TheDieselPage.com Forums  
2014 - TDP's 19th Year
What's New: | Feature Articles: | Product Reviews: | Member's Area: | Subscribe:
Duramax 6600 Diesel Page | Advertiser's Section | Classified Ads | Photo Album | Diesel Books, GM Licensed T-shirts


Go Back   TheDieselPage.com Forums > Chevrolet & GMC 2500HD/3500 Light Trucks > Duramax 6600
Register FAQ Members List Photo Album Mark Forums Read

Duramax 6600 Discussion Forum for the Duramax 6600 Diesel Engine, including the LB7, LLY, LBZ & LMM engine specific topics.

Reply
 
Thread Tools Display Modes
  #1  
Old 08-31-2007, 05:58 PM
moss6 moss6 is offline
Enthusiast
 
Join Date: Apr 2007
Location: Lubbock,Tx.
Posts: 162
Default MAF flow effects

If you were to increase the flow across the MAF sensor what effects would it have over the numerous interlinks (injector volumn, EGR valve position, timing etc.) in the PCM?
Reply With Quote
  #2  
Old 09-04-2007, 04:19 PM
moss6 moss6 is offline
Enthusiast
 
Join Date: Apr 2007
Location: Lubbock,Tx.
Posts: 162
Default

Surely someone has some idea of what would occur.
Reply With Quote
  #3  
Old 09-04-2007, 08:42 PM
DmaxMaverick DmaxMaverick is offline
Administrator
 
Join Date: Apr 2001
Location: CA
Posts: 10,651
Arrow

It will defuel sooner. The actual air volume would be less than the perceived, so it would "think" it has too much air for the fuel/power output. EGR position would not likely be effected much, if any, but could go nuts 'cuz the output doesn't match the input. It's a delicate balance, and if you lie to it w/o computer intervention, it'll throw a fit (SES, limp, etc.).

Bad idea.
__________________
1985 Blazer 6.2
2001 GMC 2500HD D/A
2014 Chevy Cruze Diesel
dmaxmaverick@thedieselpage.com
Reply With Quote
  #4  
Old 09-05-2007, 07:40 AM
jmoser jmoser is offline
Newbie
 
Join Date: Mar 2005
Location: MI
Posts: 8
Default

It is not clear to me what you mean by 'increase the flow' across the sensor ? ?

Do you mean that you would somehow 'trick' the sensor into sending the same signal it does now at higher flow rates? Why would you ever want to do that?

The MAF is a Mass Air Flow sensor - it corrects for changes in air density due to humidty, altitude, and temperature to give an accurate measurement of the mass of air flowing [Kg per minute, etc.] in order to meter the proper amount of fuel through the injectors to maintain the correct air-fuel ratio.

If what you mean is to physically increase the flow by removing restrictions, etc. then there should be no problem as long as you do not exceed the range of air flow that the MAF sensor was calibrated for. Not all sensors are universal - many have upper and lower limits, too high or too low and you will not get accurate readings.

The MAF is one of the crucial inputs to proper fueling of any engine - it would be the last thing I would ever mess with.
__________________
Jeff
Reply With Quote
  #5  
Old 09-07-2007, 04:50 PM
moss6 moss6 is offline
Enthusiast
 
Join Date: Apr 2007
Location: Lubbock,Tx.
Posts: 162
Default

Quote:
Originally Posted by DmaxMaverick View Post
It will defuel sooner. The actual air volume would be less than the perceived, so it would "think" it has too much air for the fuel/power output. EGR position would not likely be effected much, if any, but could go nuts 'cuz the output doesn't match the input. It's a delicate balance, and if you lie to it w/o computer intervention, it'll throw a fit (SES, limp, etc.).

Bad idea.
I don't understand how if it is reading more air that it would defuel, that sounds backward but that is why I'm asking------I don't know how it all interacts, but would like to learn.
Does it not effect the timing?
Reply With Quote
  #6  
Old 09-07-2007, 05:19 PM
moss6 moss6 is offline
Enthusiast
 
Join Date: Apr 2007
Location: Lubbock,Tx.
Posts: 162
Default

Quote:
Originally Posted by jmoser View Post
It is not clear to me what you mean by 'increase the flow' across the sensor ? ?

Do you mean that you would somehow 'trick' the sensor into sending the same signal it does now at higher flow rates? Why would you ever want to do that?

The MAF is a Mass Air Flow sensor - it corrects for changes in air density due to humidty, altitude, and temperature to give an accurate measurement of the mass of air flowing [Kg per minute, etc.] in order to meter the proper amount of fuel through the injectors to maintain the correct air-fuel ratio.

If what you mean is to physically increase the flow by removing restrictions, etc. then there should be no problem as long as you do not exceed the range of air flow that the MAF sensor was calibrated for. Not all sensors are universal - many have upper and lower limits, too high or too low and you will not get accurate readings.

The MAF is one of the crucial inputs to proper fueling of any engine - it would be the last thing I would ever mess with.
This post actually stems from another "LBZ Hot and Loss of Power", in which there were some good responses but not a lot of direction for what to do to find out what was causing such a loss of towing power.
One response from a Banks Tech led to a phone conversation with same; and the basic recomendation was to relocate the MAF. He said that Banks had had some problems with their intake system in developement and found that when they located the MAF in the bend just before the turbo tract, and on the outside of the bend that they found good power gains and also found that the EGR valve pretty much stayed closed all the time.
Fact or not I though it was something to check out and try; if I could get any other insight that seemed favorable.
The position of the MAF on my LBZ (others too I assume) is on the inside of the first bend past the filter box. In this position the main velocity of course is on the opposite side of the intake tube; as with any hydraulic action the inside of any bend has a lower velocity than the outside. Depending on the configuration a vaccum can actually occur on an inside of a bend at some flow rates. (In chill water systems sometimes to the exent of air pockets and pump cavitation given the right proximity.)
In any case it seems that Banks by their repositioning has increase the flow at the MAF dramatically. How does that work?----and is it possible that this could actually effect the EGR. Seems that the consenses here is that it could not.
I'm still looking for the power loss----Killer Bee says I'm on a ghost hunt!!! But this ghost sure has some real power drawbacks---hot too.
Reply With Quote
  #7  
Old 09-07-2007, 06:41 PM
Dakster Dakster is offline
Enthusiast
 
Join Date: Jan 2007
Posts: 299
Default

MAF is one the better inventions for a motor. The old speed density computers back when fuel injection first came out where a table of set values that couldn't take into account environmental conditions. Those motors were hard to add performance to since back then it was hard to rewrite the ECU tables. (OBDI was the only game in town).

Now, MAF is much better because it allows the motor to dynamically change to the environment. Messing with that signal will either cause a LEAN or a RICH Condition. More Air = More Fuel, so if you trick the MAF to report more air than is going in, then you will have RICH condition, although the 02 sensors will rat out the MAF and the motor will DEFUEL to compensate for the mixed signals. This can cause a surging motor because the MAF and other sensors are battling each other.... Same thing can happen if an onxygen sensor is going bad.
__________________
2007 Silverado, 3500HD, 4X4, CC, Long Bed, SRW, LMM Diesel, Navi, DVD, Roll-N-Lock Cover, ICI Running Boards, CoastalEtech GM Lockpick for DVD/Nav changes in Motion, Back-up Camera...

2006.5 VW Jetta Special Edition TDI - Blue Graphite - European Spec VW Fact. Nav Radio.
Reply With Quote
  #8  
Old 09-07-2007, 07:18 PM
moss6 moss6 is offline
Enthusiast
 
Join Date: Apr 2007
Location: Lubbock,Tx.
Posts: 162
Default

Quote:
Originally Posted by Dakster View Post
MAF is one the better inventions for a motor. The old speed density computers back when fuel injection first came out where a table of set values that couldn't take into account environmental conditions. Those motors were hard to add performance to since back then it was hard to rewrite the ECU tables. (OBDI was the only game in town).

Now, MAF is much better because it allows the motor to dynamically change to the environment. Messing with that signal will either cause a LEAN or a RICH Condition. More Air = More Fuel, so if you trick the MAF to report more air than is going in, then you will have RICH condition, although the 02 sensors will rat out the MAF and the motor will DEFUEL to compensate for the mixed signals. This can cause a surging motor because the MAF and other sensors are battling each other.... Same thing can happen if an onxygen sensor is going bad.
So how does that relate to what Banks is doing in their relocation which obviously places the MAF in a much higher flow area and their claim of the improvement in power. That said, Banks is pretty well known for being effiency minded which would be contridictory to the more fuel added equation that should play a major role adversant to that end.
Reply With Quote
  #9  
Old 09-09-2007, 12:41 PM
Dakster Dakster is offline
Enthusiast
 
Join Date: Jan 2007
Posts: 299
Default

If I recall, BANKS is more than just "messing" with the MAF. It is just part of the whole equation in how it relates to the engine management system (stock or not) that creates "more power." Since, I do not know about the Banks system you are talking about it is hard for me to get specific as to why/what they are doing. Although, knowing Banks kits, I would assume that it is more involved then just moving a stock MAF to a better place - although I could be wrong.

Easiest analogy I can think of help you. On a gasser with a distributor. The factory sets a specific timing that is realiable, dependable. You can gain a few HP (5-10 depending on motor) by advancing/tweaking the timing. Advance too far and you get denotation and pinging. Take that to MAF, you can gain some HP by tweaking it tricking the motor to squirt more fuel. However, tweak too much and you get driveability and computer issues.
__________________
2007 Silverado, 3500HD, 4X4, CC, Long Bed, SRW, LMM Diesel, Navi, DVD, Roll-N-Lock Cover, ICI Running Boards, CoastalEtech GM Lockpick for DVD/Nav changes in Motion, Back-up Camera...

2006.5 VW Jetta Special Edition TDI - Blue Graphite - European Spec VW Fact. Nav Radio.
Reply With Quote
  #10  
Old 09-09-2007, 01:35 PM
moss6 moss6 is offline
Enthusiast
 
Join Date: Apr 2007
Location: Lubbock,Tx.
Posts: 162
Default

Quote:
Originally Posted by Dakster View Post
If I recall, BANKS is more than just "messing" with the MAF. It is just part of the whole equation in how it relates to the engine management system (stock or not) that creates "more power." Since, I do not know about the Banks system you are talking about it is hard for me to get specific as to why/what they are doing. Although, knowing Banks kits, I would assume that it is more involved then just moving a stock MAF to a better place - although I could be wrong.

Easiest analogy I can think of help you. On a gasser with a distributor. The factory sets a specific timing that is realiable, dependable. You can gain a few HP (5-10 depending on motor) by advancing/tweaking the timing. Advance too far and you get denotation and pinging. Take that to MAF, you can gain some HP by tweaking it tricking the motor to squirt more fuel. However, tweak too much and you get driveability and computer issues.
Actually that is what Banks recommended that I do. After talking about my intake modification (stock air box with and additional 3" air source that draws thru the recovery hook hole) they said that I was probably getting as much air as what their cold air intake kit was getting. They said that their original design had the MAF located just past the air box as with the stock set up. They were having problems with the EGR staying open so started trying other MAF positions. When they located it in the bend just before the turbo tract they found that the EGR valve stayed closed most 100% of the time and they also dyno'd a very good gain in power. I can't see why they would have any reason to be less than honest about it. I feel that they were just trying to help me out because of the higher temps and loss of power that I experienced after installing their exhaust system---good customer support in my estimation.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -7. The time now is 03:42 AM.


Powered by vBulletin® Version 3.8.2
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 1996-2014 by TheDieselPage.com - All Rights Reserved