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Author Topic: Team Go Dog, Go! Modified Partial Streamliners  (Read 774444 times)

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Offline tauruck

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3240 on: December 17, 2018, 09:54:35 AM »
Bo, what filter do you use?.

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3241 on: December 17, 2018, 11:24:16 PM »
Two big K and N oiled gauze filters with a mesh sock over each.

There will be plenum chambers between each carb and filter.  Does anyone have any good design guidance on these things?  I have what Harold Bettes has in "Engine Airflow."

Offline stay`tee

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3242 on: December 18, 2018, 04:14:10 AM »
Municipal water demand is quite variable.  It is very low around midnight and extremely high at other times - such as when lots of toilet are flushed during Super Bowl halftime.  It would be very expensive and impractical for the city to size the water supply pumps for this maximum flow.  Instead, they use smaller pumps to fill a water tower or a tank on a hill with a much lower steady flow.  Demand surges are supplied by the water stored in the tower or tank.

Engine air demand is unsteady, too.  The intake valve is open and passing mixture for only a small part of the engine cycle.  The rest of the time it is shut.  The air filter is mounted directly to the carb now.  This is a lousy setup.  Their is a very small reservoir of air beyond the air intake for the engine to draw from.  It is the inside volume of the filter.  The filter is subject to pulsing flow demands.  These can be quite large.  It is a filter on a 500cc single cylinder engine turning 10,000 rpm, in reality.

A plenum will be made along with the new stack and it will be sized to provide a reservoir of air in front of the filter.  The minimum volume will be the cylinder volume x the maximum volumetric efficiency.  It will store at least one gulp of air between the bell mouth and the filter.  This will reduce peak flow loads on the filter and reduce any restriction the filter might provide during those peaks.  In addition, the two plenums will be connected so the reservoir is larger.

One thing governing the stack size is the need to keep it at least 1/4 inch from and plenum wall.  This will promote more a more even inflow rate around the stack perimeter.  This is a problem with this bike I have known about for a decade.  Right now I am finding the time to fix it. 


 
Wobbley,  calculations tell me that at 160mph one would see about .44 psi in plenum if ram air is used,, your considerations ??
First Australian to ride a motorcycle over 200mph at Bonneville,,,

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3243 on: December 18, 2018, 09:55:59 AM »
My first bike was a new '69 Yamaha 250 DT-1 and I was 17 or 18 years old during Projekt Ram Air.  The engine had Yamaha GYT kit internals with a Schwerma expansion chamber.  My buddies and me made a ram air system and could not make it work.  The problem was the main jet size.  It needed to be larger than it would be without a pressurized air box.  The exact size was variable.  It would be different when the bike was topped out in third, fourth, or fifth 'cause ram air pressure differed at varying speeds.  Also, ram air pressure changed drastically when running against or with the wind.  A hole in the piston due to a lean mixture put an end to that project.  What I learned was, it is cheapest to figure things out on a single cylinder engine and to stay away from ram air with a carb fed motor.  Maybe the folks with EFI have figured out a way to get the mixture correct.  It was prehistoric times back then.  Carbs was all we had.     

Offline tauruck

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3244 on: December 18, 2018, 10:59:23 AM »
My 2c. The airbox and filter I designed for my Harley worked so well
when we tested it (on Lefty's bike) that we had to go up three jet sizes.

Offline stay`tee

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3245 on: December 18, 2018, 03:51:05 PM »
My first bike was a new '69 Yamaha 250 DT-1 and I was 17 or 18 years old during Projekt Ram Air.  The engine had Yamaha GYT kit internals with a Schwerma expansion chamber.  My buddies and me made a ram air system and could not make it work.  The problem was the main jet size.  It needed to be larger than it would be without a pressurized air box.  The exact size was variable.  It would be different when the bike was topped out in third, fourth, or fifth 'cause ram air pressure differed at varying speeds.  Also, ram air pressure changed drastically when running against or with the wind.  A hole in the piston due to a lean mixture put an end to that project.  What I learned was, it is cheapest to figure things out on a single cylinder engine and to stay away from ram air with a carb fed motor.  Maybe the folks with EFI have figured out a way to get the mixture correct.  It was prehistoric times back then.  Carbs was all we had.     

My experience with ram air has only been with the efi bikes where the ecu compensates for a/f demands,, I had overlooked the fact that your bike is carburated,,

my thoughts with carbies and ram air would be that you would control the fuel demands with the needle,,

 as you were sir  :-)
First Australian to ride a motorcycle over 200mph at Bonneville,,,

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3246 on: December 20, 2018, 11:33:26 PM »
The plenum bases are turned from aluminum round stock.  The many hours to do this was not considered in the project planning.  These are "pancake" plenums.

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3247 on: December 21, 2018, 08:58:03 AM »
The Harley carb sticks out into the wind along the side of the bike.  Did the air box collect air like a ram air system? 

Offline tauruck

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3248 on: December 21, 2018, 09:21:40 AM »
I made one. Want a pic?. :cheers:

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3249 on: December 23, 2018, 06:06:08 PM »
Yes, Mike.  It might give me some ideas.

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3250 on: December 23, 2018, 11:33:55 PM »
Merry Christmas to everyone from here in Oregon. 

Offline Old Scrambler

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3251 on: December 25, 2018, 11:04:24 PM »
and Merry Christmas to you :-)

I run ram-air with carbs on my CB750...........it works :wink:...........the bowl-vents have to be connected to the air-box for balanced internal pressure. The science is simple............at speed you are likely to be losing some amount of available air due to the sweeping vacuum effect of the passing air. The ram-air merely provides 100% or very slightly more.............but you need a large volume air-box between the filter and carb-intake.
2011 AMA Record - 250cc M-PG TRIUMPH Tiger Cub - 82.5 mph
2013 AMA Record - 250cc MPS-PG TRIUMPH Tiger Cub - 88.7 mph
2018 AMA Record - 750cc M-CG HONDA CB750 sohc - 136.6 mph
2018 AMA Record - 750cc MPS-CG HONDA CB750 sohc - 143.005 mph
2018 AMA Record - 750cc M-CF HONDA CB750 sohc - 139.85 mph
2018 AMA Record - 750cc MPS-CF HONDA CB750 sohc - 144.2025 mph

Chassis Builder / Tuner: Dave Murre

Offline Old Scrambler

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3252 on: December 26, 2018, 05:15:29 PM »
Another benefit from ram-air is the somewhat cooler and 'clean' air obtained at the front of the bike. Pssst!......flat-sided air-ways flow better than round, and also allow more air to enter the inlet, therefore; smaller runners with square corners will flow more air than a round tube......and much, much more than a corrigated tube.
2011 AMA Record - 250cc M-PG TRIUMPH Tiger Cub - 82.5 mph
2013 AMA Record - 250cc MPS-PG TRIUMPH Tiger Cub - 88.7 mph
2018 AMA Record - 750cc M-CG HONDA CB750 sohc - 136.6 mph
2018 AMA Record - 750cc MPS-CG HONDA CB750 sohc - 143.005 mph
2018 AMA Record - 750cc M-CF HONDA CB750 sohc - 139.85 mph
2018 AMA Record - 750cc MPS-CF HONDA CB750 sohc - 144.2025 mph

Chassis Builder / Tuner: Dave Murre

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3253 on: January 03, 2019, 12:00:14 AM »
The ram air concept will be looked at.

This is how the ellipse was cut.  First, it was drawn out on graph paper at a 10:1 scale.  Ten inches on the paper equaled an inch on the part.  The book that showed me how to do this is "Engineering Graphics" ISBN 0-02-342720-5.  It is a good reference for a fabricator to have.  Type "draw ellipse trammel method" into Google and references showing it will appear.  That was how I drew it.

A cut schedule was made using the drawing, protractor, and scale.  Each cut was plotted out and so I knew the angle of the cut and its width.     

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3254 on: January 03, 2019, 12:06:52 AM »
The cut area was coated with machinist dye and the cut was made at the same width as indicated by the drawing.  A decimal machinist scale made this easy.  A 0.75 inch wide cut scaled on the drawing was a 0.075 inch wide cut on the part.  The part was roughed out on the lathe by many cuts using the tool bit and it was sanded down to final size using emery cloth.