3.5" exhaust HP limits

[Gray 5.9]

What is the highest Hp rating for a 3. 5" stock exhaust good for? I've read before that 3" is good for around 300 HP on the second generations trucks, that have a 12cm turbo.



Trying to find a better way to get more millage out of this 03" and remaining stock, and was thinking of either gutting the stock muffler or putting a straight through muffler in it's place and keeping noise levels down without having the dreaded cab resonance. Thanks for any replys

 

[Gray 5.9]

Hey is there anybody out there that has tested the 3. 5" exhaust, with and without a stock muffler, gutted muffler ETC. .

 

[Vaughn MacKenzie]

Emerald I would say the stock system as it sits is getting close to its limit, mostly because of the muffler. With the right muffler 3. 5" should be good for mid-upper 300s at the rear wheels, at which point it's time to do something about the stock turbo (go with a Bomber lite or better).



The quick easy fix for you is to talk to Diesel Power Products in Pasco WA. They sell a muffler replacement "kit" with 4" straight thru muffler and a PowerStroke intermediate pipe. Cut the stock muffler out, install the 4" muffler and the PSD intermediate pipe between the muffler & stock downpipe. Once you do this your system is all 4" except for the downpipe. The PSD pipe is angled to correct for the stock muffler offset. I was the first to do this upgrade on my '03 since I'm just down the road from DPP but quite a few TDR members have done the same.



Vaughn

 

[DocDetonancour]

Two weeks ago I drove to Dubois and had the Jardine boys put the 4" pipe and their own custom muffler. Love the sound and I have gained around two mpg. Doc

 

[Gray 5.9]

Thanks Vaughn

Yesterday I took the muffler off with the intention of just gutting it, but it didn't happen. I went out to my personal salvage yard (in my backyard pasture) and grabbed a 4" glass pack muffler that came with a jegs system for my old 94' CTD and installed it insted.



Man what a difference... my EGT's are about 200* cooler than before, and I don't have to sit in the parking lot waiting on the turbo to cool down as long either. It's also has alot more pep to it. I'm hopping that my milage increases, that was my main objective.