Exhaust for my hj61

[burger]

Just wondering what you guys think I should do. I need new exhaust from about mid truck back.Should I stay with stock exhaust or should I fab up my own exhaust or can I by aftermarket. I have the 12ht motor and am under the understanding that I should go to 3 inch exhaust and a really high flow muffler from the turbo back. Is this a good idea or not? Let me know which is my best route.

 

[The Dude]

I went 2.5" from the down pipe back with no muffler. When I can find 3" mandrel bends I will replace it with those...dropped my EGT about 100* and the turbo spools up faster, I haven't noticed a performance gain.

The straight pipe is loud but not annoying, well at least it's not as bad as the straight pipe on my Duramax

 

[burger]

Thanks for the input big blue. I am assuming that mandrel bends are bends that do not collapse as they are bent so they are a full 3 inch. Where did you get your materials for your exhaust? Also did you just cut the original pipe from the turbo exhaust side and weld on an increaser to it or did you make another flange an increase there. If the first then how much pipe did you leave on the flange before increasing.

 

[cruiser_guy]

I run 2 1/2" pipe on my BJ60 w/o a muffler. It's not exceptionally noisy even from behind! I found out later that a muffler is a requirement with DOT (I've never been stopped for that though and I passed AirCare [smog test] as well without a muffler). If you need an inspection I'd put some kind of low restriction muffler (that's what the FJ55 will be getting in order to pass inspection and after that we'll loose the muffler).

 

[burger]

Hey cruiser_guy did you run 2.5 as well because 3 inch mandrel is hard to find or is that what I should run for some other reason. I was under the understanding that bigger is better on a diesel.

 

[The Dude]

I cut the down pipe just before the first curve off the turbo. Any muffler shop will have 2.5" piping with all the Ls you need.

You are correct on the mandrel, it keeps the 3" throughout the bend and does not crush the pipe.

When I go 3" I will change the turbo flange....

 

[cruiser_guy]

Bigger is better but 2 1/2" is readily available while 3" mandrel is expensive to do. I doubt that the extra 1/2" will make an enormous difference.

 

[HZJ60 Guy]

I plan on 3" all the way on my 1HZ. No muffler either. Im runing 2.5" without a muffler on my '01 TDI.


TB