exhaust

[ncsdaonex]

okay i took my stock muffler off my 2.3 L because it was bad, now i put a glassspack on it and how do i know im getting the correct backpressure so i can get the most hp from the engine?

 

[doorgunner]

One fast way to tell is go stand by the tail- pipe with the truck running---if the exhaust fumes are strong enough to make you move away, the computer might be (trying to make up for a lack of back-pressure) re-adjusting itself and causing a problem by running too rich (you get more power, but the gas tank & your lungs empty a lot faster)....

 

[Wicked_Sludge]

backpressure is a bad thing on a 4 stroke engine.

your computer and engine doesnt know or care what muffler is on the truck. you arent going to gain or loose any power with just a muffler change.

 

[Ranger#1]

backpressure is a bad thing on a 4 stroke engine.

your computer and engine doesnt know or care what muffler is on the truck. you arent going to gain or loose any power with just a muffler change.

ever herd about the scaviging efect

 

[07rangersport]

ever herd about the scaviging efect

geez dude learn how to spell. Wicked is right. Changing a muffler does nothing

 

[Wicked_Sludge]

ever herd about the scaviging efect

yes i have heard of scavenging. whats your point?

 

[doorgunner]

So, Wicked--I'm confused(which doesn't take much)--when I took my cat & muffler off to re-do the exhaust, the O2 sensor was still working, but the smell from the exhaust was too much to handle(excess fuel?). Was lack of back-pressure the cause from not having a cat?, or was the O2 sensor causing the computer to go crazy. When I put the new cat on, the skunky exhaust went away. Just wondering...(now "eye" can see how a million cat-less trucks could really mess up the air)

 

[Wicked_Sludge]

were you running it with open manifolds? just a y-pipe? what?

its possible that the lack of backpressure right before the O2 sensor was casuing the computer to read incorrect....but its much more likely due to how you had the exhaust setup. also keep in mind that the catyletic converter is there to help burn unburnt hyrdrocarbons from the combustion chambers. it could be that your truck is running a little rich ALL the time, but the cat converter is burning the excess fuel off before it comes out the pipe...so you dont notice it.

im (ashamed to say) running my 3.0 with no cats and i dont get any O2 codes, the exhaust smells fine, and i still get 24MPG on a regular basis.

 

[Hahnsb2]

My exhaust always smelled really strong with no cat. Isn't that what the cat is there for, to clean up all that nasty shit? My rig ran great and had great emission numbers with a single aftermarket cat too, better than my dads b2 with stock cats.
The HCs were something like 275ppm with no cat (225 is the limit I think) and like 55ppm with a cat.

 

[doorgunner]

Wicked---U R Rite--#2 cylinder has only 20# compression=unburned gas--the new cat is doing it's job--now to fix #2 Oh, Y out of the cat, no muffler(s) until "duals" reach back bumper= Harley exhaust

 

[jax4bangin]

my buddy took the cat off his 95 2.3 and its loud as all hell and runs like shit.. no bottom end power to speak of.. whats the cause of the power decrease?

 

[Wicked_Sludge]

what size exhaust pipe is he running?

 

[jax4bangin]

its all 2.25 to a straight through magna but then about 2 ft length of 3" dia. turned out before the wheel

 

[Wicked_Sludge]

oh wait, a '95 is OBDII, he should have had a post-cat O2...which would explain his issues.

 

[jax4bangin]

yea its got the censor after the cat.. so is readin too much flow and makin it rich or wat? man its dog slow but he likes makin a sh** load of noise haha i been there too