I think I'm ready to take of my catalytic converter. I'm really getting tired of the 12-13mpg on my 06 5.9L cummins. I've heard through the grapevine that if you do that you'll improve mileage drastically. Anyone know where to get a chip to bypass the EGR? What is a good company to go with?? If anyone has more info. that would be great.. Thanks.

 

On an 06 model there is little to gain by removing the catalytic converter. If you have a performance problem, more than likely the cause is elsewhere. If you want to be sure, you will want a borescope inspection of the inlet side of the catalyst to be sure that it is not plugged. If it is plugged, one can burn off the accumulation with a large propane burner of the kind that is used for killing weeds. One only has to get the temperature of the inside of the system above 600F and keep it there for 1/2 to 1 hour and you should burn off anything that has been deposited. If you have access to an furnace, you might cut the inlet and outlet pipe 1" away from the catalyst and bake the catalyst in the oven at 1000F for a couple of hours. The temperature needs to be ramped up and down gradually to avoid thermal shock. But the borescope inspection will show if it is needed to begin with. The backpressure of the catalyst is more than likely equal or less than the muffler,so it should not be a factor. With gas engines, the backpressure of the catalyst is more significant since they are typically smaller in diameter and there are frequently at least 2 of them in series, sometimes in the same can.

 

My cat was clogged because it had been destroyed by a piece of a broken turbo. I had it removed. My power increased, but mileage did not. If you have good power, I would think your problem is somewhere else. I am only getting 14 mpg with my truck, and was hoping that the cat was the cause.

 

This is disappointing. I have good power. Just the mileage is poor. at 75-80, I'm lucky if I get 13mpg. If I do 65-70mph I get 15-16mpg. I guess i'm just used to 18 or better on my 03 ram. Guess I won't get it from my 06 dually. You think a chip would help, and if it would which one??

 

I can get 18-20.5 MPH empty on the Hwy with my 06 depending on how fast I drive.. Do you try to keep you speed at or below 65 MPH, have your checked to see what your tire air pressire is at, when did you last change/check your air and fuel filter? Also take off easy from dead stop and try to keep your RPM's under 1800 until you get up to speed. What type of oil do you use? A good Synthetic 5w oil can improve your fuel mileage 1 or more mpg. All of the above will help you get better fuel mileage . BTW, don't drive it like a V8 gas engine, use the TQ and not the HP.

JMHO

 

I'm getting about the same numbers. I tried the Quadzilla Max Mileage for about 1500 miles and saw no increase in mileage. I am now running a Diablo Sport Power Puck and it gives me about a .5 to 1 mpg gain if I keep my foot out of it.

I had a 2001 CTD and it would get 20 mpg on the highway easily. It got 17 mpg in town. I am very disappointed in the mpg's my 04 gets, but it does have quite a bit more power.

 

I have the same in my truck, about 16-17 empty on hwy and about 14 mixed hwy/city empty. My speedo is off from the 285's and I need an alignment so I am hoping that will help a little and I plan on getting a smarty jr to see if that helps any. My 2wd 06 would get 23mpg on the hwy and 18 in the city, needless to say I was very dissapointed when I learned that 4x4 took that much mpg away.

 

I don't think the 4wdcosts you that much in mpgs. Ihada 2001 4wdCTD that would getwell over 20 mpg on the highway.

 

Dropping the cat did absolutely nothing for mileage for me. No Hp gain, no better mileage, no different sound.
Mike
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Cant say I"ve tried to keep my speed under 65mph "EVER" I do have a 6spd manual and a 1 ton dually, I suppose that makes a difference. I would've thought the 6spd would make up for some of the heavier weight and wind reduction I can get consistantly 15 doing 65-70mph, and it seems in town driving I'll get about 14. Guess I"m just going to have to live with what I get. Doesn't sound like removing the cat helps any.. Thanks you all.