MAF Question

[ptstew]

I am is process of installing a 1993 Cobra intake manifold on to my 1991 engine. I plan to use a 75mm MAF with the 1991 ECC and 24# injectors. When trying to order a PMA unit from LMR I was told that Mustang MAF’s are either calibrated for a mustang air box or a cold air intake with a 90° bend. I was planning on just clamping an FFR type K&N filter to the inlet of the MAF and they say that isn’t recommended.

Two questions: is LMR correct that I shouldn’t attach the filter like I did with the stock MAF that came with my doner car? If I purchased BBK cold air inlet system is there room for the 90° bend piece between the MAF and the fender well?

Thanks.

[davekp]

What heads do you have?
What cam?
What throttle body?

[ptstew]

Thanks. Heads and cam are stock 1991. Have 70mm BBK 1501 throttle body. Car has been a retirement project and used only on stree. Peak performance is not primary objective.

[davekp]

24 lb injectors are probably too much. The heads won't flow well enough to get any appreciable gain. If it were me, I'd just do the intake and throttle body.

[Jeff Kleiner]

Dave is absolutely correct. The heads are the bottleneck and you won't get any benefit from 24# injectors (in fact it will become temperamental and run worse at low RPM).

Jeff

[Big Blocker]

Quote: " I was told that Mustang MAF’s are either calibrated for a mustang air box or a cold air intake with a 90° bend."

This begs for an answer to WHY would Ford calibrate something that reads air flow requiring a restriction (Air Box) or a flow direction piece of equipment (90° Bend) in the incoming air flow path?? I would think logic calls for the straightest path with little or no restriction. The MAF doesn't "read" turbulence (90° bend), it reads an electrically heated wires resistance, which correlates to an amount of air that is trying to "cool" the wire as it passes over it . . .

FWIW, I have a K&N air filter mounted straight to my MAF, have for 17 years now with no issues at all. I have moved the MAF as far as 3' away from the Throttle Body and as close as mounted right to it - no difference in engine behavior.

HTH

And just my 2¢, stay with the factory injector size until you provide better breathing - heads, cam, etc.

Doc

[Mike N]

Quote: " I was told that Mustang MAF’s are either calibrated for a mustang air box or a cold air intake with a 90° bend."

This begs for an answer to WHY would Ford calibrate something that reads air flow requiring a restriction (Air Box) or a flow direction piece of equipment (90° Bend) in the incoming air flow path?? I would think logic calls for the straightest path with little or no restriction. The MAF doesn't "read" turbulence (90° bend), it reads an electrically heated wires resistance, which correlates to an amount of air that is trying to "cool" the wire as it passes over it . . .

FWIW, I have a K&N air filter mounted straight to my MAF, have for 17 years now with no issues at all. I have moved the MAF as far as 3' away from the Throttle Body and as close as mounted right to it - no difference in engine behavior.

HTH

And just my 2¢, stay with the factory injector size until you provide better breathing - heads, cam, etc.

Doc

The factory EECIV has a 'back flow' calibration table that accounts for the MAF location in the intake. If the MAF is close to a bend, air filter, or throttle body there can be some back flow that the stock EECIV accounts for.

[ptstew]

Thanks, guys, for all the great responses. I am returning the 24# injectors and buying new 19#ers to replace my 28 year old ones. I’ll also stick with my stock 55mm air mass with the filter directly attached. Saves me a few bucks.

Phil