880 exhaust mod

[gobbypunk]

Hi guys I was milling some spalted beech yesterday and was getting a face full of exhaust this dont happen all the time , but was then looking at exhaust mods on an american site and they were just running a pipe with no baffle box , also they were inserting reducer rings in the pipe now its been a long time scince I messed with bikes but the engins aint that diffrent so to the point I would like to mod my exhaust but 1 with just a pipe its going to be very loud 2 if I alter the back preasure woulnt it need re tuneing I look forward to your thaughts

Cheers Mark

[mendiplogs]

Hi guys I was milling some spalted beech yesterday and was getting a face full of exhaust this dont happen all the time , but was then looking at exhaust mods on an american site and they were just running a pipe with no baffle box , also they were inserting reducer rings in the pipe now its been a long time scince I messed with bikes but the engins aint that diffrent so to the point I would like to mod my exhaust but 1 with just a pipe its going to be very loud 2 if I alter the back preasure woulnt it need re tuneing I look forward to your thaughts

Cheers Mark

 

Hi MARK ASK STEVE on here mate or Eddie thanks Jon

[spudulike]

Typically the only two stroke exhausts where back pressure is important are tuned expansion pipes where the wave caused by the exhaust exiting has to hit the end cone and hit the next stroke as the exhaust exits again. This is all about the return wave forcing some unburnt fuel in the exhaust back in to the combustion chamber and the down pipe, expansion length, cone diameted and angles are all critical.

 

Chainsaw exhausts are VERY basic and only offer a rudimentary baffle and containment can so offers little in the way of tuning or specific backpressure.

 

If you try any custom exhaust, I would make sure the saw is tuned to fourstroke or burble when flat out and to clean up in the cut under load. Alternatively, tune to 1,000rpm under maximum specified revs with a tach.

 

You can make a manifold and down pipe then either use a car/bike type silencer, use a bike exhaust or custom build - you need it relatively free breathing to maximise power and mount to the engine rather than handles for obvious reasons - interesting project!

[Logrod]

Probably a dumb question but if the tuning isn't an issue on a saw could you just braze a pipe on to a normal exhaust to funnel the fumes away?

[spudulike]

Probably a dumb question but if the tuning isn't an issue on a saw could you just braze a pipe on to a normal exhaust to funnel the fumes away?

 

Reasonable idea!