I have an all stock 01 Cummins. I'd like to start slowly upgrading and I was wondering which exhaust would be better? I probably won't go to extreme with the truck, just a few upgrades here and there. Any suggestions?

 

stock straight piped sounds awsome 4in flows i think 70% more than stock 5in flows 170% more than stock what are you planning on for power?

 

I put a 4" farm boys diesel exhaust on mine with a bhaf and i noticed a difference. I think 4 is waht most people use unless you are going to be towing really heavy.

 

5" Expandit Straight Pipe

 

I have a 4" silverline 409SS. I like it, but I would rather it be louder. I have a friend with a 5" and it sounds great... kinda wish I had gone that route, but I wanted a stainless steel system.

 

I put a MBRP 5" t409ss on mine left the muffler on it and it has great tone to it i love it and highly recommend this system!!!!!!!!!!!!! 5 inch has a good deep tone to it, 4 inch just sounds to high for me.....enjoy your rig!

 

According to Diesel Power Mag if you put a 4" exhaust on your truck it reduces 97% of your back pressure. So you are not going to see that much of a difference with a 5". Now the sound difference is significant.

 

iv got 5in and i love the sound. people are always telling me how good it sounds. dieseldawgs.com has good deals thats where i got mine.

 

just got my 5 inch exspamdit put on the other day and i love it

 

go with 5 inch just about 30 dollars more than 4 inch.