Why 112 LSA for EFI?
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Why 112 LSA for EFI?
The title is the question. What is the meaning behind the general rule of thumb?
More specifically, im building a 351c with ECC-IV (MAF). Sticking with flat tappet cam, I have few 112+ LSA cams to choose from off the shelf. However I have a multitude of choices for 110 LSA.
More specifically, im building a 351c with ECC-IV (MAF). Sticking with flat tappet cam, I have few 112+ LSA cams to choose from off the shelf. However I have a multitude of choices for 110 LSA.
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This is moreso for speed density EFI since they require a high vacuum signal at idle for the MAP sensor. With a MAF system, it can meter the extra air and compensate for it. The Ford Racing E303 cam is on a 110 and it idled fine in my MAF 88 5.0 Mustang with a nice lope to it. My current cam is 112 (Trickflow Stage 1) and it idles fine, even though my idle vacuum is around 15"
That being said, go 110 if you want, since you will be running MAF. When you get the duration @.050 up above around .214, this is when your vacuum starts to drop. I would recommend an adjustable fuel pressure regulator. I am getting ready to install one because with my low vacuum, my idle pressure is up to between 34 and 35 instead of 32psi and since I have 24# injectors, It runs a little rich at idle even though it still idles fine.
That being said, go 110 if you want, since you will be running MAF. When you get the duration @.050 up above around .214, this is when your vacuum starts to drop. I would recommend an adjustable fuel pressure regulator. I am getting ready to install one because with my low vacuum, my idle pressure is up to between 34 and 35 instead of 32psi and since I have 24# injectors, It runs a little rich at idle even though it still idles fine.
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