Dyno result - what do you think?

[Big Barry]

2008 S63, 66k on the clock.

What do you think? Against the handbook claim of 525 bhp/630 Nm, I get about 80% back. Should I be disappointed/not surprised/amazed that the old boy can still churn it out?

 

[sonic]

Is 525bhp at the flywheel or road wheels?

 

[Gazwould]

Silly question as he's 429.8 from 525 claimed which is always @ the fly .

And 137.7 Nm down on torque .

 

[LostKiwi]

I always take Dyno figures with a pinch of salt.
You have no knowledge of the calibration of the Dyno nor of comparative atmospheric and environmental conditions.
Dyno runs are great for comparison on the day when tuning but aside from that questionable.

 

[alexanderfoti]

I agree, seems down on power, but, echo LostKiwi's thoughts.

If making power changes, always compare WHP to WHP. They seem to be using a 21% drivetrain loss factor, which is too high for a 7G auto!

 

[Big Barry]

I was advised that the car had to be put into dyno mode so I assume this means that any limiters are in place so it didn't over-rev.

It was also suggested to me by the testers that, in their experience, MB tend to overstate the output (and the claimed figures probably reflect absolutely perfect testing conditions) and that BMWs tend to produce more than advertised.

Anyway, it gave him a good clearout to be pushed a bit and I'm convinced he's running smoother for it.

 

[daveenty]

I was advised that the car had to be put into dyno mode so I assume this means that any limiters are in place so it didn't over-rev.

Dyno mode removes all traction/ABS controls so as they're not confused when only the rear wheels are turning. In effect, no safety aspects at all are left on. The engine limiter is not affected.

It was also suggested to me by the testers that, in their experience, MB tend to overstate the output (and the claimed figures probably reflect absolutely perfect testing conditions) and that BMWs tend to produce more than advertised.

As far as I'm aware, and having spoken with lots of other people and respected tuners, it's generally Mercedes who under estimate. W211 E55 anyone? I never saw one of these producing less than the 476 which they were supposed to be outputting at the time, usually at least 20 - 25 more. This was back in the early 2000s. All my previous Mercedes have given figure well in excess of the manufacturer's own figures, even before any fettling. Not tested my current one as yet but I'm pretty sure that it won't let me down.

They seem to be using a 21% drivetrain loss factor, which is too high for a 7G auto!

I agree with this gentleman on the figures, we always worked on 18% which, whilst still being an approximation, gives a good idea, especially after several runs and adjustments.

 

[00slk]

I always thought BHP was at the flywheel and HP was at the rear wheels? Might be wrong again, I normally am

 

[Wighty]

Some redex will get that power back