sully ss

if heard two different things about getting these done. i have an a4 and ive heard that having descreened ends can screw the tranny up. then i also have heard that as long as the amt of air taken in is tuned right..then there is no problem at all. does anyone else have any input about this?

WS6FirebirdTA00

iTrader: (33)

i would like to know this too, i read in another post that ported and descreened ends can mess up line pressures, but then they said if it was tuned right there would be no need to mess with the tranny. putting a larger 85 mm MAF wouldnt that do the same to the tranny?

Jorday

The purpose of this mod is to cause the computer to read less air than actual. This has a few consequences, good and bad. First, it can result in more spark advance at WOT, which is good if you don't have any knock. It increases the timing because the computer thinks the engine is under less load than acutal. Most agree that the timing is where the power comes from and that the flow numbers of the stock MAF is sufficient unless you are producing some pretty big numbers. This also presents a possible problem in the A4 car. The decreased load reading can cause the PCM decrease the line pressure in the transmission, which can lead to slipping. This is why it is possible to end up with trans problems if you do the ported MAF ends in the A4.

Your results may vary.

WS6FirebirdTA00

iTrader: (33)

BUT if it is tuned to run right this should not be an issue right? we arent trying to "trick" anything we want to do it right and have the computer read it right, just wanna let more air come in....i can advance my timing in the programing its not an issue of tricking anything

jimmyblue

iTrader: (11)

You can tune the engine to have a proper mixture and
still have a bogus load reading that messes up the trans.
Yeah, =if= it's tuned right then (by definition) you won't.
But I see a lot of opinions about what's the right way to
tune mixture and one of them (injector scaling) will do
diddly to get the transmission control code realistic load
data. In my opinion you would want to take pre-messed-
with (stock) MAF flow data with a logger and then edit
your scaling tables to get back to the same mass air
flow value (from whatever the frequency moves to) at
corresponding MAP*RPM points. Maybe do an Excel
regression. Then you have the same load calculation as
stock.

The MAF frequency/airflow curve is not linear and a plain
scaling is probably not going to be all that realistic.

Changing the fluid-mechanics structure without matching
up the electronics or its software post-processing is the
"tricking".

Jorday

Yes, if tuned correctly, the line pressure probably wouldn't be changed. Some people choose to do this mod because they like the looks of the aftermarket MAF or MAF ends, but there is little performance to be gained from this mod if you've already got the timing, etc, where you want it. The flow of the stock MAF is plenty for nearly all 346 ci combinations.

WS6FirebirdTA00

iTrader: (33)

i get what you guys are saying now, thanks....so its almost a hit or miss senario? do that deals wiht any aftermarket MAF too? what if you adjust the line pressures and what not, and tune the car for the MAF? would it hurt anything then? thanks for the info guys!