6.7L Cummins Forum

Hi Everyone,

I know several folks have done the MBRP 5" dpf exhaust mod on their 6.7 and have a couple questions.

Did mine today, went for the 5" dpf back ali version and went for a test drive. One thing I did not do was to wash the oil out of the MBRP pipe. During my test drive with reg running, I was seeing the turbo surge to 25 psi of boost and then I would hear a deep tone .. pst .. (just like an old waste gate releasing). There are no errors on the system, engine runs really good. Just wondering if anyone had similar issues when first installed ? I hear the sound on the passenger side slightly below the turbo .... Seems to happen around 70+ mph going up a slight incline on the freeway.

Cheers,
Roberto

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Hi Everyone,

Figured out the problem and it was what I though. The pipes arrived very heavily oiled, so much so that the box was completely ruined. So when I installed the pipes, I cleaned the outside and not the inside, it also happened to be just the right time to do a regen. The 1100+ degree temp was enough to flash the oil and with each flash off, create enough of a pressure change that vacuum made the turbo spin faster. There was a engine made a long time back based on this principle ..... Darn it, the escapes me at the moment. It was based on spraying fuel into a curved pipe and igniting it at a pulse rate ....

My way of making my own after-burner

Cheers.

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Pulsejet engine, that was the name ....

Here is a video on the subject

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has it been long enough to tell any difference power or economy wise?
Patrick