4" dual exhaust

[arrowheadracing]

Since I ve been locked up in the winter months here, I ve been comptemplating many new ideas ( atleast new to me ) about my 6.5. Today while I was out enjoying some sun ( via 17 degrees cold outside ), I saw a 6.5 truck with dual exhaust. 4" at that. So I looked into it best I could without crawling in the snow. From what I could see he had 3 " down pipe, split into y pipe straight out to 4" dual pipes with no mufflers. Of course I waited about 20 mins for the owner to come out. And by chance it was his wife driving it. She didnt know anything about it,but gave me thier number so I could talk to him. She started it up and reved it. Sounded very wicked.

Then on the way home I ran into a powerstroke with dual exhaust 4" also. Now that thing whistled like a tea kettle. Sounded like something that was more suited to be in Monster Jam then on the street.

Is this a new trend I am seeing or anyone else see this also ? It almost seems like that would hinder performance more then anything else , other then sounding very nice.

Todd

[BigDiesel]

I have also recently heard a new 6.0 with dual 4" exhaust. That thing just flat out whistled :eek: . I would think that a dual 4" on a 6.5 is a waste of money and offers no benefits whatsoever other than the "cool" factor.

[cruzer]

From all that I have read on this page, once the exhaust goes thru the turbo it's job is done. You don't want any back pressure post turbo. According to JK, 3.5"exhaust showed performance gains over anything smaller in diameter and minimal gains, if any, from 3.5 to 4". Like Big D said, it would be just the cool factor going to duals.

[DA BIG ONE]

Dual turbos would benefit from dual exhaust.

Our single turbo motors need the biggest downpipe that can be stuffed in there. However, space is limited so 3" seems to be most common. A larger, say 4" or 5" downpipe into a 3" or 4" exhaust would be far better and aid spoolup big time on our rigs. Perhaps knocking back the firewall for more space for a large downpipe is the way to go here!

Our 6.5 motors are about 396 cid, so knowing cfm flow w/o boost from say 1,000rpms to 4,000rpms, then w/boost at 5 lb intervals up to about 25 lbs would be a tellall for best pipe sizing.