MAF value = Horsepower potential
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From: Alabama USA
This measurement is meant to examine the properties of AIR FLOW, which is where the power process begins. This measurement is not influenced by the conversion to mechanical power where many influences have to be factored in. There are numerous measurements and methods for the conversion to mechanical power and this is not one of them, but rather a method measuring the whole potential BEFORE the conversion takes place.
Just this past weekend I diagnosed my granddaughters 2007 Sebring with a stopped up catalytic convertor. It had a drastic reduction in power and overheating. The inability to flow air out caused the lack of power by not being able to inhale more air, and the lack of air flow caused combustion chamber temperatures to peak.
There is no more accurate or better way of measuring Mass Air Flow than a MAF sensor. Alpha-N and Speed Density are less accurate methods and only advantages are simplicity and easy to tune to a "close" value for custom applications.
What are y'alls opinion on calling this method Mhp or Mhpp? (Motorsport Horsepower) or (Motorsport Horsepower Potential)
Just this past weekend I diagnosed my granddaughters 2007 Sebring with a stopped up catalytic convertor. It had a drastic reduction in power and overheating. The inability to flow air out caused the lack of power by not being able to inhale more air, and the lack of air flow caused combustion chamber temperatures to peak.
There is no more accurate or better way of measuring Mass Air Flow than a MAF sensor. Alpha-N and Speed Density are less accurate methods and only advantages are simplicity and easy to tune to a "close" value for custom applications.
What are y'alls opinion on calling this method Mhp or Mhpp? (Motorsport Horsepower) or (Motorsport Horsepower Potential)
Race Car
Joined: Nov 2014
Posts: 3,896
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From: Melbourne, Australia
This measurement is meant to examine the properties of AIR FLOW, which is where the power process begins. This measurement is not influenced by the conversion to mechanical power where many influences have to be factored in. There are numerous measurements and methods for the conversion to mechanical power and this is not one of them, but rather a method measuring the whole potential BEFORE the conversion takes place.
Just this past weekend I diagnosed my granddaughters 2007 Sebring with a stopped up catalytic convertor. It had a drastic reduction in power and overheating. The inability to flow air out caused the lack of power by not being able to inhale more air, and the lack of air flow caused combustion chamber temperatures to peak.
There is no more accurate or better way of measuring Mass Air Flow than a MAF sensor. Alpha-N and Speed Density are less accurate methods and only advantages are simplicity and easy to tune to a "close" value for custom applications.
What are y'alls opinion on calling this method Mhp or Mhpp? (Motorsport Horsepower) or (Motorsport Horsepower Potential)
Just this past weekend I diagnosed my granddaughters 2007 Sebring with a stopped up catalytic convertor. It had a drastic reduction in power and overheating. The inability to flow air out caused the lack of power by not being able to inhale more air, and the lack of air flow caused combustion chamber temperatures to peak.
There is no more accurate or better way of measuring Mass Air Flow than a MAF sensor. Alpha-N and Speed Density are less accurate methods and only advantages are simplicity and easy to tune to a "close" value for custom applications.
What are y'alls opinion on calling this method Mhp or Mhpp? (Motorsport Horsepower) or (Motorsport Horsepower Potential)
Nordschleife Master
Joined: May 2005
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How about "air-fuel horsepower", which indicates hp generated directly by air-fuel combustion with the assumption of certain fixed AFR and AFR->hp conversion. Nothing to do with any mechanical loss and engine design.
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From: Alabama USA
Along the same lines could be "chemical horsepower" or "atomic horsepower" all descriptive of the method/process before the conversion to mechanical horsepower.
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From: Alabama USA
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Maybe something related to the total energy content of the air/fuel mixture. We already have GGE (https://en.wikipedia.org/wiki/Gasoli...lon_equivalent) and BTUs, but how those convert to actual horsepower need a converter, and we need to subtract the efficiency of the engine (since our engines might only be 20-35% efficient at transferring heat to usable power).
Racer
Joined: Apr 2015
Posts: 250
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From: Austin, TX
Personal opinion here based on a technical background: You won't be able to put together an accurate measurement of real horsepower based on MAF for a variety of reasons, many of them mentioned here. Just because my car pulls, say, 240g/s at standard elevation, humidity and temperature doesn't mean your car that pulls 240g/s at the same standards is getting the same horsepower.
What this measurement is GREAT for is checking the relative effectiveness of a change in parts. BUT there are some caveats. Change your tune? It will likely change the air-fuel mixture. You could get more or less power at the same MAF. Change your pulley? You could get the SAME MAF reading at the same RPM (in fact you should be able to) but your power at your rear wheels will be slightly higher because you've reduced parasitic losses.
So, like I said before, I'll eventually get one of these OBD-II readers and start monitoring this, but it's relative to my car and my car alone. I'll watch it so that if adjusted/normalized MAF drops, I can go see why (dirty air filter? need new spark plugs?)
What this measurement is GREAT for is checking the relative effectiveness of a change in parts. BUT there are some caveats. Change your tune? It will likely change the air-fuel mixture. You could get more or less power at the same MAF. Change your pulley? You could get the SAME MAF reading at the same RPM (in fact you should be able to) but your power at your rear wheels will be slightly higher because you've reduced parasitic losses.
So, like I said before, I'll eventually get one of these OBD-II readers and start monitoring this, but it's relative to my car and my car alone. I'll watch it so that if adjusted/normalized MAF drops, I can go see why (dirty air filter? need new spark plugs?)
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Thread Starter
Rennlist Member
Joined: Oct 2010
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From: Alabama USA
Maybe something related to the total energy content of the air/fuel mixture. We already have GGE (https://en.wikipedia.org/wiki/Gasoli...lon_equivalent) and BTUs, but how those convert to actual horsepower need a converter, and we need to subtract the efficiency of the engine (since our engines might only be 20-35% efficient at transferring heat to usable power).
Thread Starter
Rennlist Member
Joined: Oct 2010
Posts: 7,722
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From: Alabama USA
Personal opinion here based on a technical background: You won't be able to put together an accurate measurement of real horsepower based on MAF for a variety of reasons, many of them mentioned here. Just because my car pulls, say, 240g/s at standard elevation, humidity and temperature doesn't mean your car that pulls 240g/s at the same standards is getting the same horsepower.
What this measurement is GREAT for is checking the relative effectiveness of a change in parts. BUT there are some caveats. Change your tune? It will likely change the air-fuel mixture. You could get more or less power at the same MAF. Change your pulley? You could get the SAME MAF reading at the same RPM (in fact you should be able to) but your power at your rear wheels will be slightly higher because you've reduced parasitic losses.
So, like I said before, I'll eventually get one of these OBD-II readers and start monitoring this, but it's relative to my car and my car alone. I'll watch it so that if adjusted/normalized MAF drops, I can go see why (dirty air filter? need new spark plugs?)
What this measurement is GREAT for is checking the relative effectiveness of a change in parts. BUT there are some caveats. Change your tune? It will likely change the air-fuel mixture. You could get more or less power at the same MAF. Change your pulley? You could get the SAME MAF reading at the same RPM (in fact you should be able to) but your power at your rear wheels will be slightly higher because you've reduced parasitic losses.
So, like I said before, I'll eventually get one of these OBD-II readers and start monitoring this, but it's relative to my car and my car alone. I'll watch it so that if adjusted/normalized MAF drops, I can go see why (dirty air filter? need new spark plugs?)
I would not say that changing the pulley would make more horsepower, I would say that changing the pulley will "save" horsepower or not loose as much horsepower.
I would say that if we both had " identical" M96 engines ran at the same elevation, temp,humidity, and both pulled 240g/s, that they both would have the same horsepower.
But you had an M96 and changed to a longer duration camshaft, it would pull more than 240 g/s and would create more horsepower.
This measurement is about air flow into and out of the engine, without regard to anything below or after the head gaskets.
There is an old saying the racing community that I have always lived by "horsepower is made from the head gaskets up, durability is made from the head gaskets down"..
Again, we are not talking about rear wheel horsepower , net horsepower, gross horsepower, SAE horsepower, imperial horsepower, metric horsepower, flywheel horsepower ect.
Last edited by Porschetech3; Mar 13, 2019 at 10:04 PM.
Racer
Joined: Apr 2015
Posts: 250
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From: Austin, TX
“I would say that if we both had " identical" M96 engines ran at the same elevation, temp,humidity, and both pulled 240g/s, that they both would have the same horsepower.”
i can generally agree agree with that.
But it once we get to two different cars with different mileage, you can’t tell if one is lower on power (but same MAF) or not. The point being MAF only measures air. Not fuel. And can’t tell you how well that fuel was burned. And how much blowby resulted in lost power.
I still maintain that it’s AWESOME to test changes on an single engine where you change a single variable at a time.
i can generally agree agree with that.
But it once we get to two different cars with different mileage, you can’t tell if one is lower on power (but same MAF) or not. The point being MAF only measures air. Not fuel. And can’t tell you how well that fuel was burned. And how much blowby resulted in lost power.
I still maintain that it’s AWESOME to test changes on an single engine where you change a single variable at a time.
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From: Alabama USA
“I would say that if we both had " identical" M96 engines ran at the same elevation, temp,humidity, and both pulled 240g/s, that they both would have the same horsepower.”
i can generally agree agree with that.
But it once we get to two different cars with different mileage, you can’t tell if one is lower on power (but same MAF) or not. The point being MAF only measures air. Not fuel. And can’t tell you how well that fuel was burned. And how much blowby resulted in lost power.
I still maintain that it’s AWESOME to test changes on an single engine where you change a single variable at a time.
i can generally agree agree with that.
But it once we get to two different cars with different mileage, you can’t tell if one is lower on power (but same MAF) or not. The point being MAF only measures air. Not fuel. And can’t tell you how well that fuel was burned. And how much blowby resulted in lost power.
I still maintain that it’s AWESOME to test changes on an single engine where you change a single variable at a time.
In this context, we are not measuring or looking at anything below or after the head gasket(ie power loss or to more specific, mechanical power loss).
It is actually good that a high mileage engine with blowby will not show in the MAF because that would be a power loss, and we are not looking at power loss. (mechanical power loss that is). And there are other means to measure blowby.
As far as the AFR-complete combustion goes, you are correct the MAF doesn't measure fuel, BUT, the DME "depends" on MAF to inject fuel to the millisecond to produce the correct AFR for best power or most complete combustion. Otherwise the DME would just give it it's best guess.
To keep confusion down is why we should give it different name, and limit discussion to components above the head gaskets, IE air flow.
Ok I'll go ahead and give it a name "Motorsport Horsepower Potential"...
This is to used to evaluate components ABOVE the head gaskets that effect Motorsport Horsepower Potential, which WILL effect rwhp, real hp, and all the other hp's..
Last edited by Porschetech3; Mar 14, 2019 at 02:05 AM.
Thread Starter
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From: Alabama USA
"I still maintain that it’s AWESOME to test changes on an single engine where you change a single variable at a time. "
I agree, any changes should be done one at a time, with before and after measurements.
I would also say if I designed a hotter cam and got 50g/s more mass air flow 50/.75= 66.66Mhpp, and you put the same cam in your car, that you would also get 66.66 more Mhpp......
The DME will see the 50g/s more MAF and inject the appropriate fuel and the result will be more mechanical horsepower, rwhp,( or any other horsepower measurement).
I agree, any changes should be done one at a time, with before and after measurements.
I would also say if I designed a hotter cam and got 50g/s more mass air flow 50/.75= 66.66Mhpp, and you put the same cam in your car, that you would also get 66.66 more Mhpp......
The DME will see the 50g/s more MAF and inject the appropriate fuel and the result will be more mechanical horsepower, rwhp,( or any other horsepower measurement).
Last edited by Porschetech3; Mar 14, 2019 at 03:14 AM.
Thread Starter
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From: Alabama USA
Is this a 3.6? or larger? Do you feel this is accurate or a spike/glitch? What OBDII/software device are you using?
Is see your in Florida, so altitude will be near sea level.