Straight Pipe ALH

[myke_w]

The turbo exit is no bigger than 2.25, so theoretically you could run 2.25 all the way back and be relatively restriction free. If you wanted to flow a bit better on the bends (where most restriction occurs) you might do 2.5 but there's not much reason to go any bigger than that IMO, plus it makes it harder to get around the bends without hitting stuff.

[R.O.R-2.0]

a 2" section of 2.25" pipe will flow much more than a whole exhaust system..

as you add length, it makes i harder to push the gasses thru the pipe..

[myke_w]

That is true, but bends are where the major restrictions occur. It's also assuming that you have enough cfm coming out of the engine to cause a flow restriction (even in a straight pipe)

I'm not sure what the difference between 2.25 and 2.5 would be on the dyno, and I havent done the math, but I can't imagine it would be enough to worry about.

Hence my statement that anything larger than 2.5 being overkill, in addition to the problems of factory fitment.

[R.O.R-2.0]

smaller pipe makes for a more crackly exhaust.. may not have to worry about that soo much on a diesel, but i know that my diesels were loudest with small exhaust..

i had a 2.5" straight pipe on my rabbit with an ALH turbo.. it sounded really nice..

anything is going to be quiet when it has a VNT breathing into it..

[myke_w]

I agree 100%

[catlin_cava]

I did it....and just in time I cut the pipe for the muffler and moved the muffler a bit and all the hangers on the muffler where rotten and she fell off ....

right now i'm running 2" Pipe From the Turbo back and its nice and quiet inside, but you hear the turbo ALOT more and I love it...and from the outside its a noticable differences but not overlly loud.

I am Happy with it.

[theman53]

Hence my statement that anything larger than 2.5 being overkill, in addition to the problems of factory fitment.

There is no such thing as UNDERKILL