sequential fire speed density?
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Junior User
Joined: Aug 2010
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From: Canada
sequential fire speed density?
Was doing some reading on oldfuelinjection and I came across an interesting fact...
The late 80's/early 90's crown vics, grand marquis and t birds utilized a speed density system with sequential fire injection as opposed to our trucks sd bank fire. I wonder why they did this... surely there was some efficiency gain to be had, so why not make all sd vehicles sfi?
I also got to looking at the harnesses of the crown vics and t birds with comparison to our truck computers and it seemed a swap was do able until I realized those vehicles never used a pcm controlled tranny. Obviously with a 5 speed you could throw a crown vic pcm into your truck with the benefits of sfi without having to go maf.
Sorry, just thinking out loud and though everyone would be interested and maybe give some input on the potential efficiency benefits of sfi sd over bank fire sd.
The late 80's/early 90's crown vics, grand marquis and t birds utilized a speed density system with sequential fire injection as opposed to our trucks sd bank fire. I wonder why they did this... surely there was some efficiency gain to be had, so why not make all sd vehicles sfi?
I also got to looking at the harnesses of the crown vics and t birds with comparison to our truck computers and it seemed a swap was do able until I realized those vehicles never used a pcm controlled tranny. Obviously with a 5 speed you could throw a crown vic pcm into your truck with the benefits of sfi without having to go maf.
Sorry, just thinking out loud and though everyone would be interested and maybe give some input on the potential efficiency benefits of sfi sd over bank fire sd.
Lead Driver
Joined: Jul 2007
Posts: 7,868
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From: Rhode Island
It would be a pointless swap unless you just wanted a smoother engine.
The main reason why the truck guys swap to the MAF setup is to get the MAF, not the sequential injection. The MAF responds better to changing conditions outside of the truck and compensates for increased air flow from performance parts. They can hold a nice idle with far larger cams as well.
The main advantage that SEFI has over batch-fire is better idle quality, and marginally better fuel economy - probably not even 1 whole MPG point on these trucks.
The main reason why the truck guys swap to the MAF setup is to get the MAF, not the sequential injection. The MAF responds better to changing conditions outside of the truck and compensates for increased air flow from performance parts. They can hold a nice idle with far larger cams as well.
The main advantage that SEFI has over batch-fire is better idle quality, and marginally better fuel economy - probably not even 1 whole MPG point on these trucks.
Posting Guru
Joined: Dec 2008
Posts: 1,226
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From: Rusty, Maine
I agree. You wouldn't make your money back in fuel savings for years.
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