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Wanted to share my finding with you all on the new Exhaust setup on the Car.
For starters the car had the following installed prior to the Akra setup.
Renntech Intakes
Renntech Throttle Bodies
AP Long Tube Headers
200 Cell High Flow Cats
Secondary Cat / Resonator Deleted
Eisenmann Race Cat Back.
We kept all the mods on the car, however removed the High Flows and added the Akra Evolution setup.
First and foremost - The sound is nothing like the signature AMG crackle / burp and pop. The note is not as metallic sounding and definitely not as high pitched. I switched to the Akra, knowing full well I would lose the top end roar of the Eisenmann setup (Which is an amazing system BTW).
What the Akra offers in terms of sound is deep and throaty. The exhaust note is definitely more subdue. However when WOT, the exhaust speaks for itself. Its deep and menacing, From 1250 - 3500 it sounds angry.
I have had the exhaust on for several weeks now, driving 700+ KM per week. I can rest assured that my decision to tone down the Long Tubes with the Akra was the right thing to do for me. The car does not at all drone, under load it does not vibrate things in the car etc. The Akra compliments the long tubes greatly. The car is like stock when I want it to be and super aggressive when I chose to.
Gains:
I made 478 WHP / 452 TQ. Which is 3HP more then the Eisenmann Setup, and 40 LB FT TQ more.
With the additional TQ increase the car feels much more alive, I gained most of the TQ down low. The car rev's more freely and accelerates much quicker compared to the previous setup. Its a blast to drive, the driving characteristics of the car was changed dramatically.
Would I do it again? - 50/50 - I feel most of us are content with the C63's exhaust note / performance. From a pure performance stand-point, NOTHING competes with the Akra, both in weight savings and gains. However, cost of entry is steep, I refer to it as a Connoisseur mod. Its not for everyone, however every setup is different and the owners have there own taste / requirements.
Onto the good stuff. Here are the Dyno Video's of the various setups.
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Nice write up Kris. Can you clear something up - when you replaced your Eisenmann and high-flow cats, did the Akra Evolution come with new cats or is it straight-piped?
Nice write up Kris. Can you clear something up - when you replaced your Eisenmann and high-flow cats, did the Akra Evolution come with new cats or is it straight-piped?
It straight all the way through. However the evolution setup has a built in resonator. Where as the last setup had none.
I checked that too. We dyno'd the car post Akra install with the highflows still in place. Made the same numbers (within 3 hp). But the tq gains were there irregardless. The high flows aren't restrictive at all. I actually used them as a resonator more so then cats.
I should have made way more then 3HP If the cats were restrictive.
Amazing writeup and accompanying video sir! We're glad that someone has put into words here on the forums what all of our customers have been preaching for quite some time. Now go out and keep enjoying that sound
You should ask wobble63 to see if he did a post akra install dyno. I don't believe that he saw 40tq gains with his arh setup. I believe he did dyno runs with the 200 cell cats and with the test pipes.
since installing my Akra, the "data" I have that tells me its the best exhaust and the right choice is the fact that at every opportunity I have my window open, foot on it and the guys on the service drive ALWAYS huddle around me and wait for me to start the car (and a couple even shhh each other for silence).
Any time I've heard one on the c63 I've thought it sounds pretty weak *** but I prefer cars louder so to each there own
I can say the titanium and build quality are stunning
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Originally Posted by Kriston
I checked that too. We dyno'd the car post Akra install with the highflows still in place. Made the same numbers (within 3 hp). But the tq gains were there irregardless. The high flows aren't restrictive at all. I actually used them as a resonator more so then cats.
I should have made way more then 3HP If the cats were restrictive.
That's interesting. I thought straight pipes were worth a lot more over 200-cell cats. I would have expected something like 10hp.
Any time I've heard one on the c63 I've thought it sounds pretty weak *** but I prefer cars louder so to each there own
I can say the titanium and build quality are stunning
My neighbor tells me that he hears me from 1/3-1/2 mile away or more. And thats just normal acceleration from a stop sign. If I really hump it he hears me from a lot further than that!
I'm on resonator delete pipes and slip-on Akra as I planned long tubes.
Does he have the slip ons or full evolution system?
Originally Posted by I am Jeff
You should ask wobble63 to see if he did a post akra install dyno. I don't believe that he saw 40tq gains with his arh setup. I believe he did dyno runs with the 200 cell cats and with the test pipes.
Me too, but those 200 cells are pretty much straight through. I thought I would have seen a 10WHP gain without them. Didn't expect the tq to increase as much as it did.
Originally Posted by BLKROKT
That's interesting. I thought straight pipes were worth a lot more over 200-cell cats. I would have expected something like 10hp.
The Akra isn't for everyone as I mentioned before. The sound is tame compared to the stock mufflers. But It amazes me that I have a full bolt on car ,no cats and the system sounds and behaves almost like stock.
Originally Posted by deadlyvt
Any time I've heard one on the c63 I've thought it sounds pretty weak *** but I prefer cars louder so to each there own
I can say the titanium and build quality are stunning
I would hope the eisenmann isn't a poor design. Who do you think made your stock exhausts. In fact I would say the eisenmann is probably the best aftermarket setup for C63. Best price / performance ratio and you get to keep the classic oval tips!
Originally Posted by Phil Chow
Interesting that you picked up 40TQ.
I wonder if that's more of the Eisenmann Race having a poor design, or whether the AK is just that stunning.
I'm more leaning towards the Eisenmann being a poor design, because 40TQ is a huge difference.
But, great gains! I like the Titanium that AK uses, but, I just don't like the sound as much, nor do I like the square tips.
I would hope the eisenmann isn't a poor design. Who do you think made your stock exhausts. In fact I would say the eisenmann is probably the best aftermarket setup for C63. Best price / performance ratio and you get to keep the classic oval tips!
Eisenmann does make hte OEM Exhaust, but they also don't make them to flow as best as possible. They just make them to the spec that Benz requests them too.
It's just hard to say that it's not a poor design when, as shown, with the swap of a catback exhaust, you picked up 40TQ. I can understand a small variation of like 10 - 15TQ because of the Straight Pipes vs HFCs, but...40TQ is quite a lot.
The Akra for sure is built better. In all fairness though the evolution system also replaces the entire midsection of the exhaust as well. I am sure it's part of the reason why the tq gains were there. Exhaust flow is one thing but not having enough back pressure costs tq losses as well.
This is why I try to dyno my results post any upgrade I do on the car. It's truly amazing how much the cars driving dynamics can be changed.
Originally Posted by Phil Chow
Eisenmann does make hte OEM Exhaust, but they also don't make them to flow as best as possible. They just make them to the spec that Benz requests them too.
It's just hard to say that it's not a poor design when, as shown, with the swap of a catback exhaust, you picked up 40TQ. I can understand a small variation of like 10 - 15TQ because of the Straight Pipes vs HFCs, but...40TQ is quite a lot.
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