Anyone relaced the cat with a 4" front pipe?


Did you notice any difference in noise, spool up and/or EGT's?


I've already done the Max Mod (EGR disconnect) without tripping a light, so I assume I can rid myself of the cat in hopes of lowering temps.


Practical or senseless?


Thanks


Rob

It should help spool up a bit. I don't think you will have to worry about a check engine light. It definately can't hurt anything. It should also reduct EGTs.

I've been running the 4" cat-killer pipe for 6000mi. No dyno testing yet though. Seems to run better, but seems is a terrible way to judge mods.

I have been running a LB7 downpipe on my LLY with MBRP 4" 409SS exhuast for about 2000mi. I dont see where a 4" is any better than a 3.5" in regard to a mostly stock or mildly progra Edge etc..., but the removal of the CAT. definately improved turbo spool and cooled exhuast, i also have done the MAX MOD. and unplugged my EGR as well, i haven't seen any difference there except for longer warm ups and a tad more spool & smoke...





BIG

What is the MAX MOD>? I haven't heard of it before and how are you guys unplugging your EGR and does it offer and gain in performance?


thanks again


chaps

Chaps


Canadian member, Max Power and others are experimenting with disconnecting the EGR valve, posts can be found here. Good reading, great idea


http://www.dieselplace.com/forum/forum_posts.asp?TID=13040&PN=1


I only named it the MAX MOD cause he spearheaded the idea


Rob

Taking off the cat made mine sound a lot deeper. The thing I like the best is how the turbo whistles so much without the cat on. mine to seems like it spools up quicker. No codes set, and so far one of the best mods yet.