Figured out how much fuel is being burned !  By  geh3333 (Read 1,275 times)

I'll give it a shot

Or maybe I can just compare that to a stock scoots mpg . but what we really need is someone who has just done a uni and exhaust mod with an upjet and see how many mpg they get compared to the stock setup. Keeping the same bore and head size will show how much more fuel is able to be burned in the chamber then how much is being burned with the stock setup. This will show that even a stock bore can take more air and fuel , and still not be too rich .

not if you know 1 cubic foot of air at standard temperature and pressure assuming average composition weighs approximately 0.0807 lbs or 0.0366 kg

28317cc per cubic foot

28317 divided by (36.6gram /0.161g)  equals 124.56 cc of air

just about what you would expect on a 150cc with less than 100 percent volumetric filling efficiency

(Edit) please skip this post , wrong air calculation !!

Yeah , I just did the equation. So let me figure in the fuel. Which .0916 grams is .0916 cc , lol. So still about 125cc . now take into consideration that the amount of air I used in the equations was the amount needed for combustion . so its probably a lean mixture if its the exact amount needed for combustion. So let's up the air slightly and try this again.

Now let's do a calculation of a stock scoot getting mpg and see how many cc's are being filled . again this is not 100% accurate but it should be pretty darn close. Let's make this easy . say your scooting at 42.5 mph at 5500 rpms and your scoot gets mpg . you ride for 2 hr's at a steady 5500 rpms. So 120 min at 5500 RPMS is 660,000 revolutions, and 330,000 ignition strokes. So 1 gallon of gas was used which is 3785.411 ml of gas. Divide 3,785.411 by 330,00 which is .01147 ml per ignition stroke. Now the air consumption. 9,000 gallons of air needed to burn 1 gallon of gasoline. So take 9,000 ÷ 330,000 ignition strokes is .0272727273 gallons of air which is 103.23 cc's now divide by 75% for gas density is 77.4 cc's . wow , now add the fuel amount which is .01437 cc's and we get 77.4 cc , lol. I would say maybe this isn't the right way to do this , but considering these 150cc scoots top out many times around 50mph or so , well this would not surprise me if they are only burning 77.4ccs worth or air and fuel. And considering our pal millsc is hitting 56 mph with a 52mm ( 88cc ) bbk , and is probably using the entire chamber for fuel consumption with the 24mm carb , well this only makes sense. You get a 50c scoot on a good day can hit 40mph . compared to a 150cc scoot that does 55 on a good day. Your tripling the cc's but only gaining 15 mph !! Its probably because these scoots come under carbed and under jetted with restricted airflow , and the chambers are screaming for more air and fuel. Even if we drop the mpg down to 80 or 70 , the amount of cc consumption will be much lower then 150cc .

Just filled up today, I only have the uni filter, and my carb is not quite dialed in correctly but, am avg. 56.5 mpg over 162 miles and 3 fill ups. And I know you weren't asking but is costing $0.053 per mile And these calculations are using the mileage off my speedo and using Fuelly to calculate.

Relative humidity should effect the weight of the air.
As a Diver I should know this, We normally dive with a 80 cu,ft tank at 3,000 psi, it is funny as the tank empties we become more buoyant and have to compensate for this.
Most don't realize Air has weight.