Exhaust Mods and Computer Re-program ?
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Joined: Mar 2002
Posts: 93
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From: Buffalo, NY
Exhaust Mods and Computer Re-program ?
This is my truck:
2002 F-150 Supercab Offroad, 5.4, ATI Procharger 12# Boost and appropriate fuel mods and Custom Tuning.
Say now I want to do an exhasut system. I am not changing the exhaust manifolds (no headers).
Say the system is High-Flow Cats, SI=3"/DO=2.5" Magnaflow Muffler, Possibly 3" tips (not sure on the size yet)(this is the sytem basicaly/approx).
Do any adjustments need to be made to my computer programming? I figured since I am leaveing the stock manifolds then everything should be OK, true?
2002 F-150 Supercab Offroad, 5.4, ATI Procharger 12# Boost and appropriate fuel mods and Custom Tuning.
Say now I want to do an exhasut system. I am not changing the exhaust manifolds (no headers).
Say the system is High-Flow Cats, SI=3"/DO=2.5" Magnaflow Muffler, Possibly 3" tips (not sure on the size yet)(this is the sytem basicaly/approx).
Do any adjustments need to be made to my computer programming? I figured since I am leaveing the stock manifolds then everything should be OK, true?
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Joined: Mar 1998
Posts: 13,385
Likes: 4
From: Virginia
Hi Keith,
I notice in your signature you mention your truck was tuned by Kennedy's, so this is something your tuner should really be answering for you, for best accurate info.
The only thing we can really tell you that would be accurate is what happens in the programs & tuning we use here at Performance. And just speaking in very general terms, making changes to the cat-back portion of the exhaust system in these late-model F-150's usually does not require us to make changes to our PCM programming/engine tuning to compensate. This may very well be true with your current tuner as well, that's usually how it works so you're probably OK. But don't *count* on that for sure without checking with your tuner, ok? Better safe than sorry.............
12 PSI is a lot of boost for the stock cast pistons in either the SOHC 4.6 or the SOHC 5.4 non-Lightning F-150 motors, so you'll want to make sure your tune is "fat" (somewhere around 10.0-10.5:1) to try to keep the pistons a bit cooler & hopefully avoid cracking off the crown out towards the top ring land. We generally recommend not more than 9 PSI boost and not more than 450 HP on the stock pistons. They do have a healthy silica content to resist heat, but the stock SOHC slugs don't stand up well against a lot of cylinder pressure. I think you & I may have spoken before about this, I seem to have a dim memory of you telling me that your tune was pretty fat, if my memory serves me properly, so this is really not for you, it's more for others reading these posts...........
Good luck!
I notice in your signature you mention your truck was tuned by Kennedy's, so this is something your tuner should really be answering for you, for best accurate info.
The only thing we can really tell you that would be accurate is what happens in the programs & tuning we use here at Performance. And just speaking in very general terms, making changes to the cat-back portion of the exhaust system in these late-model F-150's usually does not require us to make changes to our PCM programming/engine tuning to compensate. This may very well be true with your current tuner as well, that's usually how it works so you're probably OK. But don't *count* on that for sure without checking with your tuner, ok? Better safe than sorry.............
12 PSI is a lot of boost for the stock cast pistons in either the SOHC 4.6 or the SOHC 5.4 non-Lightning F-150 motors, so you'll want to make sure your tune is "fat" (somewhere around 10.0-10.5:1) to try to keep the pistons a bit cooler & hopefully avoid cracking off the crown out towards the top ring land. We generally recommend not more than 9 PSI boost and not more than 450 HP on the stock pistons. They do have a healthy silica content to resist heat, but the stock SOHC slugs don't stand up well against a lot of cylinder pressure. I think you & I may have spoken before about this, I seem to have a dim memory of you telling me that your tune was pretty fat, if my memory serves me properly, so this is really not for you, it's more for others reading these posts...........
Good luck!