Flapper Door Mod

[90DSMTurbo]

Hey

what does the flapper door mod do to the mas?

sorry for all the dumb questions i've been asking

later

 

[Formz]

it lets more air through at wot but closes the door to stop the air flow at idle so you dont stall out.

 

[brokeawd]

The flapper mod is very is. First off you need a couple of things

#1 Dremel or cuttin tool
#2 AFC
#3 550's but 450's will work

Basically what happens is the mas meter will only flow so much air at a certain rpm so you get fuel cut, to remedy this you can hack the whole lower section off the mas meter, this will lets lots of unmetered air into the motor this lower the HZ count as to what the mas is seeing in terms of flow rate. IN return if you make no fuel adjustments the car will run lean and you will likely hurt the motor or blow a HG under boost.

From my experience with no flapper install and with stock 450's I had to crank the afc up to anout +25 to get the vacuum in the -16 to -18 range. Now with the flapper my fuel setting were down in the +5 range. The flapper is hinged on the bottom part of the mas where the lower section used to be. At lower rpm's the door hangs down not letting that much air in...at WOT ops the door swings up letting all the unmetered air in.