Stihl 026 power mods

[deerejohn]

Hi,

I just bought a used stihl 026 and I really like it. However, I would like to beef it up a little. I have heard that gutting out the muffler and widening the muffler exhaust port helps, but will the saw too loud then. What octane fuel is the best to use? Any other mods I can add? Thanks.

 

[timberwolf]

What is too loud?

A chainsaw (modified or not) produces sound levels that will damage hearing, so you should be wearing muffs or plugs anyway.

oppening up the muffler can net you about 20% and will up the sound levels 3 db or so. should be some detailed theads with photos on the site if you search the 026 and muffler mod topics.

There is also 20% or more available through engine mods, but that comes at a price (tools/knowhow to do it yourself or the cost to pay some one to do it up right, maybe also isues with useability and durability after modification.)

 

[Lobo]

With or without mods you should be using 91 to 94 octane gas.

I always purchase it from choice refinery banners with stations that move large volumes to ensure that it is as fresh as possible.

Independents and cut rate stations often sell old products the refiners want to get rid of which may be ok in a vehicle engine but not in high performance saw engines.

 

[deerejohn]

I have searched for muffler mods on this forum, but the info I have seen is very spotty. I want to modify the muffler, but I need exact info on how to do it. Do I modify the exhaust port on the engine or just on the muffler, and where do I drill holes? Do I take the muffler apart and remove all baffles (if any) and how big should the holes be? Thanks

 

[Lobo]

These are pictures of an 026 muffler mod by a member here, sorry I forget who it was presently.

 

[deerejohn]

Thanks for the pics Lobo!

 

[timberwolf]

I guess some of much of that info has disapeared with post deleations related to glens (former AS member) leaving.

Anyway, I had done and posted some measurments on opening up the muffler in the past. If I can find the work that glens and I posted I will repost it for the information value.

head temp went down, preformance and sound levels up.

for me a 7/16 x 1 1/2 inch opening works well, I have made the opening oval.

also may want to check the fit between the outlet of the exaust port and the gasket and muffler, grind away at the gasket and muffler to make that area flow the best possible.

To do anything more would take removing the jug and working with a mini grinder files ect to modify the exaust port. Lots of things can go wrong at that point.

 

[deerejohn]

Do I keep the muffler port smaller than the engine exhaust port?

 

[Lobo]

I would make the muffler exhaust port perhaps 75% of the cylinder exhaust port. It is easy to remove material not quite so simple to add some.

 

[timberwolf]

Just my point of view

But I found gains did not drop off until above 100% of the port area, and have heard numbers in the range of 1.4-1.6 times the port area tossed about as giving the best gains.

Keep in mind that the port area is the effective size of the opening where the cylindar touches the port, not the opening where the muffler bolts on to the jug.

I think it is mostly low rpm (idle) that is hurt if the hole is too big. take the muffler off, and the saw still has cutting power, but is hard to keep running at idle. I have no idle problems at all with an opening in the 150% range, in fact the saw idels better than before I drilled out the muffler.

Though I am in agreement with Lobo that it is easier to cut it bigger than make it smaller again.

The result after darn good is usaualy bad

 

[JamesTX]

Can these mods be done to a lower level saw (Stihl MS250)?

 

[rustyb]

Here ya go.

http://www.arboristsite.com/showthread.php?action=showpost&postid=53547

 

[tony marks]

congrats on moding your own saw.. but some people on this site can get you far more power.. thats just what they do.. still what the other posters said are good info.. jmo

 

[Lobo]

Can these mods be done to a lower level saw (Stihl MS250)?

Yes, same thing.

 

[tslockbo]

These are pictures of an 026 muffler mod by a member here, sorry I forget who it was presently.

Interesting. My 026 has 4 holes in the muffler. I purchased it around 93. How old is the saw in the photo?

 

[Rokon]

A 12" bar ought to make it feel like a power monster.

 

[H 2 H]

Can these mods be done to a lower level saw (Stihl MS250)?