S
dyno
What Makes the 800 down on Power? (lots of 2 stroke info)
- Thread starter RoffRider
- Start date
Hahahahahahaha that just made my day!
well played sir!
well played sir!
You forgot the "RPM" on the bottom and "HP" up the left side....
Honestly all this talk about the polaris 800 being under powered is rubish. I rode every brand of machine and different track lengths etc, I found them all pretty close to the same, minus set up differences like clutching, gearing , track choice. The skidoo defiantly is more responsive but the arctic cat being 10 hp more I cant tell. With anything clutch work is what makes them go, its everything.
C
If I had an extra 6K in the bank I would have one of Carls engines in my Pro in a heart beat. With or without a dyno sheet. A dyno is a tuning tool not a selling one.
IMO.....
IMO.....
C
Motor Change
Just a quick question on this thread given the level of expertise. Do we think this motor design will be obsolete soon? Polaris hasn't made EPA compliant emissions changes to the 800 2 stroke. The government regulations are so bizarre though that I can't even tell if this is truly an issue. Seems like there is some cap and trade thing going on where the manufacture's aggregate emissions are what matters rather than the performance of a single motor.
Just a quick question on this thread given the level of expertise. Do we think this motor design will be obsolete soon? Polaris hasn't made EPA compliant emissions changes to the 800 2 stroke. The government regulations are so bizarre though that I can't even tell if this is truly an issue. Seems like there is some cap and trade thing going on where the manufacture's aggregate emissions are what matters rather than the performance of a single motor.
Your talking about a whole different thing then what this thread is about... Your talking about weight to power at the ground ratio. The Pro is much lighter and much more effecient at putting the power to the snow IMO. Stuff like better clutching, belt dive, lighter track, lighter drivetrain, and lighter sled all together is what lets the Pro perform just as good if not better then the other two.
take all that away hook the motor up to a dyno and the Pro motor will not perform with the other two IMO...
Polaris is and has been compliant on their motors(this came up in a thread a yr. or two back), if I remember right, the others actually used pts. to meet compliance and Polaris did it by compliance(no pts to use)..
D
No it would not! Just because there is more charge above the intake side of piston the pressure across the hole top is the same!
M
Forgive me, I stumbled into the Polaris room by mistake. This thread is quite entertaining!!! I would like to address the offset combustion chamber design Roffrider bragged up numerous times in this thread. I'm sorry sir, but someone has you terribly ill informed on this design. The way to get the most complete burn in the combustion cylce, therefore producing the most power, is with a symetrical dome shaped chamber, and center located spark plug. This allows for the best and most even flame propogation during the combustion cycle. Chrysler figured this out over 50 years ago (HEMI). Now, yes I know as I say this, Doo put the injectors where the sparkplug should be, and moved the spark plug to the intake side of the dome which I really don't think was a great idea, but I guess no cylinder wash that way. My $0.02 on that idea.
Now go ahead and flame on the Doo guy
Now go ahead and flame on the Doo guy
R
wider power brand is what i was thinking too usually no matter what you do, unless its too much fueling and/or very low compression, if you dont have good top end power you get a wider and smoother power band, im thinking this is where polaris "detuned" their 800
R
if your cylinder is running cooler and has a more even heat across the piston and cylinder you can pull more, reliable horsepower out of it...shorter rods also make for more hp, does that mean everyone should shorten their rods for most hp?...how do you think that would work out?Forgive me, I stumbled into the Polaris room by mistake. This thread is quite entertaining!!! I would like to address the offset combustion chamber design Roffrider bragged up numerous times in this thread. I'm sorry sir, but someone has you terribly ill informed on this design. The way to get the most complete burn in the combustion cylce, therefore producing the most power, is with a symetrical dome shaped chamber, and center located spark plug. This allows for the best and most even flame propogation during the combustion cycle. Chrysler figured this out over 50 years ago (HEMI). Now, yes I know as I say this, Doo put the injectors where the sparkplug should be, and moved the spark plug to the intake side of the dome which I really don't think was a great idea, but I guess no cylinder wash that way. My $0.02 on that idea.
Now go ahead and flame on the Doo guy
Yeah, I gotta comment on this(not Roff's offset chamber deal) but the Hemi head deal being the best..well yeah , sort of..Top fuel went to the Chrysler Hemi in the early days for 3 basic reasons, 1 they were inexpensive and readily available, 2 they were extremely strong in the block/crank, and 3, the hemi head in an unlimited top fuel motor allows better/easier control of DETO.. so yes, today it is the motor for top fuel.But its not always the best head design and in many many cases a wedge head is better. wedge chambers will normally make more power(everything else being equal, especially normally aspirated), engine design is much easier and cheaper, engine size is much more compact and most important both fuel economy and emissions are better..Forgive me, I stumbled into the Polaris room by mistake. This thread is quite entertaining!!! I would like to address the offset combustion chamber design Roffrider bragged up numerous times in this thread. I'm sorry sir, but someone has you terribly ill informed on this design. The way to get the most complete burn in the combustion cylce, therefore producing the most power, is with a symetrical dome shaped chamber, and center located spark plug. This allows for the best and most even flame propogation during the combustion cycle. Chrysler figured this out over 50 years ago (HEMI). Now, yes I know as I say this, Doo put the injectors where the sparkplug should be, and moved the spark plug to the intake side of the dome which I really don't think was a great idea, but I guess no cylinder wash that way. My $0.02 on that idea.
Now go ahead and flame on the Doo guy
So yeah, in a top fuel engine I would run a hemi head setup, in most other apps..most likely to be a wedge head for all the reasons above.. On 2 stroke sleds, yeah hemi is a natural and most every manufacturer over the years has employed a variation of it..
HP numbers are stoopid. 
My 2013 Pro was a screamer, it got faster and faster until the 277 mile mark where I sold it because I hated the chassis and was tired of waiting for the BOOM. The engine and clutching were spot on.
MUCH better than the replacement, a couple of 13 Etecs. Throttle response, butt dyno pull, etc., the Pro smoked both of the Doos. (137 Freeride, and 154 XM.)
Clutching, gearing, driveline, etc etc all come into play, but in my experience, the motor with the least horsepower pulled the hardest, bar none. (Even better than my 12 Cat 800.) At least, until I sold it, scared of the BOOM.
My 2013 Pro was a screamer, it got faster and faster until the 277 mile mark where I sold it because I hated the chassis and was tired of waiting for the BOOM. The engine and clutching were spot on.
MUCH better than the replacement, a couple of 13 Etecs. Throttle response, butt dyno pull, etc., the Pro smoked both of the Doos. (137 Freeride, and 154 XM.)
Clutching, gearing, driveline, etc etc all come into play, but in my experience, the motor with the least horsepower pulled the hardest, bar none. (Even better than my 12 Cat 800.) At least, until I sold it, scared of the BOOM.
M
Well, this may just be speculation but I don't think it would be cooler since the exhaust side would be hotter already, and now by the design you gave as example the exhaust side would have less incoming air charge soaking some of the heat beacause of the larger squish area on that side, thereby even potentially causing a hot spot for meltdown or detonation. Now to answer your question about shorter rods, sure if your goal was faster revving and more horsepower it would work great, if you are willing to sacrifice torque. Not sure where that was going.............................
M
LOL..you arnt looking back far enough..you need to go back to the late 50's early 60's.. that's where the Hemi first became popular for top fuel....
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