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| cirvin |
Posted - Nov 07 2003 : 7:28:25 PM
i put a straight exaust pipe on a briggs and stratton engine. it is just a 10" piece of galvinized pipe. i know that it makes the exauhst gasses escape better, but will it make more power? or just malke it run smoother or something else?
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| 9 L A T E S T R E P L I E S (Newest First) |
| cirvin |
Posted - Nov 16 2003 : 5:18:56 PM
ive decided that a straight pipe sounds cool, so i don't need it quiet anymore. thax
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| kenmce |
Posted - Nov 15 2003 : 09:37:21 AM
>oh, crap. i drilled a ton of holes it an i will wrap
>a towel around it. hopefully it helps, but it
> probably on ly works like that on projectile
> weapons.so what would i use for quietness?
(KM)
Something you could try is to get a larger pipe - a fruit juice can or soda can might do - open up one end of it, place it over your existing pipe and lightly pack in fiberglass insulation. Now you have a longer path between your ear and the engine and the 'glass has a chance to muffle it but hopefully not too much.
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| cirvin |
Posted - Nov 13 2003 : 4:55:37 PM
that would lok cool, if it weren't soo close to an extreemly flammible liquid. i guess i could find a small car muffler
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| Aaron Cake |
Posted - Nov 13 2003 : 10:40:53 AM
The towel will probably burn.
For quiet, try a muffler. 
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| cirvin |
Posted - Nov 12 2003 : 6:05:48 PM
the engine is a standard B&S 5 hp. the pipe is a 10" galvinzed steel i bought from a hardware store.
oh, crap. i drilled a ton of holes it an i will wrap a towel around it. hopefully it helps, but it probably on ly works like that on projectile weapons.
so what would i use for quietness?
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| Aaron Cake |
Posted - Nov 12 2003 : 2:59:06 PM
I doubt you'll damage your engine, but if you're looking for quiet, a straight pipe is not the way to achieve it.
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| n/a |
Posted - Nov 11 2003 : 11:19:34 PM
cirvin, what is your hp, and if known, displacement of your engine? the 11.5hp block in my tractor is around 240cc, weak compression of under 8:1, the 1" internal diameter pipe i have, rougly 11" long gives it a bubbly--not rough, idle, with excellent power after 3000rpm all the way to the unofficial redline of 7000 (which hasn't stopped me from going past it on occasion), i've had the torque no matter what, all the way across the powerband, but the power, according to my findings and power charts from briggsandstratton.com on all their engines, increases to about 4500, where it flats off with a slight drop to around 6000, and loss of power from there out. the makeup of your pipe makes no difference (no composites, assuming), the now current aluminum 7/8" in. diam. tubing i have on there now on mark IV gives it smoother power, not more, just smoother delivery. i've had backfires and misses, but that's mostly from the the rich misture i run to keep things from melting at those high engine speeds ;)
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| cirvin |
Posted - Nov 10 2003 : 11:06:02 PM
so i could end up screwing up my engine?!? i think 10" should be fine, i just wanted to muffle the sound most of all
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| Aaron Cake |
Posted - Nov 10 2003 : 09:44:53 AM
Maybe, maybe not. It is undoubtably better then the existing muffler, but far from optimal.
Exhaust tuning is not a simple thing. You need to experiment with lengths and pipe diameter while you measure the power output of the engine. You are looking to find the combination that produces the most high end flow without loosing low end velocity. This translates to more HP up high, more torque down low. Note that with a piston engine, you need some backpressure to prevent burning of the exhaust valve. An expansion chamber will probably also be beneficial.
Really, exhaust tuning is a "black art", and much has been written on the subject. It just can't be summarized....
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