Please correct me if I am wrong, but.. 20wt Turbo?

[GearheadTool]

Can 20-weight motor oil be used in a turbo? 0W-20? 5W-20? Redline 0W-20.. which is actually the second-lightest possible 30-weight oil?

In the absense of the Redline 0W-20 being possibly ok, is a 20-weight too thin for a turbo?

Volvo 740, Saab 9000.. Turbos...
High temperature turbos, synthetic 5W-20 or 0W-20 oil...

?

 

[sciphi]

Good question. I'd love to hear a definitive answer, too. My personal "opinion" without any data to back it up says that a 20-weight is generally too thin. I'd love to have a good answer.

FWIW, all the new turbo 4's coming out are spec'ing at least a 30 weight, if not a 40 weight.

 

[Zacharyx]

I tend to worry more about what oil works for the engine more than the turbo ( my engine costs 10x what the turbo does). if the tolerances in the engine are made for a 20wt then there is no reason any quality oil will no be fine with the correct OCI.

 

[Eddie]

Do you want to use a 20w oil in a turbo charged engine and if so why? Certainly there will be no measurable fuel economy benefit. Any turbo engine I've owned or serviced required a 5w30 up to a 40. Since the turbo bearing run up wards of 100+F hotter than the NA temps, I think, the present run of Xw20 weight oils would not provide good protection at full boost. I am referring to the later water cooled turbos. Ed

 

[A_Harman]

Redline 5w20 would be a good oil for an SI turbo engine, but that oil is really a mid-weight 30 when you look at its HTHS number.

As far as non-boutique 20-weights, I wouldn't put them in a turbo engine. Mobil 1 5w20 does not have the Honda HTO-06 builder approval. Mobil 1 5w30 does.

Conventional and synthetic blend oils are completely out of the running for SI turbo's, in my opinion.

 

[sciphi]

Originally Posted By: A_Harman
Redline 5w20 would be a good oil for an SI turbo engine, but that oil is really a mid-weight 30 when you look at its HTHS number.

As far as non-boutique 20-weights, I wouldn't put them in a turbo engine. Mobil 1 5w20 does not have the Honda HTO-06 builder approval. Mobil 1 5w30 does.

Conventional and synthetic blend oils are completely out of the running for SI turbo's, in my opinion.


Agreed on all points.

Mobil 1 5w30 is approved for many turbo-specific and/or high-output-engine applications. I'd run that, especially seeing how it's available everywhere.

 

[Zacharyx]

Originally Posted By: Eddie
Do you want to use a 20w oil in a turbo charged engine and if so why? Certainly there will be no measurable fuel economy benefit. Any turbo engine I've owned or serviced required a 5w30 up to a 40. Since the turbo bearing run up wards of 100+F hotter than the NA temps, I think, the present run of Xw20 weight oils would not provide good protection at full boost. I am referring to the later water cooled turbos. Ed


Many of the 4.6 Mustangs running around with aftermarket turbos on stock or stock speced ( bearing clearance) engines still use 5w20 and are not having issues with the turbos.

 

[CATERHAM]

Originally Posted By: Zacharyx
I tend to worry more about what oil works for the engine more than the turbo ( my engine costs 10x what the turbo does). if the tolerances in the engine are made for a 20wt then there is no reason any quality oil will no be fine with the correct OCI.

I think the OP was refering to a "turbo engine" and not the actual turbocharger.

Anyway the answer is yes assuming your bulk oil temp's don't get too high. A light 30wt oil can handle oil temp's about 10C higher than a light HTHSV 2.6cP 20wt oil. So if your oil temp's don't get above 120C then your probabily fine. Of course you'll need a oil temp' or oil pressure gauge to determine that.

If you don't have an oil gauge installed then as you mentioned you could use a very heavy 20wt oil like RL or RLI 0W-20's which are really 30wt oils so they would work regardless, but the PAO
based Amsoil ASM 0W-20 is pretty heavy with it's HTHSV of 2.8cP and it is very shear resistant so I think that would work.

 

[bdcardinal]

The first year Ford EcoBoost motors took 5w20, now they all spec 5w30 with no back-spec, not confusing for our lube techs at all. The Mazda's we service with the DISI turbo motor all take 5w30.

 

[demarpaint]

Originally Posted By: bdcardinal
The first year Ford EcoBoost motors took 5w20, now they all spec 5w30 with no back-spec, not confusing for our lube techs at all. The Mazda's we service with the DISI turbo motor all take 5w30.


They changed the spec for a reason, and probably a good reason at that. I'd bet the 20 grade oil wasn't cutting it, if it were they'd still be using it. JMO

 

[GearheadTool]

To further the issue, I feel like the new Ecoboost turbos are running with a 5W-20 Motorcraft... For new, new cars.
Reading the replies now.

For NA cars (Normally Aspirated as well as North American,) I start with the logic that if it says 30-weight recommended, I would automatically put in a 20 weight, but keep that 20-weight on the thicker side of 20 if its not an engine that isnt a small little one like a Honda Civic, etc. This is where I am at in my oil application. Most any engine without special needs..........

 

[GearheadTool]

Originally Posted By: CATERHAM
Originally Posted By: Zacharyx
I tend to worry more about what oil works for the engine more than the turbo ( my engine costs 10x what the turbo does). if the tolerances in the engine are made for a 20wt then there is no reason any quality oil will no be fine with the correct OCI.

I think the OP was refering to a "turbo engine" and not the actual turbocharger.

Anyway the answer is yes assuming your bulk oil temp's don't get too high. A light 30wt oil can handle oil temp's about 10C higher than a light HTHSV 2.6cP 20wt oil. So if your oil temp's don't get above 120C then your probabily fine. Of course you'll need a oil temp' or oil pressure gauge to determine that.

If you don't have an oil gauge installed then as you mentioned you could use a very heavy 20wt oil like RL or RLI 0W-20's which are really 30wt oils so they would work regardless, but the PAO
based Amsoil ASM 0W-20 is pretty heavy with it's HTHSV of 2.8cP and it is very shear resistant so I think that would work.


Yes, this is more or less a really good answer to my question. In the event I ever run across a car with a turbo.

 

[bdcardinal]

2010 EcoBoost motors had 5w20, 2011+ so far are all 5w30.

 

[simple_gifts]

Quote:

They changed the spec for a reason, and probably a good reason at that. I'd bet the 20 grade oil wasn't cutting it, if it were they'd still be using it. JMO


Curious how heavier weights are spec'ed in a turbo for "a good reason" but lighter weights are spec'ed in NA cars, for, apparently, "no good reason"

 

[Ken2]

It all depends on what the engine including the turbocharger were designed to run. The big diesel turbochargers I've ran used an ISO64 turbine oil, about equal to a 20 wt engine oil. Of course, this is what they were designed for.

The viscosity of the oil at the temperature in operation is one very big factor. The size and design of the bearings, as well as the load on the bearings, are other big factors. Mobil Jet Oil II is 5.1 cSt @ 100°C, about like a light 20 wt. Works fine in the huge turbines on your nearest 747 or 787.

 

[demarpaint]

Originally Posted By: simple_gifts
Quote:

They changed the spec for a reason, and probably a good reason at that. I'd bet the 20 grade oil wasn't cutting it, if it were they'd still be using it. JMO


Curious how heavier weights are spec'ed in a turbo for "a good reason" but lighter weights are spec'ed in NA cars, for, apparently, "no good reason"



Originally Posted By: bdcardinal
2010 EcoBoost motors had 5w20, 2011+ so far are all 5w30.


He works at a Ford dealership so he knows what they call for.

I'm not the person who set the spec, maybe Ford will give you a heads up as to why.

It is a bit odd that they went from thin to thick with the newer Eco-boost engines isn't it? I think the lighter oils are to save fuel and boost the CAFE numbers in certain applications, but maybe in the Eco-boost it isn't worth the risk? Maybe Ford didn't have enough faith in 20 grade oil for the Eco-boost, or maybe they had problems. No one here has the real answer, but somewhere there is a good reason, and not a bunch of speculation. JMO

 

[jjcom]

I think in theory, a 20wt would give proper protection, but in real world use, it's on the edge. If the oil stays perfectly grade, with no fuel dilution, it'd be fine. But once the engine is put into real world service, then you can have a problem. The Ecoboost V6 motor at least, is bad about fuel dilution, so a 20wt would thin down even more, which wouldn't be a good recipe. A 30wt with some fuel thins down to a 20wt often times, so the 30 wt gives them some room for error and non perfect running conditions. If all factors are kept under control, I would think there would be no problems, but once it's in service, it's not going to be perfect.

 

[donnyj08]

makes me wonder what grade of oil was used during the eco-boost torture test

 

[oggb]

Originally Posted By: Zacharyx

Many of the 4.6 Mustangs running around with aftermarket turbos on stock or stock speced ( bearing clearance) engines still use 5w20 and are not having issues with the turbos.


They don't expect their engines/turbos to last any great deal of time, either.

 

[oggb]

Originally Posted By: GearheadTool

For NA cars (Normally Aspirated as well as North American,) I start with the logic that if it says 30-weight recommended, I would automatically put in a 20 weight, but keep that 20-weight on the thicker side of 20 if its not an engine that isnt a small little one like a Honda Civic, etc. This is where I am at in my oil application. Most any engine without special needs..........


You're overcomplicating this. Use what the manual calls for and if the turbo/engine dies you won't be sitting there thinking "Jeez, wish I'd used Xw-X". If a vehicle has a turbocharger there's going to be essentially zero difference in fuel economy using a lighter grade of oil. Every time you get into boost it's going to start using a [censored] of fuel, regardless of whether there's 0w-20 or 20w-50 in the sump.

How you drive has a much larger effect on fuel economy. 0w-20 in my Prius yields approximately a 1% increase in fuel economy - something so small that I can't be sure that I'm not sure I wasn't driving differently just because there was 0w-20 in the sump, and certainly not enough of a difference for me to justify using it in an application that may or may not be prone to ring wear and subsequent oil consumption issues.

Essentially, use what the manual says. +1 if it has a turbo.