Thanks Tom!

This type of discussion is my strong point. Feel free to ask anytime.

 

With Tony's skills I've heard he even programs ECU's in his sleep...I bet that laptop is glued to him.........if you are looking for a TRUE custom tune....he is your man....

 

How come people add what they call a diod i think to keep the car going into limp mode as with some of the earlier flashes?

If the car doesn't use the map sensor and the maf sensor is reading full volts (5 i think?), how does the car calculate the fuel load? or step into other fuel maps if the map sensor isn't being used? Does it switch over to O2 readings? and is that what makes the computer switch over?

 

2 great questions....

1. The "diode" was a bandaid. It was used to cap the amount of boost the ecu was actually able to see. If the ecu is calibrated properly, it is not needed.

2. I could write a book on this one.... A few things :

From a fueling prospective, the ecu uses load or change in load to "predict" fueling, however fuel correction is mainly driven off a few request lambda tables and routines. These request values or out puts of routines can easily be logged with Durmetric if you are interested what AF your tuner is requesting.

The ecu uses the 02 voltage to correct a/f as close as possible to the programed requested af.

What does this mean....A car can basically be fueled properly with a maf that is completely maxed out.... This is VERY far from optimal but is how most car on this forum run when producing more then chipped power.

Bacsically keep this in mind when thinking about fueling and the ME7 ecu... There really is no "Main Fuel Table", just few hundred "requested load" and "request air fuel" tables and routines.

 

hey Tony, Whats up with P-tune or P-winks when are you releasing it? inside joke)

Chris Green

 

p-winks

 

yes, there cannot be a main VE as the car has variable valve timing. the volumemetric effecieny of the motor varies as the timing changes.
so tony this then mean that the ME7 uses mathmatical equations vrs.
interpolate values.

 

Equations or PID loops....

 

Why not use a larger diameter MAF housing that flows enough air at 5v to produce desired power? Do you lose low volume resolution?

Why not use the stock MAF and stock housing and use some reducer (?) to reduce voltage by 50% and adjust the MAPS accordingly?

Seem weird to not be reading AF as I assume it's supposed to be, and tuning off of the O2's.

I don't know jack about tuning. I'm just trying to understand the logic.

Mike

 

We have now tested 4.0", 4.25" and 4.5" maf's. Even on the 4.5 inch maf, flow is maxed out before 700bhps.

We are currently testing a few different solutions that should allow airflow readings to be read at 700 bhps+.

Reducing the voltage isnt the issue...its the sensors ability to read airflow above a given point. If you reduce voltage, you will just max out the sensor at a lower voltage.

 

What you need is a variable cross section maf assembly! A small cross section with good resolution and linearity at low flow, but opens up a high flow....

 

You are correct. You MUST reduce the current passed by the MAF to the computer (in relationship to air flow) if you increase the engine's airflow beyond the stock MAF's limit. This is a requirement and not an option. The programming of the M7 is then modified in relationship to the new reduced signal from the MAF.

Whether you do this using inline resisters, housing modification or a new MAF with built in resistance doesn't matter. But you cannot increase airflow beyond a certain amount without modification of the MAF signal.

The M7 DOES NOT take direction from the O2 sensors under all conditions.

 

ME7 not m7.

Inline resisters don't solve the maf issue for many reasons and can actually cause drivabilty issues.

Under normal operating conditions, the PID that is driven off 02 voltage and requested programed a/f will calculate actual fueling of the engine...

The ecu wont use 02 in condition's such as sensor warm up, when there is an 02 sensor fault, ect...but the better part of 90% of driving conditions the ecu will largely use the 02's for fuel correction.

 

A resister works flawlessly if your tuning is done properly. For those who only tune to the high engine loads, you may have a problem when substantially increasing the airflow. In these cases, either tune to the closed loop loads, or install a variable MAF resister.

You can spend the time and money redirecting airflow, but it is not necessary.

 

I assume the 4.0 to 4.5" maf's you mention are internal tube diameters but I may be completely incorrect as I haven't understood a lot of what has been discussed on this thread----interesting, though.

My internal diameter is 95mm, about 3 3/4" and I have never dynoed my car. Judging from the numbers provided by others for their 60-130 numbers compared to mine, I feel confident my car is producing well in excess of 700HP at the crank. I'm not sure how my tuner did it, I just know my components and my results.