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Post by geh3333 on Jun 12, 2015 19:08:09 GMT -5
To be honest , I never ran at 7000 rpms on a whole tank , and I still average 60 mpg , so let's do this again , but we'll take an average rpm . I'll do 5,500 rpms . so 5,500 rpms × 60 is 330,000 ÷ 4 is 82,500 ignition strokes. So 1.21212121×10(-5) which is 0.0000121212 gallons which is .00155 ounces which is .0458 ml being burned each ignition stroke.
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Post by pistonguy on Jun 12, 2015 19:25:58 GMT -5
To be honest , I never ran at 7000 rpms on a whole tank , and I still average 60 mpg , so let's do this again , but we'll take an average rpm . I'll do 5,500 rpms . so 5,500 rpms × 60 is 330,000 ÷ 4 is 82,500 ignition strokes. So 1.21212121×10(-5) which is 0.0000121212 gallons which is .00155 ounces which is .0458 ml being burned each ignition stroke. Well I'm not going to check your math, But Very Nice!  |
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Post by geh3333 on Jun 12, 2015 19:42:10 GMT -5
To be honest , I never ran at 7000 rpms on a whole tank , and I still average 60 mpg , so let's do this again , but we'll take an average rpm . I'll do 5,500 rpms . so 5,500 rpms × 60 is 330,000 ÷ 4 is 82,500 ignition strokes. So 1.21212121×10(-5) which is 0.0000121212 gallons which is .00155 ounces which is .0458 ml being burned each ignition stroke. Well I'm not going to check your math, But Very Nice! Calculators are a godsend !, lol |
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Post by cyborg on Jun 12, 2015 19:46:24 GMT -5
A four stroke fires every other time not every fourth,, and the calculations for proper cylinder fill also take into account the phenomenon of " inertia charging",,, the cylinder is getting more fuel/air mix than the actual volume of the total cc's,,, because the air fuel mix has mass/ weight if you have the correct intake length and size to keep velocities up it will " overcharge "the cylinder,,,the mix is really moving ,,and the reason for intake " honk" or the growl you hear is the charge going supersonic,,,, mini sonic booms,,,,,,,papa likes
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Post by pistonguy on Jun 12, 2015 19:55:06 GMT -5
A four stroke fires every other time not every fourth,, and the calculations for proper cylinder fill also take into account the phenomenon of " inertia charging",,, the cylinder is getting more fuel/air mix than the actual volume of the total cc's,,, because the air fuel mix has mass/ weight if you have the correct intake length and size to keep velocities up it will " overcharge "the cylinder,,,the mix is really moving ,,and the reason for intake " honk" or the growl you hear is the charge going supersonic,,,, mini sonic booms,,,,,,,papa likes Correct there Borg. I was lets say "Behaving Myself" I'm on a roll of not being Banned. Yet!  |
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Post by geh3333 on Jun 12, 2015 19:59:37 GMT -5
A four stroke fires every other time not every fourth,, and the calculations for proper cylinder fill also take into account the phenomenon of " inertia charging",,, the cylinder is getting more fuel/air mix than the actual volume of the total cc's,,, because the air fuel mix has mass/ weight if you have the correct intake length and size to keep velocities up it will " overcharge "the cylinder,,,the mix is really moving ,,and the reason for intake " honk" or the growl you hear is the charge going supersonic,,,, mini sonic booms,,,,,,,papa likes Crap !! I was counting every stroke as every upstroke and every downstroke , but that won't work with my calculations . I'll fix it hold on |
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Post by geh3333 on Jun 12, 2015 20:01:13 GMT -5
A four stroke fires every other time not every fourth,, and the calculations for proper cylinder fill also take into account the phenomenon of " inertia charging",,, the cylinder is getting more fuel/air mix than the actual volume of the total cc's,,, because the air fuel mix has mass/ weight if you have the correct intake length and size to keep velocities up it will " overcharge "the cylinder,,,the mix is really moving ,,and the reason for intake " honk" or the growl you hear is the charge going supersonic,,,, mini sonic booms,,,,,,,papa likes Correct there Borg. I was lets say "Behaving Myself" I'm on a roll of not being Banned. Yet! Don't worry piston , if I'm wrong I def admit it , lol . please correct me next time  |
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Post by geh3333 on Jun 12, 2015 20:03:44 GMT -5
It should be rijt if I just times .0458 × 2 right? So .0916 ml of fuel every ignition stroke.
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Post by geh3333 on Jun 12, 2015 20:16:14 GMT -5
A four stroke fires every other time not every fourth,, and the calculations for proper cylinder fill also take into account the phenomenon of " inertia charging",,, the cylinder is getting more fuel/air mix than the actual volume of the total cc's,,, because the air fuel mix has mass/ weight if you have the correct intake length and size to keep velocities up it will " overcharge "the cylinder,,,the mix is really moving ,,and the reason for intake " honk" or the growl you hear is the charge going supersonic,,,, mini sonic booms,,,,,,,papa likes Taking the rpms at a steady rate at a certain time and calculating the fuel consumption will tell you the same thing . that's why you must do the test at a specific rpm and stay at that rpm for a steady pace. My numbers are not 100% accurate but should be close. The only way to know for sure it to do the actual test. |
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Post by geh3333 on Jun 12, 2015 20:24:12 GMT -5
If you can stay at the steady rpm rate , then the suction from the piston should be pretty equal each time. So calculating how much fuel was consumed during the run and how many ignition strokes where made , well that's pretty simple . you have to take into.consideration the short time it takes to get up to the specific rpms and stopping at the end , bit that would be a nominal difference. Your right that a higher rpm will create greater suction , I actually had a few posts about this in the recent past. But that's why you do the test at a steady rpm.
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Post by pistonguy on Jun 12, 2015 21:07:00 GMT -5
This is fun food for thought.
We've totally Jacked this Dudes Thread.
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Post by cyborg on Jun 12, 2015 21:42:32 GMT -5
Engine theory,,,my fave,,,,papa likes
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Post by geh3333 on Jun 12, 2015 22:20:43 GMT -5
Engine theory,,,my fave,,,,papa likes These are the things that need to be done , so we can say for certain , what works or what is to big or too much . I'm one who likes to know for sure before I point others in the that direction. Like the bigger carb theory . I've done it and succeeded as well have others with great results. Not that it is necessary , but it is not too much for these engines, and better performance can come from it. |
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Post by cyborg on Jun 13, 2015 0:22:45 GMT -5
The parameters of these types of calculations is enormous,,what we've been discussing are just a few of the variables that are required for concrete answers,,,temp ,humidity,fuel quality,closeness of tune to stoichiometric ( the perfect fuel/air ratio),,, and if you do the math then you will be close,,and you are correct real time testing is the only way to find the true answer,,,as the old saying goes " everything works great on paper",,,,
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Post by ital on Jun 13, 2015 22:36:36 GMT -5
Hi all, I am happy to say she is alive. I had handy Andy stop by and he got her starting right up. I had an air boble in the carb and a crack in the 5mm spacer. She is running very good. I thought that my rpms might go higher with more power but they are staying at about the same. I only went up 60 cmph for now. She is much faster then before hopefully she will hit st least 70cmph
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