Speed density vs MAP?
Jul 30, 2005, 12:59 PM
#16
The biggest issue will be Emmisions..
That is all.
MAP based systems generally are easier to tune. Much ..
They require that you replace your load sensor (MAF) in the EVO's case and add a Manifold Absolute Pressure sensor (MAP) and an Air temp sensor to calculate air density.
One of the biggest differences will be that a Map based setup will allow the ECU to calculate the density and VE of the engine at a given RPM, Boost and Load level.
The MAF based setup will give the computer a relative VE based on the incoming airflow induced by the turbo and the engine.
Which one is better??
It will depend on which side of the fence you are on.
I prefer Map based setups for higher performance applications SOLEY for the reason that I like to tune with more resolution in the upper load areas of the VE curve.
Normally MAF sensors or the like will have resolution for up to a specific amount of air flow and that is it.
This is basically a lamens version and Im sure others have a different point of view.
For the street, depending on the system you are using to tune with, the difference may be felt.
It doesn't matter if the car is for the street or track. MAP or MAF will depend on which EFI system you are running and its capabilities.
they both have their merits.
As far as the restriction point is concerned, There is a minimal value that can be associated with it. But once you are inducing more than the MAF sensor can measure accurately then you will definately see a difference in the upper HP figure.
Just ask the guys over in Japan with the EVO 9.
Once they change just the intake going to the turbo and pressure differential on each end they lean out under initial boost. That will tell you something about how well a MAF based system compensates for airflow...
That is all.
MAP based systems generally are easier to tune. Much ..
They require that you replace your load sensor (MAF) in the EVO's case and add a Manifold Absolute Pressure sensor (MAP) and an Air temp sensor to calculate air density.
One of the biggest differences will be that a Map based setup will allow the ECU to calculate the density and VE of the engine at a given RPM, Boost and Load level.
The MAF based setup will give the computer a relative VE based on the incoming airflow induced by the turbo and the engine.
Which one is better??
It will depend on which side of the fence you are on.
I prefer Map based setups for higher performance applications SOLEY for the reason that I like to tune with more resolution in the upper load areas of the VE curve.
Normally MAF sensors or the like will have resolution for up to a specific amount of air flow and that is it.
This is basically a lamens version and Im sure others have a different point of view.
For the street, depending on the system you are using to tune with, the difference may be felt.
It doesn't matter if the car is for the street or track. MAP or MAF will depend on which EFI system you are running and its capabilities.
they both have their merits.
As far as the restriction point is concerned, There is a minimal value that can be associated with it. But once you are inducing more than the MAF sensor can measure accurately then you will definately see a difference in the upper HP figure.
Just ask the guys over in Japan with the EVO 9.
Once they change just the intake going to the turbo and pressure differential on each end they lean out under initial boost. That will tell you something about how well a MAF based system compensates for airflow...
Aug 7, 2005, 07:42 AM
#18
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Originally Posted by ninjadoc
Depends on how they test emissions. If they just do a sniff test...lean it out. If they hook up to the OBD2 connector...switch back to MAF for emission testing, then go home and switch back. A pain but that's what I'm gonna do if my car is ever finished!
for the motor city 
Jun 3, 2009, 06:12 PM
#21
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https://www.evolutionm.net/forums/ae...ap-vs-maf.html
^^^some answers for you if interested
^^^some answers for you if interested
Well, the MAF has its issues, but I use a blowthrough setup that eliminates two of the complaints most people have about the maf, which is low airflow issues (idle problems) and misreads/disruption of airflow or blowoff valves/whatnot.
A properly tuned speed density system runs great, but the difference is a speed density system is a calculation, a MAF system is an accurate measurement (within reason)
I have been running a blowthrough FORD based MAF for over a year now, good drivability and no major idle issues that can't be resolved with some simple adjustments.
There is only one real downside to using an aftermarket MAF (besides a 90% ignorance of its existance) and that is on some types of hot-wire maf sensors, you can get some condensation on it when its cold, so it takes a bit longer for the wire to warm up and read correctly... THis seems more common on the GM sensor from the complaints I've heard.
I realize the question is of a stock maf verse speed density.. I still think a properly tuned car running MAF will be more drivable, and be more accurate to engine demands.
There's benefits to either setup.. If your already running a standalone, you might have to seriously weigh your options (The first major advantage is you can swap a stock ECU back to a MAF equipped car without any other changes to revert it, assuming your other mods don't get the ECU cranky)
But if your debating AEM vs Stock ECU, well I have a slightly biased opinion so its unfair for me to comment on..
1) Legality (OBD-II)
2) Adjustability and expertise
3) Data logging ability
4) Drivability
You have to rate each of these things and see which is a higher priority to you, Since several products can fit the bill..
I personally don't think a standalone is a great idea for a daily driver, but there's many guys who are running them and driving their cars daily. Also you have to look at your local inspection stations requirements for OBD-II check and whatnot to pass..
A properly tuned speed density system runs great, but the difference is a speed density system is a calculation, a MAF system is an accurate measurement (within reason)
I have been running a blowthrough FORD based MAF for over a year now, good drivability and no major idle issues that can't be resolved with some simple adjustments.
There is only one real downside to using an aftermarket MAF (besides a 90% ignorance of its existance) and that is on some types of hot-wire maf sensors, you can get some condensation on it when its cold, so it takes a bit longer for the wire to warm up and read correctly... THis seems more common on the GM sensor from the complaints I've heard.
I realize the question is of a stock maf verse speed density.. I still think a properly tuned car running MAF will be more drivable, and be more accurate to engine demands.
There's benefits to either setup.. If your already running a standalone, you might have to seriously weigh your options (The first major advantage is you can swap a stock ECU back to a MAF equipped car without any other changes to revert it, assuming your other mods don't get the ECU cranky)
But if your debating AEM vs Stock ECU, well I have a slightly biased opinion so its unfair for me to comment on..
1) Legality (OBD-II)
2) Adjustability and expertise
3) Data logging ability
4) Drivability
You have to rate each of these things and see which is a higher priority to you, Since several products can fit the bill..
I personally don't think a standalone is a great idea for a daily driver, but there's many guys who are running them and driving their cars daily. Also you have to look at your local inspection stations requirements for OBD-II check and whatnot to pass..
Last edited by MOREPSiTEHBETT4; Jun 3, 2009 at 06:15 PM.
Dec 27, 2009, 10:47 AM
#22
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Feb 1, 2010, 07:38 PM
#23
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One instance where I think a MAF setup shines over SD, is when you have variable cam angle.. For instance, on a K series acura they use SD, so for every 10deg of variable cam angle there is another set of maps both for high and low cam. So being that you have up to 50deg of advance, you have to tune 4 maps (fuel highcam, fuel lowcam, ignition highcam, ignition lowcam) for 0, 10, 20, 30, 40 and 50deg of cam angle.. Thats means to fully tune out that motor, you have to tune 24 MAPS!!!!.. Then you build your cam angle map for high cam and low cam!! Now there are tricks to speed this up, but it still takes quite a bit of time.. With a MAF based system since your metering actual airflow, once you have your MAF curve dialed in properly you can move the cams all around and the fueling generally stays pretty consistant. You may have to play with timing a bit still but its like 1-20th the amount of work..
Which is better?? They both have their pros and cons.
Which is better?? They both have their pros and cons.
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