aftermarket exhaust

[ironman]

what would you guys thinks would be a good aftermarket and how much extra power do you recieve out of it .For a 5hp b&s motor.

 

[2or3wheels]

depends if you want to take your motor apart, an easy one is an exhaust or maybe removing the govenor.

 

[ironman]

both sound good exhaust any ideas on any good makes

 

[Russ2251]

much extra power do you recieve out of it .For a 5hp b&s motor.

Close to .03%.

 

[ironman]

so russ do you think removing the muffler and puting on a straight pipe would help any

 

[Russ2251]

so russ do you think removing the muffler and puting on a straight pipe would help any

The gain is so small in 4 cycles (another story on 2 cycles) it can barely be measured (much less felt). Loud exhaust gives the illusion of power. Some folks will disagree.
On the other end of the scale, high end performance engines require specially designed exhaust systems to take advantage of high lift and long duration cams as well as exhaust scavenging properties. A standard consumer type muffler on these engines would restrict output.
For the most part, the engines we use on our 'toys' are not kart specific, but are considered 'all purpose' engines.
It tickles me when I see some guys put on 3 pounds of pipe and elbows and believe they have increased power. In reality they increased overall weight of kart and lose any possible gain in horsepower.
If/when I use a straight pipe on a 4 cycle it's only because I like the noise and the illusion of power.
I use a straight pipe/megaphone on 2 cycles out of necessity.

 

[2or3wheels]

but isnt an expansion chamber better for 2-strokes?? ha got you there hehehehehe

 

[Russ2251]

but isnt an expansion chamber better for 2-strokes?? ha got you there hehehehehe

You got nothin'. I have said that over and over. I'm just cheap.

 

[Jerryburger]

I have a sick old oil-burning B/S 5hp flathead, and looked up what the kart racers were running on their engines. Ended up putting a 14" straight pipe on it. Yes, it's louder and yes it does have a better top-end pull, but again, this was on a sick old Briggs.... A stock HarborFreight 6.5 will dust it. Build up a collection of parts and try what's best! I think a flathead briggs could also be improved by adapting a better carb set-up on it. (Not necessarily bigger). I've Assburgered old tecumseh diapham carbs onto Briggs 3hp engines, and they seem to run a lot better. Okay. I'll shut up now. Russ- can't wait to see how the snowblower engine works out for you!

 

[ironman]

The gain is so small in 4 cycles (another story on 2 cycles) it can barely be measured (much less felt). Loud exhaust gives the illusion of power. Some folks will disagree.
On the other end of the scale, high end performance engines require specially designed exhaust systems to take advantage of high lift and long duration cams as well as exhaust scavenging properties. A standard consumer type muffler on these engines would restrict output.
For the most part, the engines we use on our 'toys' are not kart specific, but are considered 'all purpose' engines.
It tickles me when I see some guys put on 3 pounds of pipe and elbows and believe they have increased power. In reality they increased overall weight of kart and lose any possible gain in horsepower.
If/when I use a straight pipe on a 4 cycle it's only because I like the noise and the illusion of power.
I use a straight pipe/megaphone on 2 cycles out of necessity.

today i added on a 14 inch pipe on my 5hp. and i gained 1 hp went from 23 to 24mph.i know its not much but every mph can make a different.

 

[ironman]

here is a few pictures of the new muffler i bought for the 5 b&s

 

[2or3wheels]

nice

 

[Jblankster]

today i added on a 14 inch pipe on my 5hp. and i gained 1 hp went from 23 to 24mph.i know its not much but every mph can make a different.

mph, and horsepower have no impace on each other, i highly dont think it made 1 hp. hell i bet it diddnt make half of .5 hp. it was prolly like wind or something. like russ said, its the illusion of power.

 

[jr dragster T]

Iron man you have a realy good single stage exaust there!

 

[Jblankster]

oh yea, forgot to say, its a real nice exhaust. but the words are blah

 

[jr dragster T]

But I think a little bit longer would be better

 

[kibble]

today i added on a 14 inch pipe on my 5hp. and i gained 1 hp went from 23 to 24mph.i know its not much but every mph can make a different.

I wonder if he meant to say that he gained 1mph, not 1hp.

 

[ironman]

yes correct that is what i meant to say . my bad for the miswording. yes it was 1 mph which still shows how an ad on like that can make a different in your speed.

 

[kart_racer20]

the longer the exhaust the more back pressure it will have but the exhaust alone won't give you any more hp the cam is what gives it the hp if you put a bigger cam in it, it will have more hp but you have to be careful or you will bust out your lifter carage

 

[Russ2251]

For a true test...put muffler back on and re-check mph. Do it several times and average it out. I'm sure you may have gained 1 mph ...but is it due to different exhaust? All my engines behave differently according to what brand of gas I use.
The bigger the engine...the more noticeable it is.
Weather also can affect hp. Ever notice how engines run better just before a thunder storm?
Are you running with governor?
Consider increasing compression ratio.