1 MB

Has anyone seen actual dyno results from the new BT V8 in the E550? I asked this because every time I drop the hammer on my 550, I say to myself "this thing has got WAY more than 402 horsepower". I took delivery last November and I still can't get the smile off my face! I used to own a Corvette C6 and I'm convinced that my 550 would hand the Vette it's azz.

petee1997

Just wait till the Fall of 2013 and the same block will produce 429hp with a single turbo plus better fuel efficiency.

NardoNZ

where did you get this info? I know the same motors in the S-class and cl etc do produce around 430bhp...

interesting.....

Cavu

I haven't seen any dyno results, but I'm impressed with the E550. It is fast, but I don't think it's a lot more than 402HP.
I definitely notice a difference between the E550 and the C63, though I have described the E550 acceleration as "like the C63 without the drama".
When you step on it in the C63 you get noise and a nice rumbling sensation as you zoom away. In the E550 you get almost the same acceleration, but without all the noise and vibration. You have to look at the speedo to realize how fast you just accelerated.
It's a great car.

Dueclaws

Look at the thread about the M278 RENNtech tune on this forum.
See RENNtech's info: http://www.renntechmercedes.com/www/node/702
(scroll through pictures)
Their graph compares the stock M278 engine to their tune. Stock is considerably more than 402..... or 429.

Read the results a '12 CLS 550 (on their forum) had at the strip after the RT tune: best of 12.3/ 1/4 mile: stock (including tires) except tune. Wheelspin was an issue.

FreeSpeaker

I agree on the way more horsepower thing with the 4.7.

I came from a revvy Japanese V6 and thought I was still adjusting to all that torque from the E550 starting at 1900 rpm.

I do like the subtle whine from the turbos with all the windows down pulling away from city stop lights

ronsc1985

Why in the world would MB underrate the HP? This isn't the 60's where American muscle cars did this to try and lower the insurance rates their customers would pay. Is there really any marketing advantage to advertising a lower HP number? I think not.

Does anyone really believe the MB dyno doesn't work?

BTW chassis dyno's are notoriously error prone especially when trying to apply some correction factor to get the crank horsepower. In particular they have no method to accurately control the intake temperature or the airflow over a turbo engine inter-cooler system be it air to air or air to water. Usually they attempt to blow air with a big squirrel cage fan.

Be very suspicious of any HP results that don't make a correction to SAE or whatever the european standard conditions are.

bd5400

It's sort of common knowledge that several manufacturers underrate their cars. I've heard of BMW doing it as well. It's not that they haven't done their dyno work either. I'm sure there's a reason for them to do it.

Rocketman

Not sure if this is related but the gas filler says 91 RON is required, but if you can use 93 (as I can here in VA) the computer will (?) adjust the advance and other parameters to better utilize this better fuel and may yield greater HP and torque. A guess on my part.

ronsc1985

Common knowledge based on what facts?

I think this is one of those car myth's passed on through the ages started when in fact it was done for insurance reasons as in my previous post. Those days are long gone.

In what universe would understating the horsepower result in more sales which is after all the main objective of any business.

ronsc1985

It may be some advantage depending on the piston/head/cam design. Even if it does increase the hp the gain is minimal. As an example a decrease of lead by 1 degree on my 1000 hp drag race motors from peak power resulted in a 3 hp or so loss when measured at the flywheel on a engine dyno. Generally we ran the motor at this point to decrease the possibility of detonation during the hot lapping that would occur in the later rounds.

BTW increasing the ignition lead does not always increase engine performance. At some point it results in a horsepower loss since the initiation of combustion tries to drive the piston back down into the bore.

np888

A lot of companies do it to avoid eating into another cars sales. i.e many have claimed the 1M to be VASTLY underrated because they didn't want it to encroach on the E92 M3's power.

Rocketman

I agree with your points - but some performance advantage does come with the 93 RON vs the 91 RON. When companies like Renntech "adjust" the ECU (i.e. tune the car) they manage to extract about 10% more power (+ or -) without changing any hardware. So the factory does leave a little power on the table due to the "lowest common denominator" of fuel quality and the factory's wish to provide a conservative and long-lived engine/drive-train. No?

ronsc1985

Yes but what all these tuners give away is the safety margin designed into the engine and control system. They eliminate most all the tolerance and drift margins of the various sensor components. They won't admit it and for the most part they have no idea what these margins are.

The OEM's don't understate the HP, they actually state the correct HP using prudent engineering design parameters in both the hardware and software.

I think anyone who chooses to violate these margins in a street car is foolish. That is why you in essence throw away any factory warranty when you change the tune. The auto industry is littered with denied warranty claims form people who used "tuner" upgrades".

I have no problem with people doing this. I do have a problem with people who blow something up doing this and then whine about the car being poorly designed and/or the OEM not standing behind their product.

ronsc1985

I said what facts, like in actual measurements of a statistical meaningful sample. People make a lot of claims about cars, most are BS.

Dueclaws

I agree with some of your statements, but there are engines and applications that respond to timing changes, although the timing changes might not effect your drag race engines.
My boat has 2- 1,000 hp engines and we gained 25 hp going from 30* to 32*. These engines are built for endurance and power; there are so many variables involved that it's difficult to make comparisons to other engines.

Regardless, I'm very impressed with the power of our '12 E550C.

ronsc1985

Most if not all modern design engines are designed with pistons and head chambers to promote a very fast flame front. As an example a Pro Stock drag engine uses something like 18 or less degrees lead. Older big block Chevy and Ford engines operated somewhere north of 30 degrees lead.

I have no idea how the MB engines are designed but I'd be really surprised of they were not very fast flame front designs since this in general produces more efficient and cleaner use of fuel input which these engines seem to do a very good job of given their excellent fuel economy.

If anyone knows what is the lead at full throttle at higher rpms of these engines?

Rocketman

These new engines of MB have direct injection - does this change things???

ronsc1985

Direct injection engines help mostly with part throttle performance and fuel economy. The ability to inject leaner mixtures on the compression stroke supposedly makes leaner burning possible. At full throttle, which is where max HP is measured, this ability does not contribute to larger HP number.

Direct injection does allow a little better volumetric efficiency by allowing the intake port/valve design to be a dry air design. This tends to flatten out the torque curve some but max power is at an rpm value above the peak torque point.

I wonder how direct injection engines will do in long term reliability since the injector nozzles are right in the combustion chamber. I guess we will find out down the road.

petee1997

Ridiculous! You've been smoking the drapes again.

RJC

You guys are only referring to hp...don't forget they have a nice amount of torque, and in the S class 516 lb ft

Dueclaws

Yes: it's a M278 engine. What engine is used in a S550, SL550, CLS550, E550, CL550? M278.
It would be interesting to compare part numbers in these M278's. Maybe the only difference, if any, is a tune.
Anyone have access to the 2012 M278 engine part numbers?

RJC

They're the same engine, different ecu mapping etc

Yosheego

I'm so jealous of you V8TT!

nawlinstornado

I was having a chat with a MB foreman the other day on this subject. The speculation was that there is no difference in engine or tune between the 550 models, but that the quoted numbers were lower because buyers of an SL or S expect to have more than an E-Class.

I say speculation because he also let me watch while he updated my ECU - he has no real part in it. The computer communicates with Stuttgart and uploads the correct software. He can't really see any information regarding engine tuning.