OK I've got a stock 2002 5.4L SuperCrew. I want to upgrade the muffler. I'd like to do a Lightning style exit before the rear tire. My question is...I currently have single in/out, I’d like to go with single in/ dual out. If I have 2.5 in, what should I get for dual out 2.5? If I do, won’t I lose a lot of back pressure and low end? My buddy tells me I need to go with 1.75” to keep same cross sectional area. But all I see is 2.5 or 2.25. I’m looking at Magnaflow Satin Stainless either the 5X8 or 4X9, not sure what length to get. I want something quiet at idle and cruise but you can hear me when I get on it. TIA.

 

Your buddy must drive a dudg or chevy...lol Hes full of crap ha
Its just a cat back,,you'll be fine with 2.5

Phil

 

The critical area for pipe sizing as far as losing bottom end is from the engine to the muffler. What you want is to keep the "proper" (whatever that may be...that's always debatable) exhaust velocity through the cats & muffler(s). If the gas slows down too much before you hit them, it can muddle around in the catalyst or baffles and that's one way to get inefficient flow.

Once you get past the muffler, then you're pretty much free to run whatever ya want for tailpipes. Dual 2.5" outs will be fine.

General rule of thumb...engine to muffler for performance tuning, muffler to exit for sound tuning.

I know several Ford runners that are just as full of it too. (I'm NOT insinuating you as one of em though phil)
There's lots of mis-informed folks out there...but mostly it's the ricer "fart-cannon" crowd that's way off the beaten track when it comes to pipes.

 

2.5" dual out would be just fine with a single 2.5" in. 2.25" would pop too much. I'm running true dual 2.5" exhaust and I have plenty of back pressure so you most certainly will. Have the muffler put in and the shop will make the tips for you.

The 5x8 is the si/do mufflers

The 4.9 is the single in/outs and dual in/outs

I would suggest the 14" body muffler. Magnaflows are quiet so the shorter the louder. I would suggest the 11" body but its either dual in/out or single in/out only.

So all in all, the 14" 5x8 http://store.summitracing.com/partdetail.asp?autofilter=1&part=MPE%2D12158&N=700 +4294922710+4294791975+4294906129+115&autoview=sku

And have a listen before you buy.

http://youtube.com/watch?v=06kuQgvl_Zo\

http://youtube.com/watch?v=1NAELQ8qq2A

Also dont forget to compliment it with some nice 3.5" tips.

 

what you want is exactly what i have on mine...i got the magna flow single in dual out in front of the rear tire and with 2.5"....i experienced no loss of back pressure or low end

 

yea i had a 3" in dual 2.5" outlet super 40 flowmaster...didnt see a loss or gain in anything..now i have tru dual 2.5" pipe and tru dual 3" inlet 3" outlet flowmaster 10's lol

 

You are killing exhaust flow with that super restricive factory y pipe, so you have no worries about backpressure. Get rid of that y and go true duals, 2.5" will be perfect for that.

 

josh if that was for me...i dont have a Y pipe...i have a H pipe

 

Nah, i know your setup, it's for the OP.

 

haha k man and yea Y pipes suck big 'ens theres not to much point in those suckers and people will put a Y pipe and run 2 mufflers off that..not really tru duals and cant be to good for performance

 

Cool! Thanks for all the info Guys!

phil6608, you're right........he drives a sludge....

 

i have they same truck and i am curious to two things. what is and what are the advantages of a cat back exhaust system?

 

Good info Darren, now if you're wanting the dual out merely for looks, I would think you could weld a small Y on the out of the muffler and run the two pipes out the side like you wanted. Just a suggestion if you really like the 11" I haven't seen or heard this done, I'm just trying to think outside the oval. :P

Roger That! My 3.5's came in the mail yesterday!

 

yeah man. I have true dual 11" bodies on my truck, click the link below the sig and have a listen. I like them, but if si/do was an option I would have saved money and bought that. But the true dual sound is so sweet to hear.

Also that decal is awesome

 

Bet you'll have one for yourself soon!