will

I read in another thread that somebody's friend put dual exhaust on his V6 and it suffered due to that. I know that backpressure is a necessity in 4 bangers, which makes fart pipes extremely impractical and more annoying because you, the observer, know that their engine is suffering while they cruise around thinking it added 20 hp. Annnnyway.

I know Magnaflow produced a dual exhaust cat-back for the '99-'04 V6 Mustang. I'd like to know why they would do so if it harmed the car? I only ask because I would love to buy Magnaflow's offering for the 05 V6 'stang, but if it were to take horsepower away and cause me to use 93 Octane (no way in heck), should I just get a single exit instead of dual?

kn7671

It is still a single exhaust systems until it splits into 2 pipes for the exit. This type of system would not yield much of an improvement in performance, so these systems are ususally done for looks and sound.

With the 4.0 V6 engine, I think you could do a dual type system, but, with fewer cylinders on a low hp engine, it is hard to maintain clean exhaust emissions with the proper heat to ignite the catalytic convertors.

Most V6's of today are a dual exhaust into a single pipe for the catalytic convertors, then may split back into 2 pipes.

bob

NO ENGINE BENEFITS FROM BACK PRESSURE, BACK PRESSURE SHOULD BE DEFINED BY WHAT IT REALLY IS, NEGATIVE TORQUE

Engines can suffer from over scavenging or under scavenging, that is to say either the exhaust system is to effiecient and it siphons some of the cylinder charge into the exahust (unlikely on a stock based system I think), or the exhuast system creates a situation where exhaust flow becomes lazy and doesn't properly evacuate the cylinder. In any event, back pressure is a force that acts against the piston and the engine has to divert some of its energy into driving the piston against the back pressure so that the piston can move up in the cylinder.

For a graphic demonstration of back preassure, jump up and down once, then repeat the same motion with an unabridged dictionary strapped to your head. Notice how it took a bit more force to jump up and down. That is what back pressure is doing in the engine.

BENIFICIAL BACK PRESSURE IS A MYTH LIKE RAM AIR, SONIC CARBURATORS PRODUCING 100 MPG, AND IF ITS ON THE INTERNET IT MUST BE TRUE
Okay rant off.

bob

god screaming yellow is painful to look at

Boomer

What guys on V6s do is get an exhaust that is impractical for their car.
ie: getting something WAY too large to do any more good for the car.

On the 3.8 v6...most guys won't go above 2.5" because any larger is overkill and can do more harm than good...
Considering the stock is 2.25
I think my borla stayed with the 2.25 as well. No more than a 2.5 unless your using a supercharger and need to get more exhaust out.
With larger pipes on the 6...guys were noticing while getting more HP, their TRQ numbers were dropping.

Also using Mandrel bent aftermarket pipes, as opposed to the harsh bends on the stock pipe.

The 05 uses from what we've read/seen....mandrel bent 2.5 inch stainless steel on the GT...really all that needs to be changed are the muffler/tip unit...a lot easier than replacing the whole catback piping/mufflers/tips like before.

I'm not sure, nor can I comment on the size of the V6 exhaust, but would assume (could be wrong) that its 2.25" stainless steel (maybe also mandrel bent)

They definately will not harm your car, if you get a kit made for that peticular car.
No doubt the aftermarket companies like Magnaflow will create kits for both V6/V8s
Magnaflows also are straight through mufflers as opposed to Flowmasters which are chambered...and in some things I've read, the flowmasters don't flow any better than the stock system (throught the muffler) the pipes are better than stock however.

Basic car stuff...the faster you can get air in the engine, and the faster you can get the exhaust out...the better it is.
If changing the exhaust doesn't allow any more than normal exhaust out, your not gaining any benefit....unless the exhaust is used as a tool to 'cork' flow out....
03 Cobra: case in point.
One fantastic thing about that car is the ability to change the catback and gain a great deal of HP...as the stock system seems to be made to 'keep the hp down'
Change exhaust...voila...uncorked hP

We will have to see how the 05 reacts to pipe/muffler changes...however it looks pretty darn good off the start...so my guess would be not a huge increase.

jsheehan

I've been lurking around here, reading up on the '05, but I created an account specifically to reply to this topic. I drive a 2002 V6 'stang, and I have a GT Takeoff cat-back exhaust installed on my car. What this means is that aftermarket tuners such as saleen, who buy mustang GTs and mod the heck out of them, sell the parts they take off the GTs. I purchased the pipes, mufflers, and tailpipes, everything from the cats back, from a GT. On the current V6 stang, each engine bank empties into a seperate pipe, and has it's own set of cats. It isn't until after the cats that the exhaust from each side of the engine comes together, at a Y pipe. The single pipe after the Y exits out of the back. What I, and numerous other V6 stangers out there, have done, is had the pipes cut before the Y, and had the pipes welded up after the cats.

I do not have to run 93 octane gas (I still run good ole 87 with no problems) and I experienced no power loss whatsoever. In fact, this type of mod typically yields torque and horsepower gains. I am sure something like this will be possible with the new 05. The only problem i can forsee would be making another bumper cutout for the extra pipe (I have my pipes runnning under my bumper).

Try this site for more info: 3.8 Mustang

Edit: I just saw boomer's post, and what he says, especially regarding pipe diameter, is true. 2.25" is about the optimal pipe diameter for duel exhaust on a near-stock 3.8 V6 mustang.

dave_bought_another_black_stang

Man, I worked a v6 who had duals and some pods around his dash the other day and all i have is full length flows and cold air kit. Oh yeah, and I had a mountain bike and surfboard on top of the car with my racks! That has to still be stinging him.