Echo 2511 woes?

[markrufrider]

iv got the latest model only a month old and it has been faultless so far and iv muffler modded it had to do nothing adjust the high crew a tad to get it to rev out a little but she idles fine and no issues so far 

[ArborOdyssey]

On 09/04/2019 at 08:06, wyk said:

One of the things I suspect on saws that have cats is you tune it at one temp, then you run it more, and the cat starts to heat up drastically, changing the tune. As it would since there would be much less flow and more resistance to the exhaust flow once the muffler is heated up.  Echo and Shindaiwa's home planet do not require cats. This is from Stihl's own OZ web site:

 

Yeah I wouldn't want to try tuning a modified muffler if you have the cat in there, can imagine it'd be a nightmare!!  Not just what you mention but just heat-soak from the muff to the cylinder, will admit I'm disappointed in Echo's heat-shielding here it's one of the few "misses" on the unit IMO...

Thankfully not all of them have cats (mine didn't) and from what I hear it's easy to remove them.  Anyone know if the cat mufflers are otherwise identical?  IE a baffle-wall running length-wise, with (3) holes at the far side / left side for the gas to pass from rear chamber to front chamber (and then back across the front portion of muffler to OEM exit portage)

[ArborOdyssey]

On 14/04/2019 at 03:34, spudulike said:

These saws are possessed by the devil, had a machine in, worked fine vertically, did a muffler mod and the idle would die vertically afterwards. I can say that I know what causes it but there appears to be no "Engineered" fix for it but have got a "Heath Robinson" one for it.

I also have found what I believe fixes the poor starting and dodgy idle issues - I think it must have taken around 8hrs of work or more to get through this and can say the lazered new ones seem much more stable.

 

 

 

On 17/04/2019 at 14:26, spudulike said:

I tend to like clever muffler mods that give you the performance but not the ear bleeding noise some can give. I go subtle on these saws

 

Am loving your thinking!! 

Would you please share what causes it?  I'm gonna go on a limb and share my thoughts... I think most are simply over-doing the muffler mod and losing power, and smooth functionality, in doing so.  Just over-doing it a bit shouldn't cause functionality issues but I see the holes people drill they're like 5X the OEM, both Blair & Jennings books make explicit points that for final exhaust-exit the idea would be to err towards too-small, than too-large....power drops-off radically once you go too large, and being too-small doesn't hurt power that bad (within reason, OEM-type I mean, obviously you could artificially choke it, but when working the 2511 just remember the size of exhaust portage it was built-around)

 

Re mufflers I'd love hearing your thoughts on the 2511's, I actually made a youtube on it after seeing so many awful mods but some things/notes I'd wanna share:

 

- Exhaust enters on the right side, and exits there....a baffle wall forces the gas to run to the far side, where there's that expansion bubble("chamber", lol), that's where there's (3) holes in baffle-wall for gas to get into front portion, where travels across front portion to right-side OEM exit... That's making the gas travel, lengthwise, twice.  With "an expansion chamber" in the mix.  That is *awesome* design.   But it's EPA compliant and can be opened-up, but if you go and just bore a hole through the baffle behind the OEM exit you've short-circuited the entire muffler, yes it "breathes easier" now and will piss-rev higher but that's not where power is made, mufflers make power and while we can't benefit from acoustics we certainly can&do rely on backpressure to prevent excessive charge "spill-out"....which is seen when you bore a big hole into the baffle behind the OEM slot!

 

- the muffler//exhaust-flange area is garbage, obviously, with that sharp 90deg bend...but it's also full of sharp edges and actually is a choke point by a few percentiles believe it or not, so if you carefully go port the flange, gasket, heat shield & muffler-intake you can get about 20% more flow into the muffler (and it's far smoother now)

 

- The 3 baffle holes can benefit from being opened, in fact I made my enlarged exit on the front-left so I could access those holes & enlarge them, in hindsight they aren't really that small you could probably "get away" leaving them, but if you do want "true optimum" within the OEM muffler you'd need to:

  + Fix interfacing at the entrance (exhaust flange/gaskets area)

  + Open-up some/all of the (3) baffle-wall holes to about 200% of their OEM area as to eliminate most rear-to-front muffler passage;

  + Open-up the OEM exit (not that wall behind it!) as your only exit, as it's the longest path for the gas to take (yes, this necessitates opening-up the right side so you can get those baffle-holes, and then sealing-up that hole....or splitting the muffler.....I'm going the former path, easier for me)

 

Would love to see how much more HP% a "full" muffler job added, just basic ones seem to be near 20%.... Looks like a proper 2511, unported, should be around 2HP and ported I'm not too familiar w/ the jug but have seen dyno's of 2.5HP, what a machine that's higher HP/LBS than any climbsaw available (impressive as that ratio climbs with displacement, so the 2511 beating 355t or 200t on power/weight when it's just 25cc/5lbs is very impressive!)