Why not a -20w30?
- Thread starter 660mag
- Start date
- Status
You could make it, sure...but WHY?
I would just keep using GC 0w30 though, why would I want to switch to a 20W-30?
I would just keep using GC 0w30 though, why would I want to switch to a 20W-30?
Based on how the SAE oil grading system works, -20w would be tested for cold cranking at -55C/-67F and -60C/-76F for cold pumping. The pour point would have to be lower then those number to achieve them. And then for that same oil to not thin past a 30 weight at 100C/212F? That would be one heck of a lubricant!
Last edited:
SAE J300 doesn't specify negative numbers. But if it did, the cold flow characteristics of a -20w would be out of this world!!(assuming a linear slope of the j300 numbering system extended into negative numbers some day). One wonders how useful this would be. I can see using 0w30 in freezing weather, but once you start moving to 0w-40/50 oils you start to see other compromises(sheer, base stock availability, cost). Id only use it if I were operating my vehicle in, say, -50 temps. At that point, I'd imagine other issues would manifest on my poor cold car.
OF course I would use it. 0W30 is MUCH thicker cold then when hot, "-20W30" would likely still not be close to a constant viscosity.
Now, I am not sure why people in Florida would use it, but it would make wintertime starting for frozen northerners seem like summer. Engineering studies show that cylinder wall lubrication is marginal with cold thick oil.... almost no oil flys off the rod bearing (.002 clearance) until oil thins a little.... so those doing lots of short trips should also benefit, both wear and gas mileage.
With my engines already lasting an easy 300,000 miles - with 0W20 - I suspect the winter-short-trip gas mileage would be a better selling point then the benefits of decreased engine wear.
Now, I am not sure why people in Florida would use it, but it would make wintertime starting for frozen northerners seem like summer. Engineering studies show that cylinder wall lubrication is marginal with cold thick oil.... almost no oil flys off the rod bearing (.002 clearance) until oil thins a little.... so those doing lots of short trips should also benefit, both wear and gas mileage.
With my engines already lasting an easy 300,000 miles - with 0W20 - I suspect the winter-short-trip gas mileage would be a better selling point then the benefits of decreased engine wear.
Never thought of a 20w-30, but often wondered why not a 10w-20?
- Joined
- Dec 30, 2006
- Messages
- 29,558
My fsm lists a 20W20/20W40. I`ve never heard of those weights. JDM oils maybe?
Last edited:
Originally Posted By: big_impact
Never thought of a 20w-30, but often wondered why not a 10w-20?
If you look at the values, if you could find a straight 20-weight (there are some, not many) I think you would find they almsot meet the specs to also be a 10W-20, or at least a 15W-20.
Same with straight 30-weights - most I'm sure are actually 15w30's, or at least 20W-30's.
Never thought of a 20w-30, but often wondered why not a 10w-20?
If you look at the values, if you could find a straight 20-weight (there are some, not many) I think you would find they almsot meet the specs to also be a 10W-20, or at least a 15W-20.
Same with straight 30-weights - most I'm sure are actually 15w30's, or at least 20W-30's.
Originally Posted By: big_impact
Never thought of a 20w-30, but often wondered why not a 10w-20?
The OP typed "minus 20w".
I dont think a pure PAO 6 stock will have a ccs in spec at -60.
So no typical synthetic would build a -20W - whatever that is. You know mercury freezes in the thermometer at 0w Cold crank oil test temps as it is! You should not be outdoors in those temps unless you paid a lot of buck to do so!
Never thought of a 20w-30, but often wondered why not a 10w-20?
The OP typed "minus 20w".
I dont think a pure PAO 6 stock will have a ccs in spec at -60.
So no typical synthetic would build a -20W - whatever that is. You know mercury freezes in the thermometer at 0w Cold crank oil test temps as it is! You should not be outdoors in those temps unless you paid a lot of buck to do so!
You mean a -20w as in negative 20? I don't think the rating system goes below 0w.
If it is 20w as in positive 20, like others said, 10w30 and 5w30 can be made easily with better low temp performance, so why bother with 20w?
If it is 20w as in positive 20, like others said, 10w30 and 5w30 can be made easily with better low temp performance, so why bother with 20w?
Most 0w30 flows just fine in most parts of our world
I think some 0-20s are already in the negative numbers [at least a tiny bit].
I do not believe the '0' is exactly 0 - there must be a range.
So are negative first numbers coming out?
I say yes -eventually, but maybe with a new rating system.
I do not believe the '0' is exactly 0 - there must be a range.
So are negative first numbers coming out?
I say yes -eventually, but maybe with a new rating system.
Originally Posted By: 660mag
If a 0w50 can be made, why not a -20w30. And if so would any of yall use it?
Valvoline used to make a good 20W20. Not sure if you can still get it...
If a 0w50 can be made, why not a -20w30. And if so would any of yall use it?
Valvoline used to make a good 20W20. Not sure if you can still get it...
why would it be called a 20w20 and not sae20?
Hi,
660mag - Such lubricants did exist! Castrol had a number of "close range" lubricants in the late 1940s. Their Castrolite, XL and XXL products once held a WW stage!
Other Brands were out there too of course
Note that Castrol's GTX Branding has been around for about 50 years!!!
The introduction of "Multi-Grades" - the NA introduction of 10w30 around 1950+ and the UK's (Duckhams) introduction of 20W-50 in 1958 (for the Austin-Morris Mini) changed the rules!
The API started to awaken in the 1960s too as their "Masters" developed new lubricant technologies!
Today IMO we are spoilt be truely excellent lubricants - be they Mineral, Semi-synthetic or Synthetic! Do we need more choice - not for me!!
660mag - Such lubricants did exist! Castrol had a number of "close range" lubricants in the late 1940s. Their Castrolite, XL and XXL products once held a WW stage!
Other Brands were out there too of course
Note that Castrol's GTX Branding has been around for about 50 years!!!
The introduction of "Multi-Grades" - the NA introduction of 10w30 around 1950+ and the UK's (Duckhams) introduction of 20W-50 in 1958 (for the Austin-Morris Mini) changed the rules!
The API started to awaken in the 1960s too as their "Masters" developed new lubricant technologies!
Today IMO we are spoilt be truely excellent lubricants - be they Mineral, Semi-synthetic or Synthetic! Do we need more choice - not for me!!
Last edited:
Originally Posted By: big_impact
why would it be called a 20w20 and not sae20?
Because each label weight is a combination of a prefix and a suffix, and each has different requirements. 20w, the prefix, is different then 20, the suffix.
Google SAE J300 and read the requirements.
A SAE 20w is different than a SAE 20 is different than a SAE20w20
why would it be called a 20w20 and not sae20?
Because each label weight is a combination of a prefix and a suffix, and each has different requirements. 20w, the prefix, is different then 20, the suffix.
Google SAE J300 and read the requirements.
A SAE 20w is different than a SAE 20 is different than a SAE20w20
Originally Posted By: 901Memphis
Most 0w30 flows just fine in most parts of our world
But a -20W would do a lot better than "just fine". Even for cars in fair weather places (SoCal), it would lessen the wear.
Most 0w30 flows just fine in most parts of our world
But a -20W would do a lot better than "just fine". Even for cars in fair weather places (SoCal), it would lessen the wear.
Originally Posted By: Scuderia
Originally Posted By: 901Memphis
Most 0w30 flows just fine in most parts of our world
But a -20W would do a lot better than "just fine". Even for cars in fair weather places (SoCal), it would lessen the wear.
This is more like what I was getting at. That is if most wear takes place at start up, then an even lower first number than whats out there now would be better. Even a -30w20 sounds good on paper, why not in an engine? I know the scale only goes down to zero, but oils can be made to be thinner than zero.
While were at it, why not a -30w40 some day.
Originally Posted By: 901Memphis
Most 0w30 flows just fine in most parts of our world
But a -20W would do a lot better than "just fine". Even for cars in fair weather places (SoCal), it would lessen the wear.
This is more like what I was getting at. That is if most wear takes place at start up, then an even lower first number than whats out there now would be better. Even a -30w20 sounds good on paper, why not in an engine? I know the scale only goes down to zero, but oils can be made to be thinner than zero.
While were at it, why not a -30w40 some day.
- Status