6.7L Cummins intake tube
I got the modding fever again and deciding the stock intake tube with its silencer is keeping me from some power and from hearing my turbos sing. I thought that I would just take the silencer out(whi...
Forum Discussion
IdaD wrote:
What version of 6.7 engine was that? Curious if it was the DEF or pre-DEF setup. I'm surprised to see that much of a bump from just an intake and exhaust.
It was a 2008 pre-DEF with just an EGR and DPF. The engine produces a lot of NOx when it is pushed hard and the combustion temps are above 2,500F(which is what happens on a dyno). The external EGR of the 6.7L probably kicked in full force dumping a lot of exhaust gas to lower combustion temps which lowers NOx output. This would explain the lowered power output in the much more aggressive EGR in the 6.7L versus the less aggressive in cylinder EGR of the 5.9L. These new 6.7L with DEF should have higher output numbers because it is now the SCR that takes care of NOx at high load by dumping more DEF into the catalyst(which does not hinder engine performance) while the EGR now only handles low load NOx.
As far as the numbers on the intake and exhaust, it is true. They do add quite a bit for diesels which is why people say that diesels handle well with mods. The problem is that people apply gas engine physics to diesel physics and have no idea what they are talking about.
