Originally Posted by Diabolis

That is not correct.

The aftermarket-tuned cars are producing more or less the same rear-wheel horsepower figures as the P31/APX cars, which is what the dyno actually measures. The RWHP figures are all somewhere in the 420-440 range, and there is quite a lot of variation between the dynamometers themselves, their state of calibration, the atmospheric conditions at the time (namely air temperature and humidity), even whether there is an external fan at the dyno shop blowing air at the front of the car. Now, manufacturers are always rating the engine crank horsepower, not the actual power delivered to the wheels, and there are significant frictional losses between the crank and the rear wheels (from the transmission, clutch or torque converter, differential, etc. - even the temperature of the oil in the LSD for example will affect its viscosity, which in turn will affect the frictional losses). So - the real question then becomes what is the "universally accepted" percentage of power loss from the crank to the wheels. Aftermarket companies will assume the percentage is greater because it boosts their tune claims, yet to the best of my knowledge not one of them has a proper tune where there are significant HP gains to be had from the P31/APX motor. So - if you want to call it 530HP instead of 507, that's fine, but then they're all putting out more or less the same 530 HP.

Unless the engine is in some way restricted - as it is with the non-P31 cars, a tune on a naturally aspirated car will only give minor variations because there is only so much you can do by changing ignition timing. You have to start porting and polishing the engine internals, changing camshafts to modify valve lift duration, putting in bigger throttle bodies and higher flow fuel injectors, high flow exhausts, etc. in order to achieve actual, verifiable gains. 5HP more or 5HP less on a 500HP car is the difference between a clean or dirty air filter or whether your spark plugs have 200 miles or 2,000 miles on them, a two-degree drop in air intake temperature or a cloud covers (higher relative humidity) vs. dry sunny day. Which, BTW, is exactly why the tuners don't really see any significant performance gains on the P31/APX cars.

Originally Posted by ruey220

just curious why are tuners able to get 540HP from a E63 M156 when they base at 518hp stock and I would believe the P31 C63 should be closer to the E63 motor when everyone says the non P31 is detuned. Therefore if they can get 540HP from the E63 M156, a tuner should be able to get more than 507 on a P31 rated at 481hp.

There are many here who have dyno'd to get the differences in gains between tune/non tune, P31 vs non P31, etc. but I haven't seen anyone actually break down what Mercedes is doing that is different amongst the various models to differ the various hp ratings. Non P31, vs P31, Black Series, and E63 Motor all using M156 motors. From there we can determine how to maximize the output of these motors by knowing what they've done to differ baseline, and from there increase off that platform.

Originally Posted by Diabolis

I am not familiar with the older E63 with the M156 motor, but AFAIK it does have a larger airbox than the C63 and a different ECU tune which would explain the approximate 10 hp difference between it and the P31/507 C63. Also, someone else correctly pointed out that the C63 BS has a different block bottom where each pair of cylinders is isolated from the rest and only open in their own space, which apparently creates a vacuum and helps in pulling down the cylinder during the intake stroke - which again would amount to something like the 3 hp difference between it and the P31/507.

As you mentioned, the non-P31 C63 is artificially restricted. As for the P31 and 507 vs. the rest of the M156 fleet, what Mercedes is doing to achieve the different power ratings is simple. It's called marketing.

Originally Posted by coladin

I have a hard time believing that, a 26bhp "marketing" increase then? That is a little substantial a gap to believe, imo.

Of course until we see a P31 and a 507 dynoed it will continue to be speculation.

Originally Posted by Diabolis

It has to be substantial in order to work. A 5 hp gap is not really a gap unless you're talking about lawnmowers. Mercedes is not going to cannibalize their own higher-end model sales (e.g. CLS/E/S) by offering a lower-end car like the C that has the same rated power output as its more expensive brethren and is thus faster as it weighs less. Look at the published 0-60 times for the different models and the measured ones. There has to be a clear delineation between the model ranges.

I think we have seen a couple of dynoed P31 cars that put out around 430 whp, which assuming an 18% drivetrain loss is right around 507 crank hp.

Originally Posted by coladin

The C63 buyer has different needs or standards than a CLS or E63 buyer. The difference in quality, workmanship and materials, as well as the actual size of the car have more to do with a vehicle maybe having less performance, but the total package is far superior. Even if a C63 is faster, you wouldn't catch an E63 or CLS63 in one...their needs are different.

I love my 507, but the quality of the interior is in another league ( a lower one!) compared to the E and CLS.

Originally Posted by Diabolis

I am not familiar with the older E63 with the M156 motor, but AFAIK it does have a larger airbox than the C63 and a different ECU tune which would explain the approximate 10 hp difference between it and the P31/507 C63. Also, someone else correctly pointed out that the C63 BS has a different block bottom where each pair of cylinders is isolated from the rest and only open in their own space, which apparently creates a vacuum and helps in pulling down the cylinder during the intake stroke - which again would amount to something like the 3 hp difference between it and the P31/507.

As you mentioned, the non-P31 C63 is artificially restricted. As for the P31 and 507 vs. the rest of the M156 fleet, what Mercedes is doing to achieve the different power ratings is simple. It's called marketing.

Originally Posted by jarjoug

How did this become a C vs E vs CLS?

Originally Posted by Diabolis

From what I was told by someone "in the know" at one of the MB corporate stores in Toronto, the 507 is essentially a 2012/13 Canadian APX car (P31+P30+LSD) with the BS hood, new wheels and different door trim (he had just returned from a training trip at the MB head office in Germany). I was inquiring about the possibility of putting on the 507 ECU tune on my car in order not to void the factory warranty, and he said that even the ECU maps are likely not going to be any different.

While the regular C63 is intentionally de-tuned, the P31 & APX engine horsepower figures are underrated for marketing purposes. Every P31 or APX car actually delivers more than the rated 481 hp (487 in Europe), usually upwards of 500 as numerous dyno tests have shown. The numbers are intentionally misrepresented in order to justify the price premium for the Black Series (delivering the same power), other more expensive cars using the M156 engine at the time (-2008 S63, E63, SL63, CLS63 & CL63) and, more importantly, the SLS AMG which is 2.5 times the price of the P31/APX. While the SLS does have a somewhat reworked motor (M159) with a dry sump and other modified bits that the P31/APX M156 engine does not, the difference needs to exist at least on paper so that the sales of the other more expensive AMG models do not suffer as a result. The 507 will be the last iteration of the M156 engine before the new 2015 force-fed C63, and it's just a face-lift so that MB will still manage to sell some 2014MY C63 cars.

While the gent I spoke to at the dealership knew that I had just bought a loaded 2013 car and it is conceivable that he was just saying this to make me feel good about my purchase, I have no reason to doubt his story as he is very high on the technical side of the corporate ladder if you will. I was told this is the reason why the 507 won't be brought to Canada as it is exactly the same car as a loaded APX vehicle except for the hood, wheels and exterior door trim. In other words, they are not really changing the car - only the *claimed* power rating. If he is right, then the 507 should produce exactly the same power as the current APX, P31 or tuned C63 cars.

Originally Posted by coladin

Correct me if I am wrong, but this engine, in other forms, has been rated and tuned at 481, 503, 507, 518 and 563? I am sure that what they are selling is legit. They could also be underrated as a whole, starting with the non-P31...but I don't agree that they are cannibalizing their higher end models with the C63 offering more power than more expensive models.

The C63 buyer has different needs or standards than a CLS or E63 buyer. The difference in quality, workmanship and materials, as well as the actual size of the car have more to do with a vehicle maybe having less performance, but the total package is far superior. Even if a C63 is faster, you wouldn't catch an E63 or CLS63 in one...their needs are different.

I love my 507, but the quality of the interior is in another league ( a lower one!) compared to the E and CLS.

Originally Posted by ruey220

the airboxes are the same. I sold mine to a e63 owner and it was identical. I was still referring to how a tuned c63 is closer to 507 as some indicated while the e63 tuned claims to be 540.

Originally Posted by Diabolis

If the engines are physically the same, then so are the power outputs. How can you tune an E63 motor to 540 HP if you can only get 507 out of that same motor with that same ECU tune in a C63?

The 540 HP number is also marketing - in this case by the tuner who also needs to sell their tunes, not by MB.

Originally Posted by chris135b

Hi all,


I found this article on Car and Driver highlighting the 2010 E63 making "518hp/465lb-ft torque" http://www.caranddriver.com/reviews/...e63-amg-review


Although, the article mentions, "Here it makes 518 hp, an increase of 11 over the old E63, mostly due to a freer-flowing exhaust."


Very, very interesting.


Oh well, the 507 is still a hell of a car!


-C

Originally Posted by Exhibit13

As an owner of a 2010 c63 p31 this interests me. It does seem though tat the 507 is no different.

Originally Posted by jarjoug

As I mentioned previously. I have a P31 and drove the 507. These are not the same.

Originally Posted by ruey220

I won't be surprised if someone opens up a new discussion whether Mercedes just marketed more horses on the newer E63 because they wanted to come closer to their Rival M5's when they were 510 at the time, they wanted to outdo the number and could because the m156 was averaging more hp's. Freer flowing exhaust vs what? the old model? It won't surprise me if a parts number checkup will show that the exhausts were probably the same.

Originally Posted by Diabolis

Rage2 is absolutely correct - one thing that I neglected to mention in my argument is that I was in fact comparing the 2012+ MCT-equipped cars to the 507. The pre-2012 torque-converter autos indeed have more losses in the transmission and the shifts are less aggressive so there would be a measurable and noticeable difference. A 2013 Canadian APX car (P31 engine + P30 suspension + LSD) is the same a 2014 Canadian 507 except for the cosmetic differences.

P.S. I am not sure about the various options and what was available when in the US, but there is also a difference between the cars with the lighter (forged) internals and the ones without. The 6-7 lb reduction in reciprocating mass in the M156 engines with the forged internals make them easier/faster to rev up and give them a quicker throttle response, which translates in a faster car overall. I was talking about cars with identical engine internals and drivetrains.