actual HP gains with a muffler mod

[rutterb]

Hey Guys
Has anyone here measured actual HP gains after a muffler mod? I always read how it woke up saws that had it done but I have never read about actual HP gains. How much will you get 1/4 HP 1/2 HP or less. Just curious.

 

[mountainlake]

Thats going to depends on what saw you muff modd, ones with a clogged up muff will gain a lot. Steve

 

[nmurph]

10-20% depending on the saw and how much increase in the exhaust opening.

 

[mountainlake]

Cut times went from 15 seconds to 8-1/2 on my Echo CS400, quite a bit more that 20% but they come with a clogged up cat muff. Steve

 

[rutterb]

I muffler modded all of my saws a stihl 029 super an echo cs 400 an 026 and a 017. I made sure that I retuned the carbs on all but the 017 this is because this saw does not have a adjustable carb so the muffler mod was minimal the cs 400 made the most gains it is one powerful little sucker for a 40cc saw. I guess that you can only put HP numbers on these mods if you have some sort of dynomometor.

 

[pro94lt]

Cut times are a true measurment, I ran my 346 mm against my brothers non modded and it really was not even close, It really does make a large and noticable difference.

 

[TK]

My 365 simply sounds like it has way more power. I don't even have to measure cut times, I mean, just listen to the damn thing.

 

[Ambull]

My 365 simply sounds like it has way more power. I don't even have to measure cut times, I mean, just listen to the damn thing.

I muff modded my Dolmar 5105 and removed the cat. I cut the trim tabs off the carb, so I could run it richer. This saw is very well tweaked out coming from the factory, and the gains were minimal. Good thing is that I never have to worry about the muffler getting clogged now. I have run muff modded Dolmar 7900's, and don't think that they add much. The HD filter seems to help more than a muff mod.

I added a dual port open muffler to my 395XP, and it made a huge difference. It is probably 20% more powerful, which is at least 1/2 HP more.

I think it is not an exact science. Depends on the mod and the saw. Saws with restrictive intakes will not benefit much.

 

[TK]

I muff modded my Dolmar 5105 and removed the cat. I cut the trim tabs off the carb, so I could run it richer. This saw is very well tweaked out coming from the factory, and the gains were minimal. Good thing is that I never have to worry about the muffler getting clogged now. I have run muff modded Dolmar 7900's, and don't think that they add much. The HD filter seems to help more than a muff mod.

I added a dual port open muffler to my 395XP, and it made a huge difference. It is probably 20% more powerful, which is at least 1/2 HP more.

I think it is not an exact science. Depends on the mod and the saw. Saws with restrictive intakes will not benefit much.

20% on the 395 would be about 1.5hp Which is a fantastic gain

 

[sachsmo]

What saw are you thinking about modding? Like was said, some respond much better. If it is severely choked up, look for impressive gains. If it is pretty un-restricted stock, not so much.

 

[Roanoker494]

I don't think it is as much a HP gain as it allows the saw to snap up RPMs quicker and hold them better in the cut. Any additional HP would not come from the muffler mod itself but from the fact the carb was richened up slightly during tuning, IMO.

 

[NORMZILLA44]

No matter if the gain is big , or small it will be a big benefit over time. Saw life I think all saw's should have a dual port muffler.

 

[blsnelling]

20% gains with a muff mod? I don't see that happening.

First of all, there a couple problems I see with measuring the actual HP difference. First of all, there are only a very few such devices around that can measure it. Second of all, what would that actually mean to you if I told you it would have 1/2 more HP? All that really matters is how much faster it cuts through a log.

 

[rutterb]

I am asking about HP gains only because most saws are sold with HP ratings. After a muffler mod most saws perform stronger in the cut which to me relates to HP gain though better breathing and more fuel. I was just wondering if it was measurable.

 

[blsnelling]

I am asking about HP gains only because most saws are sold with HP ratings. After a muffler mod most saws perform stronger in the cut which to me relates to HP gain though better breathing and more fuel. I was just wondering if it was measurable.

Understood. There are only a couple people that have dynos that can measure that, so basically, the answer is no. That's why everyone measures by cut time differences. The problem with that is that it is VERY subjectable. The wood is NEVER consistent. The operator is rarely consistent. There are just so many variables. Measuring gains are always a source of debate.

 

[hammerboyone]

Muffler mod..?

I'm thinking of modding one of my 039's. From all i've read over a short period of time it's a hard saw to do anything other than a muffler mod .. Any thoughts ,would be taken into consideration..:msp_confused:

 

[Axlerod74]

My 365 simply sounds like it has way more power. I don't even have to measure cut times, I mean, just listen to the damn thing.

I have a stock 372xp and have often wondered if a mm would make any difference other than sound. The muffler is very open and non-restrictive yet many threads here exist on muffler mods for the saw. I agree that a mm often makes a significant difference in sound but what if the muffler is already pretty open? Many saws like MS 290 and those with cat mufflers would most likely benefit noticable power gains but what about the big ones that are non-restrictive to begin with, is the power really increasing?

 

[blsnelling]

I have a stock 372xp and have often wondered if a mm would make any difference other than sound. The muffler is very open and non-restrictive yet many threads here exist on muffler mods for the saw.

A 372 muffler has nothing more than a small slit for exhaust area, a long ways from very open and non-restrictive.

 

[NORMZILLA44]

I agree Brad, small opening. Beside's even opening the muffler a little will help, why wouldn't it. Look at the difference in car exhaust single, and dual exhaust. Just a smaller scale with saw's.

 

[TK]

I have a stock 372xp and have often wondered if a mm would make any difference other than sound. The muffler is very open and non-restrictive yet many threads here exist on muffler mods for the saw. I agree that a mm often makes a significant difference in sound but what if the muffler is already pretty open? Many saws like MS 290 and those with cat mufflers would most likely benefit noticable power gains but what about the big ones that are non-restrictive to begin with, is the power really increasing?

My post was less than serious, and I meant no mockery to the performance of muffler mods. I noticed quite the difference on my saw when I completed the mod - more than just sound :msp_wink:

Not only does opening up the outlet help, but an additional outlet in a more strategic position to benefit flow should also produce gains. I couldn't tell you how much truth there is to that, but it sounds good in my head.