Enlighten me on back pressure

[Elrey7698]

Testing this question on a couple forums.. So ive decided to get some long tubes for my yukon plus an off road y-pipe...im going the no cats route cuz im not worried about passing emissions cuz out in los angeles $100 gets you a pass...my question is that if i go straight pipe will i loose any hp or torque? Would i need the back pressure that an exhaust system has? Also i dont mind how loud it will get or the drone..

 

[livingez_123]

as long as you get a good tune...blackbear, it shouldn't be a big issue. I wouldn't do it because these can get very annoying after a very short time listening to it drone. You must be a young person. you can have your nice exhaust note without going deaf. just put a long chamber muffler on it and have some piece of mind running around town but when you get on it you can still have a nice roar to it.

 

[NaomiSays]

You're not going to lose any power, but you should have it custom tuned and we can definitely help you with that.

 

[289NATE]

Anyone who tells you an engine needs back pressure doesn't understand what gets the intake charge started in my opinion. They are also the same group that would have previously told you that the heads on the various LS engines are way too large and high flowing for a truck engine. You're leaving a lot on the table if you're waiting for the piston's downward movement to get the intake charge moving.

 

[Gzes]

Yep it's a myth. I rock gutted cats and no resonator on y sol. It's fine and has a a nice throaty sound. Gonna put long tube headers on my Tahoe and run flow master 10s maybe idk. I have the headers just gotta get the piping

 

[tights24]

Anyone who tells you an engine needs back pressure doesn't understand what gets the intake charge started in my opinion.

Howdy Nate, can you explain this for me? I'm not in any way trying to start an argument, but rather to learn. I will tell you this though, my previous vehicle was a Titan, and it was very finicky with exhaust tubing size. This was proven on the dyno and the track. So, IMO, exhaust size does matter. But, I'm up for any learning I can do in this world, and at 43, I have lots more to learn.

I assumed all mods needed complimentary mods in order for them to truly be successful. Your statement tells me that with tuning only, any engine will run better with 6 inch exhaust tubing. I just don't buy it is all...... Again, not trying to start a pissing match, just trying to learn and also to see if this is your experience with all engines, carburetor engines, GM engines, Ford, etc etc.

 

[289NATE]

No worries tights24. Yes, everything is application dependent and it's ALL about the combination as well as how good you can tune it once a change is made.

I believe the header and collector are where it's at and the rest of the system just needs to get out of it's way. When the exhaust pulse leaves the primary it will pull on the other primaries creating a low pressure area all the way up to the back of the exhaust valve. That low pressure helps to get the intake charge moving once the intake valve begins to open during overlap even when the piston is still moving upward and has not reached top dead center or begun to move down. Creating back pressure with a smaller diameter exhaust isn't going to help the collector do it's job. This comes from being a little into drag racing and having a street/strip toy I enjoy working on and running at the track.

 

[jmgak47]

Backpressure is a myth.

Its a balancing act of heat retention, maintaining velocity and maximizing the flow.

 

[Stresst]

Backpressure is a myth? Really?? Ok.....smh