It is best to match the MAF with the injector size correct? However I have had a mech tell me that it would be best to match it to the intake size type? I have a c&l 76 mm intake with a 70 mm tb does he mean get one that would match the MAF to the 76 mm instead of the 24# injec?
MAF
- Thread starter slow5.0gt
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onefstsnake
New Member
well your MAF needs to be calibrated to the injectors. But usually people run a slightly larger MAF than their TB.
The C&L will need a #24 tube installed to work correctly with #24 injectors.
I think what your mechanic is saying is that you need the right size MAF to TB size. Like a 76mm MAF wont work well with a 90mm TB.
The C&L will need a #24 tube installed to work correctly with #24 injectors.
I think what your mechanic is saying is that you need the right size MAF to TB size. Like a 76mm MAF wont work well with a 90mm TB.
tording
Founding Member
Yeah, I agree with onefstsnake. He means you need to run the correct size maf and TB. I always run a 76mm MAF with a 70 MM TB. You want your MAF housing to be a bit bigger than your TB.
onefstsnake
New Member
venturi effect FTW.
Im currently running a 76mm C&L w/ the stock MAF, but I have a 70mm Accufab in the mail.
Im currently running a 76mm C&L w/ the stock MAF, but I have a 70mm Accufab in the mail.
Shakerhood
20+ Year Stangneter 
onefstsnake
New Member
well you do need to go into the computer and change a couple things when you change injector size. But any half decent tuner can do that.
The MAF is what tells the computer via voltage how much air the engine is getting, so the computer knows how much fuel to deliver.
Aftermarket MAF's alter voltages (there are two different ways which you can read about here: http://www.mustangworks.com/articles/electronics/InductionBlues.html)
You want to match the MAF Physical size (73mm, 76mm, etc) to the intake/throttle body. You want to match the MAF calibration with the size of injectors you have (24lb, 30lb, etc). As mentioned in the link, Pro M recalibrates sensors; C & L uses the stock sensor and recalibrates via different sized sample tubes.
make your TB the choke point for the air as it enters the engine. there is no sense in having a 76mm MAF sucking air and pushing it thru say a 90mm TB, the TB is only working at like 70% as much as it could.
your engine only flows as good as its least-flowing part. unless you have boost but thats a different deal.
your engine only flows as good as its least-flowing part. unless you have boost but thats a different deal.
All you need to worry about now is that the MAF is correct for the 24lb injectors.
C&L uses a sample tube that will alter the output of the FACTORY sensor. (be sure to use your stock sensor with the C&L meter).
Check the C&L site for which tube you need. If you don't have the right one, they are about $25 and available from C&L.
With this setup, you shouldn't need to do anything with the computer.
Keep in mind though that you are using hardware that does not match exactly with the settings in your factory computer. For example you computer will still think that it is running 19lb injectors with a 55mm MAF.
Obviously there is some margin of error involved.
In most applications, the computer is able to adapt quite well. But once in a while the only way to get the car to run right is with a custom tune.
Hope that helps clear things up,
jason
93gtmustang
10 Year Member
- Oct 21, 2006
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Pro-M (GMS / Granatelli Motor Sports offers the MAF meter and recalibrated sensor as a package. http://www.granatellimotorsports.com/
C&L Performance uses your stock sensor with their meter. Calibration for different size injectors is done by changing the sample tube.
http://www.cnlperformance.com/calibration.html
C&L Performance uses your stock sensor with their meter. Calibration for different size injectors is done by changing the sample tube.
http://www.cnlperformance.com/calibration.html
onefstsnake
New Member
Venturi Effect- This term refers to the increase in velocity of a stream of gas or liquid as it passes from one area through another area of smaller size or diameter. Conversely, if the area through which the stream is passing becomes larger, the velocity of the stream will decrease.
I wasn't looking for a definition
It's just the this is of little importance when discussing EFI.
Carb's ? - then it's appropriate.
I'm just confused how it relates to EFI.
Shakerhood
20+ Year Stangneter
A Convergent Duct is where you go from a Large area to a Smaller area "think of an Ice Cream Cone with the end cut off" That will cause a Pressure Decrease and a Volume Increase. A Divergent Duct which is the Opposite has the Small End opening up to the Larger End, that would cause the Preassure to Increase and the Volume to Decrease.
93gtmustang
10 Year Member
- Oct 21, 2006
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Your set up looks good to me. 76mm C&L MAF to 70mm throttle body. As long as you have the correct sample tube from C&L to match your 24 lb injectors, your all set.
That's only half of it. Shakerhood finished it with the information that when velocity goes up, pressure goes down. This is why the venturis in a carburetor cause fuel to be sucked into the air stream. It's due to the suction of the low pressure. The same principle is what makes airplanes fly.
Shakerhood
20+ Year Stangneter
Exactly, Bernoullis Theorem covers what happens as air goes over the wing of an Airplane creating lift.
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