kham2525

Just a quick question here i'am in the works of getting a 2007 GT Premium. Well I've done exhaust and intake with my other cars V6 but have always lost the low end torque but gained at the top end. Is it the same with the Mustang V8 otherwise it will staystock? I'am looking to get the SLP Loud Mouth the day after i get the Stang then looking into getting an intake. I love the sound of the SLP but dont want to loose any low end torque any opinions or feedback thanks...

CrazyAl

Changing your mufflers/axleback/catback: No effect on power.

Shorty Headers: Expect a minor gain in the low end and midrange but a HP loss up to. (about +5 HP peak)

LT headers: Gain everywhere (about +20 HP peak)

bonedaddyjr06

as far as axelbacks i wouldn't say you lose anything or really gain much at all except for a bad *** sound....i didnt feel like i lost any power with my flowmaster delta series but maybe thats just me

enjoy
CJ

kham2525

Interesting i wonder why i lost my Low end grunt. I have a Lexus IS300 and lost all my low endtorque when i changed to an aftermarket exhaust.I really have to stomp on it.I was thnking maybe the difference was because the Lexus is a 6 cly.I just wanted to make sure i dont do the same tothe Stang by changing theexhuast

DROCKOFTX

I just put on a SLP O/R x-pipe and definitely a loss on the bottom end torque but it more then makes up for it at 3500 rpm and up. I'm running 4.10s and if that doesn't get me off the line quick enough. I just crack the bottle.

Arwing

I don't think you lose any, but when i put my SLP LM's on it sure felt like it.

CrazyAl

Well, the lexus is a different car with a different exhaust system--you can't compare it to the 'stang. The OEM mufflers are already very free-flowing on the stang. The only thing you change when you put new mufflers on it is the sound.

kham2525

Yeah thanks i figured that you would. I bet you feelmorepowerat highspeeds right?

I know the Lexus and Stangs are different cars yes i just dont want to go through the same thing again. I feel a great gain in power at high speeds but the low end has suffered a bit. I figure it has to do with the back pressure?

CrazyAl

Despite persistent beliefs, backpressure is ALWAYS bad for power.

Now, I know you're thinking "Wait a minute Al, I've heard people say that motors need some backpressure to run properly". You might even have experienced it. For example, people sometimes see a power LOSS after removing their tailpipe.

Now, here's the kicker: This MYTH comes about because people think "oh, when I removed my tailpipe and my HP dropped, that's becasue I now have too little backpressure". That is an incorrect conclusion. The HP drop did not come from backpressure loss. It came becasue the resonant properties of the exhaust pipe changed. When you alter the shape, diameter, and length of an exhaust pipe you are changing two things: backpressure (resistance to flow) and the resonant characteristics of the pipe. They are two seperate things.

Backpressure is ALWAYS bad.

Resonance can be bad or it can be good, it depends on many circumstances and what your goals are. (This is why thin, long, headers are best for low-end HP whereas short, wide, headers are good for top-end HP).

(this textwas from an earlier post of mine)

If indeed you change a muffler and your power curve changes, then those changes are most likely to be the result of resonance changes. I have no idea about the lexus setups, but on the S197 Mustang I have yet to see a HP change on a dyno from an axleback swap. Call up one of the big tuners who has a dyno in-house such as Brent @ Brenspeed or Fred @ Evolutionand ask them what they see on their dyno from exhaust changes.

kham2525

Thanks for your input Al.. I read 2 post above saying that they did infact feel a slight loss in the low end. I want to avoid this at all cost again.Iwould be pist if that wasto happen again.lol.. Perhapsi will give a tuner a call good idea Al.I have already test drove the Car andI absolutly love the power and sound in stock form.