I took out the majority of the 3" on my 02 and swapped it to 4" .Id say 80%.The only question is that its not the place i started because thats fine I just stuck the inlet of the bigger pipe over the existing pipe and then the smaller pipe with an adapter is fitted into the 4" but its the factory pipe that goes over the axle and then the tailpipe that I have stuck inside the bigger 4" pipe.

I was just wondering if that piece of smaller factory pipe that i stuck into the 4" would cause an obstruction? I didnt have a mandrel bent exhaust piece to work with.The place i started is fine since the pipe is just going over the pipe coming from the turbo but its just the smaller pipe that i fitted into the 4" towards the end by the axle.I was just wondering if that would cause backpressure due to the fact that its blowing through the 4" and then the exhaust has to escape out the smaller pipe that i fitted into the 4" pipe and welded shut. I didnt really stick it that far inside the 4".Id say only bout 2-3 inches.

Sorry for being so long just kind of concerned.I worry bout everything.


sort of like.Hope this helps:
Bigger Pipe
____________________________________?_Weld
=================>................___________Small er Pipe______
Exhaust: ============>
=================> Exhaust:
Exhaust: ============>
=================>................________________ ___________
_____________________________________?_Weld

Sorry that was kind of up.Atleast that might give you an idea.Im just concerned about back pressure is all.Since the exhaust hits the gap between the two different sized pipes.

 

You'd probably get a little restriction going from the 4" down the 3"........how much I'm not sure but it'd probably restrict some flow.



~Nick

 

yeah? thanks.i had a little bit of trouble fitting em because lack of an adapters but still got it half.

I didnt want to go 5" because i heard that using 5" is overkill,robs power, and causes a turbelence?(spelling) Plus it would get quieter.

I noticed that it got a little quieter at idle but when i start to go and shift through gears escpecially when im towing that it gets extremly loud but with a lower tone.I liked that.Not to many complaints. I thought the rest of the factory pipe towards the end would leave a little bit of higher pitched loudness to mix with the 4" to make it sound perfect.I didnt want to really add a 4" tailpipe cause then i thought that it would get quieter.

Oh well i think itll work out great.The only problem is that I wake up everybody i been told when i leave early every morning to go to my big truck to work.hah

 

what makes it loud is removing the cat/resignator and or muffler.

what is loud?

loud outside or for you in the cab?

keep the tailpipe about 4" or more past the edge of the bed and up as close to the bed as you can without vibration. this will help with any "droan".

 

both.its extremly loud,louder than the 3" factory pipe when i had it straight piped.it seems it got a tad bit quieter from the tailpipe at idle but maybe its because i lost some of my hearing.hah


I dont think it will cause that much restriction since the exhaust has to go somewhere but just more exhaust coming through that the exiting 3" that it will have to face.