lightning maf

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Dec 23, 2006 | 10:27 AM

04markIII

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From: Lunenburg, MA

lightning maf

i need this anyway for project in sig. would it hurt anything if i installed it ahead of time? i'm talking the complete unit and sensor, not just the black piece. when i had my 93 tbird, i switched to a later year, larger maf and the car ran better and seemed quicker. rumor has it that it will be ok, just run a little rich maybe, but i wanted to confirm it. thanks.

Dec 23, 2006 | 09:05 PM

LxMan1

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From: Louisville,Ky.

It is probably calibrated for the larger injectors on the S/C engine, so the mixture will be way off.

Dec 25, 2006 | 10:10 AM

Johnny Langton

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From: SE Texas

MAFs are NOT calibrated for injector size-they never have been. The MAF has a transfer function-a voltage output relative to the airflow going through it. The EEC knows this transfer function,and uses that data to calculate the appropriate amount of fuel to inject to meet the commanded air/fuel ratio.The EEC also knows the data for injector size.If you change any of these-you need to change the data in the EEC.
JL

Dec 25, 2006 | 10:38 AM

LxMan1

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From: Louisville,Ky.

Then why do they offer different MAF's for different injector sizes????

Dec 25, 2006 | 10:48 AM

Johnny Langton

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From: SE Texas

Quote:

Originally Posted by LxMan1

Then why do they offer different MAF's for different injector sizes????

That's the aftermarket's hackjob method of making a MAF "work".They simply ratio the old injector size to the new injector size,and multiply the entire airflow range(transfer function) by that amount to make it "work". Problem is that load is calculated from MAF input along with other items,and when you ratio the output of the MAF-the EEC doesn't know this,and it can command the wrong a/f value for the actual load,or the wrong spark value for the actual load that's on the engine.
JL

Dec 26, 2006 | 07:41 AM

LxMan1

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From: Louisville,Ky.

That's kinda what I was thinking. Just alter the sample tube size. Doesn't seem real accurate to me either.

Dec 26, 2006 | 02:17 PM

Johnny Langton

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From: SE Texas

Quote:

Originally Posted by LxMan1

That's kinda what I was thinking. Just alter the sample tube size. Doesn't seem real accurate to me either.

It isn't. If you've ever been around some of the old Fox body Mustang guys when they modify those cars-have you ever noticed they drive like crap,and have all kinds of issues that they typically attribute to "that's just the way these cars run when you modify them".It's those hackjob MAF's they're using.
JL

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Jan 1, 2007 | 09:11 PM

Johnny Langton

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From: SE Texas

Quote:

Originally Posted by 04markIII

jl, so i should just wait and do it all at once? seemed to run ok with my tbird. went from the stock 1993 maf to the larger 94+ maf with no "known" issues.

There's a substantial difference between the transfer functions of the two MAF's,so I'd suggest doing it all at one time.
JL