2.5" or 3" exhaust for a '99 5.9L???
Like I said, it depends on what you want out of your vehicle. Like it or not the cat is a restriction in the exhaust system. In most cases emissions are not changed because the O2 sensors can detect the variation of carbon between the inlet and outlet and adjust mixture. You leave the cat on to pass emission inspections for varification.
Like I said before, it all depends on what you want from your vehicle.
Like I said before, it all depends on what you want from your vehicle.
They are all the same on the inside.
Hall Of Fame
Joined: Jun 2005
Posts: 14,228
Likes: 19
From: Riverton, UT
Don't know what's a Johnson is?........LOL...... I'll show ya mine....
Indy<----- Sent you a good package today. Take what you want.
Anyway back to the subject. You said you wanted you keep torque. In your motor you want a specific back pressure of about 2 thru 2 1/2 lbs so as not to burn your valves. If you run OEM manifolds and set the system up like I said to your application as specified you wil have great power and good arch. This could even work for P&P heads like mine, but shorty headers would also be an option to keep the back pressure needed.
Now if you want to do more then you install a Supercharger then install long headers, 2 1/2 to a 3" Y pipe(made by MagnaFlow), Hi-Flow 3" cat, and 3" at least 22 inch strait flow muffler out to duel 3" to rear or single 3" to rear and you'll be VERY happy.
Indy<----- Sent you a good package today. Take what you want.
Anyway back to the subject. You said you wanted you keep torque. In your motor you want a specific back pressure of about 2 thru 2 1/2 lbs so as not to burn your valves. If you run OEM manifolds and set the system up like I said to your application as specified you wil have great power and good arch. This could even work for P&P heads like mine, but shorty headers would also be an option to keep the back pressure needed.
Now if you want to do more then you install a Supercharger then install long headers, 2 1/2 to a 3" Y pipe(made by MagnaFlow), Hi-Flow 3" cat, and 3" at least 22 inch strait flow muffler out to duel 3" to rear or single 3" to rear and you'll be VERY happy.
