flowmaster super 40... FE impact?
 

so i'm on the verge of getting a flowmaster super 40 series exhaust. not a dual, just a single. hows this gonna impact my economy, if at all?

I would not expect any FE improvement.

how about a decrease

Why would you want to do such a thing?

BLUB-BU-BLUB-BU-BLUB-BU-BLUB-BU-BLUB-BLUB-BU-BLUB-BU-BU-BLUB...

BWAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA-EHH-WAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA-EHH-WAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA.

Is my guess. :D

yeah, that just about sums it up :D haha

Well then why not save all that dough and simply cut a hole in the floor and run an open pipe up to your ear?

A reduction in back pressure will improve your mileage slightly. It may not be measurable however.

Trashmasters suck.

If youre gonna do exhaust, go magnaflow or dynomax.

For absolute least restriction I would recommend a Cherry Bomb. The fact that they are so cheap means you will get a quicker return on investment.

If you run all day long at Wide Open Throttle, it might help a tiny bit. In real world driving, it usually doesn't. It might actually hurt engine efficiency. And then there's the temptation to floor it, just to hear that sound.

I wouldn't do it.

I a previous life, I put dual Flowmasters on my Suburban. The started rusting within a year. I live in Texas, where there is no salt on the roads. They're not the best quality. I then moved on to the Cherry Bombs. Sounded amazing. Neither did anything for mileage, though. That's when I traded it in for a Civic.

"Return on investment"??? :confused:

Well, if you start with the assumption that they do improve mileage... ;)

Aero Turbine

everyone we/I ever installed people loved them, with claims of improved FE also

for more subtle sound, Magnaflow is a nice muffler too

Performance Exhaust Maryland -- MBS is your Maryland source for custom performance exhaust

That has been researched, looked at, hashed over, re-hashed over, re-re-hash-hashed over, not to mention done to death, and it just plain doesn't work that way.

http://i146.photobucket.com/albums/r..._DeadHorse.gif

'zactly. I totally agree with you. I guess my e-subtlety (;)) was too subtle.

Frank and PaleMelanesian are completely right. You won't see any improvement in FE from replacing your muffler. Your car will just be louder, thats all.

I got it~ I just wanted to use my new dead horse gif! LOL :thumbup:

I'll have to save that one for later. So many times it can be useful!

yeah i didnt expect any FE gain from just the muffler, but what about an entire new exhaust system... like from the headers back.? or is it again with the, if any, "immeasureable" gains if there are any and the definite debate in regards to there being gains at all.

I don't think you'll see a difference. Diesels, which do not have throttles, have a lot more gasses passing through the system at all times than a similarly sized throttled gas engine. That makes them more sensible to back pressure and negative boost. Yet, at least for TDIs, people removing everything from the turbo back do not generally report increased FE. There probably is an advantage, but it's probably 1-2% or less.

Hmmm... guess I'll scratch the fart can off my mods list... ;)

Not true.

Lower back pressure means less work for the engine to expel gases from the cylinders on the exhaust stroke.

A common misconception is that that an increase in manifold vacuum due to increased throttling to maintan the same power offsets any gains due to more work being required by the engine to pull the fresh air charge into the cylinder. Since the crank case is connected to the intake manifold via the pcv valve any increase in the manifold vacuum increases the vacuum in the crank case eliminating any extra work needed to pull the fresh charge into the cylinder.

The crank case vacuum does however increase the work required by the piston to expel the spent charge again however this is countered by the increase in power due to the higher pressure differential across the piston on the power stroke.

Another side benefit is that the mass of air thrown around by the under side of the pistons in the crank case is reduced (I can't remember the technical term used to describe this effect). At higher rpms this reduction in air mass reduces drag on the engine.

The end result is a net gain in power (actually a reduction of a losses ) for the same amount of fuel burned.

bla bla... so has anyone gotten better fe cuz uh pulling the muffler off? Dint think so.

Put the biggest nastiest cam made in it if you are going to swap to a loud exhaust. I never liked the sound of a stock engine with loud exhaust. It needs a lope to it :) Then you can start taking it to the track and really have some fun with it.

My Camaro sound clips, clip #2 is stock engine with a loud exhaust. It sounded like every other Camaro and I thought it sucked. But I only had it like that for a week or two before the cam got installed. Clip #3 is with the cam, so with a cam like that it is ok to be loud. Also the cam/other mods dropped me from 28mpg to 15mpg driven normally. So being on ecomodder with a car like that is kind of pointless. But I guess if you want a loud farty/raspy type sound with a stock aluminum engine go for it if that is what you like, everyone has different tastes :thumbup: But it at best won't change your mileage at worst it will drop your mileage. Unless something is wrong with the exhaust on it now you won't see a gain.

Swap headers for something with scavenging and higher flow than stock, use high flow (CARB approved) cats, 60mm piping, and run it into a truly blended y-pipe (not the chevy "under the tranny pan" BS). You might see a gain of 1%, but it will sound A CRAPTONNE better, and you'll have more power when you want to use it.

This is of course provided you're running a stock engine with next to no current modifications, and it's either a V6 or V8 with a naturally crappy OEM exhaust.

It's funny when people talk about back pressure or pressure drop in the piping of charged engines. The condition they talk about is almost always at WOT. Sure, that stock exhaust is very restrictive, at WOT near redline. My IC have a 3 psi drop, at max boost over 4k rpm, but the drop does not even register on the gauge under normal highway driving.

it really depends on how ****ty the stock exhaust design is & of course how you drive it, most of the time, if your staying below say like 2500rpm, & barley using any throttle, your not going to see gains for the most part, vice versa, heavy throttle, loads, towing, etc would benifit from a properly designed exhaust

Quoted for Truth.

Umm.. not exactly. While it may be so miniscule(sp) that it isn't NOTICEable at low-load/low-rpm, fixing any restriction in your intake tract will actually promote better airflow anyway. Plus, you don't magically have 3lbs of pressure loss at full load/high RPM... it builds up to that.. meaning that at normal load/mid RPM, you might have .3PSI of boost restriction (pressure loss/drop)

Part of that pressure drop is not even restriction though, it's just b/c the air charge is more dense when it comes out than it was when it goes in! That adds a whole new dynamic to the equation. If you have a rubber ball, that just barely fits into something, so that it applies pressure on the circumference of a circle, then you nearly instantly drop it's temperature by 30% or more (depending on the setup), it will fall out of that compression fit, which shows that it's not putting as much pressure against the circle. (Or any, in this case.)

Anyway, that's why I suggested a full header and such... the scavenging effect will actually increase airflow, rather than "unrestrict" it, and the full length tube headers usually increase low-mid torque as well.

Here is a research project that shows how a good low back pressure muffler can improve things at a low rpm and variable load. The engine its tested on is a 16hp 2 cylinder diesel so results may vary slightly for a gas engine.

http://www.ripublication.com/aama/aamav2n1_4.pdf

I think I read that correctly... it's essentially saying that with the new (quieter) muffler, they got less fuel consumption and higher thermal efficiency... is that correct?

So what does that say about flow? Was the new muffler quieter with higher flow?

Also, back on the original tract of the discussion, SuperTrapp mufflers claim increased flow and HP across the board... which should mean higher efficiency due to lowered pumping losses, regardless of throttle position or RPM.

How does that conclude to "adding a muffler can't increase your fuel economy"?

My two cents....
2.0 motor, I put on a Tuned 4-2-1 header, no cat, 2.25 mandrel bent pipe to the back of the car with a straight thru resonator and a staight thru muffler. I recieved a small but noticable increase in mpg's while driving with load. I also recieved a very large and prominate rise in peak hp, 1.2 seconds quicker thru the quarter mile. The torque at low rpms has increased noticably also, however I am not able to take advantage of pulling lower rpms at slower speeds because of the ATX trans down shifts for me......at least not yet :)
At idle the if you put your hand over the muffler outlet before and after this work the pressure of the gas coming out is much higher after, ie. it feels like it is pushing against my hand much harder.

Hope this helps.

flowmaster
 

Stick with OEM.All SEMA aftermarket muffler manufacturers along with cast and crew of Fast and the Furious have been convicted of crimes against humanity,and have been conscripted into the Army as infantry "point men".They will be permanently stationed in Iraq and Afganistan and will be air-dropped,naked,with no basic training,armed only with a pea-shooter.-------Their products will be confiscated by the Alien Property Custodian and destroyed in a public exhibition during Burning-Man.-------- Vin Diesel plead for his life but was the first to be taken.-------- SEMA has apologized for the damage they've caused and vows not to resist the seizure and destruction of their assets.

it's all about how restrictive your current system is. On mustangs up until 2005, replacing the stick cat back system with a mandrel bent system and good free flowing mufflers was not only worth 5-15 up, but also gained a nice bit if low end torque to boot.

05 and up stangs have a much more efficient exhaust system stock, this making an upgrade useless.

My advice is to find a forum dedicated to your particular car and do some research. FYI a straight flow through muffler is the most efficient type.

Flowmaster 40 with a turndown helped increase FE on my buddy's GMC sierra 4.3

Obviously I must run out and buy a Flowmaster 40 with a turndown now. :rolleyes:

This post will cost you a quarter. Feed's getting pricey these days. :rolleyes:

we need more icons. :rolleyes:

It's less obvious this way. :thumbup: