RPM Range? Claimed HP and torque? Dyno runs?

[Old Bob]

If you are talking dynos for lost cost, Performance Trends is the way to go. Build an inertia dyno using their software and data aquisition equipment. Between software, DA equipment and mechanical parts you can build a dyno for under $2000. If you have machining ability less 1000.

 

[bluegoatwoods]

I once started a thread in which I suggested a home-built dyno at very little cost.

I'd link to it, but I don't know how.

But it was titled, I think, "building a dyno shouldn't be hard". I'm sure you could find it by searching. I'll do the same right now to refresh my memory. I think I thought it through enough; that it'll work. And it'll test the engine while still in the bike.

 

[fenderhole]

all this talk of dynos... if you want to know your rear wheel horsepower the formula is easy- (mph/234)cubed X weight = hp. oh, for those of you who may not be familiar, mph = your top speed. weight = bike+rider. i applied this formula and found that a 280lbs bike+rider maintaining a top speed of 30 mph has an engine making approx 1hp where the tire meets the pavement. keep in mind this is only a rough estimate not an exact science. other factors that require consideration are excluded when using this formula.

 

[bluegoatwoods]

You're right, fenderhole. Most of us don't need exact performance measurements. If my bike pulls me down the road at about the same throttle that it always did, then I'm happy.
That's why I haven't built my dyno and likely never will.

But the real tinkerers here, the guys who work on engine porting and such, could make use of a dyno to document their improvements, to determine which mods are most useful, etc.

 

[fenderhole]

i understand, as a 20 year veteran hot rodder i too feel the need for some hard numbers on these engines. but since those figures currently aren't available to the average person this rudimentary formula is a good starting point to measure improvements. for instance, if you max out at 30mph then make a engine modification and your top speed increases to 32mph you've obviously increased your horsepower. ie: (30/234)cubed X 280 = .59hp (32/234) X 280 = .71hp , that's roughly a 20% increase in output. a worthy modification to say the least...

 

[Mountainman]

post 17 ???

i too feel the need for some hard numbers on these engines.
but since those figures currently aren't available to the average person

hi fenderhole

I thought that post 17 above -- did a more than fair job ??

ride the motor bike

 

[fenderhole]

i agree completely, but most people don't have access to this type of equipment and since everyone's setup is unique i thought that this would be a easy way for anyone to measure improvements they've made.

 

[echotraveler]

that formula your talking about is making me think of diets. lol