At what point do you need 5" exhaust? I pulled my 12k 5ver into the mountains this past weekend. Towing up the hills with my juice on level 2 I was still consistantly staying at around 1350-1360 on the egt's to hold my speed. I could back out to cool down, but I want to be able to tow while holding my speed. Will 5" exhaust help, or is it a waste of money. What should I do next. My future upgrades are stacking the ez, adding the Glacier with big line kit. I would love to put on a set of twins, but that may be a long time away. I currently have the Juice w/attitude hot flashed, airaid intake and stock 4" exhaust with the silencer ring MIA.

 

the exhaust may help you. I cant see buying a whole new system thats 4" so thats why I run 5". I like the looks and the deep sound better. I think they say 4" is good up to 450hp, some companies say that, then you need 5".
my truck seemed to be quicker with 4". it spools slower now I think. I would put 5" on a stock truck, but thats me.

 

I don't think you'll see a big EGT reduction by going from 4" to 5". FWIW when I went from stock 3.5" to 4" on my 1st gen I saw no reduction in EGT's whatsoever.

I would say 4" is good to 500-600hp.

 

I know on a gas motor if you put to large of a diameter exhaust on that you can actually loose power. Will a 5" exhaust only help at WOT, or will it hurt me anywhere on power?

 

5" exhaust is only needed when your exhaust side on your turbo is 5"

 

I saw 130-150 degrees reduction in cruising at 70 mph. I did my cp3, dual feed, sticks, springs and turbo and ran the stock exhaust for a day before I put 5" on. I saw mid 600's at 55, high 700's to low 800's at 70mph. Installed 5" and I still see mid 600's all the time at 55mph but at 70 it will not top 670-680. So it did help me.

 

you can make plenty of power with a 4" exhaust, you might need a bigger turbo

 

It does drop egt's! I've seen anywhere form 150 degree drop and more!
I've never felt a loss in power??

 

I never felt a loss of power either and im still below 500hp (just barely). And it sounds much better than the straight piped 4". Its definately deeper. Im not sure exactly when its "needed" but i know that i run my smarty on 9 daily and can easily control my EGT's. I dont know if the exhaust has anything to do with that but id think so.

 

It says you're running stock exhaust. Right now the best thing you could do to drop egts would be to lose the cat and muffler for a 4" straight pipe or a high flow muffler.

 

I noticed cooler temps and no power loss when I went from 4" to 5" exhaust. I found that switching from 4-5" didn't really change the sound much at all, I actually prefer the sound of the 5" over the 4". You could save some $$ and run a straight-piped stock system which will give you a nice deep tone and only cost around $100 (if you have a shop do it)