I installed a muffler delete 2 days ago, and also had a couple other issues, so I'm not sure I can blame this on the straight pipe. But judging by my seat of the pants feel, I don't quite seem to have the low end that I did. Is the delete pipe the likely culprit? Does this motor need a little backpressure for better low end? Like I said, I'm currently having other issues I haven't quite resolved but am at wits end.

 

I didn't notice a difference either way when I did mine, could just be me though.

 

Didn't notice a change on the low end here.....

 

Mine was the same with or without and it is still the same now that I have installed a walker 4" striaght through muffler WEhat are the other probs your dealing with?

 

The only difference that i noticed was the sound. Same performance.

 

No noticeable difference with mine.

 

problems started here
tbarbee1, this is what started the whole thing. I feel I have less low end now. Temps all seem to be normal now. I have a little bit of a vibration in the go pedal, but not the steering wheel. Checked tranny fluid again-not burnt. No diesel in oil. Need to check fuel filter, but it only has 1000 miles on it. Air filter looks okay. I still have plenty of top end performance. I can lay a pretty good set of black marks from a 20 MPH punch. (poor tranny) Motor seems louder (valve noise) and it idles just slightly rough. Truck has 8000 miles on it. has had 2 oil changes and 1 fuel filter change. Tranny is 1/2 quart low, but there is no ATF+4 at the one store that was open today. I'm beginning to think its all in my head. The guages, the extra noise from the exhaust. I keep staring at those guages now! LOL

 

I have heard of this happening before on 03 and newer cummins.. I have also heard about not going bigger than a 4inch exhaust if you want to keep your fuel mileage on the 03 and newer.

 

I have a 5 inch down pipe to 4 inch duals, didnt notice any difference.

 

IMO, it COULD be possible if you truck was bone stock, though when I straight piped mine (when it was bone stock) I couldnt tell any diff.

But having a programer on the truck, you shouldnt have lost any bottom end, but this is just my opinion.