1999 cummins exhaust tips
 

Im looking to put a 4 inch turbo back exhaust on my truck. I've already done a muffler delete. How much back pressure would I lose if I did a cat delete as well and what exhaust will give the best sound but also give the best performance?

You don't need back pressure.
you can do a straight pipe, or go for the 4'' straight through muffler.
The cat isn't needed either.

shouldn't even have a cat on it unless it was a california truck...

no need for back pressure on a turbocharged diesel engine. excessive drive pressure can actually cause a head gasket failure.

as for sound...straight pipe.

performance: any 4" or 5" kit will do the same thing... 5" just has a deeper tone and doesn't clear the spare tire very well...

I will have to go with a 4in. What is better magnaflow or flowpro?

They are all pretty much the same. Between the two listed, Flo-Pro all the way. You will be paying more for the Magna Flow due to the brand name.

I have DAP house brand 5" straight pipe :tu:

brand name means nothing to me... pipe is pipe :pca1:

Expandit

Luke