung lower than the old waterboxer set-up. By using the Walker 17904 muffler, which is smaller than the suggested one, and especially using the vastly superior hanger suggested in the above part of this thread things look great, secure and it all fits perfectly. I added a 9" down-curved tail pipe from the FLAPS.
Sound is fine, the Zetec has a different pitch than the waterboxer, but highway noise is no worse than the old 2.1.
If you are just starting your build do yourself a favor and take back the suggested muffler before you cut it and substitute the smaller one.
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'89 hightop Westy Joker syncro 16" now with Bostig! |
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Guybrush
Samba Member
Joined: August 08, 2015
Posts: 453
Location: Arizona
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| Posted: Wed Jun 28, 2017 1:51 pm Post subject: Re: Bostig Muffler Upgrade |
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I use the same one too, although I find the exhaust too loud, but it's possible I didn't seal it well enough between muffler and cat.
I actually used the Bostig hangers to attach it, but only 2 of them, and that works fine.
Did the same thing as LemonCove for the tip and cut a bit of the sheet metal for clearance. I think it looks just right. The one towards the rear wanted to slip out of the rubber but I added a little clip to prevent it (the former WBX accelerator cable clip fit juuust right).
Better clearance from the A/C compressor and I'll be building a shield when I get the A/C working. |
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