I RECENTLY PUT A DUAL EXHAUST ON MY 2001 3.8 AUTOMATIC. I PUT MAGNAFLOWS WITH 2 1/4 PIPING WITH 3" TIPS. (CAT BACK) SINCE DOING THIS IT HAS BECOME SLUGGISH AT TAKE OFF. I DUNNO WHAT I CAN DO TO FIX THIS. THE SHOP I GOT IT DONE AT SAID THAT I GOT A YEAR TO BRING IN. BUT WHAT IS THE PROBLEM. I WANT TO KNOW THAT WAY I HALF WAY KNOW WHAT I'M TALKING ABOUT WHEN I BRING IT TO THE 
M.
NEED HELP W/BACKPRESSURE
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How much of the exhaust did you do? Changing the cat-back really won't effect low rpm exhaust scavanging.
What most people call "backpressure" is a miss conception. What you want is exhaust VELOCTIY. As you increase the diamter of the exhaust pipe, the exhaust gases start moving slower. You need to keep the velocity and momentum up to allow the previous pulse to draw out the next pulse. However, you can't go do small, because it can restrict flow at high rpm's.
I beleive that your problem is not related to the exhaust system. The cat back has very little effect on exhaust velocity at the header (because that is what is improtant
).
What most people call "backpressure" is a miss conception. What you want is exhaust VELOCTIY. As you increase the diamter of the exhaust pipe, the exhaust gases start moving slower. You need to keep the velocity and momentum up to allow the previous pulse to draw out the next pulse. However, you can't go do small, because it can restrict flow at high rpm's.
I beleive that your problem is not related to the exhaust system. The cat back has very little effect on exhaust velocity at the header (because that is what is improtant
).
Dude....sorry, but you're just gonna have to deal with it. I keep telling people that flow-through duals on a stock 3.8 are too much, but all I get is arguments.
bhuff30 has it right.....Not only do the gases move slower due to increased exhaust volume, but they cool down way too fast as well....cold air is heavier than hot air, and therefore slower-moving.....and that kills low-end torque. You may have gained HP on the top end, but your low end has suffered for it.
You can't compare it to a 96 because their stock numbers are way lower to begin with.
You can't have the best of both worlds without doing pretty major mods to your engine. If you want at least SOME of your low-end back, lose the Magnaflows. Go with a restrictive muffler, not an absorption muffler. You'll sacrifice some on the top end, but it'll still be better than stock. It'll sound better too, but that part's just my opinion.
Either that, or put a procharger kit on it. Woot!!!
bhuff30 has it right.....Not only do the gases move slower due to increased exhaust volume, but they cool down way too fast as well....cold air is heavier than hot air, and therefore slower-moving.....and that kills low-end torque. You may have gained HP on the top end, but your low end has suffered for it.
You can't compare it to a 96 because their stock numbers are way lower to begin with.
You can't have the best of both worlds without doing pretty major mods to your engine. If you want at least SOME of your low-end back, lose the Magnaflows. Go with a restrictive muffler, not an absorption muffler. You'll sacrifice some on the top end, but it'll still be better than stock. It'll sound better too, but that part's just my opinion.
Either that, or put a procharger kit on it. Woot!!!
GREENBIOCH
Founding Member
Go out and get some gears now 3.73s. you won't be whining anymore, that will fix your problem and you keep the hp up top.
JadeFalcon
Founding Member
GREENBIOCH
Founding Member
GREENBIOCH
Founding Member
I have straight pipes, I had no problem with losing low end trq, the difference was negligable. Although I want to try out some LT headers and X pipe.
Reading the responses from different people and actually reading all of your sigs tells me something.
If you have a 98 or lower 3.8, don't expect the 99+ to act the same way when flow-thru duals are installed on an otherwise unmodified engine. 2 different animals. 150/215 vs 190/220 hp/tq. The loss may be more noticable.
If you have a 99+ with a boatload of other mods, don't expect an unmodded 99+ to act the same. More air in=the need for more air out.
If you have a 98 or lower 3.8, don't expect the 99+ to act the same way when flow-thru duals are installed on an otherwise unmodified engine. 2 different animals. 150/215 vs 190/220 hp/tq. The loss may be more noticable.
If you have a 99+ with a boatload of other mods, don't expect an unmodded 99+ to act the same. More air in=the need for more air out.
peyotesands
New Member
xneox said:
You are absolutely right. I have/am experiencing the same problem as the dude with the 2001. I have a 2000 auto and I noticed my ride is utterly dead at takeoff which is why my ETs have been high 17s. I have to deal with it for now because eventually I'll supercharge my mustang and then the duals will come in handy. for now it's all about the looks.
peyotesands said:
Supercharger
I'm just gonna go with either the MAC or the FRPP y-pipe quasi-dual kit. I figure that'll free up a little on the top end without killing a noticable amount on the low end. I also want to avoid the ricey sound that I've heard on many a Magnaflow soundclip.
If ever I decide to throw supercharger money into it....well.....I think I'll be able to afford an exhaust upgrade too.....
peyotesands
New Member
xneox said:Supercharger
I'm just gonna go with either the MAC or the FRPP y-pipe quasi-dual kit. I figure that'll free up a little on the top end without killing a noticable amount on the low end. I also want to avoid the ricey sound that I've heard on many a Magnaflow soundclip.
If ever I decide to throw supercharger money into it....well.....I think I'll be able to afford an exhaust upgrade too.....
Unless you're going to push a lot of power through that v6 it'll always sound "ricey" although I consider it just being a low power engine. The sound of an engine always gives away it's true power regardless of the cylinders. Anyways, what I was going to say is that if you get true duals then a CAI will definitely improve the sound of the exhaust. that's the one thing I instantly noticed after installing mine.
peyotesands said:
Actually every y-pipe dual setup soundclip I've heard sounds much less ricey than true-duals.....most likely because w/true duals you're hearing 3 cylinders per pipe & with a Y-pipe you're actually hearing all 6 out of each.
From a supercharged performance standpoint I would think a good X-pipe or a pro-chamber would lessen the ricey sound when high-flow is required.
GREENBIOCH
Founding Member
xneox said:
I get anything but comments about rice. In fact I have to tell people that it is a 6, which surprises many. I think it sounds ricey after 3000rpms and no matter what mufflers you get like it was said before, the motor gives itself away. Oh and an x pipe (in my opinion)will make it sound more ricey and more so if you get rid of your Cats. If you go straight thru keep your cats you will get a nice idle, I have yet to hear a sound clip that sounds like it does when your standing next to the car.
You can try and get any mufflers you want, the only difference I hear in sound is whether it is a chambered muffler or a straight thru design, chambered is louder and not as efficent performance wise(in theory), straight thru will be less loud(or more ricey as you put it) but breaths better, thats it in a nut shell.
I felt loss of low end power when I got duals, but highway driving was a bit more fun to do. Now that I have gears that insignificant loss of low end is so negligable that it really is not worth losing sleep over wether it is a pre or post 99 car.
Quote:
If ever I decide to throw supercharger money into it....well.....I think I'll be able to afford an exhaust upgrade too.....
Why Waste your money, Do it right the first time. Obviously your speaking from lack of experience here. How is letting your engine breath a bit better hurting performance again?? Your talking about exhaust temps going down and stagnant fumes in the exhaust system. Your not changing your headers or increasing the diameter of the pipes all the way thru the system, unless you want too for SC, turbo, or Nitrous. So how is a true dual system hurting performance, I don't understand your logic here??
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