Well a few updates several days after the straight pipe install in liu of the resonator as promised. (pics in prior post)

Pro's - Fantastic head turning sound. Almost American muscle like.
Con's - A little loud for me presently, bordering on obnoxious under throttle!

I know that may not go over that will with many sound enthusiasts but here was my take.

Startup and idle, fantastic. A little louder and more pronounced in particular during a cold start. Loved that.
During regular driving and acceleration through the gears, 50-60% louder than before lets call it. Ofcourse all of this is my impression and not scientifically measured in any way.
The 'bark' as they call is during down shifting especially at higher revs, quite loud at least 100% louder.
Under heavy throttle, allot louder both inside and out of the cabin.

When I was parking at a friends place he mentioned that this thing sounds angry even at low speed. Loved that part.
Also mentioned when I pulled out that the noise you would think is coming from a lambo or something. Yes that pronounced.

Really did like the 'snap, crackle and popping' as the car came down lower in the rpm range in a certain gear.

Around here an E class does not get many looks but this past week it certainly did.

If I was 27 rather than 37, I might be tempted to keep it this way for longer.

So what did I do? Well after a little more reading on the forum I figured let me go the X-pipe route and have it put in where the straight pipes were. used the magnaflow prefab x-pipe pictured in a prior post.

My exhaust guy was fairly certain that it would not make much of a difference but he humoured me and put it in anyway this morning.

Verdict, back to square one!!

Unbelievable the x-pipe has tamed this thing down to effectively stock sound level. If it is different in any way even under heavy throttle it is in the low single digits. Damn.

So what will I do, well after more reading have read that many on the C63 forums have had a modified H-pipe built. Basically two straight pipes as I had before but joined at some point by a narrower 1.5" cross pipe. (pics attached from another post.)
Not being an exhaust expert I would suspect that if the cross pipe was the same diameter as the straight pipes it would not sound much different than what I already have. I suppose by narrowing the cross pipe it allows more of the exhaust to flow straight through.

Hopefully this gets me to the half way point of stock versus pure straight pipe.

Only other strange thing I noticed is that now with the x-pipe in, seems to have a touch more pep than when I had the straight pipes in. Cant validate though or not sure if mechanically that makes any sense but just a feeling.

Nonetheless, I am after sound and not speed so the saga continues.
Should have new pipe installed by Friday so will also update.

If any wiser than me have any other info I should consider would love to hear it.

 

Hope things turn out the way you want them. I agree the straight pipes are pretty loud, but I didn't think they were obnoxious, I mean yes, if you are 37, man they make you look like an 18 yo in a Honda Civic with a fart pipe, but when you reach the ripe old age of 38, you lose so much hearing, you won't hardly notice it

Let us know how the H pipe goes.

X

 

Suscribed and anxious for the results

 

Good write up Tas. It does make sense that the X pipe could produce a little more power as you are balancing out the flow more that way and less restriction than the resonator. If I do anything it will be the X pipe as I don't like too much noise but would welcome better performance. I think the reason a lot less noise than the straight pipes is the pulses cancel each other out with the X pipe.

 

The stock resonator is an H pipe.

 

But it is a resonator with all those little holes like swiss cheese, the H pipe proposed would be hollow tubing.

 

Assignment complete.
I actually went to another exhaust shop that I was recommended to as the guys I have seen the last couple times would definitely think I was crazy going back a third time!!
They were incredible with me BTW.

Will report back soon on results but after a very short ride home I think we may have a winner here.

Before & After.
X-pipe to hybrid H-pipe shot.
3" straight pipes with a short 1.5" cross pipe

 

On a very preliminary basis here are my thoughts.
I am going back slightly on what I said regarding the MagnaFlow x pipe pictured and say that it perhaps provided about a 5-10 pt change. Slight enough that I would not have done this of course. Most of that in the lower rpm range I found. Higher rpm nothing of not less than stock.
Of course if you had a custom x pipe fabricated that did not have such a deviation in the air direction that would likely be different.

On the new hybrid H pipe I would say a 25-40 percent increase in sound.
Because the stock resonator is also in the H pipe shape within the housing it seems that the sound profile is also very similar just louder.

Effectively this new arrangement is very similar to the geometric design of the stock resonator minus the housing around it, the holes in the internal pipes and any other deadening properties it may have within that are not apparent.
I like that. Seems to just let the air through with less interference hence the additional sound.

 

The resonator is a helmholtz chamber. The flow is the same, it just removes sound.

 

Interesting stuff. I am thinking about getting Renntech cated downpipes. Wonder how loud this mod is compared to the straight pipes? Any ideas??

 

Sounds awesome…any performance gains?

 

would have been cool if you had some crazy *** audio equipment to assess the differences in frequencies etc with the different set ups, more objective analysis

 

Looking for more feedback to anyone else who has done this? Does it affect performance?

 

I know I'm in the AMG section but I'm wondering how this last setup - straight pipes with the little crossover pipe would sound on my NA E550. It's just too damn quiet right now. But I don't want it to sound like a civic with a fart can or a big block with cherry bombs on it either.....


Take care,

George

 

If the modification comes after the catalytic converter, then no it doesn't violate CARB or emission control laws. It is in violation of the law which prohibits any modification to the exhaust system which make it louder. But that's what we want. Hope that answers your question.

 

Best $150 spent on this car

 

The wagon certainly helps the internal sound of the exhaust... can you describe how the pipes change that? It wouldnt be too hard to make it too much.

 

Haven't heard cold start yet.

Idle is almost like stock in volume but now has an odd flutter. This flutter is audible at initial throttle tip in as well but disappears almost immediately once revs rise past idle RPM. Not audible in the car.

Throttle blipping without load is louder than stock. No decibel meter but my guess is 20+% increase from the outside, 10+% increase from inside. Tone is more aggressive, sharper, and more crisp. More of a "bark."

Haven't heard it under load from the outside yet.

Inside while calmly commuting, the car sounds stock. Zero drone at freeway speeds. Mash the loud pedal and I'd say it's about 20+% louder inside than stock (so 10+% increase than without load). Tone is similar when blipping without load.

Upshifts have a sharper "crack"and downshifts have the new tone with more volume (makes sense).

Throttle lifts yield a tiny bit more burble and pop but not nearly as much as I'd like.

Overall it's a perfect compromise since I'd like to preserve my 3 year old's hearing.

Hope that helps.

 

That was very helpful. Thank you. I think I'll end up ordering the fancy X-pipe and have a decent exhaust shop weld it in. I can't quire bring myself to put a pair of slightly merged pipes together.

Onwards with the black '12 wagons!

 

The shop offered me the X pipe but from reading the posts above, I wanted more volume and a sound more similar to American muscle where the exhaust pulses are not merged.

Ideally I could get it to sound like it had a flat plane crank but that's not going to happen...

BTW, the eisenmann system will not fit our RWD wagons or I'd have gone that route.

 

I'm not sure if any of the exhaust shops told you, X-pipe should be placed before all the resonators and after the cats at the start of the pipe not mid section for slight power gains .

 

Cruising



WOT through top of 3rd

 

Sounds awesome

 

hey guys, so two different shops i talked about doing the resonator delete questioned me about it. They said it wouldnt be good for the turbos as they run off the back pressure?? has anyone that has done a res delete had any problems??

 

Taking the resonator out doesn't do crap to the back pressure in reality, Increasing the diameter of the pipe will.
The benz resonators are straight through as it is and shouldn't affect the back pressure.