Hey im new to this forum and to the mustang community, and i was wonderin what is the stock diameter of the exhaust piping for the 1999 Mustang GT, and if i decide to get a new exhaust what size piping should i look into??

 

I think the stock size piping on a 99 GT is about a 2.5 or 3' diameter. As far as exhaust goes I would recommend a flowmaster exhaust system, Probably about a 2.5 inch exhaust....

 

Your stock exhaust is 2.25'. I would probably go with a Bassani or magnaflow. Flowmasters are the best for 5.0's, not 4.6's. Get a 2.5' set-up.

 

Straight pipes would be awesome if it's leagal in your state.

 

im jus wandering y not put the pipes as large as possible? i thought that would be better but i dont know so thats y im askin.

 

lol as large as possible do u see those coffecan muffler ricers...

 

yea but i meant like about 3" and yea i have seen those thing and they look stupid

 

Bigger pipes will increase exaust flow but it'll reduce exaust velocity. To get hp, you need to get exaust out as fast as possible. Bigger is better on the high-end but smaller is better on the low-end.

 

What he said...