W. B. X-awst!

[bucko]

That tubing fits under the Vanagon? I'm trying to picture it installed.

Do you have an "empty" engine bay you're using to check the fit?
_________________
Current VW drives: 1984 Westfalia

Past VW drives: 1967 Beetle, 1973 Beetle, 1977 Bus, 1971 Military Type 181

[Crankey]

[tencentlife]

No, torch. And I sure do hope it fits. It's mocked up on the blue engine and I keep checking under my van to make sure I stay honest.
_________________
Shop for unique Vanagon accessories at the Vanistan shop:
https://intrepidoverland.com/vanistan/

Please don't PM here, I will not reply.

Experience is kryptonite to doctrine.

[msinabottle]

I don't usually lust like this for things that don't discharge projectiles... But...

OH, WOW!

Please... to the nth... Mass produce those. Oh, LUST!



Best!
_________________
'Winston,' '84 1.9 WBX Westy
Vanagon Poet Laureate: "I have suffered in
many ways, but never, never, never in silence."

[klucz]

[tencentlife]

Introducing: The New Needlenose!

In this last pic you can see the extra fillets I added between the tubing curves on the outside, to bridge to the formed collector.

It looks like some kind of howling cartoon mosquito. Once the collector goes on, Mr. NN will never be seen again.

Today I have to grind those fillets a bit to fit the collector, and weld it on. This'll be the hardest welding job of the whole project. Of course everything has to be gas-tight and pretty strong as well.

Then I add the curved section of 2.5" pipe that brings it to a flange in the muff attic, where the cat or muff will bolt on. I'm going to make my own 3-bolt flanges from 1/4" plate because I never could get the right size ones for a reasonable price. Wish I had some 3/8" plate. In future I'll get some to make more flanges from, unless I can find a supplier. The port flanges from CB are 3/8" thick, but I've found it's the large 3-bolt ones where extra thickness really matters as they distort with the heat.

I'm going to order a Borla XS muff today, and maybe a fancy chromed dress-up tip. The Borlas are all stainless with a million-mile warranty, and had a very good showing in the comparison testing I linked to above. Of course I chose it because they have cool stickers. If the sound and flow are good in this application, then that may be the muff I offer with the system, as they are inexpensive as well.

Yes indeed, Rob, copies of this will be available, hand-made by yours truly. They won't be cheap because of all the hand labor, even though it'll go a lot quicker the second time around because I've worked out the design and fabrication problems on the prototype. It's not tuned specifically for the 1.9, though. I'll do the math and see how well it will complement the 1.9's cam timing, which is worlds different from the 2.1. If it's not a good match then it may be advantageous to work out a different system with the right tube lengths for that motor.
_________________
Shop for unique Vanagon accessories at the Vanistan shop:
https://intrepidoverland.com/vanistan/

Please don't PM here, I will not reply.

Experience is kryptonite to doctrine.

[psych-illogical]

Beautiful piece of work there 10c. As I've been reading through this thread, I've been wondering about exhaust tuning. It's something I've never really understood and I'm guessing that's it's too complicated or lengthy to go into here. Got any links to a good website that explains how it works?
_________________
83 1/2 Westy waterboxer
'57 Beetle-sold
Coupla '81 BMW motorcycles (R80G/S; R100RS)
'96 BMW R1100GS

[klucz]

The Neeldenose-mosquito Howler looks like it was designed by Bon Scott for rounding up half-wild women in the outback after Midnight.

[?Waldo?]

The ability to easily replace individual pipes would be a great design feature IMO.

Andrew

[tencentlife]

That would be nice, Andrew. It would make installation easier as well as offer the abilty to replace a damaged pipe if needed. But to do it requires using a slip-fit collector. Premade ones are very expensive. I could build my own but it would add some to the sale price. I may pursue that avenue, though, just because the extra cost would be somewhat offset by easier packaging and cheaper shipping. One of the best potential benefits of a slip-fit collector is the ability to add extensions to the primaries to bring the peak torque rpm down lower, allowing field-tuning, but unfortunately there just isn't much room left under and around a rear-engine car to do that.

psych-i, I read all over the net to find out how to figure this out. It is indeed a very complex subject, but you can eventually boil it down. There are numerous online calculators, all of them return different numbers with the same inputs, but none of them tell you what parameters and assumptions they are using to produce their results. So obviously they are all approaching the problem from different angles. Who is right? Well, the differences in their results also aren't wildly disparate, at least as far as primary runner length is concerned. But there were huge differences in what the size and length of the collector/tailpipe section should be.

On top of that, no two exhaust tuners seem to agree on what parameters are most important to consider, and they aren't even in complete agreement on what, theoretically, is really happening to produce hp from optimal exhaust tuning. So it is still a bit of a black art, and I suppose that's one of the reasons that there's no way to predict which tuner will win a particular race.

So, in the end, I got as familiar as I could with theory and ran my calcs the old-fashioned way: figuring how much actual time the exhaust valve is open at a desired rpm, how much time it interacts with the intake during overlap, how fast a sonic pressure wave will travel down a pipe and back at actual gas temperature (almost twice the speed of sound at room temp, in fact), and how long that pipe should be to time the return of the wave when it can best influence the intake. The simple once-out-and-back length is usually far longer than the actual vehicle, so then you have to divide the simple return trip length by some integer to arrive at a reasonable length that can be built to fit the vehicle, so the actual pressure effect is occurring on a second or third or fourth wave event.

In the end you just have to build it and see what it does, then make adjustments to bring it to where you want it. The saving grace is that the pressure waves have considerable bandwidth.

Street use isn't nearly as exacting as race tuning; any particular tuned length will create a torque peak at a particular rpm; hopefully that peak works well with the harmonics of the intake tract, where similar pressure-wave dynamics are at play, and the engine's peak flow volume to increase volumetric efficiency in a wide enough band to be useful. In the end, any system with equal-length runners into a reasonably efficient collector will improve VE over a non-equal length system, that much is pretty safe, so just doing that is going to be an improvement over most stock systems.

Here are just a few of the links that did help me get an understanding of the dynamics involved, and helped me on my way to the design I'm building. I would say the first one did the most to open up my eyes to how the intake tract interacts with the exhaust. Try to get thru the whole thing because he does build a pretty complete picture eventually:

http://www.4m.net/showthread.php?s=155ab1b7174a4689edce839ba99deebd&t=18463

http://upnorthimports.com/forums/showthread.php?t=8214

http://www.superchevy.com/technical/engines_drivetrain/exhaust/0505phr_exh/index.html

http://myspot.neteze.com/~kdanielson/headers.html

Lots of reading, but just a start. Enjoy!
_________________
Shop for unique Vanagon accessories at the Vanistan shop:
https://intrepidoverland.com/vanistan/

Please don't PM here, I will not reply.

Experience is kryptonite to doctrine.

[klucz]

[iceracer]

That thing is fantastic 10c!!! Makes me think of a mosquito fly of some weird sort. Just my weird imagination I guess.
_________________
86 Syncro Wolfsburg edition
63 Beetle (The Iceracer)

[tencentlife]

OK, holidays are over, now I can get back to it.

Fitted up the collector, and tacked the corners

Then I heated the edge all around and hammered the skirt down to a snug fit. Sorry, takes both hands, so no pic.

Hello?

It hammered down to a close gap all around. I could have brazed it. Next time I think I will, and see if I can feed the brass from the inside to make a fillet in there for a smoother transition. It would probably be stronger, too. But this time I welded a nice wide bead all around, making sure to get a good bond especially across the steel fillets between the tubes

So now I'm working out the final curves of the collector tube

_________________
Shop for unique Vanagon accessories at the Vanistan shop:
https://intrepidoverland.com/vanistan/

Please don't PM here, I will not reply.

Experience is kryptonite to doctrine.

[ValleyHappy]

I never thought I would be this excited checking out Vanagon exhaust pipes. Excellent! Meine bleistift ist gross und gelb.
_________________
09 Suzuki SX-4 Crossover

[motelvw]

So, how you going to get that beautiful beast on your motor? Drop it and pull the mount bar through after the pipes?

[klucz]

Hey 10c, I was wondering how you came about designing the 'Needlenose-mosquito'? I think I understand its' purpose--to decrease turbulence--but is that to decrease noise or does it have to to with gas waves, sound waves, or all of the above? Needless to say I think it looks awesome and for some reason AC/DC keeps playing in my head while reading this post (in case you didn't notice!).

[wbx]

Add me to the list that also thinks what you are doing is really cool. I was wondering if getting the valve covers off/adjusting the valves would be more difficult with this arrangement. I'm not sure if the pictures are misleading, but it looks pretty tight in there (not like stock is roomy, though).

Anyway, thumbs up!
_________________
'84 Westy (first owner).......but my daily driver has pedals
My "perspective" mantra:
A Volkswagen Vanagon is just a material thing,
As such, it is of the earth,
And if i need to, I can let my Van go.

[?Waldo?]

[piledriver]

Very, very nice!

I forsee a pair of slipjoints for the rear pipes so you can pull the whole thing w/o bending it.

That or all the ex. flanges get bolts.

[tencentlife]

Hey, Greg, welcome to the Samba! You and Andrew are right, there are slipjoints that allow the system to be fitted to a wbx in the car without the need to do anything except get the old exhaust off first (I mean, really, motelvw, what kind of crappy designer do you take me for?). There are many compromises inherent in any working design, but ease of installation is pretty high on my priority list. My prototype has a fixed #1 runner, but shipped versions will have a third slipjoint on that runner to reduce the overall size of the system for ease of shipping, and to allow that runner to be slid in over the skid-plate bars on Syncros.

I'm not a fan of slipjoints, actually; they always leak a little. I've discovered some exhaust "cement" that helps quite a bit with sealing slip joints, but it's still not perfect. Rather than 3-bolt flanges that require gaskets, I plan on including stainless sleeve-clamps that allow the larger tubes to be butt-joined, for ease of service and adjustability, but I haven't found any as small as the 1.5" runners, and I don't think they are made, so slip joints may have to do. The sleeve clamps will be used to fit the cat and/or muffler to the end of the collector. There will be an additional sleeve-clamped swivel joint partway along the collector tube in production versions, to allow it to be swivelled up and down to allow for a greater range of choices of mufflers. I haven't tried these type of sleeves before, but they are popular with the racing crowd; it remains to be seen if they do a better job than a slip-joint. If they prove to be awful and leak too much, I'll have to weld on flanges, which will limit the adjustability of the final installation of the cat and muff. That or offer V-band clamps as an option, but they are very expensive so it would up the cost of the system over $50 for each one, and one ring has to be welded or brazed onto your muffler. Those are also not available in smaller diameters for the runners, unfortunately.

Damon, acess to the left-side valve cover will be a little awkward, but I'm making sure it's still doable without having to remove the exhaust. It's the same with my S&S header I have now, anyway, but I've been in there many times and you get used to it. The right side won't be affected at all.

Paul, the needle-nose is standard practice for merged headers. You guessed it; without it, there would be a flat diamond between the four runner ends which would create a constant bubble of turbulence which would worsen the faster the gas is flowing. It doesn't affect resonance at all, but slows down gas flow thru the collector. Keeping gas velocity high is important for the mass scavenging effects.