Hey, this is my first post on this site, thought you fellas would be able to help me out on this. I am building a custom exhaust myself, I am planning on doing a 5" system and 4" where it bends and goes up to the turbo as the bend radius is smaller and fits nicer. My question is should I run 4" right to the Turbo?? I have heard it is better to leave a little 3" there so the turbo spools better.. Do any of you know what I should do. What do the custom exhaust systems do????

 

Need to know what year truck, go ahead and fill out your sig, it makes it a lot easier to answer your questions.

 

Without knowing your truck & mods it's hard to say but 5" to 4" to 5" defeats the purpose of 5".

If you are over 450 HP and plan to go more go 5" all the way. Other than that 4" is fine. If your an 04.5 or newer you have good 4" and only need to change the muff and possibly coax the cat out.

DT <*)))><

 

it's a 2003 dodge cummins, air intake, and edge easy module, so should it be 5" all the way or is 4" good??

 

most 5" systems have 4" downpipes on them... some 5" systems are just 5" from the muff back... my bd 5" system is 4" dp and the midpipe has the 4"->5" transission just after the downpipe

 

S, I'd keep the downpipe until you are a> over 500hp or b> running hot on EGTS. I went with a sideout exhaust (pix in gal.) did the whole thing myself 3.5 downpipe stock to 4" straight pipe to dual 4" cool duals muffler to 2" down turn stainless exhaust tips. The only stainless in my muffler is muffler and tips. The rest is a waste of good stainless and $$$$ for me. If I had a personal pride kind of truck which most people do....I'd have a nice MBRP exhaust. My truck is a WORK and play truck. The piece of straight pipe was like $20. When it rusts out I'll put on another. Total cost of exhaust for me was $180 and most of that was the heavy ss pipe tips clamps and tig welding. Someday I might even polish the tips if I can get the dirt off them. I would have welded the straight pipe section but I figure this will make it easier to replace....I've had to tighten the clamps once but you might have to check more often.ks