The Cat is worse than the muffler, especially aged Cats, on second generation diesels.
There is no point in an intake. The only thing you stand a chance of gaining is MAF problems. The stock intake is the best combination of filtration efficiency, freedom, and code free operation that exists. The aftermarket intakes are a complete waste of money, unless you need to run over 70 lb/hr airflow. That is over 32 psi at 3400 rpm. And no box tuner does that really. Eliminating heat soak in the intake is another matter. That is the worst offense, not restriction. Airbox temps of over 200 degrees. And AFE/KN does not help with that.
A V-clamp back exhaust is definately an improvement, or splicing as mentioned earlier, and improvement to egt. The downpipe restriction is significant, but these restrictions are in series, eliminating a lesser restriction does not negate its benefit, just because there is another restriction that is even more. The garden hose idea mentioned proves this. 2 equal length hoses, a 1/2" and 3/4" hose. Put a 1/2 id" washer in each one, and the 3/4" hose still flows more, with less total pressure drop, a fact.
i agree about the cats,i noticed a big difference in the performance of my trucks when i put a straight pipe on it,i use to have the stock pipe with no muffler and no cats with a 4" tip.i didn't gain much better performance by putting in an after market air intake,i also gained 2 miles a gallon by doing the straight pipe and air intake.
__________________ James
Priority List
God
Wife
Her Car
Work Car
then the Truck
you have to go turbo back... cat back systems are more for looks and sound, if you want a true change in performance, X the cats and get a 4 or 5 inch mandrel bent kit... MBRP is one of the easiest to install... looking at about an hour tops in the driveway..
you have to go turbo back... cat back systems are more for looks and sound, if you want a true change in performance, X the cats and get a 4 or 5 inch mandrel bent kit... MBRP is one of the easiest to install... looking at about an hour tops in the driveway..
i agree with what bnkrupt said about the turbo back exhuast,i ran 5" magnaflow on my 06 lbz and i wouldn't switch back to the 4".
__________________ James
Priority List
God
Wife
Her Car
Work Car
then the Truck
You don't have to limit yourself to store bought kits, you can find a good muffler shop that will insatall a much better exhaust and place it anyway you like for 100's less. Your only problem is some will not bend the law and remove the cat. So you might have to look at more than one place.
__________________ 2006, 2500HD, Extended Cab, Short bed, 4X4, LBZ, Gray-stone Metallic, MBRP 4" down pipe back ,no cat, Edge juice w/ Attitude, Banks Ram air intake with Super Scoop, AEM Water Methanol Injection, EGR block and finger stick. BFG All Terrain KO 265/75/16.
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.