I took my 1999 3.8 to a exhaust shop to see what it would cost for a true dual exhaust for my mustang, and I found out some bad news that I didnt believe. All of the mechanics there said it didnt matter what exhaust I put onto my mustang, I WOULD NOT GAIN ANY HORSEPOWER.

I wanted a flowmaster or borla kit for around $600 and they said the ONLY thing I would be paying for is looks and sound. Is that true?



Will you gain any horsepower when putting on a true dual exhaust?

 

with that motor, not a chance... swap for a v8 and thats where its at

 

you will get around 4-6 RWHP, and screw flowmaster, go to summit racing and get some force flow mufflers for $30, they are exactly the same just half the price

 

I believe it, i did a full exhaust on my 5.0 and didnt pick up any ET

 

honestly with the 99 motor your not going to gain much, maybe a couple horses. However you will feel the difference in throttle response. Also, if your planning on further mods down the road, the dual exhaust will become more efficient