exhaust backpressure
#11
RE: exhaust backpressure
GEARHEADRT - I think the look of the side exhaust is awesome, but it is not for me, I prefer the look of the rear exit dual to the sides of the tow hitch. I am a big cup fan, but watch truck series when I can.
#15
RE: exhaust backpressure
I'm not sure on these trucks as I don't know the computers, but I know that on most cars I've dealt with it depends how you have the throttel for the target AFR. There are two modes, open and closed.
Closed mode is when you are just driving around. The computer will automatically strive to reach stoichiometric which is 14.7 as you mentioned. You also have open mode, which, at least on the cars I've dealt with, is when you floor it or have your throttle around 80% or higher. Under this the computer doesn't use all the sensors and relies on maps put in it from the factory. It is possible to run lean during this as they are preset maps and don't take in all the conditions that closed loop mode does.
However, I don't see that adding an exhaust would lean the engine out enough to actually hurt anything.
Closed mode is when you are just driving around. The computer will automatically strive to reach stoichiometric which is 14.7 as you mentioned. You also have open mode, which, at least on the cars I've dealt with, is when you floor it or have your throttle around 80% or higher. Under this the computer doesn't use all the sensors and relies on maps put in it from the factory. It is possible to run lean during this as they are preset maps and don't take in all the conditions that closed loop mode does.
However, I don't see that adding an exhaust would lean the engine out enough to actually hurt anything.
#16
RE: exhaust backpressure
BrandonS,
I was told that on my 03 silverado, it was not possible to run a cat free system. I was told that it would mess with the PCM, and i would not get the needed valve cooling. What do you think about this? Thanks for the help.
I was told that on my 03 silverado, it was not possible to run a cat free system. I was told that it would mess with the PCM, and i would not get the needed valve cooling. What do you think about this? Thanks for the help.
#17
RE: exhaust backpressure
I am running cat-free on an 02 silverado w/o any problems. I havnt got my PCM changed or anything. Two of my friends have the same thing, and thiers both work great also. One of them got there PCM reprogramed for it, and his scoots... I think it is better if you do, but runs fine if you dont. Oh yea, thiers are 2001's and 00's. Hope this helps
#20
RE: exhaust backpressure
I can't see that it would affect your valves at all, but it might throw an emissions check engine light for you. If your truck has an O2 sensor before and after the cat it'll compare the values and see it's out of wack with the cat missing and posisbly through the light. Aside from your exhaust smelling and the light, I can't imagine anything else happening.
Oh yea it's also a federal law to have one; if that matters at all.
Oh yea it's also a federal law to have one; if that matters at all.
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