What are the advantages of a 5" over a 4"? Ive heard that you need more power upgrades such as bigger turbo and injectors to get the benefit of the 5". Does anyone know if this is true? Im also needing some advice on which exhaust to get. Im wanting something that sounds agressive when you get on it, but not so obnoxiuos. I had a 4" straight pipe on my 95 Cummins and it was to loud, even at idel. Im wanting something where I can still hunt in the woods and not be heard from miles away.
i would have to agree, though i dont know for sure, that you would need the larger turbo, etc. to actually gain the benefit of a 5" exhaust. i have an mbrp 4" exhaust and love the sound of it. its a little louder than i would like the closer i get to 3k rpms, but im not sure what would be quite at that rpm. a buddy of mine has a bully dog 4" on his 03 duramax and it actually sounds good untill we hook up the trailer with his buggy on it. the exhaust sounds horrible when the truck is really working hard. ryan
It takes somewhere in the neighborhood or 600HP to start causing a 4" system to be restrictive. You don't need 5" for performance reasons. I wouldn't see a reason at all to put a 5" kit on a Dmax or PSD, they just don't sound right. The cummins is the only one I would put 5" on, since then they sound like an N14.... the sound is great with an I6. No performance gains though.
Word on the street (nomenclature for tribal knowledge) is that even the stock 3" exhaust on the 2nd gens are good for up to 400hp. Doubt there is any study to point to but that's what is taken as gospel over at TDR. opcorn:
I have the Banks 4" exhaust on my 05 D-Max and I can tell there is a small change in the exhaust note but not much. I thnk that the combination of letting the kat out of the bag and the 4" exhaust lowered my egt's about 200 degrees. I would say get a good kit from a reputable manufacturer and call it good. No reason for a 5" kit on a D-max
I went with a 5" straight from a stright piped stock 3". EGT decrease is awesome! Did feel a slight power loss but nothing I couldn't fix but bumping my fuel plate forward a little more. IMO i would skip the 4" and go to the 5". A friend just put a 4" on his 01 cummins with an edge comp and still gets warm and is looking for someone to buy it so he can go to 5"
On a Duramax 4" is all that is needed. We carry alot of brands and can get you a good price. Shoot me a PM if you are interested. waytogo
