Quote:
Originally Posted by morris
I was expecting the acceleration to feel very similar to the M3 as the power to weight is very similar. I think because there is so much extra head room with the revs on the M3 you drive higher under normal conditions without realising. With the M50 you're more conscious of approaching the red line so instinct (and exhaust noise) makes you change up too soon.
I also wonder if my diff is having an impact here as it was from an automatic donor. RealOEM says it is a 3.15 but other sources (bokchoys.com) say 3.91,which should be much better for acceleration. I actually thought it was a 2.93. The M3 has a 3.62 so if mine is a 3.15 that could account for some of the difference. So many other factors though.
I think you're right about the extra crank throw on an m54, it will give greater low end torque which is the real thing you experience during acceleration.
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I swapped a 3.14 Sierra diff into my Cabrio, but found the M50 could not make good use of fifth gear - 85mph in a Cabrio is just too fast to be reaching the start of the power band! So I swapped back to my 3.38 diff. This seems better geared through the revs, and puts the m50 into a better rev band at 70-75mph.
A 3.62 diff would be a good choice to go with the M50, although it might become tiresome on a long journey. The ideal might be pairing with a ZF 6 speed with an over driven top gear (0.85:1) driving a 3.62. This would have sharper acceleration through the lower gears, but cruise nicely in 6th.
I am hoping (confident?) my M54B30 will be happier to operate at lower revs, and with higher torque will perform nicely with the 3.36 diff, making cruising much more enjoyable.
All good in theory.........................!