Why do new diesel truck exhaust pipes have "wings" cut into them?

When you look into the pipes of the new diesel trucks, about 4-6" into the tip, there are flaps cut into the tubing, or scallops, sorta like what you find inside a glasspak.

What is the reason for those? What do they do?

 

They are question generators.

 

In 2007 or 2008, forgot which... the EPA required diesel engines have soot incinerators installed. The new requirement added thousands of dollars to the cost of a diesel vehicle. The incinerator is mounted in the exhaust like a cat or a muffler, and it is fired by diesel from the fuel tank. Similar to a kerosene burning heater.

Anyway, to the point...
The incinerator runs perodically on it's own schedule.
When the first trucks came out with the system, new owners found out the hard way that when the unit runs, it could turn the tailpipe of the truck into a 'flamethrower' from the intense heat. The trucks started catching all sorts of things on fire, including at least one home, from starting the truck in the garage.

The tips were fitted very shortly thereafter... they are supposed to be flame arrestors.

Ford stopped selling diesel trucks for about a month or so while they came up with the 'fix'. The Fords were the ones throwing flames. I don't know about the other manufacturers.

 

This shows why they now put flame arrestors...

 

I see slots cut into those tips, but they aren't the tips I see on them now...

I dunno, the ones you see now are bigger, more pronounced.

 

I agree, much more slot and wings nowadays.

Personally, I would rather have the flames...

 

Thats cool!!!! I want one on my diesel!!!

 

on early 2008 6.4 diesels they had issues on the injectors leaking adding even more fuel into the system in addition to what was going into the exhaust. they found the issue on the assembly line that was causing injector failure. crossed wires on test firing the motors from what i understand.

 

OK, still haven't figured out what the wings do...How do they work to act as a flame arrestor?

 

I think instead of arresting the flame, they actually help supply more oxygen for a better burn. It burns in the pipe, instead of burning outside of it. On some of the big trucks, there have been reports of the regen process actually damaging the fronts of trailers, especially the plastic on reefer units.....

 

Oh, that makes sense...

Thanks