Different weights of oil reduce consumption?
Discussion
If you want to see why get a pot of treacle and a cup of cooking oil.
One is thicker than the other, try to move a spoon through both? Now try to pour both through a sieve.
Obviously the thick oil is harder to push the spoon/crankshaft through, there are other losses at work too not least pumping the oil round the engine. But you notice it didn't go through the sieve, that's because the more viscous a liquid is the harder it is to push through a small gap.
Therefore simplistically thin oil will result in the engine not having to work as hard to overcome the viscosity of the oil. So it will in theory produce more power and use less fuel.
Thick oil though is better in an old engine that tends to burn oil as it will bridge the gaps better!
That's a very simplistic approach to the problem and is no more than common sense, be warned though that using thick oil in a knackered engine is a temporary measure.
One is thicker than the other, try to move a spoon through both? Now try to pour both through a sieve.
Obviously the thick oil is harder to push the spoon/crankshaft through, there are other losses at work too not least pumping the oil round the engine. But you notice it didn't go through the sieve, that's because the more viscous a liquid is the harder it is to push through a small gap.
Therefore simplistically thin oil will result in the engine not having to work as hard to overcome the viscosity of the oil. So it will in theory produce more power and use less fuel.
Thick oil though is better in an old engine that tends to burn oil as it will bridge the gaps better!
That's a very simplistic approach to the problem and is no more than common sense, be warned though that using thick oil in a knackered engine is a temporary measure.
wildoliver said:
Therefore simplistically thin oil will result in the engine not having to work as hard to overcome the viscosity of the oil. So it will in theory produce more power and use less fuel.
You're right, but I think the OP's talking about oil consumption, not fuel consumption.Yes it should reduce consumption a bit.
I had a forged bottom end built a few years ago that liked to guzzle it's 10W/40. I then moved up to Silkolene 10W/50 and the consumption reduced. Then lastly, I tried Castrol Edge Sport 10W/60 and Gulf Competition 10W/60 and consumption reduced still further.
I settled on the Gulf in the end as it was much cheaper than the Castrol and I did well over 50K miles without any oil pressure related issues.
The thing is, the oil is still a 10 weight when cold (where it's hardest to pump), but just that little extra thickness at 100 deg C to reduce consumption. Opie Oils give you all the viscosity information in their tech sheets and you can compare the 100 deg C weights across the 40s, 50s and 60s.
BMW specify a Castrol 10W/60 for some of their M engines, and Alfa specify Selenia 10W/60 for it's old T spark motors. Why? Because they drink oil!
I had a forged bottom end built a few years ago that liked to guzzle it's 10W/40. I then moved up to Silkolene 10W/50 and the consumption reduced. Then lastly, I tried Castrol Edge Sport 10W/60 and Gulf Competition 10W/60 and consumption reduced still further.
I settled on the Gulf in the end as it was much cheaper than the Castrol and I did well over 50K miles without any oil pressure related issues.
The thing is, the oil is still a 10 weight when cold (where it's hardest to pump), but just that little extra thickness at 100 deg C to reduce consumption. Opie Oils give you all the viscosity information in their tech sheets and you can compare the 100 deg C weights across the 40s, 50s and 60s.
BMW specify a Castrol 10W/60 for some of their M engines, and Alfa specify Selenia 10W/60 for it's old T spark motors. Why? Because they drink oil!
SuperchargedVR6 said:
Yes it should reduce consumption a bit.
I had a forged bottom end built a few years ago that liked to guzzle it's 10W/40. I then moved up to Silkolene 10W/50 and the consumption reduced. Then lastly, I tried Castrol Edge Sport 10W/60 and Gulf Competition 10W/60 and consumption reduced still further.
I settled on the Gulf in the end as it was much cheaper than the Castrol and I did well over 50K miles without any oil pressure related issues.
The thing is, the oil is still a 10 weight when cold (where it's hardest to pump), but just that little extra thickness at 100 deg C to reduce consumption. Opie Oils give you all the viscosity information in their tech sheets and you can compare the 100 deg C weights across the 40s, 50s and 60s.
BMW specify a Castrol 10W/60 for some of their M engines, and Alfa specify Selenia 10W/60 for it's old T spark motors. Why? Because they drink oil!
thats why you should use 15/50 in early Fords i.e.pinto/ preand later cross flows etc good post with correct inf I had a forged bottom end built a few years ago that liked to guzzle it's 10W/40. I then moved up to Silkolene 10W/50 and the consumption reduced. Then lastly, I tried Castrol Edge Sport 10W/60 and Gulf Competition 10W/60 and consumption reduced still further.
I settled on the Gulf in the end as it was much cheaper than the Castrol and I did well over 50K miles without any oil pressure related issues.
The thing is, the oil is still a 10 weight when cold (where it's hardest to pump), but just that little extra thickness at 100 deg C to reduce consumption. Opie Oils give you all the viscosity information in their tech sheets and you can compare the 100 deg C weights across the 40s, 50s and 60s.
BMW specify a Castrol 10W/60 for some of their M engines, and Alfa specify Selenia 10W/60 for it's old T spark motors. Why? Because they drink oil!
Frimley111R said:
SuperchargedVR6 said:
Unless you're pushing for every last pony, I wouldn't worry about it.
If you've got 190hp in an Elise, I doubt you will feel a couple of hp being sapped by oil viscosity.
240bhp I'll have you know! If you've got 190hp in an Elise, I doubt you will feel a couple of hp being sapped by oil viscosity.
. It due an oil change so I'll swap it for the higher viscosity.Well if you've got 240hp in such a light car, you have even less to worry about!
one eyed mick said:
It isn't thicker ,it just doesn't lose it's vicosity as quicly as lighter grades , honestly I think you are worrying about sod all get the thing driven ,miles on the clock and enjoy it
Ta, but would help reduce oil usage though? I guess c£15 per thousand miles isn't too bad. I am really just annoyed about not being told this and now having to keep an eye on it all the bloody time. Apparently the engine builder does a lot of race engines so I guess oil cosumptio isn't an isse for most customers but its a bit of a PITA for me.Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff