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Discussion Starter · #1 ·
I have a MBRP can on my sled (came with it, I didn't buy it) and it's been brought to my attention that it's pretty loud. I decided to make a removable baffle insert for it as I don't have the couple hundred bucks necessary to buy a stock exhaust or quieter silencer. I know that putting something in the exhaust to limit the sound will also limit exhaust flow and increase backpressure which is a potential issue especially for 2 stroke sleds, but I'm willing to sacrifice a little power for the benefit of decreased weight if it is about the same loudness. The baffle only weighs about a pound so you're still saving 10+lbs in some cases over the stock exhaust.

My question is, other than a decrease in power due to the increase in exhaust backpressure, am I putting the engine at risk at all by using this baffle? I'd hate to burn the sled down or something along those lines trying to appease the anti-can crowd. For reference, this is essentially what I'm duplicating:

silencer.jpg


Thanks in advance for your input.
 

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Not being a fan of loud sleds I would fish around for used stock muffler and meanwhile put up with the less restrictvie and louder aftermarket exaust until I could find one. Parts sleds do become available now and then.

I would not want to risk the engine ending up with less airflow that stock. Think could cause higher operating temperatures as the fuel mapping would not be correct for the restricted flow of the exhaust if that ended up being the case.

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My two pennies...
 

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Discussion Starter · #3 ·
See that's why I was tossing it out there--usually if you make the exhaust more restrictive although it may make a bit more heat in the pipe due to the backpressure it would end up making the sled run rich rather than lean. Rich lowers EGTs. At least that's my understanding of it but that's based on 4 stroke where my knowledge comes from.
 

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See that's why I was tossing it out there--usually if you make the exhaust more restrictive although it may make a bit more heat in the pipe due to the backpressure it would end up making the sled run rich rather than lean. Rich lowers EGTs. At least that's my understanding of it but that's based on 4 stroke where my knowledge comes from.
Think would be correct with rich condition and lower overall EGT. If is not a huge pain to make this insert you could briefly try it and monitor to see what happens and if have an issue indication take it out.

Which engine are you thinking of doing this exhaust instert with?
 

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Yeah that was kinda my thought. Without cutting the stock exhaust open and seeing its inner workings I won't know how much more or less restrictive it is. I know with 2 strokes it's about more than just how much restrictiveness there is in the system though, as the exhaust pulses have a lot to do with how it performs--moreso with the pipe and stinger than the silencer but I'm sure there is an effect there too.

I can pretty easily see if there is a power gain or difference just by seeing the peak rpms. If they drop, it means power dropped off as I would have to run less pin weight in the clutch to get the same target rpm, and vice versa for a power gain. I just want to make sure I'm not creating a lot more work for myself by being the guinea pig for this idea.

This is going on a 06 500ss which is stock other than boyesen reeds (not rage cages, just reeds) and the MBRP can.

I'll probably cut open and re-pack the silencer with steel wool in the spring as well but definitely not doing any more than this simple experiment in the middle of the season.
 

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From what I understand you will pry gain back what power you lost with the can and make the noise more appealing at the same time. I would think what you are showing will not create to much back pressure to cause heat problems. Would be pretty cool if it worked..
 

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Increasing back pressure in the pipe will increase HP until you have so much pressure that you are pushing to much heat into the piston.

A lot of the cans if not all likely had to little pressure losing hp because they weakened the negative and positive wave action that makes a two stroke with a pipe into the incredible HP producing engines they can be. That wave action gives us mild supercharging effect.

My thread here goes into it in detail and how I measured actual pipe pressure http://www.dootalk.com/forums/topic/218137-xp-500ss-full-wet-450lbs/page-8 I can now monitor it all the time and record on my dash gauge. The ideal pressure seems to be about 3 to 3.5 psi. Drag racers get away with a lot more but they only run for 500 ft or so. If you don't run full throttle across a lake for a couple miles can run more pressure etc.

Anybody that doubts this just subscribe to DynoTech Research.com and you will learn from their SuperFlow dyno how much difference it makes.
 

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Not to jump in and take a dump but today..........................

My wife and I drove our stock Renegade 900 ACE sleds on the lake.... with all the ice fishermen.... and ATV's ..... and cross-country skiers... and I gotta believe that when we drove our sleds past them they thought... WTH, I cannot hear those sleds.

I looked at my speedo and it is reading 60 mph. I am thinkin no way??????

Get there folks. Do OUR sport a favor and can the cans!!!!!
 

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I'll bet that if you asked to buy a stock can on dootalk, someone will have one for sale cheap.

Take me for instance I have several 800 stockers I'll sell cheap.
 

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I have a muffler from an 06 600 SDI that might work. Anybody know for sure if it fits his sled? The Part numbers are the same except for the last digit but the only difference is the way they have the parts listed. Check the Skidoo microfiche. Both Motors are 600s The only different is the way that the air and fuel are delivered. I will sell at a very reasonable price.
 

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Discussion Starter · #13 ·
Thank you for the offer guys. I will consider that if my experiment doesn't pan out. I wanted to make sure that it wasn't going to blow my engine up in the process. I'm expecting it will have more backpressure than the stock muffler. Once I take a couple pictures you'll understand as it has baffles that protrude into the exhaust pipe. I want to get it done first and see how it performs before I comment any more.
 

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Increasing back pressure in the pipe will increase HP until you have so much pressure that you are pushing to much heat into the piston.

A lot of the cans if not all likely had to little pressure losing hp because they weakened the negative and positive wave action that makes a two stroke with a pipe into the incredible HP producing engines they can be. That wave action gives us mild supercharging effect.

My thread here goes into it in detail and how I measured actual pipe pressure http://www.dootalk.com/forums/topic/218137-xp-500ss-full-wet-450lbs/page-8 I can now monitor it all the time and record on my dash gauge. The ideal pressure seems to be about 3 to 3.5 psi. Drag racers get away with a lot more but they only run for 500 ft or so. If you don't run full throttle across a lake for a couple miles can run more pressure etc.

Anybody that doubts this just subscribe to DynoTech Research.com and you will learn from their SuperFlow dyno how much difference it makes.
That was a helpful read. We have an 800R in a REV chassis that is showing a significant increase in power with an MBRP can over a stock REV 800 muffler, according to the owner. This is not making me happy at all, since it is way too loud and next door. Now that I know how to measure the pipe pressure I just need a little better details on how to setup my mechanical vacuum/pressure gauge to compare between the two. Do you happen to have any pictures of your setup?
 

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Why not just advertise it ,as trade for stock muffler Im sure there is someone out there looking for a can that would just trade you for the same reason as you...............They want one but don't want to drop the coin on one!!

There are plenty of people out there that don't have the can problem in there area's of riding .......unlike what most on here would like you to believe....JMO
 

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Your going to want to find a stock muffler for the year and engine model of your sled. Back about 7-8 years ago I priced a new muffler for a 05, mxz 500ss. It was around $600.00 new.

You really want to find the right one due to the pipe setup for that particular year and engine model

I would for sure be looking for a used, but they are a tough find. If you do a search, you will find there are a couple of aftermarket companies who make mufflers / cans that are not obnoxious at all. They seriously do exsist, and some even have dyno numbers to back up gains/loss.

With luck you find a correct make and model year used one, maybe even someone here can steer ya in the right direction for one, that would be really cool.

Otherwise there are a number of aftermarket choice that do exsist that are nowhere near as loud as that MBRP you have, they are obnixious!!
 

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That was a helpful read. We have an 800R in a REV chassis that is showing a significant increase in power with an MBRP can over a stock REV 800 muffler, according to the owner. This is not making me happy at all, since it is way too loud and next door. Now that I know how to measure the pipe pressure I just need a little better details on how to setup my mechanical vacuum/pressure gauge to compare between the two. Do you happen to have any pictures of your setup?
I tried using a mechanical pressure gauge that was a bout 0 to 15 psi that was intended for automotive use to measure pressure to diagnosis a plugged catalytic converter. Impossible to read and no consistency of readings. About 3 or 4 years ago a guy from Alaska having trouble sorting out his 800 big bore fund a digital gauge that worked like magic. With a warmed up engine and pipe turn on the gauge and hit reset to zero, make max rpm run and when your done hit the buttons and it gives minimum and max reading and the numbers are repeatable run after run. Some things that raise that pressure, smaller stinger, higher rpm, hotter pipe egt

That pressure number is something I've been chasing since about 1992 when I put a 617 rotax in a yami Phazer and used my 2-stroke design software to make a pipe and a silencer. Had no way of measuring the pressure or what a ball park number should be. But I did put a adjustable butterfly valve in the end of the stinger that partially blocked the flow when closed. But was reall afraid of burning the engine

down because to much pushes heat back into piston dome.
 
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