Originally posted by: head027
i dunno about 60hp but he coulda been close to that. with the correct jetting with the pure polaris pipe and carbuerator adjustments u can maybe get close to that not quite 60 maybe 55-58. Also, to the guy who said the thing from the local mag about rped only gettin 43 hp that might be true is they dont know how to jet correctly and do the adjustments to the carb. I know many people on predators who try to do this and they end up with a slower less powerful quad then stock. Most people dont understand the pred motor as it is different from the honda and yamahas because it is american made. it all just depends on if they know what they are doing.
that guy did sound like a dick and if he is beating the 250A guys they really suck or they are racing in some deep sand.

Originally posted by: head027
i didnt say 60 hp i said it could probably come close and that is with a different ignition box. polaris is an american company so their motors are different then honda, yamaha, ect... I also dont care about your little formula because you probably dont even understand it and anyone could go on the internet and find it. I dont really care if u believe me or not because i know what a predator is capable of and I have seen many predators and ours are alwasy the fastest ones because the guy who works on them knows what he is doing and understands the predator motor like the back of his hand.

Originally posted by: Freez
Head027, Please tell me what mods you have on your Predator?

It is IMPOSSIBLE to make a stock predator produce 60HP, even with a new pipe, jets, carb, you name it. Here is why.

A predator is a 499cc motor and it is running a compression ratio of 10.8:1. The manual also say that the rev limiter is kicking in at 9005 RPM.

So for those who don't know? Volumetric efficiency is a mathematical formula that calculates how much fuel and air capacity a motor can breathe in and burn to produce power. It is formula used world wide to show how well a normally aspirated 4 stroke motors performs. It gives you a percentage. Meaning if a predator motor that has a 100% volumetric efficiency, it can fill all 499cc with air/fuel and burn it efficiently to produce maximum power.

If you say the stock Predator can produce 60HP or more the formula tells me that your Predator motor is capable of a volumetric efficiency of 123%. This is assuming you are producing 60HP at 8000 RPM. This means that a Predator can breathe in as much air as a 620cc motor. A normal 4 stroke motor is produces a volumetric efficiency of about 85%. Also remember that on a dyno you are measuring Hp at the wheels. Meaning that your claimed 123% VE value is actually higher, since the motor must produce about 5 to 10 HP more at the crank to overcome the loss of HP due to the drive train. Meaning the motor is most likely producing something like 70HP at the crank. This gives you a volumetric efficiency of 144%. To produce that you’re motor must be able to breathe the same amount of air as a well tuned 720cc motor. You tell me how that this is possible with a normal aspirated 499cc motor. PS. Formula one motors don't even have a VE values that high. You telling me your mass produced stock ATV motor has the ability to do this??????

The only way for a normally aspirated Predator to produce 70 HP at the crank is if it is able to produce max HP at 11 500 RPM or higher, plus it can fill all 100% of the 499cc of capacity at that RPM. Remomber that this motor has to suck that amount of air thru little valves and a carb, so it takes a very well built motor to get a VE value of even a 100%. The motor cannot handle that or produce max HP at 11 500 RPM, and the Rev limiter will prevent you from doing it to. Please note, I am saying it has to make max HP at 11 500 RPM. Not just be able to rev to that. Your red line on the bike should be something like 13 000 RPM if that was possible.

Like I said. Normal aspirated motors have a VE value of about 85%. High performance motors can get close to 100%, sometimes a little more, with special tuning and intake and exhaust pipes. Assuming a predator motor is able to produce a VE value of 100% at 8000 RPM it will only produce a maximum of 49HP at the crank. Now it will loose about 5HP or more thru the drive train and will not be able to produce more than about 44HP on the dyno.

This is fact!

The reason why people don't believe predator owners is this BS they come up with. You either have a busted up dyno, or you have a very very special motor. Something the whole world have been looking for, for the last 100 years.

PS. the motor on a predator is made by Fuji. Are you sure it is built in the USA? Sound like a Japanese company to me.