Oil Viscousity Ratings

3stagevtec · Postby **3stagevtec** » December 21st, 2009, 3:15 am

I have already read a few articles on the subject, but i still need some clarification.. Correct me if i'm wrong anywhere..

20W - 50

The first number is the Winter or cold rating

The second figure is the Hot rating..

Oil with a viscosity rating of 20 is actually thicker than oil with a viscosity rating of 50, so an oil actually gets thinner the hotter an engine gets..

A 20W - 50 oil is better to use than a 10W - 30 oil in our hot climate.

___________________________________________

My traditional understanding is that a 20W - 50 oil is actually thicker than a 10W - 30 (looking at the '50' vs the '30').. which means you will loose some horsepower because of the thicker oil, but gain some protection in our hot climate..

The articles i've read seem to suggest that a 50 grade is thinner, which is what have me confused..

3stagevtec · Postby **3stagevtec** » December 21st, 2009, 3:22 am

A good read:
http://www.carbibles.com/engineoil_bible.html

How do I read the numbers around the 'W'? For example 5W40?

Single grade oils get too thin when hot for most modern engines which is where multigrade oil comes in. The idea is simple - use science and physics to prevent the base oil from getting as thin as it would normally do when it gets hot. There's more detail on this later in the page under both viscosity, and SAE ratings. But as a quick primer - the number before the 'W' is the 'cold' viscosity rating of the oil, and the number after the 'W' is the 'hot' viscosity rating. So a 5W40 oil is one which behaves like a 5-rated single grade oil when cold, but doesn't thin any more than a 40-rated single grade oil when hot. The lower the 'winter' number (hence the 'W'), the easier the engine will turn over when starting in cold climates.

Postby **Hook** » December 21st, 2009, 3:46 am

Climate has nothing to do with it, as the thermostat is supposed to keep engine operating temperatures to a set optimum level anyway (~82*C ent?). A thicker oil simply gets where it's supposed to go slower than a thinner oil and slows down moving parts.
The need for increased protection depends on driving habits, road conditions and engine health.

If 10W-30 is recommended by the manufacturer, I don't see why u should put such a thick oil in there under the misguided premise of getting increased protection, and have your engine using up valuable horses to push oil rather than to pull the car.

The "W" or winter rating is the viscosity at 0*C if I remember correctly.

When an oil is multi-body, it comprises a base stock and additive molecules that uncoil on heating which "thicken" the oil at normal operating temperature. A multi-weight oil with a huge difference has much more of these than one with a smaller difference, eg. say 20 pts between a 10W-30 oil as opposed to the 30pts between a 20W-50 oil. A wider difference leaves less actual base stock for protection and isn't guaranteed to get to the thicker rating if you're being cooled too rapidly or never quite get up to normal operating temperature (eg. in the case of engines with gutted thermostats etc.).

A 20-25 points difference is fine (say 10W-30 or 15W-40) as opposed to say the 35 pt difference with a 5W-40 oil which in my experience, for whatever reason, burns off more readily than a 15W-40 oil (and they supposedly have the same "hot" viscosity...pfffft!).
If your engine health requires you to use something as thick as a 50body, then there are other problems u need to address other than oil.

3stagevtec · Postby **3stagevtec** » December 21st, 2009, 4:01 am

My engine hardly uses any oil at all and i have ~245,000kms on it now.. I went with the higher 20W-50 rating because that is what was recommended in the manual for our hotter climate..

It was also recommended on a few other sites as well..

carbibles.com

Oil type Typically used in....
5W-30 Cooler climates, like Sweden or Canada
10W-40 Temperate climates, like England
15W-50 Hot climates, like Italy, Spain, Egypt

I agree that the thermostat is what maintains a steady operating temperature, but there must be a reason why manufacturers recommend the above..

Postby **Hook** » December 21st, 2009, 4:05 am

cool...well u learn something new every day...first time I seeing that recommendation as per climate...seems for the same temperature range, the 15W-40 oil is as acceptable as the 20W-50 oil

but according to that, we supposed to be using a straight 40 oil here in T&T

Alpha_2nr · Postby **Alpha_2nr** » December 21st, 2009, 4:07 am

Oil with a viscosity rating of 20 is actually thicker than oil with a viscosity rating of 50

The articles i've read seem to suggest that a 50 grade is thinner, which is what have me confused..

Increasing numbes indicate increasing viscosity at a reference temperature (SAE Standard).

20W50 is theoretically (by virtue of numbers), "thicker" (more viscous) than 10W50 for example. However, at our ambient temperatures, the viscosity of the oil at starting temps is more in line with the "50" quoted figure....implying that for our climate, 10W50 and 20W50 behave almost the same (almost).

Also, a 10W50 is "thicker" than a 10W40 oil (again, refer to the 40 or 50 weight indication). Refer to your owner's manual as to which oil you should use in your car. Most often, OE owner's manuals list 10W30 oils as having the widest range of applicability w.r.t. ambient temperatures.........

............however, if for example, they quote both a 10W30 and a 10W40 as being applicable for our local temp. range, I'd tend to shift to the 40W oil....especially if I know the car is going to be a high revving one (case in point, did this with my former Swift Sport).

but according to that, we supposed to be using a straight 40 oil here in T&T

True....but doesn't factor in the effect of engine tolerances/clearances. The upsurge of high mileage "60W" oils is testament to this, as they are envisioned for engines which have serious miles/wear. Newer engines have lots of tighter clearances (and apparently are envisioned to maintain somewhat tighter clearances of say...a 10 year period, then a current "10 year old engine") - here's an example:

The Suby's Owner's manual quotes the highest viscosity in their chart-listing as a 20W50. The Swift on the other hand, only listed a maximum of a 15W40 oil IIRC, and never went anywhere into the 50W range.

I can only assume that Suzuki built the M16A with tighter clearances than the older EJ20T (which is a 2002), and envision that the clearances over time still would not necessitate moving to a 50W oil.

Alpha_2nr · Postby **Alpha_2nr** » December 21st, 2009, 4:21 am

This may be useful (as an approximation, consider the "cranking/pumping visco" as low temperature visco, and "visco@100degC" as visco during normal operation):

Ultimately, if you want to be totally paranoid, you can always perform an oil analysis on your used/spent oil, for wear metals, silica and the like. If done for a range of different test viscosities, this can help you determine the correct range to use (overkill IMHO tho). Mora Oil Laboratories (or is it Mora Systems? Not sure of the name) used to engine voil analyses locally............

3stagevtec · Postby **3stagevtec** » December 21st, 2009, 4:56 am

carbibles quote
So a 5W40 oil is one which behaves like a 5-rated single grade oil when cold, but doesn't thin any more than a 40-rated single grade oil when hot.

so when they say it doesn't thin any more than a 40 rated oil when hot, they actually mean it will not get thicker than a 40 rating while heating up..

so oil actually gets thicker, the hotter it gets.. not thinner.. :?:

Postby **Hook** » December 21st, 2009, 11:53 am

lol...Did u not read anything I posted about multigrade oils? I said just that.

It's the watered-down version (still looking for the article to refresh my memory and quote it), but the information is basically correct about the Viscosity Index Improvers that are added to the base stock to make it multigrade.

The truth about it from experience, is that with two identical oils, one's 5W-40 and one's 15W-40, the 5W makes the engine rev easier whilst however burning off more readily, because of it's thinner base stock and the addition of significantly more V.I. improvers to make it a multigrade oil. Therefore to put it crudely, the wider the gap between the winter rating and the V.I., the less "oil" u actually get.

3stagevtec · Postby **3stagevtec** » December 21st, 2009, 10:35 pm

understood what you posted, just wanted make sure i had the thicker / thinner thing down with respect to the numbers..

originally, i used to use the 5W - 50 Castrol Syntec and because of the thin 5W, my oil driven chain tensioner wasn't building enough tension during cold start ups to keep the chain in check.. because of that, i used to get a loud chain rattle..

changing to the 20W - 50 oil had significantly reduced the chain noise during cold startups..

____________________________________________

Knight1 wrote:20W50 is theoretically (by virtue of numbers), "thicker" (more viscous) than 10W50 for example. However, at our ambient temperatures, the viscosity of the oil at starting temps is more in line with the "50" quoted figure....implying that for our climate, 10W50 and 20W50 behave almost the same (almost).

from Hook's and my experience, you will see a difference between a 10W - 50 oil and a 20W - 50 oil in our climate..

Alpha_2nr · Postby **Alpha_2nr** » December 21st, 2009, 11:21 pm

^^True, but for the average user, they behave functionally the same, which was my point....but yes, as I stated here:

20W50 is theoretically (by virtue of numbers), "thicker" (more viscous) than 10W50 for example

..the 20W50 is indeed thicker/more viscous than the 10W50 oil......the main reason for you seeing a difference between the two for the average end user, would come down to an engine which has large clearances due to mileage/age, and engines which have problems with oil flow at starting, or engines running in slightly colder climates to ours.

3stagevtec · Postby **3stagevtec** » December 21st, 2009, 11:27 pm

are there any 20W - 40 oils readily available locally? For gasoline engines...

i'm looking to free up some HP and gain a lil fuel economy..

Postby **~VēġÃ³~** » December 22nd, 2009, 12:16 am

good info!!!!!!!

chris1388 · Postby **chris1388** » December 22nd, 2009, 1:00 am

my service manual also gives different oil specs for different ambient temperature ranges.......so i dont think its right hook to say that it is not temperature dependent...if this was the case then ppl in winter climate should be using 20-50 oils if they relying on the thermostat alone....which isnt...thats why all the top manufacturers produce 0W-20 and 0W-30 oils

Postby **Hook** » December 22nd, 2009, 1:26 am

^^^

Hook wrote:
The "W" or winter rating is the viscosity at 0*C

For start-up it's necessary to have a thinner oil in colder climates. That part is understood. After that I don't see the need for a super thick oil unless the engine is aged since they'll all be operating at around the same temperature anyway.

Swifted · Postby **Swifted** » December 22nd, 2009, 11:43 am

good info here guys.

I used to use 20W50GTX in my GTi, and then one day i decided to drop the viscocity to the 10W40 GTX grade. I instalntly gained 40~50KM's more mileage to the tank full of gas, and the engine revved better! the higher the grade oil used, the more drag that will be present in the close tolerances of engine bearings (which will cause higher lube oil temperature = more wear!). when I pulled down the engine I inspected the bearings, and found them to be almost perfect in heath! I have always gone with the idea that frequent oil changes (< 4,500KM) is the secret to a long engine life! After my rebuild I broke in the engine with 10W30 GTX, and then migrated over to 10W30 Mobile 1 synthetic.

CD4Accord · Postby **CD4Accord** » December 22nd, 2009, 1:43 pm

This obsession with heavy weight oil in Trinidad doesn't really make any sense...

Case in point, in Florida people use 10w-30 throughout the year.. including the summer which is equally hot if not hotter than Trinidad..
What im saying is, there is no real need (unless you are burning or leaking like mad) to use 20w-50 and 25w-50 oils in your engine...
Coming to think of it, Hondas in the US use 5w-20 with no problems, including in the summer in the south.
Even the "Racing" Oils usually go 15w-50, so if that is designed for a car running at max throttle all the time, why would a normal car need said weight?

Give it the good stuff and let it live to its true potential..

I personally run Total Quartz 9000 5w-40 on my 13 yr old F20B Honda engine with no isses...

Swifted: Let me start the corrections one time.. Its MOBIL.. Note.. there is no E in mobil.. That said, M1 is one of the best off the shelf oils in the world, and I can say this after years of personal experience and countless hours on www.bobistheoilguy.com

I wish Trinidad carried Penzzoil Platinum though, excellent oil for the price in the states but borderline impossible to get here..

Castrol Syntec, vastly overrated oil.. definitely not worth the cost..

D_bodyguard · Postby **D_bodyguard** » December 22nd, 2009, 8:39 pm

^^and how does amsoil stand up to the other high brands ??

very good read ...highly informative!!

Alpha_2nr · Postby **Alpha_2nr** » December 23rd, 2009, 7:49 am

Swifted: Let me start the corrections one time.. Its MOBIL.. Note.. there is no E in mobil.. That said, M1 is one of the best off the shelf oils in the world, and I can say this after years of personal experience and countless hours on www.bobistheoilguy.com

Well, like yourself, I frequent the BITOG forums as well. Thing is, thanks to that forum, I I've found that M1 is a tad bit overrated......

.....i.e. given the cost locally, and that its a lower grade synth. oil (Group 3 or 4) compared to AMSOIL, redline etc etc.

At the end of day, people become too paranoid about oil changes and what needs to be bought. Using a good quality oil (even GTX depending on application), with a good filter (OE?) and on-time oil changes, should in most cases ensure proper functioning of your engine.

No matter what quality oil you put in (it could be the most ultra cool JDM-tyte expensive oil).....if you don't care for your engine (hard running after a cold start, missed-oil changes, running the wrong viscosity), you can have elevated wear in your engine over time anyways..........

chris1388 · Postby **chris1388** » December 23rd, 2009, 3:49 pm

Amsoil ppl amsoil.....

CD4Accord · Postby **CD4Accord** » December 23rd, 2009, 7:46 pm

Looks like the amsoil posse shows up.. be objective in your posting instead of kissing amsoil's ass...
I use their synthetic ATF, but what does a 3 word post have to do with anything..

Alpha_2nr · Postby **Alpha_2nr** » December 24th, 2009, 7:37 pm

^^Not sure if you're referring to me there, but actually, I'm a Castrol GTX / Royal Purple user.

As for gear lubes, pennzoil, or redline.

:oops:

Postby **Hook** » December 24th, 2009, 8:00 pm

^^^ easy there guy...he's not referring to you

chris1388 wrote:Amsoil ppl amsoil.....

CD4Accord wrote:Looks like the amsoil posse shows up.. be objective in your posting instead of kissing amsoil's ass...
I use their synthetic ATF, but what does a 3 word post have to do with anything..

see?

chris1388 · Postby **chris1388** » December 24th, 2009, 8:14 pm

i not fightin down anybody fellas....everyone have there own preference

praise · Postby **praise** » December 24th, 2009, 9:21 pm

Oil is a sensitive topic and people are very passionate about it. It's a never ending story with arguements for and against. What is important when choosing an oil is sticking with the manufacturor recommended oil or higher, as their choice is the minimum standard. Manufacturor here mean the maker and not the local dealer. The climate factor is irrelevant for Trinidad and I say this without apology. In hotter climate than ours 10W30 is the recommended oil for any season. What is important is knowing your engine normal operating temperature, the clearances for pistons, rings and bearing etc, and then making an informed choice as to what viscosity oil to choose. Most gas engines after 2001 requires a centi stroke viscosity (Cst) of 10 for proper protection and lubrication under any driving conditions and operating temperature. Engine before this required a Cst of 18. All diesel engines requires a Cst of 15 under any operating tempereture and driving conditions. These are the standards determined by automotive engineers. Now lets us examine a 20W50 oil for gas engines. A non synthetic would have a Cst of 190 at 40 degrees celcius and a Cst of 18 at 100 degrees. A synthetic 20W50 have a Cst of 120 at 40 degrees and a Cst of 18 at 100 degrees. Because of the thickness of the oil it will not lubricate the engine properly at start up and there will be too much fluid friction at operating temperature, which results in excessive heat, wear and poor fuel economy. Looking at a 10W30 oil it will have for non synthetic oil a Cst of 90 at 40 degrees and a Cst of 10 at 100 degrees. For a synthetic 10W30 it will have a Cst of 60 at 40 degrees and a Cst of 10 at 100 degrees. This would be ideal for protection, lubrication and fuel economy as there would be less fluid friction. What we need is an oil that would have a Cst of 10 at all times or the closest to 10 at all times. A 5W30 or 0W30 synthetic oil would be even a better choice as the starting Cst would be around 55 and 45 respectively. The problem is not oil being too thin but oil becoming too thick. Hence the reason most engine wear occurs at start up, because the oil is too thick to flow and properly lubricate the moving parts. With regards to brands, choose and oil that have the most stable viscosity idex, least four ball wear scar, highest TBN,least ash deposit, Best NOACK Volatility and Thin Flim Oxygen Test. I am not writing a book , so I would not go into too much details about these properties. Amsoil, Redline, Royal Purple and Shell Helix Ultra are good choices. I saw an add on Tuners for ENEOS oil but could not find the technical data sheet for this product. Maybe someone can shed some light of this product.

CD4Accord · Postby **CD4Accord** » December 24th, 2009, 10:53 pm

Good post and im interested to see you mention Shell Helix Ultra.. being up in the states half the year, I was asking about this oil, and people made it clear the only place you can get it is the Ferrari dealership...
Talking to people online and some obscure references on shell's website, I have read that shell helix ultra = Quaker State Q Horsepower (SOPUS or Shell owns both, along with Pennzoil).. This leads some to even go as far as to say that Quaker State Q Horsepower = Pennzoil Platinum, and the price points in the US are identical...

The point i'm making is this.. In the US, QS Q and PP are two of the cheaper full synthetics (group 3 mind you) and are always under mobil1 and castrol syntec/edge in pricing. Thus, paying the excessive prices asked for Shell Helix Ultra in Trinidad, is a bit ludicrous.. It should cost you less than Mobil1 and certainly no more than other respected Synthetics ..

^
I would go with the 10w-30 for Trinidad ideally as I think it is a great compromise of viscousity/quick lubrication at startup..

Alpha_2nr · Postby **Alpha_2nr** » December 25th, 2009, 7:58 am

Hook wrote:^^^ easy there guy...he's not referring to you

chris1388 wrote:Amsoil ppl amsoil.....

CD4Accord wrote:Looks like the amsoil posse shows up.. be objective in your posting instead of kissing amsoil's ass...
I use their synthetic ATF, but what does a 3 word post have to do with anything..

see?

Orrr.......w3rd. :oops:

alking to people online and some obscure references on shell's website, I have read that shell helix ultra = Quaker State Q Horsepower (SOPUS or Shell owns both, along with Pennzoil).. This leads some to even go as far as to say that Quaker State Q Horsepower = Pennzoil Platinum, and the price points in the US are identical...

The point i'm making is this.. In the US, QS Q and PP are two of the cheaper full synthetics (group 3 mind you) and are always under mobil1 and castrol syntec/edge in pricing. Thus, paying the excessive prices asked for Shell Helix Ultra in Trinidad, is a bit ludicrous.. It should cost you less than Mobil1 and certainly no more than other respected Synthetics ..

W3rd. Well it makes sense, as chances are Penn, Shell, and Quaker have their sources from the basestock oils anyways (none of them are all out Gp 5 synth oils, so will have some mineral bases in them.....right??).

It's strange though, at least to me, I've hardly heard of folks using shell down here. Everybody's on the Mobil / Syntec bandwagon..........

:shock:

I saw an add on Tuners for ENEOS oil but could not find the technical data sheet for this product. Maybe someone can shed some light of this product.

They say that this oil is big in Japan, but I've asked at least two JDM tuning companies (Sunline SLR and Last Station tuning)....and they don't use it

CD4Accord · Postby **CD4Accord** » December 26th, 2009, 1:51 am

Well, i'm waiting to see if Castrol Edge makes its grand appearance in Trinidad if it hasnt already done so.. It is pretty much a direct rival to Mobil1 Extended Performance (15,000) miles, and it most certainly blows Castrol Syntec out of the water...

That said, if the price was right, I would use Shell Helix Ultra, but not at what they ask for it.. For years I used the Shell Helix Plus blend, good oil but as of late I find the prices been inching up too much for my taste, plus I'm running full syn..

There are superb oils out there that are hard to find, eg. Motul, but so called boutique oils have way too much of a price premium down here...

Hear this shocker.. Not sure how many of you know this, but imported mineral oil has a duty of 30% (including syn blends) but full syn (group 3 or better) has 0 duty...
Now, contrast this to retail prices in the US at walmart...

Castrol GTX is about $14 US for a 5qt jug, Castrol syntec is about $23 for the same size

Ie. Conventional oil is roughly 60% the cost of syn at least in the castrol line..

Compare that now to Trinidad.. Castrol gtx is about what, $35 a qt? I cant remember offhand so correct me if anything, full castrol syn is about 67-70 a qt.. Ie. Twice the price..
Explain to me, if there is 0% duty on synthetics why the hell are we paying so much for it.. most certainly both the wholesalers and retailers are abusing us as consumers...
If you do not believe me, call customs, they will tell you the same thing...

Food for thought

Alpha_2nr · Postby **Alpha_2nr** » December 26th, 2009, 7:54 am

Compare that now to Trinidad.. Castrol gtx is about what, $35 a qt? I cant remember offhand so correct me if anything, full castrol syn is about 67-70 a qt.. Ie. Twice the price..
Explain to me, if there is 0% duty on synthetics why the hell are we paying so much for it.. most certainly both the wholesalers and retailers are abusing us as consumers...
If you do not believe me, call customs, they will tell you the same thing...

Good points there bro. At the end of the day, the suppliers are increasing overheads on synth oils, not only because of "name", but because lotsa folks have started buying them IMHO, w/o understanding whether their car actually needs it or not.

One of the reasons I ended up using RP anyways......it was the most "cost effective ---read - cheapest" group 4 synth oil when I buy in bulk.....circa 10 dollars less per qt (or even more) than the typical Mobil 1 price. I do believe that prices went up since my last purchase in May 2009........

:oops: