Off road y pipe for the 5.3 2015 with stock manifolds??

SILVER SLED · December 30, 2015

I disagree. Long tube headers and a performance muffler on any engine will increase sound output. I do agree tho that a different muffler is the easiest cheapest way to increase sound

I wasn't talking about sound gains when I was mentioning the flow of the stock manifolds. Of course headers will sound diff, but when it comes to the science of exhaust flow, headers won't give much if any performance gains. With all the fuel mileage concerns these days, GM actually puts some thought into these manifolds.

Willshire · December 30, 2015

Again. I disagree.

https://www.physicsforums.com/threads/long-tube-headers-vs-short-tube-headers.208674/

Easier air comes out the more air and fuel you can put in.

If headers had no effect on performance there wouldn't be as many companies designing and selling them.

No question engineers are making the air in to the air out as efficient as the confines of the bean counters. Why does the supercharged hellcat come with factory headers? Gotta be more than sound

SILVER SLED · December 30, 2015

Again. I disagree.

https://www.physicsforums.com/threads/long-tube-headers-vs-short-tube-headers.208674/

Easier air comes out the more air and fuel you can put in.

If headers had no effect on performance there wouldn't be as many companies designing and selling them.

No question engineers are making the air in to the air out as efficient as the confines of the bean counters. Why does the supercharged hellcat come with factory headers? Gotta be more than sound

Don't let after market hype sway your decision. Of course a long tube header can flow more. The fact is your 5.3 with it's cam and head design and intake design...... makes 355 hp. Your stock exhaust manifolds will support 355hp, and much more, like I said, they will support 420hp. Now if you go and put a blower on your 5.3, then headers will definately show a power improvement. So basically, basically yes of course headers flow more than stock manifolds, but these stock manifolds flow more than your engine is putting out.

Txjose · December 30, 2015

Don't let after market hype sway your decision. Of course a long tube header can flow more. The fact is your 5.3 with it's cam and head design and intake design...... makes 355 hp. Your stock exhaust manifolds will support 355hp, and much more, like I said, they will support 420hp. Now if you go and put a blower on your 5.3, then headers will definately show a power improvement. So basically, basically yes of course headers flow more than stock manifolds, but these stock manifolds flow more than your engine is putting out.

If that were the case why are gains present from a stock internal 5.3 with intake/exhaust /header upgrades??

OP.... Get electric cutouts.... Problem solved lol

Willshire · December 30, 2015

This is a question of exhuast gas scavenging efficiency. Effective scavenging is an extremely important factor to consider in maximizing your engine's volumetric efficiency, or "V.E." Although the most thorough answer is one that takes far too long to put in this post, Ill give you the shortened one. Long tube headers are headers where your primary tubes are on average, at least 28" in length, they are also much more narrow that thier short tube counter parts. These type of headers, generally speaking, are best when used on a street rod, or "smoke show" application. Basically, lighting up the tires from stoplight to stoplight, generally with a mid to low power band. This is because of the way the engine breathes at mid and lower RPM's. At the low to mid end, the best way to maximize your scavenging effect, thus helping to maximize your engine's V.E., Is to move the exhuast out of the engine as fast as possible, or with as much velocity as possible. Long tubes work best for this because of their length, and their width (well, lack of width). Thier length allows an elongated path for the gas to flow, thus allowing the gas to leave the cylinder with more speed because the gas has more time to gain velocity before it hits the collector.

Not a matter of how much it can flow but how fast it can flow (velocity). More velocity when cylinder one exhaust isn't crashing into cylinder 3, 5 and 7

SILVER SLED · December 30, 2015

I am well aware of the scavanging effect and possabilities of an exhaust system. Your not talking about a NASCAR motor here. My Trailblazer SS ran 12's with stock manifolds. People with Trailblazer SS's didn't put headers on stock motors because they were proven just about worthless. You MAY gain a few horsepower, but is it worth the hundreds spent? So go ahead and spend money on headers, it will sound better, but thats about it.

07Softail · December 31, 2015

The slowblaster muffler will be plenty loud!

RT

Willshire · December 31, 2015

I am well aware of the scavanging effect and possabilities of an exhaust system. Your not talking about a NASCAR motor here. My Trailblazer SS ran 12's with stock manifolds. People with Trailblazer SS's didn't put headers on stock motors because they were proven just about worthless. You MAY gain a few horsepower, but is it worth the hundreds spent? So go ahead and spend money on headers, it will sound better, but thats about it.

I meant no disrespect SS, I am no exhaust guru but I do have experience. I am one opinion. Headers are usually, in my experience, part of a combo of performance upgrades

07Softail · December 31, 2015

Headers have been proven to out flow manifolds for 50+ years and the great sound is a side affect of sound wave pulses shooting down the primary tubes at super sonic speeds.

RT

TheLPGuy · July 20, 2016

I was looking to get a little more sound out of the truck, currently have the 40 series flowmaster, and resonator deleted. But after driving it around for a bit now, I want little more out of it...

I called the muffler shop and they suggested switching out to a 10 series flowmaster, is that my only option or do they make a off road y pipe to fit the stock manifolds? Everything I found on summit and jegs states (works with long tube headers)

If the y pipe is an option, id rather go for that as a bolt in/out so I can swap out as needed for inspections and so on.. instead of welding in another muffler.

I do already have a CAI which did provide some additional agressivness, but want little more..

Any suggestions would be great.

thanks.

I'm 100% in the same boat as you right now. I have a muffler and resonator delete on my 15 and would love to be fully straight piped. Right now I'm trying to find a 3" dummy cat to replace the California cat because the California cat isn't required in my state so they wouldn't void warranty or fail inspection. Also the California cat isn't hooked up to an o2 sensor so no codes will be thrown by getting rid of it. I also want loud, all my past vehicles were straight piped but they were older with no warranties lol.