i can recalculate the figures going by 35 hp instead of 47 to get what the new hp will be. i was told that the banshee stock was around 47 and thats what i based my figure on. i was looking at an ad for the big bore with the p&p & windowed wisecos they claim an increase of 50 hp, that would put it at 85 then instead of 100.

 

I just recalculated the hp using 35 hp as the base and i come out with 56 hp. its really easy to figure if you know what the base hp is and the jet size. if you increase velocity with jet size to maintain the correct mixture. however a jump of 20 hp. is nothing to sneeze at on a light machine like the shee. the powerband comes on really fast. my next step is to go to the 3 reed valves setup and pro shift kit. maybe in a couple of seasons i will do the the big bore deal. i like to stay away from nos because too many things can happen, if you know what i mean.

 

A stock Banshee is 38HP. The mods you were talking about won't give you the power you're looking for. You can get to 75 or so horsepower if you have the cylinders race ported, buy CPI pipes and some decent carbs. Your best bet for HP is to do a 4 mm cub cylinder, some 35 mm kheins, a 4mm hotrod crank and and some CPI pipes. You'll see around 90 HP or more. You're looking at around 3K to do it all. Of course, then you'll need a lockup clutch, a longer swingarm....LOL..it never ends.

 

Oh,Yeah H.P. = money = speed or a fast heart beat.

 

somebody said a friend dynoed theirs with the same mods and they got 55 hp. my ? is, was he sitting on the quad when it dynoed?

 

i havnt got an answer yet so i will take for granted that he was on the machine when it dynoed, if he weights in at 150 lbs, then the real rwhp would have been closer to 70 hp.

 

Sitting on the quad isn't going to change the outcome of the dyno run. I have never seen anyone dyno a bike without someone sitting on it.

If you are referring to the added weight of the rider effecting power to weight ratio, a dyno probably thinks a quad weighs 1000 lbs as tightly as the quad is strapped down to the dyno. The drum that the tires turn on has a resistance setting that effects how hard it is for the quad's motor to turn it. This resistance tries to simulate load which is effected by traction, overall weight and riding surface in the real world.

Also, I have never personally bought into calculating output by what jet size you will be running. There are way too many other variables for that to work......IMHO.

How do you know before the fact that you will actually be running optimal mix with 320 mains?

 

ok,thats right, but resistance takes away hp, or it takes more hp to over come the increased load.ie wind and as you stated rolling.If you set 1k lb on a small mtr that lets say can only develope 40 hp. I just cant see it being able to overcome that much resistance to reach its maximium hp. maybe if it had 25 gears.

 

Exactly. The resistance is designed to simulate real world load on the motor then there is a correction factor that makes the numbers relevant. I think most dyno's for ATV's have a capability of simulating about a 500 lb drum. That works good for hard pack but it is not accurate for simulating sand load.

Think about this.........Lets say you have a dyno that is set at a 500 lb drum. You make a pass and turn 50 hp at 7000 rpm. Lets say your hp at 3500 rpm is 20. (weird curve, I know). Your E.T. from 2000 rpm to 7500 rpm is 1.75 seconds.

Now put this same motor on a dyno that has the capability of simulating a 1000 lb drum that would more accurately demonstrate real world load found on the sand. You most likely will come to almost the same peak hp but your hp at 3500 rpm will be quite a bit lower percentage-wise and your over-rev after 7000 rpm will drop off quicker and your E.T. from 2000 rpm to 7500 rpm will be noticably slower.

The higher the torque at a given rpm, the less the load applied by drum resistance (or real world load) will effect hp.


Btw, how many LbFt of torque would it take to turn a 1000 lb drum on its axis? How much would it take to turn a 500 lb drum?

 

Yes the slower to reach maximium speed is lower torque curve. now heres one, i watched them setup a small car for road racing. they did a stock run on the dyno to get the figures. the first thing they changed was to go to larger rotors and larger calipers, then dyno and guess what, they had 14 less hp just because they added a little more unsprung weight. does that say anything?