AMG///Merc

I recently bought an Eisenmann "race" muffler for my CLK55, strictly as a cosmetic/sound enhancement, and I don't expect any power gains. When I went to have it installed, it was brought to my attention that the pipe where the muffler attaches to what I assume is the "mid pipe", is of a smaller diameter than the "mid pipe", which would require some sort of sleeve that will neck down to the smaller diameter of the muffler's pipe. I believe that we would be going from about a 3 1/4 inches, down to about 2 3/4 inches. My concern is if whether or not that section is narrow enough to create a restriction. I'm thinking that it would be, if it wasn't for the fact that the muffler itself is so much less restrictive to where it "equals out". As I mentioned, I don't expect any kind of power gains, but I also don't want to lose any power either. I'm pretty sure that there will be no power loss, I'd like to know for sure.

When I asked Eisenmann about it, they said that the taper was necessary in order to creat some back pressure, as the muffler is so much less restrictive. I'm having trouble believeing that because for one, I understand that NA engines "needing backpressure" could be a myth and secondly, if it's NOT a myth, I have to imagine that the ultra restrictive stock exhaust manifolds and cats provide all the backpressure the engine could need.

Well, I know that it's hard to say for sure without a dyno, but I'm curious to hear what everyone thinks. I thought that maybe the tapered section could act as a venturi, but I can't imagine to what effect that would be beneficial. Personally, I believe that Eissenhaus sells the same muffler for the CLK500 which has a smaller diameter exhaust (I'm guessing 2 3/4 inches). Anyway, I'd really appreceiate your opinions!


Best regards,
Matt

Fast55

Actually, they may be telling you the truth. Without a dyno it's impossible to know for sure, but it is true that as the exhaust restrictions are removed, you may see a power increase, but usually at the expense of torque. Torque is what gets your car moving, not horsepower. Any increase in power due to a less restrictive exhaust system is usually at higher RPM where your motor spends very little time. Of course, there are limits to how restrictive the exhaust can be to promote torque without a loss of high RPM horsepower. The factory exhaust is a fairly good compromise and very little will be gained (or lost) by modifying it.

AMG///Merc

But I would like to know for sure. Again, I'm not expecting any gain in power, and this was strictly as a sound/cosmetic enhancement. I agree that the factory exhaust is pretty good from the catalytic converters on back, but there's NO doubt that the factory exhaust manifolds are far from an ideal design. Not only do they restrict flow, they can't possibly do any sort of exhaust scavenging. The AMG 55 engines imho, would benefit from a proper set of equal length primary headers about as well as any car can benefit from them. In other words, I believe that the oem manifolds are about as restrictive as they come!

Fast55

No, the worst exhaust I ever saw was the 3.0 liter V6 Toyota trucks. They actually have a crossover pipe from the passenger side manifold that connects to the drivers' side manifold IN THE OPPOSITE DIRECTION OF EXHAUST FLOW! The manifold actually "Y's" on the drivers' side with the bottom pipe heading back to the cat and muffler and the passenger side exhaust flowing against the output from the driver's side. A set of long tube (small diameter) headers on these trucks is like you just added a turbo or blower. You would not believe the difference. On 55's, the manifolds are so-so. Evo or Kleemann headers offer no more than 10-20 HP by themselves and ALWAYS raise your powerband. Very expensive 20 HP.

E55Cent

I have heard the HP gains on Headers are small, sometimes too small for the driver to notice on the "butt dyno". On a car that is force fed, then the hearders should give you some nice HP gains. The problem is by having headers to gain 35hp on a supercharged benz wouldn only be slightly noticable because the car is already running 420hp. 35hp would be very noticable on car that that had under 300hp. Plus headers for our cars are very costly to buy and install.
BTW, Eisenmann makes great exhaust and I'm sure you haven't gained any HP but I'm sure nothing was lost. Like yourself I removed my resenator and replaced my muffler just for the deep bass sound, not for performance.

PTE

Hi Folks:
I did a review on the Kleemann headers I installed , and should have a dyno report next week. Look at CLK 55 amg w208 / w209. Kleemann Header review

I can tell you this . I have gone through 20 dyno pulls , to see what really works on a N/A motor. The ECU upgrade works great for more bottom end power, maybe 3 hp on top. Underdrive pulleys , added more mid hp , but not a thing on top. These were done on a stock amg exhaust system. I had sent my ecu back too Kleemann , asking for MORE. They found me some!! I did not lose any of the gains on bottom or mid range. Now I have a total of +8 hp on top. Thats with the 3 HP , I got with the 1st ECU upgrade.. HERE IS WERE IT STARTS TOO HURT
I then install a new low back pressure Carlsson Muffler. I'm all proud of my install , and it looks good. Off to the dyno. I'm down 9 hp!!! and toast a set of spark plugs. OOPS , So I send the ECU back to Kleemann, Tell them what I did and showed them the A/f chart. They put back in Rev #2. It was NOT , and I repete NOT THEIR FAULT. I asked them to lean the motor A/F ratio, Looking for more HP!! They warned me.

So your new muffler , with your stock ECU setting , you may expect an increase in HP, It generally is rich from the factory and can handle some lose in exhaust back pressure . I pays to dyno your car , before and after. Any future ecu changes you make , be sure to tell the tuner what mods you have made , and what future changes you are planning on. Hope this makes senses

PTE

The mid pipe / exhaust pipe on my CLK 5.5 amg is 3"in dia. I had to open it up to 3 1/4" to fit the inlet pipe on the Carlsson Muffler. Here is the dyno sheets!! Sorry about the picture Quality. Scan lines are limited by the adminstration

E55Cent

I"m a little unclear. How much id you gain on HP and Tq by going with the headers?

PTE

Going to the dyno tomorrow . We will see what the headers got me. It felt stronger between 5000 & 6000 rpm I've got 20 dyno runs , pre header installation. We will see tomorrow. Take care ___PTE___

E55Cent

Please let me know. I will be putting my car on the dyno with my new Super Vortec FMU on Tuesday. I'm just hoping to get my car to run safe and not too lean.

Mario

PTE

I'm very please and it was worth it. It was the biggest most single increase in HP. since I did the Kleemann ECU Chip and you can feel it!!

E55Cent

Very nice dyno and Tq gains. I can't really see some of your old dyno's but what were your old hight HP and TQ with all your mods except headers? I'm just trying to figure out total HP gains and TQ gains from just the headers. Also what was the total cost with headers and labor?
thank you.
I will post my results on Tuesday night. Let's see what my mini blower will do.
Mario

steve872

Who do you talk to about the Kleeman ECU upgrade. Name and contact info please. Thanks!