V Force Power band
#21
10-06-2003, 12:32 PM
V Force Power band
For quick info here is the formula.
VE = (HP * 792001.6)/(AP * CR * CID * RPM)
HP = Horse Power (49.1)
AP = Air Pressure (14.7 at sea level)
CR = Compression Ration (9.9)
CID = Cubic Inch Displacement (697 CC = 42.54)
RPM = (6500) RPM's at max HP output
Gives you a value of 96.64% at the crank.
At the real wheels things are a bit worse. Use the same formula, but RWHP is about 33.
This gives you a VE value of 64.95%
Just for interest sake:
Stock Raptor has a VE of 87.41% and with a CT racing pipe, K&N, and jets it shoots up to 101.2% at the wheels.
DS650 Stock has 86.36% and with a FMH pipe and jets it has a VE value of 77.73% at the real wheels. (Strange but true) The exhaust makes more power but in the big scheame of things its actually reduced the VE value of the motor. If you look at the FMH web site and the dino results youll see why it reduces the VE value compaired to other bikes that might increase with a new exhaust.
Check out this web site.
They explain the whole thing.
http://www.pro-flow.com/tech%20info/mustmath.htm
VE = (HP * 792001.6)/(AP * CR * CID * RPM)
HP = Horse Power (49.1)
AP = Air Pressure (14.7 at sea level)
CR = Compression Ration (9.9)
CID = Cubic Inch Displacement (697 CC = 42.54)
RPM = (6500) RPM's at max HP output
Gives you a value of 96.64% at the crank.
At the real wheels things are a bit worse. Use the same formula, but RWHP is about 33.
This gives you a VE value of 64.95%
Just for interest sake:
Stock Raptor has a VE of 87.41% and with a CT racing pipe, K&N, and jets it shoots up to 101.2% at the wheels.
DS650 Stock has 86.36% and with a FMH pipe and jets it has a VE value of 77.73% at the real wheels. (Strange but true) The exhaust makes more power but in the big scheame of things its actually reduced the VE value of the motor. If you look at the FMH web site and the dino results youll see why it reduces the VE value compaired to other bikes that might increase with a new exhaust.
Check out this web site.
They explain the whole thing.
http://www.pro-flow.com/tech%20info/mustmath.htm
#22
10-06-2003, 02:44 PM
V Force Power band
Here goes. Ill try and explain what volumetric efficiency is and how it effects a motors output.
First ill start with the basics. The amount of power an engine delivers is dependant on how much oxygen and fuel (gas) it can burn. The amount of air (air we breath mixed with gas) it can take in, is called engine capacity. In the case of the V Force it has a 700 cc (697 cc) motor. Most engines cannot suck their full air capacity in one intake stroke of the piston. This is due to the air friction, intake and exhaust port size, port design and restrictions like the air cleaner and exhaust muffler This means that some motors get 50% to 100% full of air before the intake valve closes. This ratio of air intake to engine size is the volumetric efficiency, or in other words how efficiently does it fill the cylinder with air and fuel.
So as before I have shown that the v Force have a 97% volumetric efficiency. This means that the motor actually burns 679 cc’s of air and fuel mixture. Similar than a 680 cc motor with a 100% volumetric efficiency.
Now it is possible to have more than 100% volumetric efficiency. This is done by adding a turbo, supercharger, extra oxygen to the intake gas (NOS) or it can be done with some clever induction tuned intake and exhaust systems. This means that a 700 cc motor with a VE value of 120% is actually able to burn 840 cc’s of air and gas. Basically making it a 840cc motor. It is extremely difficult to get 110% to 150% or more VE values. You need very clever people to do this and no stock motor have come close to this. Most cars have a VE value of about 80% to 90% and racing cars and bikes have about a 100% plus.
There are only two things that will make more power, Engine Capacity and Volumetric Efficiency. Both meaning the more capacity you have the more power you have. The V Force have a VE value close to 100%. To make it have 25HP more (147% VE) you will need much much more than just some timing advancement.
First ill start with the basics. The amount of power an engine delivers is dependant on how much oxygen and fuel (gas) it can burn. The amount of air (air we breath mixed with gas) it can take in, is called engine capacity. In the case of the V Force it has a 700 cc (697 cc) motor. Most engines cannot suck their full air capacity in one intake stroke of the piston. This is due to the air friction, intake and exhaust port size, port design and restrictions like the air cleaner and exhaust muffler This means that some motors get 50% to 100% full of air before the intake valve closes. This ratio of air intake to engine size is the volumetric efficiency, or in other words how efficiently does it fill the cylinder with air and fuel.
So as before I have shown that the v Force have a 97% volumetric efficiency. This means that the motor actually burns 679 cc’s of air and fuel mixture. Similar than a 680 cc motor with a 100% volumetric efficiency.
Now it is possible to have more than 100% volumetric efficiency. This is done by adding a turbo, supercharger, extra oxygen to the intake gas (NOS) or it can be done with some clever induction tuned intake and exhaust systems. This means that a 700 cc motor with a VE value of 120% is actually able to burn 840 cc’s of air and gas. Basically making it a 840cc motor. It is extremely difficult to get 110% to 150% or more VE values. You need very clever people to do this and no stock motor have come close to this. Most cars have a VE value of about 80% to 90% and racing cars and bikes have about a 100% plus.
There are only two things that will make more power, Engine Capacity and Volumetric Efficiency. Both meaning the more capacity you have the more power you have. The V Force have a VE value close to 100%. To make it have 25HP more (147% VE) you will need much much more than just some timing advancement.
#23
10-06-2003, 02:54 PM
V Force Power band
LMAO.
Not to slight your informative posts, but does anyone with a little common sense REALLY need an explanation of why a 50HP quad cannot gain 25HP from a timing advance?
V-Force FAQ
Not to slight your informative posts, but does anyone with a little common sense REALLY need an explanation of why a 50HP quad cannot gain 25HP from a timing advance?
V-Force FAQ
#24
10-06-2003, 04:05 PM
V Force Power band
So if we add more air and fuel and a free flowing exhaust we can not increase this VE value? I just did your calculation and its correct but its alot lower with RWHP, like 64% VE. I think we get 25 RWHP by advancing the timing not just to 28 degrees but past that, I think Alltoys bumped it up to 33 or so. So with a value of 64% an increase of 25 RWHP is very realistic, plus he moddified his exhaust and probably some other things.
#25
10-07-2003, 04:14 AM
V Force Power band
Hi KevinM.
The reason why I explained it to this detail is to remind people not to believe anything they hear form the "tuners" or people making false statements and empty promises. Think for yourself and test their theory, before you believe them. You’ll find that some people might spend good money on this and get nothing for it. Some might even go all out, do the mods, blow the motor and have nothing to show for it in the end.
bbertram.
One should not use RWHP as it gives a much lower value. The CVT (Gearbox), drivetrain and tires are things that rob power from the motor and you cannot do much to it, to make it rob less power. VE is about how much air a motor breathes. using RWHP will not help the motor to breathe better, no matter how small the VE value is at the rear wheels. The 25 HP story now have seem to change a bit. You mention that Alltoys might have done some other changes to the bike. Changing the exhaust, intake system, timing and fuel mixture will help you increase your VE value and add more power. If you use the formula I have given you, you will see that if you keep everything as standard and you only increase HP with 25, you end up with a VE value of 147%. This is an impossible value to achieve without some serious mods (Turbo, NOS). If you take the 97% VE value of the stock motor (measured at crank) you can increase the VE value to about 105% maybe slightly more by changing the exhaust, timing, intake and fuel delivery. If you now rework the formula and use a VE value of 105% you need to rev the bike to 9000 RPM to give you the 25HP increase they talk about. That is way higher than the stock motor, plus you’ll have to redo the CDI and rev limiter on the bike. That is if the bike is able to handle 9000 RMP with good reliability. There is another way to get 25HP at lower rpm, but then you’ll have to increase the capacity of the motor.
Adding power is always a trade of. Adding power at high rpm’s rob low rpm HP output, Adding HP to low rpm rob high rpm power output. You cannot do both on this motor. The way a motor makes HP is determined by how much air and fuel it breathes, and this in turn can be changed by the cam in the motor. Most manufacturers now use variable cam shafts to add power at low and high rpm ranges. No quad I know of have this sort of cam shaft.
So play with the formula, check what happens when you change things in the formula. Just always remember that you cannot have a VE value of more than about 110 on this motor without some NOS or turbo.
The reason why I explained it to this detail is to remind people not to believe anything they hear form the "tuners" or people making false statements and empty promises. Think for yourself and test their theory, before you believe them. You’ll find that some people might spend good money on this and get nothing for it. Some might even go all out, do the mods, blow the motor and have nothing to show for it in the end.
bbertram.
One should not use RWHP as it gives a much lower value. The CVT (Gearbox), drivetrain and tires are things that rob power from the motor and you cannot do much to it, to make it rob less power. VE is about how much air a motor breathes. using RWHP will not help the motor to breathe better, no matter how small the VE value is at the rear wheels. The 25 HP story now have seem to change a bit. You mention that Alltoys might have done some other changes to the bike. Changing the exhaust, intake system, timing and fuel mixture will help you increase your VE value and add more power. If you use the formula I have given you, you will see that if you keep everything as standard and you only increase HP with 25, you end up with a VE value of 147%. This is an impossible value to achieve without some serious mods (Turbo, NOS). If you take the 97% VE value of the stock motor (measured at crank) you can increase the VE value to about 105% maybe slightly more by changing the exhaust, timing, intake and fuel delivery. If you now rework the formula and use a VE value of 105% you need to rev the bike to 9000 RPM to give you the 25HP increase they talk about. That is way higher than the stock motor, plus you’ll have to redo the CDI and rev limiter on the bike. That is if the bike is able to handle 9000 RMP with good reliability. There is another way to get 25HP at lower rpm, but then you’ll have to increase the capacity of the motor.
Adding power is always a trade of. Adding power at high rpm’s rob low rpm HP output, Adding HP to low rpm rob high rpm power output. You cannot do both on this motor. The way a motor makes HP is determined by how much air and fuel it breathes, and this in turn can be changed by the cam in the motor. Most manufacturers now use variable cam shafts to add power at low and high rpm ranges. No quad I know of have this sort of cam shaft.
So play with the formula, check what happens when you change things in the formula. Just always remember that you cannot have a VE value of more than about 110 on this motor without some NOS or turbo.
#26
10-07-2003, 09:35 AM
V Force Power band
I should say that I think Alltoys got his V-Force up to 11000 rpm with his custom ignition, I don't have time to run it throught formula as I have to take off.
EDIT: That can't be correct, it would be 38%! Hmmm.......he did say this motor has huge potential but that much? Add his 25 RWHP which is more like 30 at the crank and your up to 93%. Sounds good to me. Thats if my calculations were correct, my second one might be off.
EDIT: That can't be correct, it would be 38%! Hmmm.......he did say this motor has huge potential but that much? Add his 25 RWHP which is more like 30 at the crank and your up to 93%. Sounds good to me. Thats if my calculations were correct, my second one might be off.
#29
10-07-2003, 10:55 AM
V Force Power band
Was it alltoys that posted he ran a 3--something run in 300' aboard his prairie (or was it a v force). Did'nt mean too sound like I was bashing....it's just not realistic. On the plus side, the twin cylinder engine enjoys more inherent efficiency over a single cylinder engine...[img]i/expressions/face-icon-small-smile.gif[/img].
#30
10-07-2003, 11:00 AM