Flowmaster American Thunder Exhaust
 

I know everyone keeps saying that changing out the mufflers doesn't give you and HP but I was reading the August 2005 edition fo Hot Rod and on page 144 they did a quick test of the exhaust on the 2005 Mustang. The article says "The mufflers didn't pick up anything through the low and mid-range (and actually lost a little bit here and there), but at the HP peak they were worth 2 HP. The car did have a K&N FIPK already installed which bumped the HP from stock of 263 HP and 283 ft/lb to 272 HP and 289 ft/lb before the install of the exhaust.

Just thought I would share this.

RE: Flowmaster American Thunder Exhaust
 

For a street car this is a bad trade off (low-mid torque for top-end hp), and one that can easily be avoided. Don't just spend the $400-$500 you would spend on the axle backs, spend $350 and an hour or so of your time and get a Meziere electric water pump and 10HP+ all the time. The pump is equally as cheap as a CAI and ECU programmer on a cost per HP basis and adds a proven 10HP+ to your wheels. Your car will be much more consistent running and you will not suffer from the hot soak that the '05 GT's are so sensitive to.

Cheers

RE: Flowmaster American Thunder Exhaust
 

When it comes to mufflers on these cars, its all about sound. I have the Flows and it has a healthy tone at low rpms, but no drone at road speed. Cant tell any power difference, but even Flowmaster says you wont gain any power, just a sweet sound. Gotta admire their honesty.;)

RE: Flowmaster American Thunder Exhaust
 

I too have the Flowmaster axle backs.......And they sound sooo sweet ! As far as losing low end, or gaining top end? Youll never notice either one , I promise. I also put on the C&L intake with SCT tune, honestly I dont even notice a power increase from either one of those as well, but the WOT exhaust note is pretty mean sounding !!

RE: Flowmaster American Thunder Exhaust
 

You really cant tell any power difference with the cai and a tune?? I dont have either yet, because Im debating wether 15 or so horse is worth over $400. It seems it isnt. Think I'll start a poll on this.

RE: Flowmaster American Thunder Exhaust
 

For the average street driven or road raced car the midrange is very important and you will feel and see it in your lap times it if you've got it. I got my car dyno tuned and picked up 16HP in the mid-range and it's noticable when accellerating out of a corner and just around town without a downshift. If you don't notice any difference with the C&L and SCT tune there is something wrong with the work that was done or you NEVER get on the gas. Even a 10HP difference is noticable to the casual driver. My wife who never notices anything noticed the power added with the Meziere water pump and that's only 10HP or so. With a C&L intake and SCT tune up you should get at least 20HP minimum and more likely a 22-25HP bump.

Cheers

RE: Flowmaster American Thunder Exhaust
 

how much was that water pump again? and can I use it with the SC? =-/

RE: Flowmaster American Thunder Exhaust
 

Hi lost,

$300 give or take, fits exactly like the stock one, all you have to do is a standard R&R for the pump and then connect it to the fuse box with a relay that is switched with the ignition key. You can also turn on the fans with a switch for cool downs wih the engine not running. There was a post with pix and diagrams. Mine is just on with the key at the moment until I manage to decide what I want to do with it.

HTH

RE: Flowmaster American Thunder Exhaust
 

sweet.. thanks for the info.. the fan option is a great idea.. procharger has you replace the fan with a high speed one (still looks like sheet).

RE: Flowmaster American Thunder Exhaust
 

I totally agree with Redfire and Nitrojunkee. I love the deep bass sound the Flows give. It just makes the car feel more masculine! I always modify the exhaust on my cars as I love the sweet music that it makes. I even put Flowmaster Series 40 Original Flow on my Lincoln Mark VIII LSC. You should see the heads turn. They just don't expect that deep growl from a Lincoln. What was that old 50's song, Hot Rod Lincoln?