jacob711

what kind of exhaust pipes do you use on weedys, i want to make a loud one but im not sure what way i should do it (either canister or make a whole pipe)

could you please post pics if you have any

martno1fan

use the one thats on the engine now,otherwise you would need to make your own pipe as for how i dont know but there is the linked pipe designer afraid i cant help you on how to use it but maybe someone else can.
[link]http://www.mh-aerotools.de/airfoils/javapipe_en.htm[/link]

TERBObob

My Feedback: (21)

First , you really don not want a LOUD one ... any neigbors or folks close by will bi*ch and scream to the local authorities and make all kinds of complaints and then you'll loose your running spot .[&o]
Next , take the original cannister muffler that is on it , widen the exhausts exit hole by almost double , and gut the insides out . This will increase the output power from the engine .

rickburnout666

i use a programme design like the one martno1fan linked to, you can make the pipes in 2 ways, 1 using rolled sheet metal, or 2 hydro forming i prefer hydro forming , a little bit of math, PI work is used to work out the final sizes

OLD_SLOW and in the WAY

Loud wont make it faster. might even slow it down with the weedy's port iming, or lack there of.

rickburnout666

OLD_SLOW and in the WAY, Yes loud don`t make them faster, but it can give the effect of more speed, but if you have the speed with the tuned pipe but want it quieter try someting like this
http://cgi.ebay.co.uk/Marine-Racing-...QQcmdZViewItem

jacob711

the only good places to run it dont really have many houses nearby and the local model powerboat club have the loudest posible boats and they get away with it

what is "hydroforming"

rickburnout666

Hydroforming is when you get the shape and size of the exhaust you want , you then cut it into sheet steel or aluminium or the metal of your choice, you then cut the shape twice, but you will need to allow an extra half inch or so at the inlet and outlet ends but mark the metal where the exhaust needs cutting for the final size , then you drill a hole in one sheet weld a nozzel that you can fix a water pump to , then weld the 2 sheet exhaust shapes together around the outside edges , when that is done, you then pump the water in, under pressure the metal expands and takes the shape of the wanted pipe when it is fully pumped and expanded, cut the extra off each end to the designed length and remove the filling nozzel and weld up the fole that is left, You now have one Hydroformed pipe

jacob711

imagine how much presure would be needed for that though

also do you have any other programs

rickburnout666

Not sure of the pressure rating,but do know the thicker the steel/aluminium, the more pressure you will need to form the pipes I used an old bilge pump to make exhausts for my motorcycles ,When i worked at a firm that made air duct from sheet metal ,I am now making a pump to make a tuned aluminium exhaust for martno1fan`s 28cc weedy engine the plan i use i will not hand out as i have not tried and tested myself on the boat engines It works well on my daughters 125cc track bike been dynod around 38 BHP,
but there is a programe here that is free to use
http://www.mh-aerotools.de/airfoils/javapipe_en.htm
I dont know about the results of it but give it a try

glennb2006

Don't make it too good, not sure that Martin will be able to handle that much power Rick!!

Glenn

rickburnout666

will be a long time yet , i`m still trying to find a house, and have lots to build for myself along with the pump build, if it works on the weedy engines, i might start selling them, Mart`s gonna be my ginea pig
marts boat is looking good and strong so it will handle more power than any weedy could push

jacob711

i have made a rough design but i dont know the transfer port timing or the exhaust gas temp thing so i just done a rough guess but i might just make it anyway and see how it goes because i cant just use the canister muffler because it will just go into the hull and theres no point in modifying the canister muffler

rickburnout666

To be honest with you the fiirst pipes i made for bikes, i didn`t use a design , the header/down pipe was cleared of any restrictions, and was the same diameter as the exhaust port, the expansion chambers/tuned pipe was basicaly the standard pipe, it was gutted and i removed any restrictions (noise and power)and welded it back together the bikes had better acceleration , the top speed was faster , but not great, but they did sound a whole lot better ,in my opinion the tuned pipes people sell are not realy tuned unless they state which engine they are tuned for, as each engine has diffent temps,piston face to exhaust port flange measurements, port diameters internal and external,a tuned pipe is tuned by using all these different temps and measure ments to get the max power out of each engine. you will most likely get more power out of a canister by cutting it open and removing any internal restrictions,than running a standard canister. what i have said i know will annoy some people but its my opinion (read signiture)

jacob711

i think ill have a go at making a pipe

i just went down to see the local model powerboat club and some of their boats absoloutely fly along, they are just so much faster than they are in videos

martno1fan

Don't make it too good, not sure that Martin will be able to handle that much power Rick!!

Glenn
[/quote]

Glenn you cheaky begger ill manage just fine dont you worry about that !!,and once ive got every bit of speed i can out of this engine ill be sticking a zen in it so watch outlol.
Rick whatyaa mean it wont be for a long time yet [X(]!!

rickburnout666

wot i mean is it Will be for a long time yet, but it`ll be as quick as i can get myself sorted

martno1fan

hehe rick you can move in with us ill have a word with the misus so long as i get my pipe lol .mind youll need to sleep in the cabin in the garden lol.

TERBObob

My Feedback: (21)

Pipes are a BLAST ....
I mean , I have tried different already manufactured pipes ( yeah , like I would be able to make one ) from sizes ranging from ones rated for .40's up to 1.48's on different weedies and although , they might have improved in one power range ( either bottom end , mid range , or top end ) , they ALL were different for diffferent weedies . For example - Had a TANAKA and SHIN , both same size ( cc's ) and yet different bore and stroke and the same pipe would NOT work on them . On the Shin , the pipe gave a good bottom end boost , whilst on the Tanaka - nothing ... actually seemed like it lost power in all ranges . ( sorry , do not have a dyno , so this comes from observations and readings from an ETREX )
Now , of course , these were all tested from cheaply bought , used name brand nitro pipes I bought off EBAY when nobody else seemed to be interested in them . ( wish I could do that with different gasser pipes [&o] buy them cheap for testing puposes )
Being honest ... the best results it seems , in the long run , was to take the original cannister muffler and open the exhaust opening almost twice the size and to gut the insides out - seems to give me best results for all around improvement - especially when tossing on an bigger bored carb .