Indy Dan; Poo 800 CFI originally was one of the first to crack 160 Dyno HP but we saw this was not sustainable lol.
Can your modification support that kind of HP with the warranty? Say I sent you a Engine with the SLP stage 4 kit installed. Would you do your very experienced thing to it and would you still provide the warranty with the obvious disclaimers for improper fuel or engine management.
PAR (1200psi), I ask the same of you. What kind of HP (dependable) will your crank-cylinder mod support?
What I really want is a 155 HP, 120 Ft Lb torque at 7400rpm. Do either of you build something close from the stock Poo 800 cases?
First - Thanks Andrew Johnson. you're.
geo - It sounds like you need a 900 Polaris 80mm stroke Stock they were about 155hp @ 7400
You ask alot of questions to alot of people. Sometimes I think people think snowmobile motors are like New diesel pick-ups. ( Spend alittle money relative to the factory sticker price ) and BANG you have a dependable 10 to 15% power gain.
I am here to say that is not possible on the Polaris 800 Small Block.
Kelsey, I have answered all your questions about 5 years ago. ( On this very Forum ) do a search or ask people that have been on here that long, many will remember I wrote full pape on the problems this motor would have before it was ever released.
I said there was NO WAY that the small block could make or handle 160hp in stock form with the cylinder & head combo it was built with.
The motor is physically to small and it cannot remove enough heat from around the front of the motor ( I.E. The exhaust port ) I also said there is to much heat on the front of the piston.
Take a long hard look at any successful aftermarket cylinder and look how big the front is swelled up to increase waterflow. ( Suzuki is great at this )
Look back in time just alittle to 1994 Polaris 800 storm, Train wreck on pistons................Then in 1996 Polaris swelled up the front of the cylinder right above the exhaust port and removed the sleeve & Nicasil the cylinder and the piston life was over tripled. the 1996 could go thousands of miles farther and the pistons always looked better.
The 800 Storm had 3 cylinders, 3 carbs, and 3 pipes making about 145hp, Now we have a twin making close to that number.
If you big bored the OEM Storm cylinders to 900 you turned it into a pile of steaming dog poop.
But then if you big bore a OEM ZRT 800 Cat to 1000cc it ran like a swiss watch trouble free for years. Both 65mm stroke and the Polaris had a better rod ratio but yet the Polaris was a piston eater in 1994 & 95.
I will simplify this ( BTU's )
Britsh Thermal Unit
A question asked by many youngster over the years......" Dan how do you make a motor make power power ?"
Simple, I respond, " Increase its ability to burn fuel. "
A top Fuel car can burn over 5 gallons of fuel in under 4 seconds, Thats faster then you can empty a 5 gallon can with a 10 inch opening by tipping it upside down and The top fuel car can give you a head start and let you get it tipped upside down before he Hits the throttle.
When increasing a motors ability to burn fuel you have also increrased its ability to make power, and physics tells you have also increased its ability to build heat.
If you build heat you have to get rid if it.
The Longer Rod ( The better rod ratio ) Reduces the side load on the piston and that reduces heat on the front of the piston.
A Big Bore on the stock cylinder increases heat ( Where is it going to go )
A top fuel car doesn't even have a radiator, Nor does it have coolant.
Its got a Super Charger that puts so much air thru the motor it does not need coolant for the task at hand in the time allowed to complete the job to 300+mph>
And finally the answer many have wonder for years.
Why do OEM Stock Pistons in a 800 Polaris with a Turbo last so long and look so good ??
The Turbo increases the motors ability to burn fuel, It increases power, and most important !!
It gets rid of the heat better then a stock motor because the basic nature of a 2 stroke pipe is not needed ( The signal that is sent back to the motor to hold the waiting charge in the cylinder until the exhaust port closes is no longer needed or applied ) the turbo rams the air thru the motor and out the pipe and the front of the piston stays cool.
I have attached 2 pictures of the Polaris Storm cylinders.
1 early version, and 1 1996 update cylinder.
Look at the exhaust area - This will show you what I am talking about. ( The view from the top speaks volumes ) Look at the MASSIVE Increase for water to get around the exhaust area.
OHHHHHHHHH!!! I Love their Chicken.
Dan
