When is it really time to upgrade the exhaust?

jcain · May 28, 2015

I'm still rockin' the factory exhaust with a delete pipe, factory resonator and factory tip(s). I actually really like the sound and decibal level, to be honest. But at what power level is it becoming an honest restriction ? The H&S turbo kit came with a full 4" down pipe so I'm 3.5" after that I reckon.

With that in mind, knowing how heavily Kansas salts their roads, what aftermarket exhaust can tolerate it as well as the factory exhaust is currently doing ?

ChattyCathy · May 28, 2015

jcain said:
I'm still rockin' the factory exhaust with a delete pipe, factory resonator and factory tip(s). I actually really like the sound and decibal level, to be honest. But at what power level is it becoming an honest restriction ?

With that in mind, knowing how heavily Kansas salts their roads, what aftermarket exhaust can tolerate it as well as the factory exhaust is currently doing ?

I would buy it bare and have it powder coated, that coated in bed liner.

drunk on diesel · May 28, 2015

I doubt you'd see more than 10hp or so upgrading.

I run factory 3.5" exhaust, tailpipe, tip(s), etc. with a hushpower muffler added in series with the stocker in my 6.4 and it's not leaving me wanting for any performance.

I went from the same setup to a 4" straight on my previous 6.4 and saw absolutely zero quantifiable difference.

when I put the 71/59's on, I'm not touching the exhaust. I anticipate 600-625rwhp and have no plans on modifying the exhaust in any way from where it is now.

HeavyAssault · May 29, 2015

T409 or T304 stainless is pretty decent for exhaust material.

CWAY6.7 · May 29, 2015

I have the delete pipe and factory tail piece w/resonater on my 12. I love it way more than the 4" straight pipe I had. Way quieter and I didnt notice a bit of performance difference. Im honestly considering putting a muffler in my delete pipe eventually

stevens6.7 · May 29, 2015

I know Flo Pro makes a stainless setup which I'd like to think would hold up to the salt but then again I've never had to deal with that.

dseitler · May 29, 2015

To answer the original question. From day one.

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leland88 · May 29, 2015

I bought the stainless steel flo pro. Can't comment on how well it stands up. But my trailer has ss hard wear and it stands up. Can't be much different

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drunk on diesel · May 29, 2015

dseitler said:
To answer the original question. From day one.

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what kind of gains can he expect going from 3.5" to 4"?

bigrpowr · May 30, 2015

drunk on diesel said:
what kind of gains can he expect going from 3.5" to 4"?

i'd say its not the diameter , its the restrictive nature. i would say 10-15 hp max, most say they can feel it , as well egt's typically come down a few points. theres many variables though , and for as much as he has done i would have the stock sections long gone.

lincolnlocker · May 30, 2015

i just got a price quote from Rudy's on 4" stainless dpf back.. dam good price if ya ask me... i cant imagine that there was no significant drop in egt's when getting rid of the factory dpf back crap.. going from 4" to 3.5 with a resonator has to be turbulent as ***.

live life full throttle

ccmac · May 30, 2015

What 4 or 5 inch straight pipe exhaust would everyone recommend?

HeavyAssault · May 30, 2015

There is some science you can explore regarding air, heat, and flow. Quite interesting to say the least.

stevens6.7 · May 30, 2015

ccmac said:
What 4 or 5 inch straight pipe exhaust would everyone recommend?

I'm running a 5" Flo Pro and the fit is perfect in my opinion.

drunk on diesel · May 30, 2015

lincolnlocker said:
i just got a price quote from Rudy's on 4" stainless dpf back.. dam good price if ya ask me... i cant imagine that there was no significant drop in egt's when getting rid of the factory dpf back crap.. going from 4" to 3.5 with a resonator has to be turbulent as ***.

live life full throttle

The 6.4 resonator is straight through. As is the 6.7 resonator.

People get way hung up splitting hairs on these trucks.

Recommending anything other than replacing every single component on the truck with an aftermarket replacement is heresy! Lol

I'm sorry, but even a $700 "stainless" system (I put it in quotes because 409 rapidly looks like **** and will rust it faster than stock because it's half the thickness, etc.) Isn't worth 10hp to me.

If you want sound? Get after it! If you think anything less than 5" straight pipe will put a curve in your bill? Get after it!

But if you're asking is it worth it or if it's necessary? I'm going to be honest with my unpopular opinion and say that I don't think it is.

Nobody quantifies what "yeah, you need it" means, but if it means they make $60 selling an exhaust system, then "yeah you need it" because it's better.

Meanwhile, I'll continue to outrun every 6.7 I encounter while wearing a junk, restrictive, tailpipe and dual tip just for the sake of not buying into the "gotta replace everything because my daily driver is a ****ing race car and I need an extra 4hp and more importantly, I need everybody to see and hear that it's a race car!" mentality.

Enjoy!

drunk on diesel · May 30, 2015

Anybody remember when Hellmann made 700 on an early common rail through the factory exhaust system and muffler?

I'm pretty sure he needed 5" on that truck... at least that's what everybody on the forums told him.

lincolnlocker · May 30, 2015

drunk on diesel said:
The 6.4 resonator is straight through. As is the 6.7 resonator.

People get way hung up splitting hairs on these trucks.

Recommending anything other than replacing every single component on the truck with an aftermarket replacement is heresy! Lol

I'm sorry, but even a $700 "stainless" system (I put it in quotes because 409 rapidly looks like **** and will rust it faster than stock because it's half the thickness, etc.) Isn't worth 10hp to me.

If you want sound? Get after it! If you think anything less than 5" straight pipe will put a curve in your bill? Get after it!

But if you're asking is it worth it or if it's necessary? I'm going to be honest with my unpopular opinion and say that I don't think it is.

Nobody quantifies what "yeah, you need it" means, but if it means they make $60 selling an exhaust system, then "yeah you need it" because it's better.

Meanwhile, I'll continue to outrun every 6.7 I encounter while wearing a junk, restrictive, tailpipe and dual tip just for the sake of not buying into the "gotta replace everything because my daily driver is a ****ing race car and I need an extra 4hp and more importantly, I need everybody to see and hear that it's a race car!" mentality.

Enjoy!

lol.. i never mentioned hp. i said egt's.. and unless the resonator has a smooth chunk of pipe through the center with no holes in it then it does create turbulence... i dont give a chit about power gains on dd exhaust unless we are talking above 600hp.. that is close to when it will make a difference hp wise.. and i dont give a crap about sound either..

live life full throttle

drunk on diesel · May 30, 2015

You're not going to see a major reduction in EGT. The exhaust tip is probably five times the restriction of the resonator. Have you ever actually looked at a 6.7 resonator?

If you could actually quantify a 5 degree difference in EGT between it and straight 3.5" pipe, I'll kiss your ass.