Best TB/MAF size for Explorer intake swap?

[broncaholic]

Currently getting my stuff together for the Explorer intake swap and have been reading up on the TB/MAF size for torque & HP. I recieved a 70MM TB with the intake and have a 70MM MAF sitting on my shelf. Is this overkill and will it affect my lower RPM torque? Should I use my stock 60MM TB and MAF? I am currently running an Edelbrock Rollin' Thunder Performer-Plus Hydraulic Roller with the following specs.,

#3722
ENGINE: FORD 5.0L V8
RPM RANGE: Idle-5500

Duration at 0.006" Lift: Intake: 282° Exhaust: 282°
Duration at 0.050" Lift: Intake: 220° Exhaust: 220°
Lift at Cam: Intake: 0.311" Exhaust: 0.311"
Lift at Valve: Intake: 0.498" Exhaust: 0.498"
Timing at 0.050" lift: Open Close
Intake: 0° ATDC 40° ABDC
Exhaust: 40° BBDC 0° BTDC
Centerlines: Lobe Separation - 110° Intake Centerline - 110°

Note: May use original hyd. roller lifters. For mass-air engines only.
I may junk the cam and go back to my stock roller cam if any combo is significantly better than the other. Any advise is appreciated.

Thanks.

 

[fungus]

Larger TB and MAF = more air into the engine = GOOD! Just make sure your MAF is calibrated for the size injectors you're running. If your 70mm MAF housing is cal'd for 24#ers and you're running 19#ers the computer won't like it!

 

[Broncobowsher]

I had a 70mm on my 330" stroked 5.0
It had tip in issues. I could not get a gently progressive throttle opening. Crack the throttle just a little and it flowed so much air that it didn't matter how far you really pressed down. The throttle was too digital.

So I put the stock Explorer 65mm on it. The engine was way more built then what you have (stroker, huge heads, larger cam, etc) but the 65 had the same feel on the top end as the 70. but I could control it off idle. Made the engine much more drivable.

Now for the MAF. could care less what one you run. As long as the computer is programmed for the MAF and the injectors are the size the computer is expecting then it should be good. Throwing some random MAF on therewill not make it run better. The sole purpose of the MAF is to measure the amount of air entering the engine. Depending on the calibration of the MAF (that is the sampling part and the housing working together) there is a specific voltage for the amount of air entering. The computer knows that for ever 14.7 pounds of air that it needs to inject 1 pound of fuel. The computer is programmed for injectors that flow a given number of pounds per hour, simple math and it squirts the fuel. For idle and cruise it takes a look at the O2 sensor and does very minor adjustments to fine tune it. Just putting a bigger MAF housing, that is not the same calibration for voltage per pound of air and the computer no longer knows how much air is entering and can no longer accurately figure out how much fuel to spray. If it isn't too far off it might be able to learn, but that larning is just enough to make up build variation, not enough for completely wrong parts and values. The nice thing is with an aftermarket chip (properly programmed is important) the computer can be re-programmed for the calibration of most any MAF and most any injector as well.

The general rule I have been taught is the MAF should be the same size as the throttle body to 10mm larger, usually 5mm larger is about ideal. Too large and it can't sample low speed airflow accurate enough, too small and it chokes. For your relitivly stock engine, smaller is probably better.

 

[broncaholic]

Larger TB and MAF = more air into the engine = GOOD! Just make sure your MAF is calibrated for the size injectors you're running. If your 70mm MAF housing is cal'd for 24#ers and you're running 19#ers the computer won't like it!

I am currently running 19# injectors and the new (used) Explorer setup I purchased came with orange (19#) injectors as well. I have read that the 19# injectors will handle a motor up to 300hp. @ 39 psi and 330hp @ 60 psi. The TB is stock off the explorer setup as well. Could be a 65MM TB?
As for the MAF I have on my shelf, it is calibrated for 19# injectors as well, or at least that is what I was told when I bought it on EBAY.
Thanks

 

[fungus]

I am currently running 19# injectors and the new (used) Explorer setup I purchased came with orange (19#) injectors as well. I have read that the 19# injectors will handle a motor up to 300hp. @ 39 psi and 330hp @ 60 psi. The TB is stock off the explorer setup as well. Could be a 65MM TB?
As for the MAF I have on my shelf, it is calibrated for 19# injectors as well, or at least that is what I was told when I bought it on EBAY.
Thanks

That being the case I'd say you're good to give it a shot. The exploder TB is 65mm. If the 70mm MAF acts like BroncoBowshers did you could always throw on the smaller MAF.

 

[broncaholic]

That being the case I'd say you're good to give it a shot. The exploder TB is 65mm. If the 70mm MAF acts like BroncoBowshers did you could always throw on the smaller MAF.

I must have measured it wrong. The throat must be 5mm bigger than the butterfly? Maybe I measured the MAF wrong too.
Thanks

 

[gravy]

I would run a 75 or 76 mass air with a 70mm throttle body- 65 is stock explorer- 55 stock mustang. I run this with 24's and explorer intake, Pro-M is my preference for the MA but BBk has a new one out that people are talking about- as said earier make sure it is calibrated for the correct injectors and for the filter set up you are running- it does effect it.