HI, I was wondering if anyone could tell me if an aftermarket exhaust will lower your egt,s any and if so about how much ? My truck is 04.5 CTD and it already has a 4" exhaust and was thinking of putting aftermarket muffler on it. Would the muffler lower the egt,s any over the stock muffler? THANKS

 

A high flow straight through muffler will improve exhaust flow and potentially lower EGTs a little. Normally air intake upgrade and muffler will do the best.

 

Yes. The stock muffler is very restrictive. Cat not so much.

 

It will help...not a lot

But every little bit helps.

Add a hi flow air filter, and that will help a little bit too...

Better throttle response also.