GM-Diesel.com

rfengin · #1 October 27th, 2009, 14:35

I have an LBZ that I tow a very heavy trailer. When it is 90 degrees out with the air conditioning running and going up a long hill, the auxiliary engine cooling fan will come on.

Will a Cat back or a turbo back exhaust upgrade help with cooling the engine?
If so, is one better than the other

North Maine · #2 October 27th, 2009, 19:52

An exhaust will help lower your EGTs, which indirectly *should* lower your engine temps. Turbo back is nearly always better than cat back, IMO for temps it should be turbo back, period. Any free-flowing high-diameter radius (mandrel) bent exhaust with a flow-thru muffler will produce better results.

M.Novak · #3 October 27th, 2009, 22:42

The turbo back exhaust system is the way to go except... If you still have any of the 100K engine/drivetrain warranty left. The way GM is getting with their warranty on the diesels-looking for any and every excuse to void that warranty, if you need any work done and they see the cat removed on their GM required modification inspection they will void any warranty you have left. My LBZ needed a new turbo about 7 months ago and I was sure glad I hadn't done much to mine, only a Banks air intake system and their cat back Monster Dual exhaust. They questioned me about where my tuner was hidden at, but I didn't have one. I still have a warranty, but I think maybe just barely. Wait till the warranty is gone before doing any real mods. Mike

rfengin · #4 October 28th, 2009, 00:59

Did you see any improvement with the CAT back mod?

M.Novak · #5 October 28th, 2009, 14:21

Quote:

Originally Posted by rfengin

Did you see any improvement with the CAT back mod?

Not that I noticed. The cat is the major restriction after the turbo. I kind of figured this out after doing an exhaust upgrade to my 6.5 about 10 years ago. I changed everything from the turbo back and also put on a mandrel bent crossover pipe. It was all 3" pipe (larger than the stock 2 3/4" pipe) with a dual outlet Flowmaster and 2 1/2" dual tailpipes. No noticeable improvement other than exhaust tone. Then the cat disappeared and that is when I could feel the difference. I pretty much expected the same thing on the LBZ and so I wasn't that disappointed when my thoughts turned out to be right. Mike

Tom S. · #6 November 2nd, 2009, 05:46

When you say 'very heavy trailer', how heavy are you talking about?