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Discussion Starter #1
What you see below represents about 1 1/2 days work so far. I posted here about the prototype cutout.

To be honest, I hate spending the time to build mockups which will only be thrown away. In this case I had to build two before starting on the final cutouts. However, it was necessary to get the design right and you guys helped quite a bit with input from the last post. Realizing that two butterfly flappers were unnecessary with the resultant exhaust flow restrictions, I shelved the idea of building a version of that mockup you see on the left side of the picture below. That design is complicated with all the linkage and is not very easy to build.

I originally wanted to build a single diverter flapper which would pivot at the apex of the wye to regulate flow either to the open exhaust or the muffler'd exhaust. That would require a perfect join at the wye and a very perfect elliptically shaped flapper which would need to be precisely located in order to function and seal properly. I don't have the tools or expertise to accomplish that, hence the original mockup of the two butterfly system.

So I reached a nice compromise. Taking your advice to eliminate the unneeded flapper from the muffler side exhaust outlet, I was able to simplify the design considerably. After laying awake all night, harhar, I decided to pursue a single pivoting flapper diverter...inside a square diversion chamber. So I built that mockup you see on the right in the picture. It also needed some refinement, but the idea was sound and the diverter functioned perfectly. And it satisfies my requirement of diverting ALL the exhaust through either the open pipe or ALL the exhaust through the mufflers with minimal flow restriction.

With that said, I included a couple pics below to illustrate the design and build so far. If I just deleted one of the butterflies on the old mockup, I still couldn't get a perfect seal when the flap was closed. I cannot create a perfect circle and make it fit in a round tube perfectly. So I came up with the square diversion chamber idea. Its simply square tubing with a hole cut into the side for the cutout. A steel diverter flapper pivots at one corner to deflect the exhaust into either the mufflers or the open pipe. Since the diverter chamber is square, so is the shape of the butterfly flapper. I can make things more squared whereas I cant make things perfectly round without a lathe, which I couldn't utilize for this project. Nice thing with the square flapper is it simply covers the exhaust cutout hole by laying flat against the wall of the diverter box for muffled exhaust, or pivots about 45 degrees in the chamber to block off the muffler exhaust and create a nice flow path into the open pipe! Plus it seals well. And,,,,the flapper is always out of the way of the exhaust paths, thus elimating exhaust restriction problems associated with the old design.

I figured I'd have the exhaust system completed by the end of the weekend....WRONG!!!!!!!! Totally misfigured the time. It is going to take a couple more days of solid hours to finish. However, I'm over the hump now with a solid design and the progress so far was the most difficult. The diversion chamber is completed and the flappers work like they should. It took almost two hours to cut the 6 round holes in the metal you see; the two holes in the chamber and the 4 endcaps for the main inlet and muffler exhaust outlet. Took about 10 minutes with the hole saw in the drill press to cut each hole using copious amounts of cutting oil. Plus the metal prep and setup.

Tommorrow I'll finish the diverter chamber with the endcaps and exhaust pipes welded in. At that point the cutouts can be welded into the current exhaust sytem right behind the h-pipe. I'll then install the choke cables to control the flow in the cutouts, and route the open exhaust to exit ahead of the rear tires. I'll neck down the open pipe from 2 1/4" to 2", which will hopefully help with backpressure issues.

More pics tommorrow nite! We are closed tommorrow, so I'll have time to fabricate!!!


Old Mockup On Left, New Mockup On Right...Both Will Go To The Trash Bin...But Gives You An Idea Of The Design Evolution And Fabrication So Far.
In The Center Are The Various Pieces Which Comprise The Exhaust Diverter Chamber...Box, Endcaps, Flappers, and Pivot Pins.
http://pic3.picturetrail.com/VOL25/910966/4461912/123937764.jpg

Completed Exhaust Diverter Chambers. Flappers Work Perfectly. Next Step, Weld On Endcaps and Exhaust Pipe. The Cutout Pipe Will Exit At A 45 Degree Angle Instead Of 90 Like The Mockup Above On The Right.
http://pic3.picturetrail.com/VOL25/910966/4461912/123937771.jpg
 

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Bud you make me laugh. Your mind has to be going at full speed all the time! You remind me of a friend that I work with. He can build anything! I wish you lived around here. We could make some money! ::
 

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"...I wish you lived around here. We could make some money!..."

Me too! We'd have our own really cool restomod shop. Think of the $$$$$....and the beer we'd drink! :highfive: We'd probably spend more on beer than we'd make in revenues, LOL!!!
 
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