V6 dual exhust problem

Bills Stang · 10-16-2009

So I had them change my exhaust to a dual. I went with 3" pipes (i may regret them talking me into 3"), h-pipe and flowmasters. I am going back to Midas tomorrow because the pipe is hitting the axle when I hit bigger bumps! not good! not good at all!
My question is that it is very loud now when ever I touch the gas at all. drove to work the day after and at cruising speeds it was loud and lots of vibration. I have seen past post about different issues but not sure if any of them will work for me.
Any ideas? Did they maybe not weld all the joints completely, do I need exhaust clamps, more hangers. One on each pipe close to cat and two on each muffler. Hangers don't seem to be loose.
I don't want to be making 5-6 trips to Midas like I have read others have done.

Thanks!!

amustangrocks · 10-16-2009

goin 3" was probably not so good. the stock system is 2 1/2, the mufflers are made for 2 1/2 in and its already overkill for the v6. i had to shorten one side of my h pipe cause it was too close to the rear end. i didnt add any extra hangers and its just fine. my kit is just bolted on, no welds and no rattles. i like my exaust being sorta quite, with no drones, but i`m old

dcmab · 10-17-2009

mine also hits the axle on big bumps. as for the rattling just see if you can tell where its coming from

Torch_Vert · 10-17-2009

Well, 3" is definitely overkill for a 4.0L V6 (It's even overkill for a V8 unless the engine is seriously built/modded)

Exhaust is sort of like water pressure in a garden hose. Ideally you want it to flow quickly with little restriction for best performance. Too small a diameter pipe chokes the flow, and too large kills the flow velocity as the exhaust sort of meanders through the overlarge pipes.

If your car isn't lowered, they should be able to get 3" pipes in there without anything hitting if they're positioned correctly.

johnnshepherd · 10-17-2009

it's probably because the piping is so big. make them switch it to 2 1/2 and claim that as the problem

johnnshepherd · 10-18-2009

correction factory piping is 2 1/4
just measured mine.
the only setup that would even think of needing 3 inch piping is a twin turbo setup

graz · 10-18-2009

i guess you can say in this case "size did matter!"

sometimes bigger isnt best,you went too big,go down to the 2 1/2

i have a pypes system on my stang,never had a problem yet.

Bills Stang · 10-20-2009

sooo basically I need to either add turbo

or change to 2 1/2" ? Wishful thinking and I think the wife would kill me for the turbo

so that leaves 2 1/2"

I took it in and they fixed the axle hitng the pipe now it's just kind of loud at 1500- 2000 rpm. This is not what I hoped for. Makes a loud commute! I get my JLT CAI and tuner in a couple days. Any chances the tuner will help? or just bite the bullet and go back and have them change to 2 1/2? If it's 3" up to the bend before the axle and then goto 2 1/2" will that still work or do I need to go back further with 2 1/2" ?

bboy_spy · 10-20-2009

Hmm... I have the pypes system and I yes it is a very loud drone (if that is what you are talking about) around 2,000 rpm. One simple way to kill the drone part is the change out the mufflers. I'm changing out my street pros for gt500 take offs. You have flowmasters which are nice so.. you may not want to do that. I would say reduce the exhaust to 2 1/2 all the way through. That way you get more pressure like torch vert was saying. The end result of a smaller piping will be no more drone and quieter.... however, because there will be larger amounts of gases escaping through the smaller pipes(more pressure) during hard acceleration, you will likely get a loud throaty and aggressive sound on take offs, but not suffer from that dull drone during cruising. She'll be quiet at idle and cruise, but come time to gas it, she'll roar with an aggressive growl! Good luck man.

08v6 · 10-20-2009

The 3s Are WAY to Big And You Prob Lost A Lot Of Tourque Cause Now Youve Got No Backpressure In THe Motor......Its True You Do Want To Increase Flow But Only So Much Or Else Your Just Making You Car Stupid Loud And Stupid Slow.....My Suggestion.......Go Back To The Stock Size And Throw on a straight through muffler. like a cherry bomb, Borla Or magna Flow...Personally I Like Cherry Bomb...Sounds And looks Awesome And Like A quarter Of The Price Of The Others That Do The Same Thing. Then When You Get Your CAI You Will Notice The Growl And Get like No Incar Drone...Plus Your Car Will Run Smoother And You Will Notice More Torque In your Assometer.

Good Luck.

Bills Stang · 10-24-2009

Thanks everyone. I will be taking it in today or tomorrow to get them reduced. They are also still hitting when I go over large bumps. Plus a couple days ago I added the JLT CAI and tuner so I want everything to run smoothly

bboy_spy · 10-24-2009

hey Bill, I just solve the problem yesterday with the rattle over bumps, when I had my gt500 take offs put on. I did a little snoopin around before taking it into the muffler shop because I wanted to tell them where the problem was so that they could correct it (and put on my new mufflers

) Anyways after examining the left and right side, I noticed on the left (drivers) the pipe was awfully close to the a rear support/ sway bar... probably about 1/4 inch. So when my car got on the lift at the muffler shop, I showed the guy my problem and he said it was an easy fix. All they did was raise the pipe a little by welding on a little support cradle a little further up on the pipe. It now clears the bar by about 1 inch... no more rattle! Had this done + my muffler install for 40 bucks. Pretty happy. I posted pictures for ya so that you can see where the problem is.

Bills Stang · 10-25-2009

Thanks Bboy I will check that out. Already back from the Muffler shop but haven't gone for a ride to test things out. I will look at that before I do.