Well I have made custom intakes for a large assortment of vehicles in the past, but this is quite puzzling. Fiance has a new 2011 gts auto. Bought the evo X MAF sensor housing and installed the maf sensor on it. After that used my 3" piping with a brand new 3.5" spectre filter. Threw the lean code, so looked at the aftermarket ones and noticed they use 2.5" piping so i had some laying around, cut it up and smoothed it out and tried that with unplugging the battery for about 30 minutes. Well after driving around for a day code came back. Tried erasing it and using a smaller filter, still there. Pain in the ***, about to return to stock for the time being. Honestly I would like to see pics of other setups on the GTS using the evo X maf sensor housing fro comparison. Judging from what I have read these MAF sensors on these specific cars are quite sensitive and the stock air intake seems to be quite inefficient (plugged in datalogger AIT's of 120+ from stock) and needs improvement. Thanks.

 

Instead of erasing the code - disconnect the battery and hit the brake pedal like 12 times. Reconnect and let the ECU learn the new set up.

[shrug]

 

IIRC, the diameter of the evo x maf housing is larger than the stock gts maf housing, thus you are throwing a lean code.

 

i figured that was the problem. but cutting the stock one doesnt leave much to clamp onto. so for now i was just going to replace the rubber tube with aluminum and k&n drop in filter with a ralliart scoop. if a stock airbox goes up fro sale i will buy it and cut it.

 

Here is a post I started in another forum

http://9glancers.com/index.php/topic,15248.0.html

Maybe it can give you an idea how to fab a maf housing

I plan on making a tube for mine and see if it would work

 

The MAF sensor on the lancer is very sensitive and great care should be done when design / fabricating a custom intake. Manufacturers have tried and failed many times before releasing intakes. Fujita had many problems and after 3 redesigns / releases of the same intake. Some customers were reporting CEL codes (lean).

But I am glad to see there are guys still out there making their own stuff