1971 stock muffler modification?

[aeromech]

I'm building an 1800 type 1 for my 1971 bus. I want to use all stock components but will modify the carburetor to flow more. I am trying to pick an appropriate exhaust and need good manifold preheat. Is it possible to modify a stock exhaust to flow more air? Is there a better option for me? Please keep in mind that I've given this a lot of thought and looked at several exhausts. I want one as quiet as possible too.
_________________
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Boeing 727,737-200-300-400,757,767
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Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
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Capable of leaping tall buildings in a single bound

[bay window dude]

These are 1-1/2 inch heater boxes which have less restriction and flanged connectors: http://www.cbperformance.com/product-p/3678.htm

paired with one of these would be a good setup:
http://vwparts.aircooled.net/Vintage-Speed-SS-Sport-Muffler-155-209-05200-p/155-209-05200.htm
http://vwparts.aircooled.net/Vintage-Speed-SS-Sport-Muffler-155-210-05200-p/155-210-05200.htm

They also have an even higher flow version, but you probably don't need it with an 1800. Make sure to specify to add the flanges and get a pair of adaptors. Alas, I have not purchased one yet, so i cant speak for noise, but the single quitepack i have which also has preheat flanges (http://www.cbperformance.com/product-p/3613.htm) is loud AF.
_________________
1972 Westfalia Weekender - Sold
1965 Chevrolet Corvair Convertible - 110 PG - Sold
1970 Westfalia Weekender

[aeromech]

I'm sorry, I should have mentioned that I'm using stock heater boxes. I've considered Vintage Speed but have heard they are loud and crack out. If I could make my stock muffler flow about 25% more I think I'd be happy
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[richparker]

I agree that Gary should go with a VS Sport exhaust, but I think a stock port would be fine. However, I think the "bad press" has made him lean against one. There is a total of 25k on mine and it's the best all around system I've had on my bus.
_________________
__________
’71 Westy build
Adventure thread
’65 Deluxe Build
’63 Deluxe Build

[aeromech]

Maybe I should call Tiger?
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[Bulli Klinik]

How about a beetle muffler? I've run one on my 70 for years. I've also run one on a split with dual pipes similar to a single peashooter.
My old split:

_________________
I've never met a Bus I didn't like.
Mike K
Bulli Klinik
Colorado Springs

[airschooled]

The split stock pipe system above has always intrigued me, but the stock restrictors in the 2/4 manifolds would hold WAY more flow back than the tailpipe. Remember, exhaust gases shrink as they cool, so the farther downstream a pipe is, the less large is has to be to flow the same amount as something upstream.

Didn't someone on here recently drill out the "cone" waffle restrictors in the 2/4 headers? Anybody?

Robbie
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[Abscate]

[aeromech]

[richparker]

[Bulli Klinik]

If you are running stock size valves a stock carb and heater boxes, you will be fine running a stock Beetle exhaust. Even with the extra displacement.

I've had the same setup in my Dormobile (1776) for over 50K miles. I use these oversize tail-pipes on mine so it doesn't whistle like a Bug.

_________________
I've never met a Bus I didn't like.
Mike K
Bulli Klinik
Colorado Springs

[aeromech]

I don't want to run a bug exhaust with two pea shooters. I guess you're saying I need to for the extra flow. Can I get a muffler shop to weld on a larger outlet pipe to a stock bus muffler?
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[Bulli Klinik]

With a welder and some skill, anything is possible.

Here's a link to help you determine if you want to or not:
http://www.vwdcqinc.org.au/insideabug-insideamuffler

After thinking about it, I think one could make a single tailpipe which joins the two exhaust outlets into a single, side outlet with a slightly bigger pipe.

I'm stuck with a stock-style exhaust because I have a trailer hitch.
_________________
I've never met a Bus I didn't like.
Mike K
Bulli Klinik
Colorado Springs

[busdaddy]

How about a bug muffler with a modified custom zoom tube? I guess you'd have to add the diameter of the 2 slightly smaller outlets together to determine the potential % of gain. Lining the tube with the perforated stuff like the stock damper pipe may even quiet it down enough to compensate for removing the cones.
I experimented with a larger tailpipe a few years ago and discovered I lost much of the low end torque, but that was with a stock engine, displacement and cams will no doubt interact differently.
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[aeromech]

That's got my attention.
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[Brian]

-1 for the VS
+1 for modifying a bug muffler
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[airschooled]

[richparker]

[aeromech]

Brian is like Stu, they just beat the living shit out of stuff. Don't think I'd listen to a review from either one of them.

No Rich, it's actually very useful information if you want to know what five years of wear and tear looks like in a fraction of the time.
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[Brian]

yea, what's his name with the nice bus did that as well. you just weld in some t3 stuff or something like that and you have ''sport'' muffler.