offset ported MAF line pressure using hpp3??
Thread Starter
TECH Apprentice
Joined: Jul 2002
Posts: 308
Likes: 0
From: Canada
offset ported MAF line pressure using hpp3?? Can anyone tell me if reprogramming the ECM using a HPP3 with 25% increase shift firmness setting will offset any reduction in A4 line pressure being caused by my Whisper ported MAF shells in my 99 WS6. I have had no problems but after reading some of your posts, have heard that the line pressure is reduced by the ECM when using the ported MAF shells possibly causing transmission clutch failure further down the road.
TECH Addict
Joined: Nov 2001
Posts: 2,003
Likes: 0
From: Live Oak, FL - in the woods where the creatures lurk.
Re: offset ported MAF line pressure using hpp3?? That's a good question. I have monitored the pressure control solenoid current with Autotap through different shift firmness settings.This was with stock MAF. There seems to be several variables that affect the line pressure commanded by the pcm that make it difficult to get repeatable results. Even trans oil temp -seems- to be factored in.
TTT for ya.
TTT for ya.
Thread Starter
TECH Apprentice
Joined: Jul 2002
Posts: 308
Likes: 0
From: Canada
Re: offset ported MAF line pressure using hpp3?? Thanks for the reply gwj. By the sounds of it, maybe the ported MAF shells are not such a great idea for us A4 guys. Especially when the ECM relies so heavily on MAF readings to properly control the auto trans. as you seem to suggest. Any ideas on what would occur if trans.line pressure is reduced significantly by the ECM at WOT? Also any idea on how much line pressure the HPP3 is capable of boosting at 25%, 50%, 75%, 100% and can I adjust line pressure to these settings without causing damage to my stock tranny?
Re: offset ported MAF line pressure using hpp3?? You are correct, when I was using a stock PCM/maft with 38lb injectors I overheated my trans several times (2nd gear only 'overheat' mode) after making one or two passes. My first fix was the HPP3 at 100%, that got me by the next couple times out but I eventually hooked up a hobbs switch to open the wire to the PCM that gives it full line pressure - could make unlimited passes then. BTW, I had a huge cooler on there but the maf signal was so far skewed it was really bad - never made much difference in ET with the trans shifting sloppy so I just left it until it got too warm out <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
I dont think ported ends on a fairly stock car would make any difference, but once you start really leaning with a maft
I dont think ported ends on a fairly stock car would make any difference, but once you start really leaning with a maft
