Engine 94 GT to Cobra conversion

opsman

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Apr 17, 2022
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Green Bay, WI
Hello, I recently started converting my 94 GT engine to a cobra. I upgraded to world heads, cam, cobra intake and 24lb injectors. Now I'm stuck at the MAF sensor. I'm told the GT and cobra uses the same sensor but the sensor needs to be modified to use with the 24lb injectors. Is this the case, and if so what is the modification or do I need to send it some where to be calibrated? I would really appreciate any help ending my confusion. Thank you
 
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Well while the maf and sensor may be the same (not sure) the computer specific to the cobra is what is calibrated for 24lb injectors, unless you have a cobra computer you will need to put a maf in that is for 24s.
Someone will correct me if I'm wrong.
And they love to correct me :doh:
 
the computer specific to the cobra is what is calibrated for 24lb injectors,
I will agree that it is the Cobra specific computer that has the calibration for 24lb injectors, MAFs are the same. You can use your stock computer but will need a MAF for 24lb injectors. I am a C&L guy as well so a 73 or 76mm MAF and appropriate sample tube would be a suitable solution. Other brand MAFs should work as well.
 
As the Cobra computers are quite expensive, you might be better off getting a chip for your current computer that loads the Cobra tune. If you want to learn how to do your own tuning, I'd recommend buying a QuarterHorse from Moates.net. You can then load the J4J1 Cobra tune onto your current GT computer as a starting point.

However, be careful if you have an AODE automatic transmission. Cobras only came with manual transmissions, so if you've got an AODE you can't just load-and-go with the J4J1 tune.
 
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Just stick the 19# injectors in it for now. That will allow you to get your setup up and running. At a later date, you can either have a tune done to run the 24s or just go with a “calibrated” MAF.
 
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Here is a MAF compare plot I put together a long time ago. This is based on the MAF transfer function data posted on TunerExchange. (I wish that site was still around.) The '94/'95 GT MAF is the same part as the Cobra MAF. The calibrations are nearly identical. There are some small differences in the values and break point selection, which could be from fine tuning changes the calibrators made at the time. I believe Ford calibrated the GT and Roush calibrated the Cobra.

The Pro-M 80mm data is from a friend's part where Pro-M provided the flow data sheet. This meter is calibrated for 24 lb/h injectors with a stock GT ECU expecting 19 pound/hour injectors, so it has a 26% flow shift high to correct for the difference in fuel flow rate. However, the best approach would be to change the calibration itself to match both the air meter and the injector flow rates to minimize issues.

1650376399304.png
 
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