KATOOM

I'm finally at the potential point where I may be able to acquire a 4" exhaust w/muffler. But before I order any system I was really really hoping that I could get some honest feedback from anyone who truly and personally knows the real reductions in EGT's going from a straight piped stock 3" to an aftermarket 4" w/muffler system. If its negligible, like 25* then I may not bother and invest that kinda money in something else, but if its more in the 100* or more range then I consider that a worthy move for towing my trailer. That said, I do also understand that the level of fueling matters so consider that I currently only have an EZ and "may" sooooomeday get some RV275's or around 60 hp injectors.....but thats it. Thanks guys.

KATOOM

I guess its safe to make the assumption that no one knows.....

patdaly

I almost wish I had gauges to tell you.

For me, the difference in sound was worth the investment...... She sounds so much better breathing thru the 4"

high bid

I went from a stock 3"straight piped exhaust to 5" w/muffler and would say, I noticed about 100-125* drop in temp. Most noticeable benefit is when towing. It's a combination of Upgrade items that's going to provide the overall benefit.

torquefan

I don't think there was too much difference in EGT, but I replaced my factory muffler and tailpipe with a 4" catback system, and did notice an immediate improvement in spoolup, it was small but it was there. Not sure if you'd notice anything if your muffler is already gone.

KATOOM

Thats probably my main reason for being so not sure of what to expect. Yes, even though the stock 3" system isnt mandrel bent and probably equals more around 2.75-2.5" in some bend locations, it has to be worlds more free flowing without the stock muffler and possibly as free flowing as a 4" with a muffler. But.....I was hopping someone has some positive data to say otherwise.

hzemax

The egt drops if changed to the 4" yube . And thats a fact.
Bought the Eagle Eye racing exhaust 4" pipe n egt drops.

Doesnt matter wich brand 4"makes the difference.

hzemax

There are some 5" pipes for sale but i dunno if theyre worth it.

high bid

I went straight from 3" to 5" looking mainly to lower egt temps. Flow, less back psi and a slight increase in mpg were other benefits.

hallio217

KATOOM, I dont have anything to offer in response to your question, but can I ask you what difference you saw in going from stock exhaust system to straight pipe? I currently have all stock exhaust and Im considering unbolting the muffler system to have a straight pipe set up.

KATOOM

Unfortunately I didnt have gauges when I straight piped the stock 3" exhaust. I didnt have a very heavy trailer back then either but now I'm hauling around a 14k lb tank on wheels and getting the EGT's down another 100* would help a lot.

hallio217

Ok. Any noticeable power or fuel economy improvements?

KATOOM

No gains I could notice.

DIESELWRKS

IMO a gutted stock system would net some HP and EGT's for all trucks. now the HP would be more and more noticed with a slightly bombed truck. say less than 375HP. Anything over 400HP usually will get better gains with HP and EGT's with a 4". if it lowers just 25 degrees with temp that to me is still huge. If you keep your truck for many many more years that 25-50 degrees cooling over that life time does have an impact. There is a time when someone bombs so much that they need to jump to a 4 or even a hybrid 4/5 like mine. with all that I have in my truck I dont think my temps or how the truck felt would be the same with a stock gutted exhaust. It certainly would sound worse to me. I like the open exhaust big pipe sound. I even think with the right "MATURE" driving foot an open exhaust will even net better MPG. most love the sound they hear and want to keep hearing it and then MPG goes out the window.

but again the HP gains just like what you always hear or see advertised for big name exhaust systems are ## HP or ## TQ. but they dont advertise with it that those gains are typically in the power band past 2200-2800 RPM's most folks dont drive in that band. my Engine is built enough that I drive in the RPM range so often but good lord that is loud and the 64/71 is screaming.

DIESELWRKS

I have been even entertaining the thought of doing a 45 elbow and dumping it before the back wheel toward the outside. But with the traction bars and how these frames are I'm limited with space. oh how that would be loud. That would certainly stop the wife from riding with me. What? what? I cant hear you dear.