I started the same thread on the M5BOARD and this recent reply caught my attention ...
Check the dyno graphs:
Is this right?
Quote:
Originally Posted by evolve automotive
What about consistency of power and let's talk about how a stock M5 loses power so quickly on the dyno and in real world driving.
By ramping up the boost it's all going to get a lot hotter!
On this platform tuners are going to need to do alot better than just present one single cool run.
We tested the F10 M5 and the power drops so damn fast it's unreal. We did do one run @ 570+hp but that was once and it was the calibration run so could not show it anyway as the tacho was not set.
We saw as low as 530 bhp on our dyno after just a few runs.
So let's see a few runs within 30 seconds of each other or atleast 1 min....
No point having 600+hp with a tune and some downpipes if it's only going to make it once.
Ideally we should have 4 runs on stock and the lowest graph taken and then the same on the tuned version and the 4th run taken with no more than 1 min intervals between runs.
This particular platform is so massively open to abuse on the dyno by tuners it's unreal and it's because of this heatsoak issue. Any operator can just do a few runs and he has a massive range of power to choose from with as wide as 40hp variance.
Then tune it, do a cool run.... show BIG gains.
Supersprint also dyno tested a stock F10 M5 on the highly acclaimed and accuate Maha:
Supersprint being Supersprint - they always show the best runs.
603 flywheel HP on this one!... stock.
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Quote:
Originally Posted by evolve automotive
Actually... this is very interesting:
Manhart Tuned
Here we can see a correction factor of 1.04 (adding 4%)
Uncorrected - 626hp.
Uncorrected wheel - 489
Supersprint Stock
Correction factor 0.99 (taking away 1%)
Uncorrected 609hp
Uncorrected Wheel - 506
Clearly same gears used for the tests.
However the run down losses on the Manhart test are 34hp higher. The wheel HP is lower on the Manhart test.
Very interesting....
Did Supersprint get a 'demo' stock car or one that was already tuned? Will have to enquire.
While the MAHA might be very accurate I would strongly warn anyone about SAE correction factors. SAE can very easily over and under compensate. The uncorrected figures should also be studied as not all engines react to barometric pressure as much as SAE might think. The above two tests show very similar ambient air temperature. The difference of 5% in correction factor is coming predominantly from the barometric pressure difference.
Manhart - can you please display your temperature and boost values to compare with the Supersprint test car?
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