Mastermind
Work Saw Specialist
Reading up on squish velocity is a great feather for one's cap.....
Mythbusters Max flow vs HD2 and Oem vs Dual port muffler
- Thread starter chadihman
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Reading up on squish velocity is a great feather for one's cap.....
chadihman
Addicted to ArboristSite
Welcome back Randy! Got any saws you wanna dyno? What do you think about a saw build off for dyno runs?
Mastermind
Work Saw Specialist
I'm in a neutral frame of mind right now.........:msp_wink:
srcarr52
We can't stop here, this is bat country.
I bet you might pick up a little with the MaxFlow filter now that its not restricted by the muffler.
No. A member here a while ago built a flow meter, and the max flow and the hd2 both passed about the same amount of air. The only advantage of the max flow is the increased surface area let's you trap more dirt (longer service interval between cleanings.)
srcarr52
We can't stop here, this is bat country.
The hd2's are much better than the originals. I fear they are not as durable, be careful if you use a blowgun on them. Either way it's still a band-aid on a bullet hole, in a couple of hours of heavy cutting any of them are getting plugged up and causing a loss in power.
Did I read that right? You got a 20% improvement in HP by simply adding the factory dual port muffler and retuning the carb?
chadihman
Addicted to ArboristSite
Yep. A while back stumpy had a thread on a port job on a saw that already had a dual port muffler. His before and after vid wasn't really impressive as most of his port jobs are. I really think that a muffler mod gives at least 50% of the power gain in a woods port.
Nitroman
Addicted to ArboristSite
An internal combustion engine is an air-pump: air in...air out. If'n you can't get the old air out...
Considering what my 394 did once I got the holes and 288 deflector back on, I believe your results with no reservations.
Man, it sounds like a Friday night in my 20's. Now? ****, an apple pie could probly do the job. Hahaha
That's one of the interesting things ya learn when you start to dyno the saws. Another are the torque and hp curves, which are just as important, or maybe even more so, than top HP. I would gather a decent woods port adds a lot of torque.
chadihman
Addicted to ArboristSite
I sure cant wait to see the hp and torque changes through a wide range of rpms. I was amazed at the my stock oem 460 with a dual port. The max hp was max at 9000 rpms but within .06 hp from 9500-7600 rpms. The torque continued to rise all the way down to 6200 rpms. I really don't think torque is means as much as people think in chainsaws. Max torque comes out at low rpms and who cuts wood at 7000 rpms. I have a tach mounted on my 460 and I rarely ever cut below 9000 rpms in the wood.
Someone needs to send me a strong ported 460 so I can test against my oem 460:msp_wink:
It depends on what you use your saw for. The biggest thing I noticed between saw modders that cut, or have cut, for a living and those that don't, is torque. When the wood moves or when you bury your bar and it gets pinched a bit - the torque is the difference between the saw dying in the cut, or chugging along until it can raise the rpms up and finish. High end HP is more important when it comes to cutting cookies. In any case, an increase in torque will bring an increase in HP when it comes to these motors.
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I've done some dyno time with motorbikes and what's generally considered the most useable power
is the point where torque and hp intersect (torque always peaks first, so it's somewhere between the two).
is the point where torque and hp intersect (torque always peaks first, so it's somewhere between the two).
It certainly can, depending on the model. I get nearly a 40% improvement on a 201T without any porting. About half of the gains I get on a MS261 are from the MM and timing advance. Most of the gains I got on the 550XP were from a simple MM. Of course, your mileage may vary.
nmurph
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I have the GTG winner that Randy built. It's just hanging in the shop bc it's too hot to cut.
Who was the last person to win the MS460 raffle saw? I can't keep track of it, lol.
I recently repaired a Husqvarna trimmer. A 245R or some such? It had damage to the internal muffler baffle. I removed it, added another port to the muffler and retuned it - it is an entirely different machine now.
Hedgerow
HACK
Yeah... And on some models, you get little of nothin' but more noise... The Stihl clamshell's sure do benefit from a good ole' muffler "Gutting" though...
chadihman
Addicted to ArboristSite
I'd love to have that saw with Randy's permission only of course. Is it a 460?
