home-made tuned pipes

[_laxmasta2039]

hey guys,

does anyone know of a website that could give me any info on making a tuned pipe? it seems like it shouldn't be that hard to do with a piece of steel electrical tubing and the right tools....... [No, not just a LATHE, PJ]

any info or tips would be appreciated

joe

 

[Ron Olson]

Here is one site that I know of right off hand, there is one more that I'll try to find for you. http://rcboat.com/past.htm BTW Joe, welcome to this site, it looks as if you are enjoying it already.

 

[TomMoorehouse]

how are tuned pipes made??? i could never figure that out. i know some are stamped and welded but how about like the mac pipes that are 1 piece aluminum??

 

[_laxmasta2039]

Ron:

ok. i'll take a look at that site, and try to learn a little from it. propjockey sent me an excel spreadsheet that had the calculations for the different dimensions for a tuned pipe, all it needs is for you to fill in the info on ur engine, and excel does the math for you. unfortunately, im not really sure how to measure BHP and the likes, but i can get a good idea of how the pipe should look from the diagram....

Tom:

im not sure how tuned pipes are made either [obviously] but im another step back, too. im not really sure what they do besides channel the exhaust out of the boat. the other thing that has me stumped is what is that rubber tubing attached to the tuned pipe in all the pics i've seen? one pic from RCBM had a caption saying it was the fuel line. THE FUEL LINE? why does the fuel line connect to the tuned pipe? i mean, shouldn't the fuel flow through the carb, explode, THEN be channeled through the exhaust? ???

am i missing something big?

joe

 

[wswatzell]

Another site with a ton of info about tuned pipes & how they work is http://www.fanatic-ass.com/gasboat/dummies/pipe.html it is a gas boat site, but the theory is the same for all 2 cycles. at the bottom of the site there is a link to a small program that will help you determine all the measurements for making a pipe. hope this helps

Wade

 

[_laxmasta2039]

k. thanks wade.

im beginning to get a good idea of how to make a tuned pipe, but i still cant figure out what's with the rubber tubing attached to all the ones ive seen in pics.... :-[ ???

 

[TimD]

laxmasta2039,

The fuel tubing that goes from the tuned pipe is to pressurise the fuel tank. This is done to supply fuel pressure to the carb.

Tom, The Mac's unmuffled pipes are a 2 piece arrangement - they are welded at the wide point - it is very hard to see the weld.

Tim.

 

[Tom Kenny]

how are tuned pipes made??? i could never figure that out. i know some are stamped and welded but how about like the mac pipes that are 1 piece aluminum??

Hi Tom,

Now I am not 100% sure but it might be that they heat the tube until it is almost to the melting point, stick it in a mold and pressurize it with extremely super heated steam.

Seems to be the only reasonable explanation. Well except for the one above! :-

Tom

 

[_laxmasta2039]

thanks a mil, tim. i think im gonna sleep easier now that i know why there's supposed to be fuel line running into a tuned pipe. more importantly, that'll help w/ setting up my boat once my engine comes....

joe

 

[TimD]

Joe,

Glad I could help.

When you build your new boat you definately want pipe pressure to your fuel tank - makes tuning possible ;D

Tim

 

[_laxmasta2039]

ok, i'll be sure to include a pipe outlet on my tuned pipe if i make one [otherwise i'll buy one that has a pipe outlet]

i've got one more stupid question though..... what's stopping the exhaust from entering the fuel pipe? ???

if it's the exhaust that causes the fuel-propelling pressure, doesn't that create a problem when the exhaust mixes w/ the fuel in the fuel tank?

joe

 

[GTR]

Hi,

Yes exhaust gas pressure goes to the tank. It not's an issue with the exhaust gas mixing weith the fuel as the pick-up in the tank is submerged in the fuel. For your interest the pressure line is places at the widest part of the pipe because the gasses at the end of the divergent cone and on their return for the convergent cone are travelling the slowest at this point and the pressure pulses are almost a continuous outward pressure (eg consistent tank pressure). As you reserach pipe design you will find as a general rule pipes for models are very primitive compared to how they should be - a lot of this has to do with simplicity to manufacture and ease of set-up for the majority.

GT 8)

 

[GTR]

Hi,

Yes exhaust gas pressure goes to the tank. It not's an issue with the exhaust gas mixing weith the fuel as the pick-up in the tank is submerged in the fuel. For your interest the pressure line is places at the widest part of the pipe because the gasses at the end of the divergent cone and on their return for the convergent cone are travelling the slowest at this point and the pressure pulses are almost a continuous outward pressure (eg consistent tank pressure). As you reserach pipe design you will find as a general rule pipes for models are very primitive compared to how they should be - a lot of this has to do with simplicity to manufacture and ease of set-up for the majority.

GT 8)

 

[_laxmasta2039]

oh. noooow i get it!!

for some reason i was thinking the pressure line was coming out in the bottom of the tank, and the fuel pickup on the side.

joe