link
Gone fishing
You know.. perhaps some really important detail just slipped your mind...
Porting
- Thread starter somebigman
- Start date
Help Support Arborist Forum:
I’m sure several important details have slipped my mind over the years. It happens.
But the major manufacturers are limited by EPA constraints. A single pencil sized hole in the muffler outlet designed to keep the heat inside of the can to burn off excess hydrocarbons in an 80cc saw comes to mind.
You’ve not proven that a stock saw will outlast a ported one, let alone the opposite.
link
Gone fishing
But there's a pretty vicious billion dollars competition out there... to have the most powerful chainsaw to weight.
That's not the knowledge of "you", thats the knowledge of a "team" of top educated engineers...
You just saying they are all wrong... and that "you" are right.
Just how many people does that - 5 billion ?
StihlPotlicker
ArboristSite Operative
$350.00 last I paid for Tree Monkey to port my 881
StihlPotlicker
ArboristSite Operative
my buddy out in Cali, was cutting on the fire units and had a 500i ported and max air flow put on. and did a YouTube video and he had Stihl headquarters wanting to know where he bought the saw and who did the port work on it. I guess they didn't take to kindly to the 500i being bashed LOL. and they did a ton of field testing on the 500i before they released it too.
Damn coffee drinkers
You think the best engine builders are factory????
Cosworth went against the WORLD as a privateer
And beat everyone……
Huski and stihl May have the most educated and highest paid. And that don’t mean squat……
They just aren’t the best.
And what experience do you have with well ported saws?
Oh……..none……
Sierra_rider
Piss revver
It's already been said, but stock saws are limited by sound and emissions regulations. Power isn't their only consideration, they also have to have a quiet saw and one that runs cleanly. It seems pretty reasonable that, if you don't care about sound or emissions, you can build a saw that's optimized for power.
I'm not a guy that's a professional porter, just merely an informed "redneck," although I mostly drink hipster IPA beers or whiskey instead of gin. Just because I'm not a Stihl engineer, doesn't mean that I'm just some ***** with a dremel...I'm actually an ***** with flex shaft grinders and a lathe.
Even some ***** hillbilly like me has an understanding of how compression, port timing, and even port shapes affect the powerband of the saw. Coupled with exhaust mods, I can build a saw that is a definite improvement over stock. All of my saws are work saws...they are used for falling trees or are climbing saws. I'm usually not reinventing the wheel with them, just prioritizing power over noise and EPA compliance.
I'll add that that I don't hold saw engineers on some pedestal...like we already established, they are designed as a compromise for factors that a lot of the end users don't care about. Besides that, saw technology is in the dark ages compared to other types of 2 stroke motors. Just look at dirtbikes...they've had powervalves and reed valves for the better part of 40 years now. Going even further, most of them are now case-reed inducted with boost ports located where the intake port would be on a cylinder fed jug. Just looking at how much the transfers can flow compared to a traditional 2 stroke motor is eye opening. Suddenly, saw motors don't look so high tech. I understand that they have to build the saw in a small, lightweight package, but it's not the dark art you think it is.
Hummmm, let me think, what is the difference between the highly edumacated enganneer and the home saw builder? Budget. You think that the OEM's are going to spend the time and $$ that Kevin and other saw porters do to make things "just right" NO. They just care about profit because of the Bean counters. AND the saws have to last with idiots that sometime get them into their hands. So there is the difference. I have only scattered 1 modded saw and that was because of the piston being lightened and windowed too much. The rest have been running great, some for years so far. My 346 has roughly 75+ gallons of gas through it with my 562 closely following that. Both get ran HARD. Kevin's saws perform as he states and usually better. CJ
I'm pretty sure the engineers you mention have some restrictions on what they are paid to design. It would be very interesting to know if any of them run saws of their own design & whether or not any of them have been "tweaked" a bit to enhance performance.
Very true
A friend of mines dad worked at ford engine R&D.
They put Chevy heads on a 289.
Project over it went out the back door. As many concept cars did also.
It would push a 20’ jet boat. Big Block area for sure.
But they never sold that version. Lol
Yeah, I get it. At one time I had a 1973 Olds Toronado with a 455 powerplant which had some early version a PCvalve & some recycling technology. This was known to rob the engine of some power. I knew a guy who put this stuff on by day & took it off by night! I had him "unrecycle" my Toro, & it really perked it up as well as improving fuel economy!! There is no doubt that the engine having been relieved of it's EPA (employment prevention agency) mandated burden would not be subjected to as much wear & tear & would have a much longer life span!
Had a one ton 4X4 Chevrolet van. Part of a bunch made for the phone company
Tuned it on the Dyno after all smog stuff was removed.
Passed.California smog test
All production engines are designed to serve a finite period of time . The old extended serviceability of early Chev 283 or Ford 289 & Dodge 318 will not be replicated . Durability & simplicity of repair are today not a part of the master plan . Today production engines like much of every thing produced , is disposable commodities . That must meet even more epa restrictive regulations & work within those defined perimeters for a specific hour life . So as I said before , a good engine builder can fine tune & massage these set points for a better overall performance package & potential longer life cycle . How much is determined by how far he goes . e.g. Simple minor porting & polishing & muffler modification or more radical piston & ring porting & muffler redesign or replacement . Yes people like Kevin & Randy & others have yrs of experience within these design changes that can provide a durable & more reliable daily cutter , to a all out performance saw on the ragged edge ! 
A well tuned & carburated engine tuned on the lean side within fuel and timing numbers will easily pass even todays restrictive epa regulations in most cases . However must maintain those numbers consistently & continually . This requires constant preventative maintenance , which requires constant tweaking that the average owner does not maintain adequately unfortunately !
Wait now... I thought us fools with grinders and such were in the dark ages, hum.
A chainsaw won't benefit much from exhaust valves imho. Other valves, maybe.
Casting a proper cylinder and updating ancient technology would be and improvement on these old vibration boxes we still use. Engineering usually nails it till they actually try to get it built. Then comes the long walk down to their fabrication shop for some more learning about things like straight ports won't fit or don't work well for X application. And the ever popular,
"We have no way to service that design."
from your builders.Soon after a lawyer chimes in and says, "Nope... we can't insure that either, sorry."
Then the EPA or DEP maybe CARB, just take your pic shuts it down after fifty hours testing
link
Gone fishing
Well, no doubt professional porting can achieve something when you discard environmental considerations.
But you see what you want to see... and you hear what you want to hear...
and increasing rpm and hp will certainly reduce endurance - just how it is. So how you gonna sell it - barely used
Burning your candle in both ends at the same time does - what ?
But you see what you want to see... and you hear what you want to hear...
and increasing rpm and hp will certainly reduce endurance - just how it is. So how you gonna sell it - barely used
Burning your candle in both ends at the same time does - what ?
link
Gone fishing
Down at the chainsaw forum bucking fire wood you might have fun, but in "this" part of the forum - you are looking for love at "all" the wrong places.
Sierra_rider
Piss revver
Well, no doubt professional porting can achieve something when you discard environmental considerations.
But you see what you want to see... and you hear what you want to hear...
and increasing rpm and hp will certainly reduce endurance - just how it is. So how you gonna sell it - barely used
View attachment 1019350
Burning your candle in both ends at the same time does - what ?
...but higher rpm means less time actually cutting, so is it not a wash? I'd also venture to guess that less energy is wasted as heat...
Similar threads
Want to Sell
Ported 361
