Bigger MAF houseing Mistake maybe?

[huntman58]

Okay I here how well many have done with a 70mm MAF so I tried what I believed was one and my MPG went down not a lot but some and no it was not from the lead foot problem. Well today I finally measured the opening and its 75MM. is that too much for a stock motor and set up?

I have done the half shaft mod and a K & N filter and they both helped. I did Swiss cheese the air box but all it did was make more sound. I have gone back to the stock air box and MAF and all seams to be back to normal but this has been nagging me. If it is too big I think I will sell it. I believe I bone yard it from a newer Explorer but not 100% sure but it did come from a ford SUV I do know that. Thanks for any info on this before I part with it.

 

[2000StreetRod]

Increased MAF sensor diameter

As I have posted many times, when you increase the diameter (and cross sectional area) of the MAF sensor you decrease the speed of the air flowing across the sensor element. The element incorrectly indicates a lower than stock air mass flow and a lean mixture results. Your fuel economy may improve if you avoid loading the engine but your performance will suffer. When the PCM is in closed loop the lean condition reported by the O2 sensors will cause the PCM to richen the fuel trims until 14.7:1 is achieved unless the limits of the trims are exceeded. In open loop (heavy load and WOT) the PCM ignores the O2 sensors and reverts to stored tables for air/fuel ratios. The only way to achieve good overall performance with an increased diameter MAF sensor is to use a custom tune.

 

[huntman58]

Thanks streetrod and I have read your post on it before. I did get or it felt like I did gain some power improvement but at the cost of MPG. The incress of power I felt was not worth the cost of MPG to me at lest and is the main reason for going back to stock. What your saying makes a lot of conmen science s even going back to the old carb days just because you can stuff more gas and air into a motor dose not mean it can dell well with it all or that the changes are in a RPM band that you can use. Your post were one reason I always held off on doing this but I had to try finally as some things just do work out but not this time at lest for me.

Was just looking for other PO on it before I say good by to it.