GT Bob

OK..here's the problem... bare with me as it requires a bit of an explanation...

When you install an intake on a car that requires a tune, the most basic function of that tune, that allows the intake to work with the computer is an update to a table called the MAF transfer function. What this table is, is a reference chart for the computer to know how much air the MAF is flowing based on the current that the MAF sensor is drawing to maintain it's temp. So, for example (and these are made up numbers, not actual numbers), if the MAF is drawing 4.734 volts, it looks at the table and sees that that much voltage means the MAF is flowing 3.75# of air. It then uses this air volume in just about every calculation that the computer does, from fueling, to timing, and even when to read the O2 sensors. An incorrect MAF transfer will effect every other facet of performance in a very negative way.

Now, if your using a tune for a Steeda intake, the MAF transfer is completely different from what a BBK would need... The MAF sizes are very different and so are the placement of the MAF and how the intake inducts the air to the sensor... The reaosn your recieving the too rich code is because the Steeda has one of the biggest MAF's there is.. at 90mm. If the BBK is advertised as a No tune intake, then I can garentee that that the MAF is no where near that size..and so the engine in effect thinks its getting alot more air than it really is... So much in fact that the O2 sensors don't havbe enough ability to cut out the extra fuel.

AtHomeTech

Hey Bob. I am not trying to start anything here but I question this logic a little. TheMAF works because it knows it takes X amount of air to cool the maf toX temp. So if 3.75lbs/hr of air is passing then it outputs 4.734 volts (made up numbers) andcalculates the other functionsappropriately. 3.75lbs/hr is the same coming from the stock airbox, and airaid, a whipple, a paxton or anything else. Itis still 3.75 lbs/hr.I could be wrong. Anyonehave any thoughts on this?

-Ken

Norm Peterson

I think 3.75 lb/hr of air will cool the wire in a 90mm MAF differently than it would in a 75 mm MAF (more made-up numbers),at the very least because the velocity is lower through the 90. And velocity affects heat transfer. This sounds very much like the thermal transient analyses that I used to do for certain power plant piping systems.


Norm

HaneyMotorsport.Com

Ken, I will try to explain as basic as I can here. The MAF has a transfer function......air flow and voltage. These 2 do work together. example #s 3v = 580kg/hr air flow. The t.f. must be correct for the right size housing/opening to read true. For example, you have a MAF set up/designed for a 90mmopening. Now, take that sensor and put it in a 80mm housing. At 3v it now reads 625kg/hr, it thinks more air is entering, thus adding more fuel. This is due to a smaller flow path, which makes more velocity..air is passing over the sensor faster. So in truth, the engine is not taking in more, the maf just thinks it is! At this point, the t.f. needs to be changed/lowered. There are other things that this will affect, not just fuel control.

Casey

AtHomeTech

I was stuck thinking about the same size opening. and the same MAF sensor. With the larger tube on the new intakes I can see how the MAF is not seeing all the air and not able to meter it. Thanks for smackin me strait!

-Ken