I know this goes against the core ethos of M5 ownership but.....
due to traffic conditions and multiple speed cameras near where I live in central London it is often necessary to drive at slow speed for several miles at a time (20-30mph)
(for those who know the area i am talking of Lower Thames St, Tower Bridge, Rotherhithe Tunnel, Canary Wharf area)
A Bugatti Veyron would not get you anywhere any quicker than a clapped out old Nissan Micra - if you want to keep you license.
So in those conditions what is the best way to drive the beast for the best combination of fuel efficiency and prolonging the life of the engine?
For example:
At 20 mph in 3rd gear the engine is running at just over 1000 rpm.
20 mph in 2nd gear is just over 2000 rpm, and
20 mph in 1st gear is about 3500 rpm.
Generally, of course, lower rpm for any given speed would give better fuel efficiency but too low rpm, almost to the point of stalling stresses the engine in other ways, no? and may increase exhaust carbon build up?
Some may disagree, but as long as you are not bogging the engine with an excessively high gear for a given demand, the S62 will happily comply with low-speed performance. An occasion exercise run to heat up the cylinder heads will keep combustion chamber carbon at bay.
I like to shift around 4K. Given your situation, I would stay in 2nd because it gives me a little more flexiblity in the RPM range should traffic go to 30 MPH. I agree with wilsonh in avoiding bogging your motor.
If you drive slowly, at low RPM a good deal of the time; then you need to take the car out onto some back roads (outside the city) and let her loose, taking her to redline a number of times.
I would probably run 2nd gear if in traffic unless the whole pack is moving at a steady 20 or so mph. Nice balance of low rpms against not lugging the motor. At 2000, the motor is also more responsive to inputs.
Regards,
Jerry
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'01 Black/caramel
Dinan Stage 3 suspension, SS jet coated headers, ESS SC kit, open brake ducts, Hamann front splitters, TEC cupholder, U.S.(Euro style) tilt/slide armrest, 6k HID fogs, 6k super white low beams, V1/Stealth1, dual head LI, 2.65 diff w/40% lockup/2x dynamic, compact spare, Euro trailer hitch, Mocal oil cooler, ACS type rear spoiler, Rogue custom SSK and tranny mounts, ST 355 BBK (fronts), BP sway bar brackets, Bluetooth retrofit
Some may disagree, but as long as you are not bogging the engine with an excessively high gear for a given demand, the S62 will happily comply with low-speed performance. An occasion exercise run to heat up the cylinder heads will keep combustion chamber carbon at bay.
Dave
+1 here. The S62 definitely needs to be blown out every so often though!
__________________ Current Toys: 2000 M5 with lots of goodies, 1997 993 Targa mostly stock, 2002 Jeep GC all set for offroad, 2004 Acura TL bone stock
I tend to be very gentle with all the cars/motorbikes i have owned.
In the M5 in hum-drum driving i change up from 1st at 2000 rpm and change at around 3250rpm in the other gears - if i am not 'racing'
However with the type of driving i am restricted to much of the time it can be weeks between giving it a good 'clear-out' blast!
Is this bad for the engine? Is there such a thing as treating it too carefully and not revving it enough?
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