What does a Muffler do besides "muffle" the sound?

[Mike_W]

What does a Muffler do besides \"muffle\" the sound?

If you take off a stock muffler, and just install straight pipes, will that give it an increase in HP?

I swear my car feels faster.

Second question... can an after market muffler give more HP than just removing the thing? If so, why?

Also - are mufflers necessary to pass smog?

Mike

 

[Mike_W]

Re: What does a Muffler do besides

Wait, here is the easy way of asking...

Will having straight pipes (no muffler) give me more HP than having something like Corsa, Borla, or any other muffler? Doesn't a muffler restrict HP?

Thanks,
Mike

 

[RedEnuf93]

Re: What does a Muffler do besides

Motors need some backpressure, some more, some less.
Cut the exhaust out completely and most of your trq is gone.
My Gen1 did benefit greatly of having no cats and only (see-thru) Dynomax Bullit 23" "muffler".
If you have gen 2 it might be a different story.

 

[Mike_W]

Re: What does a Muffler do besides

I don't feel like I lost one bit of torque. I can still put the car in 2nd gear, take my foot off the gas, push ******* the brake, and it will still move forward without stalling. I can also start moving forward from 5th gear... (Was trying to go into reverse)

Without a muffler, my car just responds better all around. I do have a Gen 2 though.

Mike

 

[joe117]

Re: What does a Muffler do besides

I'm not sure why a motor need's backpressure. Perhaps if the cam timing is set up for an exhaust that is restricted, I don't know.

I know that "most of your trq is gone" isn't true.

I've heard this "backpressure is good" talk for years but you never see anyone selling exhaust restrictors as an aftermarket performance item.

I think there might be a little mix up between the need to keep the exhaust flowing fast and a restriction.

If your header of pipes are too big, you may not have the exhaust flow speed you want.
So the use of smaller diameter tube will keep up the speed and yes, cause some backpressure.

Getting that same amount of backpressure from a cat or a muffler isn't the same thing.

So I'm saying that the backpressure isn't needed by any engine.
A properly tuned exhaust is what is needed.

 

[Nexus-6]

Re: What does a Muffler do besides

A few weeks back I found that I had a rather significant exhaust leak on the Lighthing. The header gaskets had gone to heck and were coming apart in chunks. It happened so gradually that I didn't really notice the "farm truck" noise until the leak had gotten quite bad. I had some minor leaks at the clamp joints as well all the way back.

We replaced the gaskets and welded the entire thing shut tip to tip (no clamps) and I know for a fact that low end torque came back up straight away.

I was baffled by this too Joe and mentioned it to the tech doing the work...he told me, for example, that the C5 PCM will actually cut back on fuel when an exhaust leak is detected and wondered if the Lighthing was doing the same thing.

Now, I have heard that in most SC applications a little backpressure is a good thing and I can certainly vouch for a massive restoration of low end grunt once that thing was buttoned back up and the leaks were taken care of. My leak was rather significant and in many spots - for all intents and purposes the driver side plumbing was spewing into the atmosphere before hitting the mufflers.