Rebuilding 5.0 EFI
Thread Starter
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Freshman User
Joined: Jan 2003
Posts: 38
Likes: 0
From: Queensland, Australia
Rebuilding 5.0 EFI
All,
Been thinking about rebuilding my 5.0 EFI as its getting on in years. I have heard that these SD EFI motors dont go any harder with any head work (or anything else for that matter) unless you you do a Mass Air conversion?
I'm sure someone out there knows about this stuff! I certainly dont.
Cheers
Nordo
Been thinking about rebuilding my 5.0 EFI as its getting on in years. I have heard that these SD EFI motors dont go any harder with any head work (or anything else for that matter) unless you you do a Mass Air conversion?
I'm sure someone out there knows about this stuff! I certainly dont.
Cheers
Nordo
Senior User
Joined: Mar 2002
Posts: 450
Likes: 0
From: Charter Oak, Iowa
Rebuilding 5.0 EFI
You can do more to a SD system than most people will tell you. The truck in my sig is speed density. I just finished it up and have a couple hundred miles on it. I'm currently evaluating for any problems in the air/fuel ratio and haven't found any strange things yet. The SD system is compensating very well to the mods. Cam choice is probably the most important thing. This engine runs very well and I'm quite pleased with it.
Randy
Randy
Moderator
Joined: Jan 2001
Posts: 56,984
Likes: 2,738
From: Virginia
Rebuilding 5.0 EFI
I know the theory, but don't have any actual experiences like the other guys.
The computer has to have a way to know how much fuel to add to the engine to make it run it's best. On a speed density system, they take a specific engine combo, and using throttle position, vacuum(map sensor), and a few other inputs, from testing at the factory they know the engine needs a certain amount of fuel. They plug these fuel numbers in a chart in the memory in the computer, so it continually looks in it's memory for how much fuel to deliver for the inputs it receives.
If you change the engine combo too much, the computer does not know it in a speed density system since it was programmed for a stock engine. So for the inputs it receives, the numbers in the memory chart are now wrong for the new combo.
In a mass air system, instead of assuming how much air is going into the engine from throttle position and the map sensor, it is measuring the flow of air directly. So it can adapt if the engine is modified from stock.
The computer has to have a way to know how much fuel to add to the engine to make it run it's best. On a speed density system, they take a specific engine combo, and using throttle position, vacuum(map sensor), and a few other inputs, from testing at the factory they know the engine needs a certain amount of fuel. They plug these fuel numbers in a chart in the memory in the computer, so it continually looks in it's memory for how much fuel to deliver for the inputs it receives.
If you change the engine combo too much, the computer does not know it in a speed density system since it was programmed for a stock engine. So for the inputs it receives, the numbers in the memory chart are now wrong for the new combo.
In a mass air system, instead of assuming how much air is going into the engine from throttle position and the map sensor, it is measuring the flow of air directly. So it can adapt if the engine is modified from stock.
Thread Starter
|
Freshman User
Joined: Jan 2003
Posts: 38
Likes: 0
From: Queensland, Australia
Rebuilding 5.0 EFI
I have heard that some Mustangs in the States came out with MA, I believe this is some type of sensor in the throtle body. Was this a 5.0litre or 5.8?
Q.Has anyone done this converion? will this be compatible with AOD or will u need E4OD?
Q.can you get a MA computer/harness on to a 351 SD?
Ponderings
Nordo
Q.Has anyone done this converion? will this be compatible with AOD or will u need E4OD?
Q.can you get a MA computer/harness on to a 351 SD?
Ponderings
Nordo
