Well the gauges are done, Predator is in 100 HP mode and I got the exhaust hung yesterday. I installed the 3.5 down pipe, did not see the cat working to fit the application and it is a Magna Flow exhaust. The truck is running just fine, but I have to say the whistle ... ...has to go. It is like someone is just running their finger nails across a chalk board type pitch. I have been around diesels all my life, but this one is annoying. If anyone does not have a fix, the stock exhaust is going back on the truck next week.

Anyone care to elaborate? I am not looking for well you should have bought brand XYZ.

 

The turbo whistle is music to the ears of some.... and indicative of a free flowing exhaust,
but it IS a personal preference and not the nicest to others...

Not sure which year you have, but some have a resonator in the stock downpipe to mitigate the turbo whistle and between that, the cat, and the stock muffler, the whistle goes away.... along with ANY possibility of a free flow of exhaust gases

I ran my turbo back without the cat for a week or so and decided to put it back into the mix... for a few reasons...
one - some have done much testing with cat and no cat (both on dragstrip and dyno) and proven that the cat does nothing statistically significant to the performance...
two - it did soften the turbo whistle...
three - it IS a federally mandated piece of the emission system and I want to spend money on mods for my X, not potentially on steep fines for no cat (probably would not get caught, but the fines were a deterrent enough for me )

the cat can be welded into the 4 " pipe by judicious trimming of the intake and exit pipes...
trim the front such that the front pipe JUST slides into the front of the cat and weld it..
trim the back such that the cat pipe JUST slides over the tailpipe and weld it...

the cat's interior is larger than the 4" pipe and should offer a free flow to your exhaust and soften the turbo whistle a bit....

I barely hear it inside...
with my windows up and a/c and radio on - I don't hear it except when it's REALLY screaming....
but I like it !!!

 

jdadamsjr

Glad to hear from you. I checked through some earlier posts on exhaust. I also was wondering about trimming the cat up or finding one aftermarket to fit. I have operated many pieces of heavy equipment, I used to work construction and I farm, so I enjoy the diesel and the turbo whine. The exhaust is really quiet with some whine, but right at about 7 to 8 pounds of boost it raises the hair on the back of your neck so bad I almost puked.... ... so somewhere out here I figured others had figured this out.

 

Maybe you're just hyper-sensitive....

are you a democrat from California ????

j/k

 

jdadamsjr

Hummm...Ohio here and you know all to well we are dominate Republicans....

I am going to work on putting in the cat as you suggested. If I can just knock off the one point in the pitch it will be fine.

My wife tells me I am hard of hearing, I just call it selective hearing. My grandfather was that way, I have been married long enough to know why he was doing it.

 

You can always get a cheap spare straight pipe to play with from most muffler shops until you get it sized right....

good luck and let us know how it turns out...
but the old adage measure twice and cut once is WRONG in this case...
measure, turn it over, measure again, think about it and measure again
you only have ONE very expensive cat there