[trent5.0]

Will a 94/95 cobra computer work in a 94 GT if i change the 19lbs injuectors to 24lbs? Also how big is the stock TB in a 94 5.0 GT? And if I do chang out the injuectors what eles do i have to do to make it run good?

[adriano_917]

56mm is the stock throttle body, and about the computer of the cobra that i dont know but u need to calibrate the mass air flow sensor to make it good. But why do u want the computer of the cobra its not gonna do u any good, the cobra had different set up than the GT, or what mods do u have ?

[stanger007]

The Cobra computer will swap over and run fine if you put 24s on your 5speed GT.

The MAF is identical on the v6, GT and Cobra Mustangs, it has nothing to do with the size of the injectors. That is handled in the PCM itself.

BUT, you won't gain anything going to the J4J1 Cobra PCM, in fact, you will probably lose power because the Cobra computer has less timing than the GT.

Put your money spent on a Cobra PCM towards a custom tune.

Wes

[adriano_917]

the mass air flow was the same but not the calibration, the COBRA needed more gas thus 24# vs 19# GT, different heads,rockers,pullies,TB,intake, etc so more air equals more gas.

[stanger007]

Originally Posted by adriano_917

the mass air flow was the same but not the calibration, the COBRA needed more gas thus 24# vs 19# GT, different heads,rockers,pullies,TB,intake, etc so more air equals more gas.

You are losing me... how does this relate to the original question?

Wes

[GTS 5.7]

Originally Posted by stanger007

You are losing me... how does this relate to the original question?

Wes

The Cobra computer made the car run right with the 24#ers even though the MAF was the same.Those differences made more power possible,Ford decided to set the A/F ratio with the larger injector by computer control rather than using a differently calibrated MAF

[stanger007]

I was confused because his first post said that the MAF needed to be calibrated to the 24# injectors which is untrue and the second one seemed to say that the calibration is done in the PCM tune (where it actually is).

The MAF "calibration" that you see done in aftermarket MAFs is actually a hack to get around changing the injector settings in the PCM.

Here's how it works. Say you have a car that came with 19lb injectors and now upgrade to 42lb injectors. If you run the car as-is, you will be getting roughly twice the fuel you need (the injectors are twice as big).

So what the aftermarket MAFs do is they underreport the incoming air by half, causing the injectors to only be fired half as long and making the 42s work.

This works pretty well, but this trickery will influence several areas of the car's tune because the engine is really taking in double the air that it believes is coming in. One easy to understand area that is affected is cranking, where the MAF trickery is not in play, and the injectors are fired at a pre-defined pulsewidth.

Our 94-95 PCMs are extremely dependant on LOAD, which is a figure primarily based on accurate MAF readings, so you can see how a custom tune that sets the values of the injectors and MAF in the PCM to exactly match the parts on the car will do better than trying to trick the PCM into working correctly.

Wes

[stanger007]

All that being said, a Cobra PCM will swap into your 5 speed GT with 24# injectors and run just fine.

You will lose some power because of the less aggressive spark tables. This can be somewhat gained back by advancing the base timing of the distributor.

I have done this on several cars. It works.

Wes