That's all I have ever ran, except a few very rare occasions and I don't notice a damn bit of a difference. My butt dyno must be off quite a bit if I can't feel a 75% loss of power. =))
Race fuel or pump gas
- Thread starter Kennedy_Power
- Start date
That's all I have ever ran, except a few very rare occasions and I don't notice a damn bit of a difference. My butt dyno must be off quite a bit if I can't feel a 75% loss of power. =))
^^ if you run 115 octane in a stock blaster, your a fool. not so much as the performance loss, but the god damn cost of the stuff.
I don't see this "performace loss" you're talking about. I have to run it in my bike so the Blaster gets the same stuff, regardless of a couple extra dollars. I'm not going to carry around different mixtures of gas just to save a couple dollars per ride.
thanks angus! I'm glad someone thinks i'm smart. lol
but flotek, i'm curious as to how exhaust port design would play into octane considerations. is it just that bringing your exhaust port up lowers compression? or is there more to it?
but flotek, i'm curious as to how exhaust port design would play into octane considerations. is it just that bringing your exhaust port up lowers compression? or is there more to it?
Waiting for flotek to respond to your post hickskateboarder
Where is peak cylinder pressure in relation to crank angle? Is it before or after TDC and at what crank angle?
Lets here what you guys think
I know where it’s at from having high speed pressure transducers and high speed encoders mounted on test engines.
Where is peak cylinder pressure in relation to crank angle? Is it before or after TDC and at what crank angle?
Lets here what you guys think
I know where it’s at from having high speed pressure transducers and high speed encoders mounted on test engines.
its becuase of the time your cylinder has to burn the fuel off i n the cycle , different durations and blowdowns are going to alter how much compressed fuel is effectively pumped through the engine and when ,and ported or not a 130 static compression bike will not be nearly as torquey as one with say 180 pounds on correct octane race gas even more if its oxygenated
Explain to us where max cylinder pressure is in relation to crank angle and why? If the total trapped volume is 15cc and I am sure you can figure out compression ratio based on engine displacement. Why is 190 exhaust duration to 195 exhaust duration going to change the compression ratio? Why would a 15:1:1 engine requires a higher octane rating then one with 11:5:1 if you have the same exhaust duration?
for those of you freaking out about the 10hp loss from switching to the higher octane plz calm down haha. he is not talking about a blaster i have no clue what quad he is talking about but it is deff not a blaster if you were to run 115 octane fuel in the blaster you might lose prolly about 1-3hp thats in a stock compression and stock timing blaster....
stock motors get no benifit from the higher octane 115.
and correct me if i am wrong but doesnt the fuel have lead in it just to help with eliminating spark knock i know early 20's and 30's cars had problems with spark knock so im pretty sure that what the reason why they even had lead in the fuel......just my 2cents
stock motors get no benifit from the higher octane 115.
and correct me if i am wrong but doesnt the fuel have lead in it just to help with eliminating spark knock i know early 20's and 30's cars had problems with spark knock so im pretty sure that what the reason why they even had lead in the fuel......just my 2cents
i beleive the reason why you need higher octane for the 15:1:1 would be because the air fuel mixture gets alot hotter put under much more pressure and could produce spark knock at 15:1:1 then 11:5:1
I will go into detail on this shortly; just waiting for flowtek to explain in more detail.
Thanks everyone for your questions and inputs
I enjoy helping out as much as I can!
That 10 horsepower loss was from a banshee that made 100hp and went to 90hp. Once the timing was pulled back out; the power went back up by 1hp
Once the race fuel and timing was set back the power came back up to 100hp
Thanks everyone for your questions and inputs
I enjoy helping out as much as I can!
That 10 horsepower loss was from a banshee that made 100hp and went to 90hp. Once the timing was pulled back out; the power went back up by 1hp
Once the race fuel and timing was set back the power came back up to 100hp
peak cylinder pressure. u talking about an engine with the spark grounded out so it's not firing? if ur talking about a running engine, it would obviously have to be a few degrees after tdc, making the power to push the piston down. where would depend on spark timing, octane, compression ratio, etc. but if ur talking about just cranking a motor and where the highest compression is reached, i would say it would also depend on where in the chamber you are talking. top of piston would be top dead center, b/c it's being compressed into the smallest area and the piston is doin the work, but if ur talking about the top of the combustion chamber where the spark plug is, i would say a few degrees after tdc b/c of squish velocity and the momentum of the air. it would take a (although very small) fraction of a second for that pressure wave being created by the piston to compress thru the air and reach the spark plug. hope that made sense lol.
the 195 duration would have a (very slightly) smaller static compression ratio compared with the 190 b/c the top of the exhaust port is higher. so although you are compressing into the same area, your starting from a slightly smaller volume. but thats just static, dealing with simple math. when you factor in for what kind of pipe ur running a dynamic compression ratio might actually be higher cuase it give the pipe that little bit longer time to push the air back into the chamber.
i agree with samolia about the compression ratios and octane. ideal gas law states that if you compress a gas it gets hotter. one proffessor showed us this crazy little experiment that made me realize just how hot that compressed gas gets. he took a glass tube sealed at one end and put a very small piece of toilet paper in it. then took a rod that fit tightly into the tube and set the bottom of the tube on the table and smacked the rod, creating like a small combustion chamber, but without spark. when he hit it the toilet paper burst into flames. all b/c of the air getting heated up, hot enough to light the paper. that's exactly what happens when you get detonation, only the toilet paper is replaced with gasoline.
this part is irrelevant so don't read it unless ur bored. he told us a story that he read on one of his physics professors forum things that it was suggested to use a few square centimeters of flash paper. so he did it in class once and it blew the glass tube apart, mildly injuring a few of the the students. lol. he went back on and told his forum what happened and the guy that suggested it said ooops, i meant a few square millimeters, not centimeters. lol. so he put 100 times as much as he should have. then he told us this is why he always harps on us about including appropriate units with our answers.
ok flotek, so your talking dynamic compression. makes sense. but also then with dynamic compression what kinda pipe u run is going to effect compression too....
gotta remember. the engine is a system, not just a compilation of parts.
the 195 duration would have a (very slightly) smaller static compression ratio compared with the 190 b/c the top of the exhaust port is higher. so although you are compressing into the same area, your starting from a slightly smaller volume. but thats just static, dealing with simple math. when you factor in for what kind of pipe ur running a dynamic compression ratio might actually be higher cuase it give the pipe that little bit longer time to push the air back into the chamber.
i agree with samolia about the compression ratios and octane. ideal gas law states that if you compress a gas it gets hotter. one proffessor showed us this crazy little experiment that made me realize just how hot that compressed gas gets. he took a glass tube sealed at one end and put a very small piece of toilet paper in it. then took a rod that fit tightly into the tube and set the bottom of the tube on the table and smacked the rod, creating like a small combustion chamber, but without spark. when he hit it the toilet paper burst into flames. all b/c of the air getting heated up, hot enough to light the paper. that's exactly what happens when you get detonation, only the toilet paper is replaced with gasoline.
this part is irrelevant so don't read it unless ur bored. he told us a story that he read on one of his physics professors forum things that it was suggested to use a few square centimeters of flash paper. so he did it in class once and it blew the glass tube apart, mildly injuring a few of the the students. lol. he went back on and told his forum what happened and the guy that suggested it said ooops, i meant a few square millimeters, not centimeters. lol. so he put 100 times as much as he should have. then he told us this is why he always harps on us about including appropriate units with our answers.
ok flotek, so your talking dynamic compression. makes sense. but also then with dynamic compression what kinda pipe u run is going to effect compression too....
gotta remember. the engine is a system, not just a compilation of parts.
Dude your getting smart; keep up on those books and school
I am talk about a running engine at peak power that is tuned for maximum performance
I am talk about a running engine at peak power that is tuned for maximum performance
That’s why we have a mill, lathe, dyno all the other tools and spend time at the track
To make things run faster.
Look at my banshee dyno curve that I posted; it has a smooth transition in power. Go to Flowtek and look at his banshee curve, His exhaust port does not match the pipe; that’s why there is that huge dip in the curve. The bike comes on slow and makes week power through out the curve.
Hickskateboader is doing his home work and figuring things out.
That young man, hickskateboarder is very smart and on the right path!!!!!!!!!!!
To make things run faster.
Look at my banshee dyno curve that I posted; it has a smooth transition in power. Go to Flowtek and look at his banshee curve, His exhaust port does not match the pipe; that’s why there is that huge dip in the curve. The bike comes on slow and makes week power through out the curve.
Hickskateboader is doing his home work and figuring things out.
That young man, hickskateboarder is very smart and on the right path!!!!!!!!!!!
Last edited:
thats funny sh*t right there ,actually genius that was stock igniton cutting out and the curve has since changed ,guess that why you do ebay porting though seems thats the difference between us as im not here to bust anybodies balls or belittle anyone to make myself look good ..peace
I am not here to cause you trouble, post some dyno curves for all of us to see. Come on that banshee dyno curve is week. Are saying that the stock banshee ignition curve cuts out that early? Do you even know where peak cylinder pressure occurs at full power when the ignition timing is correct?
Tell us why your porting is so good and your head design. The lighten flywheel is BS, lets lighten a flywheel on a diesel engine; why not, you probably would. Until you get educated and have 1000 dyno pulls under your belt; its just a guessing game!
Last edited:
