hey guys i have a 04 gt completly stock exhaust im looking to go with shorty headers and a off road x pipe and was curious about mufflers what muffler do you guys think will give me the best power with that setup? would straight be the best? im not sure thanks for your input!
Good luck on the header install, it is a PITA for real!! The difference in power between mufflers is minimal. With that said I do prefer the blow-thru style mufflers. They'll all have similar gains. My first exhaust was Pypes but then I swapped out the mufflers for Cherry Bombs. No noticeable difference. Just the CB has a deeper note to it.
It's going to the shop for the header install for sure ! I think I'm going with the pypes x pipe they make the violater muffler to that sounds nice thinking of going that route
If you are planning to stay the naturally aspirated route, go for the long tubes. Shortys don't scavenge as well as the long tubes. Long Tubes are a major PITA, but if you are planning to change the manifolds then the "one and done!" motto is applicable.
Mufflers really come down to your preference in sound. Pipe sizing also plays a big role here. 3", 2.5" and 2.25" all sound a little difference. There are also some caveats here. Big pipe will make more power if a smaller pipe is restricting flow from the engine, but if there is no restriction, torque numbers may fall due to a lack of back pressure. Smaller pipe will keep good back pressure, but must be replaced when the engine is upgraded and making more power. Superchargers and Turbos would require a larger piping size, so if these are in your plans for the car in the near future, you may want to consider a 2.5" or 3" system. Hit up youtube and listen to many sound clips to determine what you like best.
The mid pipe is also another consideration as well! An X is said to make more power, but an H is said to make more torque. An X will sound more raspy like a European sports car like a Ferrari, whereas the H will have a deep rumble like our 1960's forefathers! The midpipe, besides the stock manifolds is one of the biggest corks in the Mustang's exhaust system. Ford graced our cars with 4 cats. Make sure to check where you live and ensure that you can legally run an off road midpipe. Emissions as well as safety inspections can be tricky!
Let us know how it goes and upload a video to youtube!
Hard to say, muffler selection is totally sound preference based in my opinion. Gains from a muffler swap alone are practically nothing.. maybe a few but nothing you'll feel. I've always preferred the sound of Flowmasters on that engine, but that's just me, and I can't recall hearing Flows with an X pipe before. I had the Mac O/R H mid-pipe on mine and loved the sound, but the unburned gas smell just got to me after a while, and I went back to just the flows. Based on other vehicles I've owned that had straight pipes only, I felt a loss of low end torque, noticeable enough that I didn't care for it and switched to something else.. I would avoid that.
Straight pipe not only sounds terrible and is entirely too loud but it will cost you power. A good quality exhaust system will make more Hp/Tq than just running straight pipe like the good ol' days. Long tube headers will sound amazing and make more power than their shorty counterparts but be prepared to scrape on every driveway and speed bump. Which leads to a lot of exhaust leaks and major headaches in the long run in my book. I ran a set of Hooker long tubes once upon a time, never again.
If your going to go with shorties, I would suggest ditching that idea and keeping the stock manifolds, there isn't really any gains from swapping to shorties... In which case, get an off-road x or h pipe, bolt it to the stock manifolds, and get cat-back of choice. Personally, I liked the sound of an o/r h with flowmaster catback. If I could do it over, I would have kept my o/r h and bought a new flowmaster catback instead of magnapacks...