Help Exhaust question!!

[Essence]

Hello, I've been a mustang owner since 1999 with the new body style and I've loved my 05 stang since ive had it.

I have a questio nabout my exhaust. I had Flowmaster super 40's put in the same week i bought it in 05, they sound great but i want it louder. I found a shop that will removed my 4 cats but the guy recomended me cutting my flowmasters off and just running a pipe to the back. My question is will i lose HP doing this? and is this a good idea?

Thank you to all that reply!

 

[MATRIX4.6]

No, and no. my experience has been with the FRPP stingers which are deeper and louder than Flow 40's imo. Second I added tuned headers (added slight decible increase) and an xpipe. Third sold FRPP stingers and got SLP Loudmouth's. By far the loudest I have heard with cats. You have to be carefull though the louder you go the more rasp and cackle you get. For me the SLP's did not last long and I had to splice in magnaflow mufflers before the axle, I kept the SLP's as tips. Now its loud when I want it to be and yet I still have a melow rumble at idle.

If loud and crackley is your thing by all means I would just cut off your cats and stop there, that is basically what this guy is recomending. Loud yes but imo not a good loud. Your car will sound beat and worn which im sure its not. If you have some money to spend look at corsa or pypes mid muffler package. I would stay away from no cats and no muffler.

quick vid. ( I still have cats with an x ) if you remove the cats its even louder. You can see the round magnaflow mufflers barely under the car as I put down the cam.

YouTube - Custom mid muffler cat back 06 GT

 

[COBESGT]

IMO, I wouldn't do what they are recommending. I don't think it's going to be the sound that you're looking for. I have basically fought the same battle that you're up against. I had the Flowmaster American Thunders with the stock h-pipe and I too wanted it to be louder. So I installed an O/R H-Pipe to not only gain some power but also gain the great exhaust tone that I was use to with all of my previous Mustangs. Well, these cars are very different and the sound was nothing close to what I was looking for, too loud and very raspy! So I did a bunch of searching and finally ended up installing some Pypes M80's after the O/R H-Pipe. After doing this I can say that I am now very pleased with the exhaust tone. It's not what I was use to with my previous Mustangs, but it does sound very good. If louder is what you want and you're not worried about messing up the stock h-pipe, I would remove the stock h-pipe from the car and pound/pry/knock-out all of the catalyst from the converters, then re-install the stock h-pipe. This may do 3 things for you, give you the sound (loud) that you're looking for, the empty cats will act like open chamber resonators and should reduce the raspyness, and you may also gain some HP. Be warned though, once you remove the Cats, you're going to get a Check Engine Light. This isn't a big deal and can easily be cleared. But if you want it to stay off forever, you'll need a tuner programed to turn off the rear O2's.

I hope this has been helpful advice. Here are some videos off my exhaust.

 

[Essence]

Thank you both for the tips. Matrix i really really like the sound your stang is putting out, I'm going to see what it will cost me to follow the steps you took to make your pony sound like a stallion! Do you have a ball park price on how much you spent on your setup?
Thanks again guys!

 

[MATRIX4.6]

Thank you both for the tips. Matrix i really really like the sound your stang is putting out, I'm going to see what it will cost me to follow the steps you took to make your pony sound like a stallion! Do you have a ball park price on how much you spent on your setup?
Thanks again guys!

BBK ceramic shorties: $368.00
FRPP X pipe (uses stock cats): $180.00
2 Magnaflow 4 1/2 x 14" round mufflers: $118.00 ($59.00 each ebay)
SLP loud mouth axel back: $329.00
Total labor cost: $300
-------------------
Total cost approx: $1295.00

But thats everything. SLP's are basically just tips so you can skip them and get a set a really nice 3.5" tips and save a ton. Also, the shorties did not add a tremendous amount of volume either, for me it was more asthetic and performance. So you can see if you just added the X pipe, mags and some tips with labor you should come under $400. Most quality axel back systems start at or near that mark. I wish I would have done this from the beginning.

 

[Essence]

BBK ceramic shorties: $368.00
FRPP X pipe (uses stock cats): $180.00
2 Magnaflow 4 1/2 x 14" round mufflers: $118.00 ($59.00 each ebay)
SLP loud mouth axel back: $329.00
Total labor cost: $300
-------------------
Total cost approx: $1295.00

But thats everything. SLP's are basically just tips so you can skip them and get a set a really nice 3.5" tips and save a ton. Also, the shorties did not add a tremendous amount of volume either, for me it was more asthetic and performance. So you can see if you just added the X pipe, mags and some tips with labor you should come under $400. Most quality axel back systems start at or near that mark. I wish I would have done this from the beginning.

I dont have that much money to drop all at once, can it be done in steps? or would that be more expensive in the long run? Sorry im a noob at working on cars and i appreciate all your advice again thank you!!

 

[MATRIX4.6]

Absolutely, it can be done in steps or sections but becarefull because exhuast can be a money pit for lightly modded cars. If you have a tuner and an CAI already I would just go straight to the x pipe, then magnaflow mufflers and swap the flow 40's for just a nice set of tips. Either way you will have to eliminate an axel back muffler if you are going to due this route because you will be adding back pressure instead of freeing it up causing a loss in power. Think of a straw if you pinch one end of it you cant blow through it...adding magnaflow mufflers and keeping the flow 40's will pinch off your exhaust and you will sufficate your ride.
Also, the flows will still manipulate the sound because they are not a straight through muffler, There are chambers the air has to pass through and that will affect the sound.

Going this route a straight through approach is optimal for an x pipe and a straight through designed muffler like the magnaflows or pypes M80. If you had a 99 stang think of how those cobras sounded like with their x pipe... In my opinion this will offer the best sound and performance.

Headers can come later as I mentioned it is more for asthetics as the stock manifolds actually flow very well. So if you budget allows maybe start with the FRPP or similar x pipe that will allow you to keep your stock cats and then save up for the magnaflow or similar round mufflers and tips to replace your flowmaster 40's. In my experience I have heard 100 different exhaust set ups and have had a couple on mine and In my opinion this option sounds the best.

 

[Essence]

Going this route a straight through approach is optimal for an x pipe and a straight through designed muffler like the magnaflows or pypes M80. If you had a 99 stang think of how those cobras sounded like with their x pipe... In my opinion this will offer the best sound and performance.

Headers can come later as I mentioned it is more for asthetics as the stock manifolds actually flow very well. So if you budget allows maybe start with the FRPP or similar x pipe that will allow you to keep your stock cats and then save up for the magnaflow or similar round mufflers and tips to replace your flowmaster 40's. In my experience I have heard 100 different exhaust set ups and have had a couple on mine and In my opinion this option sounds the best.

Thank you again for the detailed advice, Just one more thing. Will it make a difference which Intake i have on my stang? which is best? Right now i have a K&N "cold air" intake i bought when they first came out. combined with my exhause it makes it sound like an old becuase before i read your first reply i had my 40's cut off and have just a straight pipe now. I miss the mustang grumble noise i had and will get the xpipe and magna flows to fix this issue. Again im not sure about the intake. Thank you very much for all your help!!

 

[Wind-Farmer]

So what is being said is that putting an axel back/cat back (same thing) will add back pressure? Lowering power?

I could see this, when I put my Borla cat back on, there was terrible back pressure, or well, I could hear it and feel it more than when I had stock mufflers.

What is the deal with that.

 

[MATRIX4.6]

So what is being said is that putting an axel back/cat back (same thing) will add back pressure? Lowering power?

I could see this, when I put my Borla cat back on, there was terrible back pressure, or well, I could hear it and feel it more than when I had stock mufflers.

What is the deal with that.

This was said thinking essence was going to keep the Flowmaster 40's, cats, and also add another muffler by way of round magnaflows. Basically having 4 mufflers. That is when I mentioned that would add back pressure and power loss.

No, adding a different catback system from borla or similiar will not add back pressure. Some cars though depending on elevation may need more tuning to get the max out of their set ups.