Have a stock 05 - just in front of the muffler Ford clamped it to the pipe connecting to the Cat... I disconnected the muffler and rest of tail pipe section and essentially ran straight pipe out of the cat - wow, what a sound...a rumbling roar like you hear out of a nice Gasser V8 that's piped... Not really too loud - did hit it's loudest right at about 2400 RPM then it gets quieter...

What do you guys think? Any drawbacks to having a muffler shop simply straight pipe out of the cat and not have a muffler?? Is it legal?? Is it as good as spending 300+ on a cat back system or 400+ on a turbo back system like MBRP???

 

I don't know but i hear that there could be a back pressure problem but i sure you will hear more from other. good luck

 

I would be very interested in the results as well. I have done the same thing by cutting out the muffler and putting a piece of pipe in its place. I can't tell thats any louder but I think it ahs better power. Without a Dyno it just a SWAG but it seems like it. I am worried my mileage may suffer which is not the desired effect. I would be very interested in your results.

 

I would think the mileage might be a little better - what I'm concerned about is back pressure - enough of it to keep the turbo running properly - I've read on here from a few guys who went 4 " turbo back or even 4 1/2" turbo back and no longer could get boost as this new turbo wouldn't function correctly...

 

the turbo itself creates all the backpressure the engine needs. the only reason you need it is to activate the EBP (exhaust back-pressure sensor). but most people have their EBP sensor unplugged. so therefore you need NO backpressure behind the turbo. best to run 3.5'' downpipe and 4'' exhaust all the way back. i like how a muffled one sounds, JMHO. removing the factory catalytic converter on 6.0 engines is ILLEGAL and you can suffer MAJOR penalties if the right person catches you with it off. best to stay legal and leave it in. paint it silver so it blends in. it doesnt create much restriction at all, not enough to be noticeable. or if you want to live life on the edge, take it off and see what happens.

 

On mine I left the CAT so as too stay legal and keep some back pressure for turbo ans its systems. I only removed the muffler and put a lenth of pipe in its place. Was told this would help power and mileage. So far the power does seem better but mileage seems about the same. I am on a trip so I have'nt driven my truck in 2 weeks and only burned a partial tank before I left. This board is a great source for info. Thanks to all.

 

Hi, MD11drvr, welcome to Ford Truck Enthusiasts, the best place on the planet for Fords!

 

Any exhaust that is less restrictive than stock will be beneficial. Less restrictive would be bigger diameter, no cat, and no muffler. Any one of those will be less restrictive, all three will be the best. The main benefit and purpouse is lowered EGT's. Most that I've read have said they've noticed a bit quicker spool up in the turbo. You'll also get a louder exhaust. Some have experienced a slight gain in fuel mileage, but it's usually pretty insignificant.

As far as backpressure, after the turbo, you want as LITTLE restriction as possible... so no cat, no muffler, and larger diameter will achieve that.

If you search on here and at the Diesel Stop, you're bound to find a lot of information on the subject... I guess that's where the little bit I know came from, anyway.

 

Don't know about Idaho noise/emissions, but CA (at least my area) is 'somewhat' relaxed in the noise standards "unless" you go to the extreme.. Can't imagine Idaho is much different.. ALOT of Harley D's and such running straight pipe, custom LOUD pipes, and there was a 'purposed' enforcement plan to get them into compliance for noise, but never was put into play.. Or at least not completely.. But is does give the CHP a reason for a stop and check.. It's illegal to remove the muffler (tamper with a emmision device) but if you/I were not to far of legal DB's chances are it wouldn't be an issue.. At least not in my area.. I know that they do check DB's from time to time, and have been pulling 'rice racers' for small issues like clear tailights ect, and then they 'completely' check for CARB compliance parts and exhaust note.. Has been, or was intended to help capture stolen vehicles/parts, and by hitting 'legal' repeat offenders in the pocket book as well as control racing/side shows..

"BUT" on another note.. if you have a gasser Honda ect. here that has had "lets say" a non compliant intake, exhaust/header ect. installed and emisions components removed, you'd be cited, and the aftermarkets pieces have to be removed/sent through a Smog Referee for compliance, and then "EVERY" year thereafter!! Fines apply as well...

I'm not sure about Idaho as far as a fine, but CA would be more of a fix it ticket for just a muffler gone.. You'd 'probably' just be cited for excessive noise, rather than tampering.. Officers discretion.. I've 'heard' some loud diesels here, and none off them have been stopped that I've been witness too.. If it sounds the way you like, straight piping it is an option over an aftermarket setup.. OR, even a temp straight pipe as a test for noise 'comfort' for some miles over a aftermarket investment, should you change your mind.. Might see some lower EGT as well.. I wouldn't think (depending on the exhaust manufacturer) that a 'stock' pipe diameter with muffler removed, would be a whole lot louder than a larger diameter pipe (turbo back) with a free'r flowing muffler.. But I'd check your local law/s for a 'missing' muffler.. Just in case!!

Shouldn't be any driveability issues, but if you do have any running changes, and need to go in for service/warranty it may need to be reinstalled depending on the reason and dealer/tech.. Muffler delete OR aftermaket completes..

.......................HP..................

 

Where did you get the pipe at?
I tried a bunch of muffler shops and none of them have 3.5 inch pipes or the capability to bend them. All I want is a piece to go behind the the cat to shoot the exhaust out the side from under the bed.
steve

 

Try some of the local truck shops (International/Freightliner/Cat ect.) or 3.5 pipe and pre-bent elbows can be ordered from NAPA..

.......................HP................

 

I purchased a complete Turbo back 4" system from Bullydog. It's configurable for cat delete, muffler delete, or run their highflow muffler. So far, I've installed the portion from the cat back. Muffler deleted. In essence exactly what you're asking about 4" cat back straight.

Sounds great! I cute the tube just after the bend from the spare tire and added a 5" x 18" stainless tip for a bit of a unique sound. But at idle, it sounds like a 40,000 watt hair drier on steroids. Not as loud as a GE J52 turbine, but has a nice whirl to it. Then on the throttle there are a couple nice power roll rumbles at 1,200 and 2,200 rpm or so. With nice turbo whine from 1,300 to 2,000 or so.

I'll be installing the down tube in the next week or so, leaving the cat in.

I don't think I'll be installing the muffler. That'll go on Ebay soon...

-Steve

 

The owner of a local tire/muffler etc. shop is also a rancher and AVID PSD owner. He had it in stock and made the suggestion to me about cutting the muffler out. He also does Hvy. Tractor maint. so he has a good all around knowledge and keeps a good selection of parts. He also showed me his preditor (sp) programmer and that is a must have for my truck in the future.

But I think I will be doing the additional oil filter that gets one micron and then the Turbo saver before the progarmmer. My wife has become concerned that this new truck may become an expensive obsession like firearms. I keep reminding her that if I am spending my spare money on the truck there won't be any left over for a girlfriend or beer. Some how I don't think she that is enough to get her excited about the new obsession.

Oh well I guess if I always agreed with she would know something was up...