Peripheral Port Renesis dyno's
The Professor
Joined: Aug 2004
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From: Omaha, NE
Well unfortunately that is the application we are talking about, or hadn't you noticed?
Bit difficult to change the afr of your arm muscles, and you can still manipulate the engine function to fit the muscle scenario, if you couldn't then there would be a problem with your physics model.
Bit difficult to change the afr of your arm muscles, and you can still manipulate the engine function to fit the muscle scenario, if you couldn't then there would be a problem with your physics model.
BDC Motorsports
Joined: Nov 2006
Posts: 417
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From: Dallas, Tx
but i agree with Jeff as well- the two are only seperated by the spark event. that is the only thing that distinguishes them. either can cause the other. they are both combustion events when you dont want them which cause pressure rises when you dont want them. to me , as i said before, it puts to fine a point on it to seperate them. you could just as easily say that pre-ignition is a form of detonation.
detonation - in the context of the definitions above- can be fatal to an engine. pre-ignition is nearly always fatal. the times its not it causes more detonation and more heat leading to another pre-ignition event that is fatal.
but as with a different thread where it was tried- I agree to these definitions so we can talk about the POINT of the discussion.
detonation - in the context of the definitions above- can be fatal to an engine. pre-ignition is nearly always fatal. the times its not it causes more detonation and more heat leading to another pre-ignition event that is fatal.
but as with a different thread where it was tried- I agree to these definitions so we can talk about the POINT of the discussion.
B
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From: UK
That depends how fast you are trying to move your arm and apply pressure at the time.
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From: UK
Ok, if you can tune for them seperatey, at a given rpm point, talk me through how you would do it
You've just told me yourself one is a function of the other ffs!
I'm not talking about the constant or the calculation.
Maximum power will occur at LBT. However, we don't tune for LBT because MBT is higher and safer (and on a turbo motor we tune for RBT). The torque curve will change shape because of this. Since peak power occurs at a higher RPM than peak torque, the peak power will be a function of the instantaneous torque at that RPM, which will be somewhat less than "optimum" because of the slightly richer A/F.
[[Didn't this entire discussion already happen about a million times on this forum over the past 3 years?]]
Maximum power will occur at LBT. However, we don't tune for LBT because MBT is higher and safer (and on a turbo motor we tune for RBT). The torque curve will change shape because of this. Since peak power occurs at a higher RPM than peak torque, the peak power will be a function of the instantaneous torque at that RPM, which will be somewhat less than "optimum" because of the slightly richer A/F.
[[Didn't this entire discussion already happen about a million times on this forum over the past 3 years?]]
www.evoperform.com
Joined: Apr 2005
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From: tax free delaware
the only constant is what you divide the product of your torque multiplied by rpm
The Professor
Joined: Aug 2004
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From: Omaha, NE
I can do that also,
watch
my bank account X constant
Hmm, I want a million dollars
$1 x $1,000,000
No, its not applied in all situations,
Registered
Joined: Dec 2007
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From: UK
Now this is getting weird, the constant is a simple conversion rate between units, what are you smoking?
If the unit conversion were taken out of it it'd simply be
Power= Torque x RPM
Now, as we at a single RPM point when altering AFR (as per the original remark), we now get the equation
Power = Torque.
Now, please explain how you'd increase one without the other?!
The Professor
Joined: Aug 2004
Posts: 3,479
Likes: 7
From: Omaha, NE
I'm not talking about the constant or the calculation.
Maximum power will occur at LBT. However, we don't tune for LBT because MBT is higher and safer (and on a turbo motor we tune for RBT). The torque curve will change shape because of this. Since peak power occurs at a higher RPM than peak torque, the peak power will be a function of the instantaneous torque at that RPM, which will be somewhat less than "optimum" because of the slightly richer A/F.
[[Didn't this entire discussion already happen about a million times on this forum over the past 3 years?]]
Maximum power will occur at LBT. However, we don't tune for LBT because MBT is higher and safer (and on a turbo motor we tune for RBT). The torque curve will change shape because of this. Since peak power occurs at a higher RPM than peak torque, the peak power will be a function of the instantaneous torque at that RPM, which will be somewhat less than "optimum" because of the slightly richer A/F.
[[Didn't this entire discussion already happen about a million times on this forum over the past 3 years?]]
I'm with MM
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From: UK
I'm not talking about the constant or the calculation.
Maximum power will occur at LBT. However, we don't tune for LBT because MBT is higher and safer (and on a turbo motor we tune for RBT). The torque curve will change shape because of this. Since peak power occurs at a higher RPM than peak torque, the peak power will be a function of the instantaneous torque at that RPM, which will be somewhat less than "optimum" because of the slightly richer A/F.
[[Didn't this entire discussion already happen about a million times on this forum over the past 3 years?]]
Maximum power will occur at LBT. However, we don't tune for LBT because MBT is higher and safer (and on a turbo motor we tune for RBT). The torque curve will change shape because of this. Since peak power occurs at a higher RPM than peak torque, the peak power will be a function of the instantaneous torque at that RPM, which will be somewhat less than "optimum" because of the slightly richer A/F.
[[Didn't this entire discussion already happen about a million times on this forum over the past 3 years?]]
As you said, you'd only get more power by shifting away from that to a riskier map, but even then you'll get more torque too!
Last edited by PhillipM; Dec 27, 2007 at 08:44 PM.
I think you are kinda missing the forest cause you found the biggest tree.
The A/F that will yield the highest torque peak will not be the A/F that will make the highest power peak because of the constant - time.
If the power peak occurred at the same time as the torque peak, they would be in lock step.
Your maximum power will happen at one ratio. Your maximum torque at another.
"Safe" is a side benefit. On an FI motor, the flame front is fastest at RBT.
The A/F that will yield the highest torque peak will not be the A/F that will make the highest power peak because of the constant - time.
If the power peak occurred at the same time as the torque peak, they would be in lock step.
"Safe" is a side benefit. On an FI motor, the flame front is fastest at RBT.
The Professor
Joined: Aug 2004
Posts: 3,479
Likes: 7
From: Omaha, NE
Now this is getting weird, the constant is a simple conversion rate between units, what are you smoking?
If the unit conversion were taken out of it it'd simply be
Power= Torque x RPM
Now, as we at a single RPM point when altering AFR (as per the original remark), we now get the equation
Power = Torque.
Now, please explain how you'd increase one without the other?!
If the unit conversion were taken out of it it'd simply be
Power= Torque x RPM
Now, as we at a single RPM point when altering AFR (as per the original remark), we now get the equation
Power = Torque.
Now, please explain how you'd increase one without the other?!
Your totally right!
www.evoperform.com
Joined: Apr 2005
Posts: 2,010
Likes: 1
From: tax free delaware
Now this is getting weird, the constant is a simple conversion rate between units, what are you smoking?
If the unit conversion were taken out of it it'd simply be
Power= Torque x RPM
Now, as we at a single RPM point when altering AFR (as per the original remark), we now get the equation
Power = Torque.
Now, please explain how you'd increase one without the other?!
If the unit conversion were taken out of it it'd simply be
Power= Torque x RPM
Now, as we at a single RPM point when altering AFR (as per the original remark), we now get the equation
Power = Torque.
Now, please explain how you'd increase one without the other?!
your equation should be
(power x 5252)/rpm = torque
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From: UK
I think you are kinda missing the forest cause you found the biggest tree.
The A/F that will yield the highest torque peak will not be the A/F that will make the highest power peak because of the constant - time.
If the power peak occurred at the same time as the torque peak, they would be in lock step.
Your maximum power will happen at one ratio. Your maximum torque at another.
"Safe" is a side benefit. On an FI motor, the flame front is fastest at RBT.
The A/F that will yield the highest torque peak will not be the A/F that will make the highest power peak because of the constant - time.
If the power peak occurred at the same time as the torque peak, they would be in lock step.
Your maximum power will happen at one ratio. Your maximum torque at another.
"Safe" is a side benefit. On an FI motor, the flame front is fastest at RBT.
Obviously occuring at different rpm, but even then you should be able to compensate for that on a proper map by adding a little ignition advance up top to compensate for the slightly lower flame front speed.
Again, since maximum power is a function of torque at that rpm you have to make more torque to make more power, bit of crossed wire here as what you are refering to is the peak power and peak torque spots?
Obviously occuring at different rpm, but even then you should be able to compensate for that on a proper map by adding a little ignition advance up top to compensate for the slightly lower flame front speed.
Obviously occuring at different rpm, but even then you should be able to compensate for that on a proper map by adding a little ignition advance up top to compensate for the slightly lower flame front speed.
But, even so, you are adding ignition as you increase RPM, so your detonation threshold remains constant (because your BMEP should fall at the same crank angle).
So, no, you can't. (Only in your theoretical world.)
Registered
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From: UK
But ignition changes will affect A/F, especially if you tune simply to a lambda reading, which isn't advisable as they aren't infalliable.
The extra fuel when moving away to MBT-R should raise the detonation threshold from the cooling effect at the top end, after all the only reason you are keeping your torque peak and dropping the power peak is because you've effective de-optimised your ignition timing at the top end as the flame front speed has more effect here, the torque peak isn't so effected because of it's position in the rpm range, but it's still changed slightly.
If you're shifting 1 point richer and getting better torque but lower peak power then there something wrong with the map.
The extra fuel when moving away to MBT-R should raise the detonation threshold from the cooling effect at the top end, after all the only reason you are keeping your torque peak and dropping the power peak is because you've effective de-optimised your ignition timing at the top end as the flame front speed has more effect here, the torque peak isn't so effected because of it's position in the rpm range, but it's still changed slightly.
If you're shifting 1 point richer and getting better torque but lower peak power then there something wrong with the map.
Last edited by PhillipM; Dec 27, 2007 at 09:38 PM.
Administrator
Joined: Jul 2002
Posts: 21,958
Likes: 115
From: portland oregon
thats because the octane of the fuel doesnt make a bit of difference how much power an engine can make on it as long as there is no detonation/knock/pre-ignition
Maximum Best Torque (MBT) by a given fuel is mainly determined by WHEN the ingition occurs and Flame Front speed. Flame front speed is determined by the shape of the chamber and how much turbulence is created(turbulence i.e. swirling increase flame front propagation) by that shape , and by the burn speed of the fuel.
the OCTANE of the fuel has no bearing on what the speed is. Only what is mixed in the fuel does.The specific mixture of paraffins, olefins , aromatics oxygenates are what determine the flame speed. some octane boosters may lead to lower flame speeds while others can increase it. and the pressures can effect how much the given chemical will increase or decrease the speed.
some other links in no particular order of importance
http://www.daytona-sensors.com/tech_tuning.html
http://72.14.205.104/search?q=cache:...ient=firefox-a
http://www.sacskyranch.com/deton.htm
http://72.14.205.104/search?q=cache:...ient=firefox-a
alcohol is actually a good example. high octane because of its cooling properties and high energy due to high flame speed. it works well in the injected scenario above because it is cooling AND fuel
Maximum Best Torque (MBT) by a given fuel is mainly determined by WHEN the ingition occurs and Flame Front speed. Flame front speed is determined by the shape of the chamber and how much turbulence is created(turbulence i.e. swirling increase flame front propagation) by that shape , and by the burn speed of the fuel.
the OCTANE of the fuel has no bearing on what the speed is. Only what is mixed in the fuel does.The specific mixture of paraffins, olefins , aromatics oxygenates are what determine the flame speed. some octane boosters may lead to lower flame speeds while others can increase it. and the pressures can effect how much the given chemical will increase or decrease the speed.
some other links in no particular order of importance
http://www.daytona-sensors.com/tech_tuning.html
http://72.14.205.104/search?q=cache:...ient=firefox-a
http://www.sacskyranch.com/deton.htm
http://72.14.205.104/search?q=cache:...ient=firefox-a
alcohol is actually a good example. high octane because of its cooling properties and high energy due to high flame speed. it works well in the injected scenario above because it is cooling AND fuel
If the last part of your statement were effectively true, the entire industry would be in a LOT of trouble.
after all the only reason you are keeping your torque peak and dropping the power peak is because you've effective de-optimised your ignition timing at the top end as the flame front speed has more effect here, the torque peak isn't so effected because of it's position in the rpm range, but it's still changed slightly.
You haven't actually done a lot of this before, have you?
Last edited by MazdaManiac; Dec 27, 2007 at 10:51 PM.