When is an aftermarket MAF a good idea?
08-06-2002, 11:18 PM
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When is an aftermarket MAF a good idea?
Hi guys,
Just as the question says. If i have a CAI and aftermarket exhaust, i dont have headers though, would i benifit from a different MAF, or is the stock one good enough. Thanks
Just as the question says. If i have a CAI and aftermarket exhaust, i dont have headers though, would i benifit from a different MAF, or is the stock one good enough. Thanks
08-09-2002, 03:12 AM
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Chances are your stock MAF is fine. Here is some info about flow rates and a link to where I got it.
From: https://www.thirdgen.org/techbb2/sho...hreadid=117164
A little Hard MAF Data
Reposted here, from my original posting on a GN list.
Please, read this fully before just jumping in and removing your MAF screens or updating your systems. The following is a short version of lots of info., and related items. First off, the intake tract is made up of every little component from the intake valve clear thru to the air filter. For this simple little bit of data I'm just looking at one small element of it.
While air flow is of critical importance to an engine, the metering of fuel to that column of air is what makes the power. Any engine is just the some of it's parts, and each component must be matched, to all the others. If you want to get into making changes, then you MUST understand ALL the ramifications. Not some, all. As per my normal petulant self, I want to stress that HP is a function of knowledge, and that knowledge is only
beneficial when executed in a proper tuning route.
Now for the News:
At 28" of water,
A LS1 MAF with screen, will flow 747 CFM
without screen, 800 CFM
A LT1 MAF with screen, will flow 637 CFM
without screen, 730 CFM
A GN MAF with screen, will flow 583 CFM
without screen, 660 CFM
In the case of the LS1 you might go owww, ohhh, that's 50 CFM, or a 7% change. Knowing that for every 1% reduction in intake restriction, you can generate 2% more HP you might go yepeee, 14% more HP. But, that's not the case, Unless your MAF is located at the TB, and your not using any other intake tract ducting (ie no turbo)(and that if removed, the actual transistion is 0% restrictive). But, it is an indication that there is
room for improvement.
As per an old post by Mike Pitts, and a new Hot Rod Mag article, there is some HP to be gained in removing the MAF. Both seem to have shown about 30HP.
The trouble with just removing the screen is that it throws the MAFs calibration completely out the window. If you're doing your own chips, then you can tune things properly and get things right again. But, be prepared for a real learning process.
If you're seriously thinking of wanting to get this right, I'd suggest you go thru the old procedures of getting 128s across the board, and then base lining your WOT performance. Then once that's PERFECT. Then remove the screen, and start over. And by start over, I mean start with your virgin bin file, and then table by table rebuild your scalers and MAF tables till you again get your 128s, and then start working on your WOT stuff.
Again, improper use of this info., WILL melt your motor down. Diligent testing, note taking, and patience is mandatory. All changes need to be made one step at a time.
It also might be an advantage to pick up a spare MAF, and then swap MAFs/chips while trying to get this right.
For related reading, please peruse:
http://www.gnttype.org/techarea/engine/mafrelocate.html
If you really want to understand the scalers, and MAF tables, an ecm bench is an excellent learning tool.
From: https://www.thirdgen.org/techbb2/sho...hreadid=117164
A little Hard MAF Data
Reposted here, from my original posting on a GN list.
Please, read this fully before just jumping in and removing your MAF screens or updating your systems. The following is a short version of lots of info., and related items. First off, the intake tract is made up of every little component from the intake valve clear thru to the air filter. For this simple little bit of data I'm just looking at one small element of it.
While air flow is of critical importance to an engine, the metering of fuel to that column of air is what makes the power. Any engine is just the some of it's parts, and each component must be matched, to all the others. If you want to get into making changes, then you MUST understand ALL the ramifications. Not some, all. As per my normal petulant self, I want to stress that HP is a function of knowledge, and that knowledge is only
beneficial when executed in a proper tuning route.
Now for the News:
At 28" of water,
A LS1 MAF with screen, will flow 747 CFM
without screen, 800 CFM
A LT1 MAF with screen, will flow 637 CFM
without screen, 730 CFM
A GN MAF with screen, will flow 583 CFM
without screen, 660 CFM
In the case of the LS1 you might go owww, ohhh, that's 50 CFM, or a 7% change. Knowing that for every 1% reduction in intake restriction, you can generate 2% more HP you might go yepeee, 14% more HP. But, that's not the case, Unless your MAF is located at the TB, and your not using any other intake tract ducting (ie no turbo)(and that if removed, the actual transistion is 0% restrictive). But, it is an indication that there is
room for improvement.
As per an old post by Mike Pitts, and a new Hot Rod Mag article, there is some HP to be gained in removing the MAF. Both seem to have shown about 30HP.
The trouble with just removing the screen is that it throws the MAFs calibration completely out the window. If you're doing your own chips, then you can tune things properly and get things right again. But, be prepared for a real learning process.
If you're seriously thinking of wanting to get this right, I'd suggest you go thru the old procedures of getting 128s across the board, and then base lining your WOT performance. Then once that's PERFECT. Then remove the screen, and start over. And by start over, I mean start with your virgin bin file, and then table by table rebuild your scalers and MAF tables till you again get your 128s, and then start working on your WOT stuff.
Again, improper use of this info., WILL melt your motor down. Diligent testing, note taking, and patience is mandatory. All changes need to be made one step at a time.
It also might be an advantage to pick up a spare MAF, and then swap MAFs/chips while trying to get this right.
For related reading, please peruse:
http://www.gnttype.org/techarea/engine/mafrelocate.html
If you really want to understand the scalers, and MAF tables, an ecm bench is an excellent learning tool.
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