Duckhams Q 20-50budman200210 wrote: What's the best oil should i put in my boxercup???

Oh no - sorry!! That's a mistake - I was just having a senior moment

sandbar
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Oh, OK, I stand corrected about the energy contained in the fuel, although it does surprise me. I believe that diesel engines are more efficient than petrol ones, though, in terms of the percentage of potential energy in the fuel that they turn into mechanical power/torque? This might mean that less is wasted as heat.Stevie wrote:Actually, burning diesel oil releases 40.9 MJ per litre compared with 34.8 MJ per litre for petrol - about 15% more. This is why diesel engines are more fuel efficient. I would have thought that overall heat levels would have been the same in diesel and petrol engines
A couple of years ago I found a local village petrol station that still had stocks of Duckhams Q, along with countless other oils that disappeared from other peoples' shelves a decade or so earlier. I bought a couple of cans of the Duckhams - my GS seemed to thrive on it even thought it probably didn't meet SF/SG/SH classification....sandbar wrote:Duckhams Q 20-50
Oh no - sorry!! That's a mistake - I was just having a senior moment
Italy in June = temperatures over 30 degrees. You need 20W50 because if you look in the "Service and Technical Booklet" (page 84 in mine) you'll find that 20W50 (or 15W50) is an appropriate grade for running in ambient temperatures over 30 degrees. Anything lighter isn't. Whether you go for mineral, semi-synth or synthetic is down to personal preference (unless the bike's done less than about 12k miles in which case you should use mineral to aid bedding in), as is brand.budman200210 wrote:Im off to italy on 3rd week of june. So What's the best oil should i put in my boxercup??? and why?
Well what I'm actually saying is that the company which designed, manufactured and extensively tested the engine in your bike are recommending 15W50 or 20W50! For the temperatures you'll be riding in.budman200210 wrote:Ok,
So your saying go up to 15 or 20/50.
The first time I took my GS (same engine) to Mugello in June it was running 10W40 Castrol GPS. Sitting in the queue to get in to the circuit with the temperature approaching 40 degrees the engine sounded like a bag of bolts - if you'd heard it you'd have no hesitation in going for something heavier! Since then I've spent a fair amount of time riding in Spain in similar temperatures but with 20W50 and the engine is far smoother and 'happier' sounding (fewer rattles both when cold and hot).budman200210 wrote:15 or 20 seems to be too thick to me (from what i know) but i will value your advice.
Yes, certainly it's 'best' in some respects (it costs more.....). But will the engine benefit from "the best" given its design, tolerances and fairly frequent service intervals? Only you can decide that. I reckon not.budman200210 wrote:Surely synthetic is best???
Changing to semi-synth at 10k is OK - lots of people do that. But GPS is 10W40 which isn't heavy enough for hot summer use. BMW use GPS at service because they have some sort of 'arrangement' with Castrol. Funny how they sell their own branded 20W50 mineral oil alongside it (in the parts dept.), though, isn't it.....budman200210 wrote:Its only done 10k, and last service was the first with the GPS from BMW.
Of course - everyone does. But there's no absolute right or wrong as long as you get the grade right. Formulation (mineral, semi-synth, fully-synth) and brand really make little difference at the end of the day and it comes down to what's available locally, any personal preferences as to brand, what special offers are on etc etc.budman200210 wrote:want to get this right.