(dumb) MAFterburner question

[f4sfed]

I'll apologize ahead of time for this question. But I have to ask: using the MAFterburner.....this device uses intellligence (the O2 sensor, etc) to adjust the fuel mixture, correct? Once it's adjusted, you're good to go, until you physically change something, right?

So (for example) when the temp and humidity change, there's no need to retune using the MAFterburner (like having to change the jets on the carb depending on the conditions), correct? Only when you physically change something (like the exhaust) should you retune....yes?

Can someone either confirm or deny please?

Thanks in advance!

 

[Mowgli]

Remember that for anything other than WOT, the engine computer aready in there stock learns/ adapts/ and readjusts. So if you intercept and adjust the mixtures with the MAFburner, over time, the car will return them to stock setting, even WITH the MAFburner in the circuit.

Do a couple cycles of this: tune/car readjusts... tune/car readjusts, etc, and you could have a real problem down the road if you ever need to take the MAFBurner out. You could instantly be running super rich or super lean.

I reccomend using it at WOT only. I was intrigued by the numbers posted by the fellow (sorry, name escapes me at moment) here tuning his car with it.

I am also now convinced, as he is, that many of the problems we are hearing comes from it being tuned by Ford overly-rich from the factory.

 

[Mowgli]

Also, there are no dumb tech questions in here.

 

[f4sfed]

Thanks.

 

[f4sfed]

Here's another reply I received:
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Hi 4sfed,

The MAFterburner does not read the O2 sensors. The way this product is tuned is that you install it, take your car to a shop with a chassis dyno AND wideband-O2 setup and you make some baseline runs to see what your power and a/f mixture look like. Once you get a baseline, you then optimize your a/f across the RPM range.

Since late model mass-air systems compensate for changes in air density (humidity and temperature), there is no need to retune under different environmental conditions. However, large disparities in altitudes may require retuning.

You will need to retune if you make changes to your configuration (i.e. heads/cams, intake, exhaust, etc.).

Hope this helps!

Cheers,

Mark
_________________
Zone-5 Performance Products

________________________________

Thanks Mark!
4sfed

 

[mjchip]

Originally posted by Mowgli
Remember that for anything other than WOT, the engine computer aready in there stock learns/ adapts/ and readjusts. So if you intercept and adjust the mixtures with the MAFburner, over time, the car will return them to stock setting, even WITH the MAFburner in the circuit.

Well, yes and no. The MAFterburner is most commonly used for WOT tuning. However, another application where it becomes extremely valuable is "recalibrating" the MAF sensor to cope with inadvertant changes to the sensor system (including intake tract mods, CAI, aftermarket MAF bodies, porting stock MAFs, etc.). You are actually using to your advantage the fact that the PCM, when running its adaptive strategies, will react to your tuning changes.

By using a scan tool to log the LTFT/STFT cells, you can see exactly how the PCM had to adapt to compensate for the error that your mod introduced. You then use this data to tune out the fuel trims so that they get closer to zero. By doing this, you are recalibrating your MAF system to match the transfer function in the PCM. Why bother, you might ask? Because, if you do not effectively zero out the fuel trims, your open-loop tuning might be affected by the way the PCM has adapted while running closed-loop. It does this via the open-loop fuel modifier which is taken from the LTFTs.

Check out this thread:

http://www.corral.net/forums/showthread.php?threadid=105613&highlight=mafterburner

The guy who started it is a tuner AND the DiabloSport rep for Southern California. He is VERY knowledgable on this subject.

Do a couple cycles of this: tune/car readjusts... tune/car readjusts, etc, and you could have a real problem down the road if you ever need to take the MAFBurner out. You could instantly be running super rich or super lean.

You cannot change the target a/f ratio that the PCM is shooting for while in closed-loop. It will always try to maintain stoiciometric (14.7:1). The reason why changes are made to the closed-loop table in the MAFterburner is to "recalibrate" a thrown-off MAF transfer function.

I reccomend using it at WOT only. I was intrigued by the numbers posted by the fellow (sorry, name escapes me at moment) here tuning his car with it.

Most people only need to tune the open-loop table in the MAFterburner. However, if you make intake mods that cause the PCM to throw rich or lean trouble codes or you have driveability issues, then you can use the MAFterburner to recalibrate the MAF sensor using *both* the closed-loop and open-loop tables.

I am also now convinced, as he is, that many of the problems we are hearing comes from it being tuned by Ford overly-rich from the factory.

Yup. You saw my gains and they will be characteristic to what people will be getting with a dyno-tuned chip.

Cheers,

Mark

 

[IRON MACHINE]

MJchip, the MAFterburner sounds really intriguing.....
If you tune with the MAFterburner, will the computer show trouble codes, much like a chip change would, or are these eliminated because the computer is sort of readapting to new standards and does not think anything is wrong?
Also, what is the difference between tuning with the MAFterburner and using an aftermarket "chip"? Does the chip control more "stuff"? Thanks!

 

[mjchip]

Originally posted by IRON MACHINE
MJchip, the MAFterburner sounds really intriguing.....
If you tune with the MAFterburner, will the computer show trouble codes, much like a chip change would, or are these eliminated because the computer is sort of readapting to new standards and does not think anything is wrong?
Also, what is the difference between tuning with the MAFterburner and using an aftermarket "chip"? Does the chip control more "stuff"? Thanks!

Hey IRON MACHINE,

I'm not sure that I understand your first question. Some intake mods can cause a trouble code like an overly rich or lean condition. For example, I put a C&L meter on my Bullitt and after driving around for a while, my PCM threw "Bank1 too Lean" and "Bank2 too Lean" codes. When I went in and looked at the fuel trims with a scan tool, I found out that the idle LTFTs were at +25% and the STFTs were around 7%. Therefore, the PCM was trying to add 32% fuel to compensate for a lean condition caused by this meter. The rest of the fuel trims, up to around 3500rpm, were also pretty high (adding fuel). So, I was able to use the MAFterburner to recalibrate the meter to effectively zero out the fuel trims and extinguish the MIL.

The big differences between the MAFterburner and a chip are as follows:

MAFterburner: Lets the *end user* tune his/her own air-fuel maps accurately and rapidly. The interface is very simple and intuitive. However, it only controls air-fuel. The big benefit here is that a tuner or the end user (with the help of a knowledgeable tuner) can tune a car's WOT air-fuel map to EXACTLY what they want it to be. Also, as you continue to mod your car, you are in complete control and can retune to maintain optimum mixture. There is no waiting for chips to be reburnt, no hit-or-miss on the "cookie cutter" variety.

Chips: Chips are awesome, in fact, the MAFterburner is a chip. However, they typically can control many more parameters like spark maps, fuel, shift points, etc.. As far as air-fuel tuning goes, WOT tuning with the MAFterburner is MUCH quicker than tuning with a chip burning setup. Also, you can tune idle and part-throttle cruise by hooking up a scan tool and the MAFterburner software on a laptop and go out on the road. If you read the thread posted by that Diablo Sport tuner that I posted earlier, you will see how fast he took his rough-running car with hot cams to something with excellent driveability. Here it is again in case you missed it:

http://www.corral.net/forums/showthread.php?threadid=105613&highlight=mafterburner

Well, if you have any further questions, head on over to the website and read about it:

www.seanhylandmotorsport.com/mafterburner

There is also a technical forum there for you to ask your questions:

www.seanhylandmotorsport.com/forum

Hope this is of a little help!

Cheers,

Mark