Straight-Pipe or not? Potential Exhaust Problems?

[Robotek]

Hey Guys,

So I daily a '15 GT Manual PP. About a month ago I was searching for an axleback option since I had already installed an H-Pipe resonator delete in July. I settled on Solo Performance Exhausts Axleback for a number of reasons (if you're really curious I did a YouTube review Here). Anyway, I have the factory headers and cats still in place, but obviously no resonator, and the Solo axleback is without mufflers save for a J-tube on each side to eliminate drone.

I was reading tonight about the potential drawbacks of having a straight pipe system (ignore noise as a factor; its a non-issue for me) and things like "back pressure" get thrown around alot. Mainly, backpressure myth or not (I know it actually has to do with gas velocity exiting the cylinder head) it seemed like loss of low end torque and even valve burning were resultant. Which brings me to my question...

Do I even have a real staight pipe exhaust? I was always under the impression that straight pipes consisted of having absolutely 0 restrictions, whereas I still have my cats, and most of the time did not run the full length of the car. Someone on this forum has to have some engineering experience, to the point where they can tell me if I'm really putting my car at any type of risk by running this system, or if its really not something to worry about. Ive been considering throwing a mid muffler on but I cant find that seems to sound right...

In case its relevant, my mods besides the exhaust are a JLT Passengers side catch can, JLT intake, and Steeda tune. Also I apologize for any typos, Its 2 AM and I'm enjoying a pint of Goose Island BCBS :cheers:

Sponsored

 

[Robotek]

Bump?

 

[ifly680g]

Hey Guys,

So I daily a '15 GT Manual PP. About a month ago I was searching for an axleback option since I had already installed an H-Pipe resonator delete in July. I settled on Solo Performance Exhausts Axleback for a number of reasons (if you're really curious I did a YouTube review Here). Anyway, I have the factory headers and cats still in place, but obviously no resonator, and the Solo axleback is without mufflers save for a J-tube on each side to eliminate drone.

I was reading tonight about the potential drawbacks of having a straight pipe system (ignore noise as a factor; its a non-issue for me) and things like "back pressure" get thrown around alot. Mainly, backpressure myth or not (I know it actually has to do with gas velocity exiting the cylinder head) it seemed like loss of low end torque and even valve burning were resultant. Which brings me to my question...

Do I even have a real staight pipe exhaust? I was always under the impression that straight pipes consisted of having absolutely 0 restrictions, whereas I still have my cats, and most of the time did not run the full length of the car. Someone on this forum has to have some engineering experience, to the point where they can tell me if I'm really putting my car at any type of risk by running this system, or if its really not something to worry about. Ive been considering throwing a mid muffler on but I cant find that seems to sound right...

In case its relevant, my mods besides the exhaust are a JLT Passengers side catch can, JLT intake, and Steeda tune. Also I apologize for any typos, Its 2 AM and I'm enjoying a pint of Goose Island BCBS :cheers:

I don't know about the question but I do know that BCBS is awesome! I had a 2014 last night, have not tried the 2015 yet.

 

[Robotek]

I don't know about the question but I do know that BCBS is awesome! I had a 2014 last night, have not tried the 2015 yet.

Its phenomenal this year! The bourbon is like butter. Was lucky enough to score a Rare too!

 

[dubster99]

You do not have a straight pipe exhaust.

 

[Robotek]

IMO, the back pressure necessity is a myth. Coming from an engineer friend, 0 restriction is always ideal. HOWEVER, the issue with loss of horsepower comes with the tune. (So I've been told.) To find out how exactly all that works, you'll have to supply me with some tuition money for an engineering degree so I can tell you. Hopefully someone else here can affirm this and shed more light.

Ha thanks for the reply Jill. From what I can tell after minimal research, it he back pressure myth is true, but not because of back pressure. It has to do with the fact that gas velocity moves more quickly in a tighter diameter tube (think about when you plug the end of a hose with your finger: water shoots out at a faster rate). Because people open up the diameter of their piping when they add larger pipes or delete restrictive components, the gas moves at a slower velocity than before, and thus doesn't "get out of the way" of new gasses leaving the head quickly enough, which in turn causes loss of power. Science!

 

[daltron]

Hey Guys,

So I daily a '15 GT Manual PP. About a month ago I was searching for an axleback option since I had already installed an H-Pipe resonator delete in July. I settled on Solo Performance Exhausts Axleback for a number of reasons (if you're really curious I did a YouTube review Here). Anyway, I have the factory headers and cats still in place, but obviously no resonator, and the Solo axleback is without mufflers save for a J-tube on each side to eliminate drone.

I was reading tonight about the potential drawbacks of having a straight pipe system (ignore noise as a factor; its a non-issue for me) and things like "back pressure" get thrown around alot. Mainly, backpressure myth or not (I know it actually has to do with gas velocity exiting the cylinder head) it seemed like loss of low end torque and even valve burning were resultant. Which brings me to my question...

Do I even have a real staight pipe exhaust? I was always under the impression that straight pipes consisted of having absolutely 0 restrictions, whereas I still have my cats, and most of the time did not run the full length of the car. Someone on this forum has to have some engineering experience, to the point where they can tell me if I'm really putting my car at any type of risk by running this system, or if its really not something to worry about. Ive been considering throwing a mid muffler on but I cant find that seems to sound right...

In case its relevant, my mods besides the exhaust are a JLT Passengers side catch can, JLT intake, and Steeda tune. Also I apologize for any typos, Its 2 AM and I'm enjoying a pint of Goose Island BCBS :cheers:

Zero issues, all myths. My 05 GT had a muffler delete and my buddies GT had a legit straight pipe system (aftermarket OR headers and straight pipes). Zero issues. As for power, that is 100% tune related.

 

[Derek@Lethal]

I'm not sure why this myth keeps circulating, back pressure issues haven't been a thing since maybe the gas crunch era when V8's had 8:1 compression and made 130 hp. You do not have to worry about having any type of a free flow exhaust on your car that has zero restrictions.

First, having exhaust that runs back to the bumper creates enough back pressure, with or without mufflers, and this also takes care of any burned valve myths as well. Next, you still have catalytic convertors which are THE LARGEST restriction in an exhaust system to start with.

My ONLY concern is the sound quality (or lack of) a muffler delete system usually gives. Of course, exhaust is very subjective, but IMO, not having some type of a muffler makes the exhaust sound like poop. If you just want something that will be loud, then a muffler delete system may just be your cup of tea.

 

[Robotek]

I'm not sure why this myth keeps circulating, back pressure issues haven't been a thing since maybe the gas crunch era when V8's had 8:1 compression and made 130 hp. You do not have to worry about having any type of a free flow exhaust on your car that has zero restrictions.

First, having exhaust that runs back to the bumper creates enough back pressure, with or without mufflers, and this also takes care of any burned valve myths as well. Next, you still have catalytic convertors which are THE LARGEST restriction in an exhaust system to start with.

My ONLY concern is the sound quality (or lack of) a muffler delete system usually gives. Of course, exhaust is very subjective, but IMO, not having some type of a muffler makes the exhaust sound like poop. If you just want something that will be loud, then a muffler delete system may just be your cup of tea.

Thanks Derek, this is exactly what I wanted to hear. As far as sound goes, it is definitely on the loud side, but it almost sounds exotic (especially with the 7k redline) and the J-tubes help cut drone so it doesn't sound like a V8 fart can. Planning on doing a follow up video with drive bys and in cabin clips soon.

Sponsored