vrus

Does anyone know what size our exhaust pipes are from the cat-back?

Do we have 2.5" diameter exhaust on the W211 E55??

vrus

No one on this board knows the size of the exhaust tubing on our cars??

MR X

The O.D. diameter of the tubing is actually in mm not in SAE inches. I wanna say its either 58 or 60mm. 2.500 O.D. tubing is close so you may need to have a muffler shop swedge the ends to get the correct fit.

TCM

The stock exhaust on the W211 E55 is almost 3' O.D. I beleive. Eisenmann offers their exhaust for it in 2.5' O.D. so you need a coupler to make them fit correctly. Supposidly, this icreases backpressure resulting in minimal rwhp gains. Hope this helps.

vrus

Thanks Guys for the info!

I am working with a very big exhaust manufacturer/distributor to manufacture a full stainless steel system for the W211 E55 (to start with.. then make them for the other models). I am hoping to get a target retail price of $1,200 - $1,500 for the complete system from cat back.

I am just trying to get him the full specs on our cars so he can mock-up a system for me. We need bend lengths, muffler specs, etc...

I think I am going to have to put my car on a lift and just drop the exhaust to get all the measurements for him...

Stay tuned...

JBrady

The "backpressure" myth just will not go away. I have posted so many times in so many forums but even "tuners" as suggested above... still spread the rumor.

While in some cases it is true that a larger diameter pipe will reduce low/mid rpm torque/power... it is NOT because of backpressure. Velocity is the key. Backpressure only helps in 2 stroke engines and that is with highly developed tuned expansion chambers and is not anything like a 4 strokes dynamics.

I cannot help with identifying pipe size but can say that German cars (as are Japanese cars) metric in dimensions. Manufacturers typically use smallish pipe sizes. On a 350hp engine my guess would be 60mm-75mm... 60 on the dual sections and 75mm on single pipe sections.

Standard metric pipes size and their standard conversions are as follows:

50mm = 1.97"
60mm = 2.36"
65mm = 2.56"
70mm = 2.76"
75mm = 2.95"
80mm = 3.15"

Standard sizes:
2.00" = 50.8mm
2.25" = 57.1mm
2.50" = 63.5mm
2.75" = 69.9mm
3.00" = 76.2mm

clco

What changes if any to your suspension?

SoCalCLK

I recently changed my exhaust from stock to the AMG muffler.

The muffler piping was 2.75" and mated to the stock piping which was also 2.75".

Is it same to assume that for all the 430 cars (E430, CLK430, S430) that the tubing is 2.75" and on the AMG versions as well? The piping was larger than I expected, but a pleasant surprise.

prof.griff

To my knowledge, the piping size on a 430 is 2.25 not 2.75. You might want to check again.

Siggy_freud

While for the most part JBrady is right, the size of the piping has a direct coorilation (sp) to the velocity of the exhaust gases. The exhaust gas is going to want to move the same speed no matter what pipe size it is, however the smaller pipes cannot move the exhaust as fast, thus what people call backpressure, can build. The effect should be refered to more correctly as exhaust scavenging. The minimal amount of pressure actually helps draw more air into the system thus creating more velocity at a lower RPM. Its somewhat confusing. Exhaust pipe diameter can make a difference in the car. As a standard, dual 2.5 can flow enough to sufficiently breathe a 600hp engine as can a single 3 inch.

JBrady

Siggy, you appear to have a grasp on what is going on but your post is a bit confusing. I think what you meant to say is the engine wants to flow the same VOLUME regardless of pipe size and therefore smaller pipes have a higher gas VELOCITY (speed of flow). Backpressure is not scavenging. Backpressure reduces velocity at any given flow rate. Velocity reduces reversion and "can" but does not always produce scavenging.

The effect of the interrelationship of pressure pulses (that start very high and quickly drop in pressure for each event) between cylinders is a dynamic one. Tight restrictive manifolds are OK during the high pressure times and at the same time restrict reverse flow back into the cylinder during the low pressure period of the exhaust event. When designing both manifolding and secondary piping it is important to maximize the flow energy available at each merge thereby facilitating both flow and velocity and reducing reversion and in optimized systems actually creating scavenging (the "vacuum" effect that actually creates a pressure drop that in some cases can be dramatic).

H-MAN

I want a full exhaust for my W208 CLK55, including headers!