Throttle body and MAF size

[VA-MTX]

Just finished my 60k and got my VA inspection sticker on my new to me '95 SHO so time for a shakedown cruise. Runs great, pulls good but seems to bog on acceleration. I recalled that the previous owner said he had swapped in a larger MAF, but didn't have a LPM or any other mods besides a Borla cat back. I remembered reading online that the stock MAF is 55mm.

Tonight I measured the MAF and throttle body.

MAF inside dia 73mm
MAF sensor labeled:
F1ZF-12B579-AA
AFH55-03B
OM13

Throttle body inside dia 70mm
Casting #:
KOA-03
B28

Looks like stock MAF sensor is installed on a larger MAF. What do I have and, what should I have, and what junkyard donors have my stock parts? Not counting on finding another 3.0 SHO at Pick-a-part.

Thanks in advance.

 

[luigisho]

I think aftermarket C&L MAF were 73mm. used stock sensor I think. You can look for a parts car on the forum, ebay or wherever and get a stock one.

 

[VA-MTX]

I think aftermarket C&L MAF were 73mm. used stock sensor I think. You can look for a parts car on the forum, ebay or wherever and get a stock one.

Question-
Were SHO and SHO MAFs the same?

 

[Irish Pride]

The opening to the throttle body should measure 70mm but the back side where it mounts to the intake should measure 65mm if it is a stock TB. It is considered a pretty good mod to bore the TB out to 69mm(I have one on my 89) but then you need to source the correct throttle plate so it seals properly when closed. Measure the back side and see what you get.

If I remember correct, the 73mm MAFs didn't require a tune(I have one on my 89 too) and were plug and play. The 80mm Lincoln MAF is a different story though.

 

[kevinspann]

Pics of the MAF? The stock one tapers way down inside.

 

[luigisho]

The C&L MAF and Nook used to sell a throttle body over bored to 69ish mm were mostly sold at about the same time frame years ago, so those two items paired together makes sense. Whether they work better or worse than stock is open for debate

 

[reags8]

I am following .... Cause ......

I picked up a 92 MTX with a 88mm cobra MAF installed and the car doesn't have the low end like my 94 ATX had AT ALL ! Granted I have no idea what else has been done but the stock MAF is in the trunk and I'm contemplating installing it.

 

[luigisho]

I would install the stock one. A huge MAF without a ton more modifications to make use of increased air capacity is usually counter productive. I've had 3 different ones and the best running MAF was the stock one even with a chip programmed for the aftermarket MAF. Check your PCM for a tuning chip sticking out of the rear port plug.

 

[VA-MTX]

The opening to the throttle body should measure 70mm but the back side where it mounts to the intake should measure 65mm if it is a stock TB. It is considered a pretty good mod to bore the TB out to 69mm(I have one on my 89) but then you need to source the correct throttle plate so it seals properly when closed. Measure the back side and see what you get.

If I remember correct, the 73mm MAFs didn't require a tune(I have one on my 89 too) and were plug and play. The 80mm Lincoln MAF is a different story though.

I'm in L.A. now, so will pull the TB and measure the plate. Or if I can find my calipers...
Previous owner had a few interesting projects and seemed knowledgeable. I'm not ready to panic yet. Then there is the matter of original y pipe and cats that could be responsible for the perceived sluggishness.

 

[reags8]

Re-installed the stock MAF (it was in trunk) completely different car ! Low end is back ....... Anyone want a 88mm MAF ?