I'm afraid I may have jumped the gun on a modification to my 7.3 powerstroke exhaust. I was under the impression that a chipped 7.3 Powerstroke motor doesn't need back pressure when I chopped my exhaust, but since the chop, I feel like I have lost some low end power; it seems like the auto trans has to downshift to get up hills it usually didn't. High end power seems the about the same. I was under the impression that decreasing back pressure would also increase fuel economy, but it doesn't seem to be the case.

Here's my mod:

I just chopped the stock exhaust at the muffler and used the final bend in the tailpipe to angle the exhaust out to the passenger side. I spanned one end of the tailpipe bend to fit over and U-bolted it in place with the stock U-bolt that held the muffler on. I added a 14" long 4" tip, which brought the exit just about 4" short of clearing the body and about 1 1/2' ahead of the rear passenger wheel, pointing out 45 degrees. I haven't noticed any soot on the truck or wheel, I think the angle of the exit has helped. It's not much louder than stock in the cab, but pretty raspy outside. The turbo is audible at any rpm. The total cost: $35 for a cheap tip from O'reilly.

So my question is, should the fact that the exhaust is so short hurt anything? Fuel Economy? Power? back pressure sensor? Is some of the lack of low-end power just in my head?

I love the sound, but hoped for more high end horsepower+better fuel economy. Would maybe an MBPR 4" strait pipe help the performance (i know it would sound better)? Why?

Thanks

 

There is no gain from a muffler delete, Just remove it all and get a MBRP 4" exhaust and do it right. All the free flowing Exhausts help with is lower EGT's and maybe a very slight boost in power, fuel economy not so much. The turbo generates all the back pressure you need.

MBRP is 285.00

Ford - 99-03 Super Duty 7.3L - Exhaust - Exhaust Systems - Aluminized Turbo Back Exhaust Systems - Riffraff Diesel Performance