What is the difference between a C7 exhaust and a non C7 exhaust. I've seen both cars at separate occasions but never side by side so I cannot really compare. To me it looks the same.

What's the scoop?

 

well according to the mb site, it says that the exhaust tip that comes with the c7 package is slightly larger than the non c7

 

the C7 exhaust does not have a resonator; the non-C7 does; the C7's exhaust tip is also a bit larger.

 

The difference in appearance is so minor that you would probably not notice it. C7 is louder as well expecially noticeable at startup in a closed garage.

 

In a few months (before I get a new exhaust system) I will have a local shop remove the resonator. Its only about a $50 job, it weill make the note a little louder, plus its alot cheaper than a couple hundred dollar system. I will keep all posted

 

Where is the resonator? Do C240 sedan have it? Timmy can you let us know. So I guess you just gonna make a straight pipe for it right? Is that effect smog?

 

I think that you're confusing a resonator with a catalytic converter.

The cat controls emissions, the resonator doesn't. A straight pipe goes in place of the cat, is for the track only, and is a really dumb idea for a street car. You'd fail at inspection time, and pollute the rest.

 

The resonator is between the muffler and the catalytic converter. The muffler is at the rear of the car and the cat converter is just to the rear of the firewall. As Tim says, removing the resonator will have no effect on exhaust emissions. It will just make the exhaust sound a lttle louder.

 

So is it possible to remove the resonator from a non-C7 Coupe to make it sound like a C7 Coupe?

Who can do this kind of job? Bring to MB dealer or an autobody shop? It costs $50???

 

its relativley simple. Any muffler shop can or should be able to do it. My muffler shop said they would do it for $50. Not sure how much it would change the sound but to me $50 is alot cheaper than the $500 remus one. I will keep people posted

 

I use to have a test pipe (No Cat) and I pass smog check easy. But I did not gain any notice power so I switch to hi flow Cat. I will take that resonator out when I talk to my muffler shop.

 

I'm thinking of trying these mufflers. They are supposed to have a low deep rumble and be 35% louder than stock and they look really nice. The best part is that they are under $100.

 

Any cat-back systems for the C-coupe yet? Or still in R&D phases?

 

Remove the resonator and you have one. It is a pretty straight shot from the cat to the muffler. If you are expecting more power, you will be disappointed. The place that needs improving is the exhaust manifold/header.

 

that probally because u can not compare them.

i had just the C7 stock exhaust and thought it sounded terrible.

My remus make the car feel a little more responsive and makes it sound like a very well tuned car. I actually get a cupple people complemting the sound of it. Especually when i floor it it sounds great.



Buellwinke -

In my opinion i would never get a no name weld on exhuat like that. especually for this car. and 35% louder is pretty loud. i think it may sound a little ricey. But thats up to u. A muffler designed for any car can not give u any good results. Therefore i can almost garantee u will not get even 1% power gain just the noise to make u feel like its fast. u may even loose some of your bottom end power 2.

 

Yeah, I get a kick out of claims about things being x% louder or quieter or whatever. I want to know how they define what 35% louder is. And I want to know how many people think they understand what 35% louder really is.

Anyway, getting back to the muffler... I highly doubt the Remus muffler has better performance than any other muffler with similar restriction. When someone designs an intake or exhaust for better performance, they need to work with the dynamics of the flow, not just the restriction. To say that one muffler adds more horsepower than another because it was "designed for the car" is false. Manifolds may be designed for a specific engine/vehicle/use whatever. Locations/geometry of a crossover may be designed with the torque curve in mind. But the internals of the muffler are virtually never designed with flow dynamics in mind, no matter what the marketing department would like you to think. The muffler is all about acoustics, NOT horsepower. When a muffler is designed for a specific car, it's the acoustics that are being studied.

Mufflers are desgned to quiet down the car with the least amount of restriction. That's basically it. By the time the flow has reached the muffler, there is no more oppourtunity to take advantage of any flow dynamics to help scavenge the exhaust or whatever. A lot of the aftermarket stuff is a simple tri-flow design, meaning there is an inlet, a return, and an outlet. These tubes typically have louvers or perfs in them to expose the sound to some sort of fiberglass which does a great job at attenuating high frequency sound (above about 500hz). So you get a nice rumble with no high pitch harshness.

The next step is a "straight through" design, where there's only one pipe that runs through the muffler. This is lower restriction and obviously louder.

Which brings up my last point... if the resonator on the non-c7 cars is a straight through design (which I would expect, but, having a C7 car I can't check), it's restriction level is so low that, compared to a straight pipe, any performance benefit will be so small it will be difficult to measure.

Sorry about the novel, but let's not get carried away thinking the aftermarket companies spend a lot of dyno hours tweaking the muffler internals...

 

SPYKE: all I'm hoping for be removing the resonator is to change the exhaust note just a little. i know there will no hp gain what so ever. And yes the resonator is a straight-through design

 

It will be louder without the resonator, but only a little.

 

I disagree, i dont think all mufflers are the same and can not do different things on different cars. I dont know about other muffler companies but i have seen some sketches of the remus muflers and its not just an empty can, its got alot of different small chambers for the exhaust to flow thew. I know not all mufflers have that.

I can almost garantee that if someone was to put a weld on muffler as Buell posted on and did a dyno vs. the same car only with a remus muffler like mine, u would definitly see more gain on the remus. (small but definitly a gain.)

All muflers can be very similar but not all the same.
There is alot of work into some of these mufflers that are designed from big muffler companies.

 

I realize this all too well: I'm a development engineering supervisor for one of those companies, and have been designing mufflers for 12 years now... you may have seen my work on the new Thunderbird, the 2002 Harley Edition F150, and other vehicles...

I certainly wouldn't expect Remus or anyone else to be selling an empty can. Yes, there are tubes and things inside there. But I WILL bet money that two mufflers with the same restriction curve will produce virtually the same dyno curve. "A lot of small chambers to flow through" sounds like they're using Helmholtz chambers, which are there for acoustics. And for what it's worth, flowing through small chambers is not the best choice for high performance applications... though it could be a way to get a different sound without changing the restriction much, so the stock calibration still works...

In the thousand or so designs I've had prototyped, not one of them has ever had anything inside to help engine performance other than reducing restriction. If there was power to be had by altering the flow in the muffler, I'm guessing the various Superbike teams around the world would be doing it, and they all use straight through designs.

And by the way, I never said all mufflers were the same. I said many aftermarket designs are triflows.

 

I would like to bet ALOT of money on this. I know u would definitly get more gain with the remus vs. just a weld on universal muffer.

The remus muffer or any other muffler may still be a little restrictive, but not as restrictive as the stock muffler so there for its definitly better than the stock muffler.

If u are saying there all the same, then why dont we all buy those $49.99 mufflers we see at pep boys if they do the same thing.

Again i am not saying the remus muffler is going to give u 15 hp. and the weld on will give u 1 if any. You may definitly get a small gain on the weld on muffler but the remus can definitly give u some more better results. They may be very very tiny but i am sure u would be able to see them.

 

So tell me how you KNOW this? Enlighten me. I've been doing this for a while now but still learn something new everyday. Teach me. Show me data. At least offer up some explanation that makes sense. Failing that, give me an example of any engine modeling software that uses anything other than the restriction of the muffler to predict a torque curve.

Please re-read my last post where I explicitly stated "I never said all mufflers are the same".

There are any number of reasons people don't buy the $50 universal fit. The universal fit probably doesn't really fit all that well. It's also probably made out of cold rolled steel and won't last more than a couple years. It's uglier. it looks like an add on. It doesn't say "Remus" on it. Ya can't polish it. I'm sure there are a million reasons not to buy the cheap stuff. BUT; Performance-wise, if the restriction is similar, the power will be similar. (This whole thing reminds me of the general feeling that a Ferrari must be faster than a Chevy, because, dang, it's a FERRARI...)

I'm somewhat amused you are so confident in the begining of your post but then qualify it in the end with "They may be very very tiny but I'm sure you would be able to see them". I live in the real world, if differences in torque curves are very very tiny, they're not worth talking about. Why? because there are so many other factors going on that any very very tiny change in results is likely not repeatable.

Believe it, don't believe it, whatever. I'm done. As you don't seem to be grasping a word I've said up to this point, I'll shut up and leave it with... The people in marketing love guys like you.

 

You can see a picture of a non C7 exhaust here for details on the resonator. Also, for what it's worth, Eisenmann makes and exhaust for the Coupe. See details here.

 

Here is a pic of the exhaust from Bos' site. The lumps om the pipe from front to back are the catalytic converter, the resonator and the muffler.

 

1. I am not going to explain how i know or think the remus will give u better performance. i know it will if u wanna put money on it i would be more than happy to. put both cars stock on the dyno with a remus and a weld on and i bet u will see more gain with the remus.

2. about how u said a ferrari is faster than a chevy. IT IS? show me a chevy that can beat a new ferrari besides maybe a Z06. STOCK.

3. You said earlier that u helped design the exhauts for the Thunderbird, the 2002 Harley Edition F150, and other vehicles...
TO ME that can now explain why those cars sound like ****.