993 Oil Recommendation
05-23-2006, 03:43 PM
#32
Addicted Specialist
Rennlist Member
Rennlist Member
Hi texas,
I haven't tried it, but the "oil gurus" I've spoken with (guys with actual degrees in this stuff AND making a living out of it) don't like the wider spreads between the lowest number (pour weight) and the high number (protective weight). Somehing about "long chains" or this or that molecule ...but the bottom line is that to engineer an oil to do "that," you make compromises elsewhere in the oil's structure. Bottom line is to suit your oil weight to your conditions as best as you can. ...or at least that's what I've gleaned from them, being ignorant of the chemistry myself
Edward
I haven't tried it, but the "oil gurus" I've spoken with (guys with actual degrees in this stuff AND making a living out of it) don't like the wider spreads between the lowest number (pour weight) and the high number (protective weight). Somehing about "long chains" or this or that molecule ...but the bottom line is that to engineer an oil to do "that," you make compromises elsewhere in the oil's structure. Bottom line is to suit your oil weight to your conditions as best as you can. ...or at least that's what I've gleaned from them, being ignorant of the chemistry myself
Edward
05-23-2006, 10:20 PM
#33
Passed On
Rennlist Member
Rennlist Member
For the umpteenth time - use Mobil 1 0W-40; done it for many years. Have 93K miles on original engine, get 3+K miles/quart oil consumption and no oil leaks. Engine never been apart.
Bruce Anderson in "Panorama" recommends it, also.
50W needs are apparently carryovers from non-synthetic oil days, when you needed heavy-weight oils to be able to last under high temps. Not the case on newest synthetics. LIkewise fears of big spreads between cold and warm viscosity values (think old Castrol 5W-50 had problems) far as I know is gone on newest Mobil 1 oils.
Also, with lower weight oils you have less pumping power needs, so car has more power and you get better fuel mileage - all important!
Bruce Anderson in "Panorama" recommends it, also.
50W needs are apparently carryovers from non-synthetic oil days, when you needed heavy-weight oils to be able to last under high temps. Not the case on newest synthetics. LIkewise fears of big spreads between cold and warm viscosity values (think old Castrol 5W-50 had problems) far as I know is gone on newest Mobil 1 oils.
Also, with lower weight oils you have less pumping power needs, so car has more power and you get better fuel mileage - all important!
05-26-2006, 08:53 AM
#34
Rennlist Member
I still remember back in engineering school the question came up in a quicktest.
Please keep in mind that the wider the viscosity spread, the better the oil is, ALWAYS.
In english, a 5W-50 oil is far more better than a 10W-50 or a 15W-50.
so a 10W-30 is of lesser quality than a 15W-40. the first has a spread of 20 points, the latter 25pts.
if u have the same spread with different grades, that is, 5W-30 and 15W-40, then you should consider the time of the year in which the car will run. The lower W figure for cold.
The largest spread on the market today is 50 points.
We can find competition grade oils with such viscosity as the CASTROL RS 10W-60.
these are good for old engines. the viscosity stays dense at high temperatures, and of course for racing.
If you use it on a good engine, you might see your pressure gauge stay high.
but these are the best.
A 5W-50 oil? I think this is excellent two.
As to the brand I don't bother much (knowing this is going to bother some who stuck a lifetime with the same brand). Since these oils with such viscosities are forcfully 100% synthetic, they are all good.
When is the real WEAR your engine takes most? when is the friction the most killing?
the moment you turn it on . . . the first few seconds of cold run are the most criminal.
this is why we still need less viscous oils in cold start and viscous in warm.
that is, the best scenario would be a 0W-60 but for this we have to wait.
conclusion to me, if you run your car normal, go for the widest spread that you find everywhere.
If you push it, go for higher viscosity spread. Thus 10W-60 where you find this oil at special stores.
george
_____________________________
'97 Carrera S 100% original
Please keep in mind that the wider the viscosity spread, the better the oil is, ALWAYS.
In english, a 5W-50 oil is far more better than a 10W-50 or a 15W-50.
so a 10W-30 is of lesser quality than a 15W-40. the first has a spread of 20 points, the latter 25pts.
if u have the same spread with different grades, that is, 5W-30 and 15W-40, then you should consider the time of the year in which the car will run. The lower W figure for cold.
The largest spread on the market today is 50 points.
We can find competition grade oils with such viscosity as the CASTROL RS 10W-60.
these are good for old engines. the viscosity stays dense at high temperatures, and of course for racing.
If you use it on a good engine, you might see your pressure gauge stay high.
but these are the best.
A 5W-50 oil? I think this is excellent two.
As to the brand I don't bother much (knowing this is going to bother some who stuck a lifetime with the same brand). Since these oils with such viscosities are forcfully 100% synthetic, they are all good.
When is the real WEAR your engine takes most? when is the friction the most killing?
the moment you turn it on . . . the first few seconds of cold run are the most criminal.
this is why we still need less viscous oils in cold start and viscous in warm.
that is, the best scenario would be a 0W-60 but for this we have to wait.
conclusion to me, if you run your car normal, go for the widest spread that you find everywhere.
If you push it, go for higher viscosity spread. Thus 10W-60 where you find this oil at special stores.
george
_____________________________
'97 Carrera S 100% original
Last edited by geolab; 05-26-2006 at 12:13 PM.
