cus_deluxe
Commie Satan turd
honestly that thing has way more compression than it needs. never checked it.
Up the compression or big bore
- Thread starter Joseph W Santora
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honestly that thing has way more compression than it needs. never checked it.
cus_deluxe
Commie Satan turd
next thing i do is gonna be to add .010 or so to squish. id almost guarantee it gains.
cus_deluxe
Commie Satan turd
ohhh that video is painful lol. cant believe i didnt melt it down lol
cus_deluxe
Commie Satan turd
sounds much better in this vid. this was bwfore i made 20 cuts in a row then put a pipe on it 
I’m guessing your high octane fuel is oxygenated. To get it to run properly, you’d need to open the screws enough to compensate for that. The saw needs 14.6 parts of oxygen to 1 part gas, and doesn't care which orifice it travels through.Maybe I was wearing thinner pants, yes that must be it!
Yes VP U4.4 is oxygenated fuel. But I changed nothing on the fuel settings.
Says it's 7.50 oxygenated.
VP fuel charts for all there motorcycle and ATV racing fuels as of 2019
The last time I used it was 2015 and the color was blue, (now it's green) there may have been more changes since 2015
https://vpracingfuels.com/master-fuel-tables/#fuel-tables
VP chart sheet for U4.4REG
https://3m5311q30z3nqc7x1a69xidu-wp...oads/2019/12/U4_4-REG-Spec-Sheets_100419A.pdf
They only list U4.4 REG vs. U4.4 that I was using back then.
When I started using VP fuel it was U4, then they changed it to U4.2, then changed it again to U4.4. It seems they have once again changed to U4.4 REG
No it' wasn't my imagination, I tested it many times and the outcome was always the same in all my stock stihl saws. ms290,ms362,ms391, ms170
You need higher octane gas in the bikes than saws as they run under heavy loads at low to mid rpms where detonation occurs, saws don't have any load on them under 5-6000rpm so detonation isn't an issue unless the timing is way off.
My yz250 has 220 psi of compression, it runs fine on 91 octane gas, you need to have more compression than that to need race gas in a bike, a saw would be even higher.
Oxygenated race gas makes more power than regular gas, due to simply being better gas not just higher octane. It's illegal in some forms of racing.
The date I wrote on my last can is 1-10-15 but I do still have a single gallon I transferred to a 1 gallon true fuel steel can some years back when the 5 gallon can go low. Now that I am looking at the last 5 gallon pail I bought back in 2015 is U4.4REG but it's blue not green like the spec sheet says.
This thread started out by a new guy asking about some basic hot rod questions, and morfed into a race saw discussion. I was into drag racing till my late 20's. I drove race cars on the road, but I didn't drive them as my daily driver. My question to the OP was an honest desire to know what he wanted/needed, and what he expected to gain by the mods he was talking about. We almost always gutted the mufflers on saws and opened them up a little, back in the 70's. They were louder, so they had to be more powerful, right? Like putting Hush Thrush mufflers on your 318 Monoco, it was louder, it had to be faster. But, that's the seat of the pants effect. If I want a more powerful saw I just buy one, but every one is not in a position to do that. I'm curious where would the OP's money be best spent, on some modest mods where he can get the best out of this saw, or just save up and buy a new one. Since my wife won't let me buy cars every other month, I have to settle on saws. So, I never pass up the opportunity to buy one.
Racing has verbals, that make seeing a difference questionable, but the dyno doesn't usually lie.
Someone needs to make a dyno for chainsaws that will take out human differences and chain sharpness and wood density and give a more accurate result in power, and torque.
It goes back to the seat of the pants test. You may feel like you are applying the same pressure cut after cut and each cut does take some of the sharpness out of the chain and wood density can change even though you are cutting the same log only inches apart.
Racing uses a electronic timing device like a light tree and laser beam or transponder. Chainsaw timing uses a stop watch witch can have variables because a human is starting and stopping the clock.
Someone needs to make a dyno for chainsaws that will take out human differences and chain sharpness and wood density and give a more accurate result in power, and torque.
It goes back to the seat of the pants test. You may feel like you are applying the same pressure cut after cut and each cut does take some of the sharpness out of the chain and wood density can change even though you are cutting the same log only inches apart.
Racing uses a electronic timing device like a light tree and laser beam or transponder. Chainsaw timing uses a stop watch witch can have variables because a human is starting and stopping the clock.
cuinrearview
Red saw lover
Love when peeps compare bikes and quads to saws. @Huskybill
Joseph W Santora
ArboristSite Operative
And morphed it has. The question was simply which of the two would you choose. Slightly higher efficiency with the higher comp or more displacement with the big bore kit.
Capitalist
Addicted to ArboristSite
Upping compression and increasing octane creates more power.
Likewise higher octane is not good for early 2000 vehicles and it pays for the added cost in newer higher compression vehicles.
On big bore kits dont waste your time.
The cheap chinese crap online will burn up quick and runs less power than stock husky parts. I fried one this summer and when I switched back to stock (readjusted jets) I couldn't believe I ever screwed with the big bore.
Likewise higher octane is not good for early 2000 vehicles and it pays for the added cost in newer higher compression vehicles.
On big bore kits dont waste your time.
The cheap chinese crap online will burn up quick and runs less power than stock husky parts. I fried one this summer and when I switched back to stock (readjusted jets) I couldn't believe I ever screwed with the big bore.
I would go for the higher compression, base gasket delete and maybe a pop up, and keep the 357 cylinder.
Capitalist
Addicted to ArboristSite
"Compression ratios usually range from 8:1 to 10:1. A higher compression ratio -- say, from 12:1 to 14:1 -- means higher combustion efficiency. Higher compression ratios and combustion efficiency mean more power with less fuel, and fewer exhaust gases."
Just googled compression ratios first thing that popped up.
But.... It doesnt apply to saws... Hmmm.
Actually it applies to any internal combustion engine ever created.
Precisely why newer cars are increasing comp ratio to meet emissions and why there has been talk of taking all gasoline and making a universal 95 octane option only.
Power per gallon....
Every hippies dream
Also...
Xp premixed fuel is 95 octane.
What do those guys at husqvarna know though lol
Just googled compression ratios first thing that popped up.
But.... It doesnt apply to saws... Hmmm.
Actually it applies to any internal combustion engine ever created.
Precisely why newer cars are increasing comp ratio to meet emissions and why there has been talk of taking all gasoline and making a universal 95 octane option only.
Power per gallon....
Every hippies dream
Also...
Xp premixed fuel is 95 octane.
What do those guys at husqvarna know though lol
If you didn’t adjust the screws, your saw is running leaner due to the added oxygen. That’s why it ran faster
You asked what seems like a simple question but it wasn't as simple as you might have thought. Sorry I/we got into the technical aspects but we all get excited about our saws and there performance. It's sickness we all share.
Raising compression raises torque. Raising octane creates less power. Octane is a measurement of a fuel’s resistance to combust. Higher octane fuels burn slower creating less power in a chainsaw.
