Stratified saws and temps

[Haywire Haywood]

I probably spelled that wrong, but I was doing a dangerous thing this morning...thinking while I was reading. Everyone that's running the new 441 is saying how it sips fuel. In the WHS440/460 thread, Dean said that the increased fuel consumption that comes with porting helps cool the engine.

Are the new stratified saws running hotter than their equivalents with standard carburetion?

Ian

 

[Jacob J.]

We've sold three new 441s to logging companies already, and so far, so good. They really like them, and these are companies that have run 044/440s for over 20 years. Typically, they'll bring a new 440 in after the first week or so to have us check the adjustment, and the front of the muffler will have a light tan or whitish "sheen" from heat. When we checked out the 441s there was no discoloration at all, which indicates at least initially that they may be running a bit cooler. Although one thing to keep in mind is that the 441 muffler has a full length internal baffle which play a role.

 

[klickitatsacket]

the 441 is better on fuel because it is using straight air to push the last of the exhaust out rather than fuel air charge. This saves fuel and polution. The easy thing to do is to put a thermocouple on both saws and see which one is running hotter if any. I will dollars to doghnuts that if you were to run fuel through the stratocharged part of the carburetor you will cool the engine down conciderably. I have lowered the engine temp enough on saws that they will not run properly and need to have the ignition advanced to bring the temp back up.

 

[Lakeside53]

I'm not sure it really matters... the engines are designed to run at the temperatures they develop... Hot is good.. cooler is not necessarily better, but it is a matter of degree (no pun intended).

I've never seen an material difference in engine life or heat related stress between and older non-EPA 044 and the latest restricted muffler/lean carb setttings on an MS440.

I assume someone has figured this all out on the 441... Stihl must be confident of the design - they tout 30% additional engine life, whatever that means.

If you start messing with the output power, all bets are off...

 

[Lakeside53]

. Although one thing to keep in mind is that the 441 muffler has a full length internal baffle which play a role.

????

The 441 muffler is an open can...