Muffler removal
 

I was thinking about testing out whether or not my muffler was helping my fuel efficiency or harming it, and was wondering if I should take it off next tank just to test and see.

I'm not gonna worry about the noise violation problem, I live in such a rural area, If I got caught I'd most likely get a verbal warning to get it fixed. Not too bad since I've already been yelled at for having my Sub woofers too loud.

Think I should do it? I checked out my pipes, and they look to be mandrel smooth bent, and I've got such high gears (low ratio), that my exhaust probably needs more backpressure, but I'm willing to try and see.

If it works in favor, I might just pick up a more free flowing muffler, if not, I might get a washer to put more backpressure on the exhaust and see where that goes.

I do about 1500ish rpm's at 55mph, at 60 I do about 1700. Need more backpressure? Maybe, maybe not?

Take it off, backpressure does nothing for you.

Except keep you sane ... LOL The noise may be unbearable, definately not a chick magnet ...

Exhaust gas velocity is a good thing, this is accomplished with small (restrictive) pipes. Big restrictive pipes accomplish nothing.

Sorry, but I'm gonna have to say this is wrong

It's a common misconception, Backpressure does nothing for you IF YOUR FULL THROTTLE RACING!!

you need backpressure IF you have AN EXHAUST SYSTEM AT ALL, Or else economy is screwed up.

exhaust basics
Here's some things about exhaust basics. Notice how the plume distances are important? we need backpressure at cruising speeds, but not during acceleration. For HP we need no backpressure, for efficiency we need backpressure.

Jeep Probably did, considering it made an engine with all the torque 3k rpm's and lower, anything above 3k makes the engine wheeze. capable of towing 5k lbs.

Removing your muffler does help because the noise will drive you insane if you try to accelerate to fast, you can hear how the engine is running so much better and if it starts to run rich at all it gets really loud! so this is not an accurate test as your driving style will drastically change.

Take it off, record some data and prove me wrong!

Shouldnt be too loud, how many cats are on it? Resonators.

I personally believe in free flowing exhausts. But look at what I drive. The turbo provides all the backpressure the engine could ever need.

TEST IT! Give it a go, it'll be fun. I'd test without the muffler, then go with the washer with a relatively small hole and slowly drill it larger as you test to tune it.

On a side note I replaced the muffler on the TDI with a straight pipe when the muffler broke off. It did not make a noise difference at all. But then again the turbine itself makes a pretty good job at muffling already.

Excellent load indicator. You will have no use for a vac gauge then.

From the sound of your town, it might just attract women.

I drove a friends MKIV supra around Houston in March with no Exhaust (not to be confused with no muffler) and let me tell you, DWL was a necessity. I couldn't make it over overpasses without fear of permanent hearing damage. (FYI he smashed the exhaust/ back left corner in to the wall at TWS, he normally has a Cat + Muffler)

I hear every one here say performance mods hurt FE.. Well i would think anything after the gas has been used to make less work for the motor would be beneficial to FE.. at that point its a waste product of the process.. get rid of it the easiest way you can.. In My Hyundai Accent I did a cat back exhaust with a flow master muffler and its didn't hurt gas mileage..and yes you can tell when your getting on the gas with louder exhaust..

It wasn't overly loud but you could hear it and when you got on it, it rapped a bit more.

Since you don't live near me:) give it a go but without a scan gauge it will be pretty hard to quantify your results because the increase will not be above the noise of tank to tank fills.

Flowmasters actually dont flow that well, and provide a lot of backpressure. Thats why theyre a BIG nono in the turbo world.

Well, the integra article was interesting, but the final paragraph illustrates his lack of knowledge. At that point he has basically forgotten that you have to treat the entire exhaust as a complete system, and that the exhaust flow is limited by your 'tightest' component. Sure, putting a fire hose on a garden hose does squat, but putting a garden hose on a fire hose _will_ restrict flow.
Honestly, I can't imagine what backpressure does for you beyond increasing your pumping losses. I'd much rather have some properly tuned equal length headers tuned for my cruising speed that properly scavenge exhaust (providing negative backpressure.)
http://www.cobbtuning.com/info/?ID=3222

x2
I don’t subscribe to the thinking in the Integra article either. If adding backpressure did anything for FE you would have seen throttled exhaust become mainstream decades ago. If you think that your exhaust is too free flowing my recommendation would be to change to a 1/4" smaller pipe from the manifold back instead of welding washers into the existing pipe.

It could be quite possible that in low RPM, economy load region that the gains are so small to be immeasurable as Frank says and definitely outweighed by the noise increase. Although nothing ventured, nothing gained.

I'm not sure if it would hurt or help, but my friend has a removable muffler on his honda. He jacks up the back of the car, takes the tire off, and theres just a clamp holding the muffler on. Takes about 5 minutes.

And yet I have one on my TDI, I 'm rather certain that it is quieter than stock.

One procedure is a bit more involved than the other. It costs nothing to try the washers first.

I used to have a 1997 Dodge Ram 1500 4X4 with a huge "20 gallon drum" muffler on it that weighed about 40 pounds. I hacked that gas-sucking tank off my pipes and installed a 2 1/2" Cherry Bomb. The truck sounded good, but not real loud at cruising speed, but when you opened it up, it sounded pretty damn good. I also got better fuel mileage from the swap.

Same here, except I don't have to jack up the car, I've got enough clearence to get under and cut the time in half taking it off. I just wanna test it with another tank.

A friend of mine took the muffler off another friends Jeep I6, and it basically sounds like a v8 with a flow master exhaust. It's not much louder than some people with flow masters. Also, the sound won't bother me. I hear it everyday from people with nice pipes, also I'm in a band and when we play shows, we mic. everything, we mic. amps and we mic. drums. So basically our ears get blown out. I've also got a 2400wpeak amp blasting power at me constantly, so the only concern I'm gonna get is I can't listen to music and exhaust at the same time unless I don't wanna hear next year.

Oh, and I don't know about your chicks, but around here, chicks dig the loudest exhaust pipes :D

All the chicks around here work on cars the same amount or more than the guys around here. They're into nice pipes. It's like the chick that rides a harley. She's into the masculine rumble of the exhaust.

Why yes, isn't that how you get to be the alpha male?

It sure is nice talking about gas mileage here.

Don't do it. A Jeep inline 6 without a muffler sounds like a bad running tractor. Besides, in some locales, you could easily exceed sound ordinances.

My old minivan with a Cherry Bomb glasspack was plenty loud. But you will drive it with a softer foot.

My attitude concerning FE is:

1) Safety is first
2) Courtesy is next
3) Driving for FE is third

Nobody will complain if you are NOT making excessive noise.

If I were courteous I'd be driving 65 like everyone else, but I guess not cause people get mad at me for obeying the law anyway. Might as well make some noise. I probably make the same amount of db's from my sound system anyway as without a muffler.


Ran into a problem. Muffler U-Clamps are frozen on there (more like the nuts have melted to the bolts). Instead of hacking them off, I'm just going to try more back pressure for more low end torque since running down the highway I produce 1500rpm. I'll need more torque down there (even though there's already plenty:D)

sorry this thread is a month old, but, i just wanted to point out that an i-6 without a muffler sounds like a tractor and also that i cut off my muffler and had 2.5" piping run from the cat all the way out the back to a 3" tip and it actually increased it by about 2mpgs.

edit:: i have the 5.2L V8

My major experience with driving without an exhaust system involved the S10 I had when I was in college. The original catalytic converter had given up the ghost, so my roommate and I drilled holes into it until I could get it replaced. You could literally hear it a mile away, and the lack of backpressure pretty much removed most of the already-meager low-end torque from that wheezy little Cavalier lump. When I finally did get it fixed, some half-assed welding and clamping meant that the joint on the back end of the replacement cat hand to be held together with hose clamps and cans after a short while. Needless to say, I'd find myself driving with open headers. Again, same loss of basic driveability.

Minimal exhaust backpressure is really only desireable in high-rpm turbo applications. Driving like a sane person on public roads pretty much rules that out. I think, however, the loss of FE from an open exhaust comes more from unconsciously trying to compensate for the low-end power loss while driving.

wow, i see alot of BS with this subject

first of all, your factory pipes are crush bent, just because there is no ripples, does not mean its not crush bent

second of all, exhausts can help MPG, but it mostly depends on the car & how bad the stock exhaust is to begin with, & how you drive

i work at the only tri-state area mandrel bending exhaust shop, I know a few things about exhaust ;)

www.mandrelbend.com is our website

There's a company that makes aftermarket turbo kits that install way down the exhaust system; they pull the muffler and let the turbo serve that function. The noise is about the same. They skip the intercooler, too: ten feet of turbo pipe dumps a fair amount of heat from the compressed charge.

how about one of these... exhaust whistle!!!
http://www.youtube.com/watch?v=lwTokillnU4
:) lol

She likes the vibration more than the rumble. :cool: