FireHive

Hey all,

I have recently installed straight pipes on my 2010 C300 and it sounds mad.

Question is, i have heard that since the exhaust gases are flowing more freely (see backpressure) , i would have to flash my ecu to get the fuel to air ratio back on track and instal a cold air intake too.

Is this true? will the ecu, as it is stock, be able to regulate the fuel to air mix already without having to do anything?

thanks for replies

Spd Racr

The ecu should make the adjustments needed. When you say straight pipes, did you remove the cats as well? If so, that may require a tune, but merely removing the muffler/s shouldn't affect your afr. The increased airflow via intakes/exhaust is too minor to "need" a tune.

FireHive

Negative sir. The cats are still up (for legal reasons and because i dont want my car to smell like a lawn mower).

I hope you didnt misunderstand me. My mufflers are still up. What was removed was the resonator.

black lavender

So you didn't straight pipe anything. You just removed the resonator.

diodia

Basically, you did an x-pipe? From what I have read on the forums, it does not change anything that would relate to the engine. The only difference it makes is the sound, which is awesome.

FireHive

yes. Basically thats what i did but instead of it being an X, its two straigh pipes joining the cats to the mufflers.

w204_Generic

Lol.

OP how did you think you have a straight pipe if you just removed the resonator?

There are still the Mufflers, Primary and Secondary Cats, which make it not a straight pipe by all means.

splinter

MB already did that for you..no extra charge.

FireHive

Thank you all for replies. this next question might sound a little bit odd but does this mod affect mpg in anyway?

Claudela

Wish we could hear the new sound, I would like get a bit more music from my 2013 C350

Becksan

Magnaflow mufflers will do the trick for you! - got it installed on my C350 a few weeks ago. adds a nice rumble to it, though it can be pretty loud around 2500rpm

EvolutionDrock

If you don't want your car smell like a lawn mower and 2 cycle oil install oil catch can.

FireHive

View My Video


here you go good sir

FireHive

With this said, i would really apreciate it if somebody could give me a hand with figuring out if having the exhaust in a "true dual" manner has any pros and cons over having the X-pipe. ( i asked this since, upon looking through the resonator, i saw an X-patern, which would explain why people decide to put x-pipes, it follows how the stock exhaust was designed to flow but without the silencing effect)

Rodpwnz

I know its super late, but would this video on a V6 mustang exhaust help to differentiate x pipe from H pipe? I'm not quite sure what to make of the flow animations, but looks pretty interesting nonetheless.

ickdeep

Here is my two cents...

I did the resonator to xpipe first. It was pretty good, doesn't really kick in until 4k+ rpms. After having that on for a few months, I wanted something more. A few friends were getting ready to get muffler delete and I thought "sure, why not". Getting my mufflers delete plus having the xpipe makes my sounds so perfect. Its such an exotic sound (even with all my other friend's car around ie bmw audi infinty sti evo...). I have some videos on my youtube channel if you would to see.
As for the cats, I'm always going to keep those in because I dont want to mess around with legal stuff.



EDIT: as for the back pressure, there is some but not too much. Normally only happens when I hold a gear and slow down. Sometimes I'll hear a loud pop but its random.

Shimee

I only have academic experience with fluid dynamics so I'm sure someone else will be able to elaborate more. The main difference is the H-pipe mainly serves to mix sound waves whereas the X-pipe mixes both sound waves and exhaust gases. Both will sound differently though.

See how on the high pressure flow with the H-pipe there is a concentration of gas in the bridge? This high pressure region effectively serves as a dam preventing the free flowing gases from freely passing through, but it does not stop sound waves, however; because of the higher density of gas in the high pressure bridge the sound waves will be attenuated more.

The X-pipe does not have a bridge but instead a smooth transition crossover which prevents the formation of a high pressure region. This allows the gases and sound waves to mix more freely and evenly.

As for what will happen at what RPM with what kind of sound, I have no experience so I have no idea. Hope this helps somewhat.







So you kept the stock resonator, added an X-pipe after it, then deleted your mufflers? Sounds very nice. I have my resonator completely replaced with an X-pipe and for a day (after I cut my mufflers out to be replaced with a pair of Magnaflow 10416's) I had straight pipes after the cats. I did not like it. Yours sounds a lot more refined which, I'm assuming, is because of the resonator helping to manage the sound waves.

The way I had it the drone was unbearable cruising at 1500 rpms but surprisingly no drone on the highway. There was definitely a noticeable affect from the lack of back pressure too. In your case you have the resonator, which helps; in my case there was nothing and certain gear shifts became more sluggish and acceleration took a hit.

I'm sure the ECU would've straightened it out but after the Magnaflow's went on everything was back to normal. So the myth with back pressure is partial and subjective to the individuals liking.

ickdeep

I dont have the resonator in anymore. I replaced the resonator with the x pipe completely.

Rodpwnz

I can see, so that extra chamber in the middle is causing turbulence, and back pressure? The xpipe still has some turbulence and little back pressure, while straight pipes cause no turbulence or back pressure.

I'll have to go dig up an old thread about how back pressure will affect performance in our cars, or if the difference is even noticeable. I'll probably just spend a few hours googling and reading up on backpressure and exhaust performance in general lol

Thanks for the insight

FuMMoD

Since it doesn't kick in until 4k rpm does it make a lot of noise while just cruising? I like how quite my w204 is but sometimes i just want to let the monster roar.