90mm MAF?????

[Broosedamoose]

I need some help quick! I have my engine almost built and need to purchase a MAF. I purchased a 90mm throttlebody so I was going to get a 90mm MAF. However, will it be to big for my application? From what I've been reading the 90mm is for supercharged applications! My top end is, like I said, a 90mm BBK throttlebody connected to the stock 90 going into a TrickFlow TracHeat upper and lower intake with aftermarket aluminum GT40 heads. Anyone with knowledge about this plese share! Thank you!

 

[Bird76Mojo]

From everything I've read over the years, a 90mm throttle body is far too large, even with aftermarket heads. Unless you're going with forced induction.

I wouldn't be afraid to run a large MAF though, as long as the sample tube is calibrated/matched to the size of injectors you have.

 

[lvwill]

I'm not sure what you're building, but I do know that you seem to have a bunch of expensive mis matched parts. To function properly the maf should be a little larger than the throttle body and calibrated for the injectors being used. Track heat intake has a 90 mm inlet and huge ports which will kill low end power. Gt40 heads have much smaller ports than the intake. The stock 90 you speak of is from an explorer 5.0? If so it is going to be around 67 mm.
Honestly the foxbody guys are making a lot of power using the explorer intake and heads with a 67mm throttle body and a 70-75mm maf.

 

[decipha]

no such thing as too big of a maf it will be perfectly fine
calibrated mafs are for stock tunes only. If your tuning it then a calibrated maf is null

 

[Bird76Mojo]

no such thing as too big of a maf it will be perfectly fine
calibrated mafs are for stock tunes only. If your tuning it then a calibrated maf is null

I've always read that the MAF is calibrated to injector size, so in that scenario it's not just for stock tunes..

 

[decipha]

It's not your fault your sources are wrong.

Here's all the details you will ever need to know about a maf

MAF / EFIDynoTuning

 

[Bird76Mojo]

Then why do aftermarket companies sell MAF's and injectors as a package, stating that they're matched?

It's extremely common in the 5.0 Mustang world for people to sell MAF's and injectors as a set. Some MAF's are even tuneable.

 

[lvwill]

Basically the stock computer is tuned for the injector size with the stock maf. The so called calibrated mafs are designed to actually trick the stock computer when using larger injectors. The tunable mafs use different size sample tubes with the stock maf sensor to do basically the same thing. With a custom tune none of this really matters.

 

[decipha]

copy and pasted from the link I posted

"A "calibrated" MAF is an aftermarket METER designed to be used with a STOCK TUNE for a specific application. "

...

"With this knowledge, it is not required to have a calibrated meter for an injector swap if you will be tuning your vehicle. "

again, calibrated MAFs are for STOCK TUNES ONLY. Once you modify your calibration and actually tell the computer what maf you have and what injectors you have the maf's "calibration" is no longer relevant.

 

[Broosedamoose]

Ok, so my throttle body is actually a 75mm TrickFlow so I am going to use the stock MAF. I will have it tuned once it's up and running so I should be fine. Right?

 

[Broosedamoose]

I'm not sure what you're building, but I do know that you seem to have a bunch of expensive mis matched parts. To function properly the maf should be a little larger than the throttle body and calibrated for the injectors being used. Track heat intake has a 90 mm inlet and huge ports which will kill low end power. Gt40 heads have much smaller ports than the intake. The stock 90 you speak of is from an explorer 5.0? If so it is going to be around 67 mm.
Honestly the foxbody guys are making a lot of power using the explorer intake and heads with a 67mm throttle body and a 70-75mm maf.

Not sure where you got your info but Summit lists it as a 75mm throttle body opening and the runners port at the heads measures 2.00 x 1.2! It is designed to work in the 1,500 to 6,000 RPM range and for a stock/OEM engine block!

 

[Drspencer5]

Yeah, this is a bit mismatched. Those cylinder heads can't even support 400hp to the wheels. That intake is kind of ok but for the application, the GT40/Explorer stuff has been proven to be matched. Imagine a vacuum cleaner with a 2" hose and a 4" wide hose attachment. Is it goin to actually pick up the dirt from that 4" attachment? The velocity would be very low. Same with a 90mm MAF. In order to function properly, the heated wire inside the MAF needs to be cooled by air going by it. If the velocity of the air passing by the MAF isn't enough to cool it to tell the computer to adjust fuel, the motor will not run efficiently.

You never mentioned what cam you're running. With those heads, I hope it's not anything exceeding 230 degrees of duration at .050 or higher than .550 lift.

What do you plan on doing with the truck? Is it a daily, a cruiser, or something committed more to the track? Where will it be spending most of it's time, 2500RPM or 6000RPM?

 

[Broosedamoose]

Yeah, this is a bit mismatched. Those cylinder heads can't even support 400hp to the wheels. That intake is kind of ok but for the application, the GT40/Explorer stuff has been proven to be matched. Imagine a vacuum cleaner with a 2" hose and a 4" wide hose attachment. Is it goin to actually pick up the dirt from that 4" attachment? The velocity would be very low. Same with a 90mm MAF. In order to function properly, the heated wire inside the MAF needs to be cooled by air going by it. If the velocity of the air passing by the MAF isn't enough to cool it to tell the computer to adjust fuel, the motor will not run efficiently.

You never mentioned what cam you're running. With those heads, I hope it's not anything exceeding 230 degrees of duration at .050 or higher than .550 lift.

What do you plan on doing with the truck? Is it a daily, a cruiser, or something committed more to the track? Where will it be spending most of it's time, 2500RPM or 6000RPM?

The heads are listed as being able to support 400+ horsepower on pump gas!
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The truck is going to live a lot of it's life between 3,000 and 6,000 rpms. The cam I opted for when I had the engine built was called a "Mild Muscle" cam and was listed as 270. I'm not looking for crazy horsepower for drag racing! Just a daily driver that's fun to drive! Like I said, I am going with a stock MAF and the 75mm throttle body to match the intake. That will work just fine!

 

[Broosedamoose]

So I've talked to my mechanic, who is very experienced with Mustangs, and my neighbor, who has a lot of knowledge with Mustangs and built two from the ground up, and they both said I will have no problems running what I have. My mechanic said he has actually built two 302's using the same parts I'm using ( 75mm Throttlebody and the Trickflow intake) except the heads and they have run very well. One used Dart aluminum heads and the other rebuilt GT40P heads from an Explorer. Both engines used the Ford Racing B303 camshaft which is more aggressive than the one I'm using (286 vs. 270). They both guessed that the engine should put out somewhere around 350-400 Hp at the crank which is fine for what I want. Once I get it up and running and can get it to the dyno to be tuned I'll know an exact number. So I'm feeling a little more comfortable with my build now.