Magnaflow Exhaust

[Dixie Design]

Originally Posted by jfuller5

Hey Bill, What exhaust do you reccomend for 08 F150 supercrew 5.4 for daily driver and light towing? Looking for HP and MPG but still fairly quiet. Going to get a Gryphon with your Custom 87 performance tune but think I should get exhaust first, no CAI planned. What have you seen work? Single exhaust is ok . Thanks: Jim

Corey made a great recommendation there! I know you're asking Bill, but I'll chime in too if you don't mind The first exhaust mod I made was to replace my factory muffler with a 14" SI/SO and really liked it. With your truck having only 2 cats as opposed as the 4 mine came from the factory with, you'd a bit louder than I was with the SI/SO swap. A magnaflow SI/DO would be cost effective and sound even better! I'd probably stick with a 14" or 18" certainly nothing larger if you want more sound.

[jfuller5]

Thanks for the quick replies Corey and Dixie, sounds great but I am looking to not be too loud, what do you think. Jim

[Cajun]

What does removing the rear cats do to you at inspection time? I had no idea the new trucks had FOUR cats. :omg: With that much restriction, I'd bet exhaust doesn't do much for you performance wise unless you remove at least one set. GEEEZZZZ the government is killing the hot rodder....stupid government.....

[Dixie Design]

Originally Posted by jfuller5

Thanks for the quick replies Corey and Dixie, sounds great but I am looking to not be too loud, what do you think. Jim

Can always start with a 14" SI/SO, from what you've said thus far I'd say you'd be thrilled!

As for my inspection woe, have none. Down here in South Georgia they don't only skip the "sniffer" we don't even HAVE inspections!!

[Cajun]

Originally Posted by Dixie Design

Down here in South Georgia they don't only skip the "sniffer" we don't even HAVE inspections!!

Well that makes it easy...I don't have it so lucky here in North Carolina. It's a fairly extensive check that includes a sniffer and hooking you up to a diagnostic computer. That's another reason I'm a little worried about having a tune in place when I get the inspection, the sniffer could be bypassed by a more efficent tune for sure, but what does that computer tell them?

[Jackpine]

Originally Posted by Cajun

Well that makes it easy...I don't have it so lucky here in North Carolina. It's a fairly extensive check that includes a sniffer and hooking you up to a diagnostic computer. That's another reason I'm a little worried about having a tune in place when I get the inspection, the sniffer could be bypassed by a more efficent tune for sure, but what does that computer tell them?

Cajun, everything I've read in the tuners section of the f150 forums says DO NOT deprogram your vehicle prior to a diagnostic computer check. If you do, it will set a code that causes the vehicle to fail unless it has been driven long enough to "unset" the code (about 30 miles I believe). Those that have had the diagnostic test and have left their tunes in place have all passed without any difficulty.

I kind of think all the tester does is look for malfunctioning items like O2 sensors, EGR valves, and so on. One thing though: I believe if you run up against the speed limiter, it sets a code, and I don't know when/or if that code goes away by itself. For that reason, I adjusted my max speed up to 110mph, even though I don't intend to get there.

And, remember you can use your Gryphon to check for codes before you take your truck in to be tested. It can clear these codes too if the cause of them has been eliminated.

I intend to leave my tune in place when my truck is inspected (which won't happen for another year in Tucson).

- Jack

[Cajun]

Yep, that makes a lot of sense Jack, thanks for explaining it that way. Thanks for the tip on the limiter code, too. I'll probably do the same thing you did, although it would take one heck of an emergency for me to hit any sort of speed limiter. Those days are passed, I'm a little sad to say, but who knows, Pinks might comes to town looking for an all truck 12 sec field or I might get a wild hair and bracket race it one weekend. Yeah....who knows?

[Dixie Design]

Never thought my truck would hit 85....then my wife borrowed it for a weekend while I had her truck tore apart. Went through the "records" on my edge, top speed: 97mph....

[04FX4]

Which gives best overall performance? si/so or si/do???

[GSXRider]

Bill,

I know what I've read, but what do you recommend best for HP & MPG in the Magnaflow line SI/SO or SI/DO on a 5.4L and should I run a 14" or 18" if running the SI/DO if you recommend the SI/SO, what 14" or 18". The only upgrade I have presently is K&N cai and it will be some time before I do anymore . It's my daily driver and my commute is 36mi round trip, do love the HP but would also like to keep or gain the MPG . Last, but not least, will be upgrading my Edge Evo to Gryphon with 87 Perf. custom tune after all I've read on this great forum thanks to everyone for the info, I've learned alot.

GSXRider