Exhaust Questions

[joepizuro]

So a while back I took some suggestions on a decent system and I liked one of the suggestions..


Shorty Headers + True Dual Straight Pipe. No Cats/Mufflers.
Maybe Rolled Tips.

Now a few of my buddys told me that I would get terrible gas mileage due to the o2 sensor but I thought the o2 sensor in a 95 was before the Cat anyway?

Also another thing was the back pressure. I heard that 95 5.9s LOVE back pressure so would I need a baffle for back pressure?

Just trying to verify all this before I get to work.

EDIT: Also. I was recommended 1.5" pipe but someone told me that you need 3" pipe or it crackles real bad when you let off the gas.

 

[Okiespaniel]

Majority of folks feel that 2.25 to 2.5 pipe is best...you'll have your occasional exception. I don't believe in dropping the cat either unless its for racing.
What is the truck used for? Generally the bigger pipe the higher the rpm needed for optimum power
I would not go with 1.5 inch pipe...your stock exhaust would flow better! Straight pipes are cackly no matter what. Decent mufflers would probably enhance the useful powerband over straight pipes!

 

[joepizuro]

I use it for hauling a gooseneck with 3-4 horses normally. (I know it's not meant for that) But its so close to 300k miles and doing fine.

 

[ParrotHead FA]

I've got a 5.2 with shorty headers and true dual straight pipes. (no mufflers/cats) It's strong as hell, gets good mileage, and great for hauling/towing, mudding and off roading. She'll also light up all 4 tires in 4 wheel drive. It's pretty loud and crackly during hard acceleration, but mellows out to a quiet rumble when you reach cruising speed. The setup I use is 2" pipe from the header collectors all the way to the rear bumper, with screw ins welded to the pipes below the headers for the oxygen sensors. The long run of 2" pipe gives just enough back pressure without robbing any flow- you can see the exhaust stream moving the grass a full 15' away from the truck when I'm off road. It's my estimation that these engines love low backpressure, my little 5.2 loves to rev up and pass with plenty of get up and go on the highway, and can still accelerate when hauling a heavy load up a long hill. If the noise is a factor for you, you can use the same true dual setup, only use a pair of fairly long glasspacks. They provide negligible backpressure over straight pipe, and the longer the shell length, the quieter it will be. A short (10-15" shell) glasspack will be loud and snotty, whereas a long one (24-28" shell) will have more of a quiet rumble and less of the loud crackling motorcycle type sound. I have a couple friends who run 2nd gen 5.9 Rams with true duals, 2" pipe and 'packs, no cats, and they both reported better power/acceleration and improved fuel economy also. IMHO I think there is a lot of government induced propaganda/myth floating around out there misleading people to believe modern engines run better with backpressure in order to discourage people from removing their cats and altering their emission controls. I have installed true duals on many 2005 and later vehicles of all types (both 8 cyl and 6 cyl) with no cats and race type mufflers or no mufflers, and nearly everyone said they could feel an increase in power, and most reported at least some improvement in fuel economy.
Dave