Turbocharger oiling - how thick is too thick?

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RP does indeed contain those compounds but they are buffered so they wont attack yellow metals at typical gear oil temps.

Running them through a turbo is 100% not recommended.
 
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It’s not about “the list” whatever that means exactly. It’s about the requirements to obtain the approval. Or are you saying that there are counterfeit oils on the approved oil list?

You seem to think you have a handle on that though so maybe it doesn’t make any difference.
 

Ike84

Thread starter
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Rand - That's really great to know. I guess I misread the wording on their spec sheet. Thanks for clarifying that though - I guess that's what they mean when they say that there are no "conventional" sulfur-phorphorus compounds.

Kschachn - the issue with the list is several fold - first, it is a paid endosement of sorts. You have to pay porsche on a regular basis to be put on that list. A lot of guys aren't ok with that idea. Second, some of the oils listed (like mobil 1) aren't the same quality they once were but are still on the list. Third, the majority of oils are 0w40s and almost all guys with my generation of car agree that you will absolutely have cold start issues with such a low winter rating oil. lastly, a lot of guys especially track guys, run oils - both weight and brand - that aren't on that list and have fantastic results in terms of running temp, pressure, and lack of other oil related "complications".
 
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Unfortunately, most turbo manufactures don't actually endorse a specific brand or weight of oil! The company line is "use high quality oem recommended oil for your motor". I am actually a certified garrett installer (not bragging here, it's quite a joke of a process to obtain that certification) and trust me when I say that I have tried every way I know to get this info out of them (and BW) but no go.

Is that what you do when you install turbos for other people? And if so, have you seen any problems using the OEM recommend oil for the motor?
 
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.....the issue with the list is several fold - first, it is a paid endosement of sorts. You have to pay porsche on a regular basis to be put on that list. A lot of guys aren't ok with that idea.
As long as Porsche is transparent about the process then who cares? Do you think Porsche should maintain the list of approved oils at no cost? That seems like a swell idea but it's not really practical in the real world where everything costs money.

Second, some of the oils listed (like mobil 1) aren't the same quality they once were but are still on the list.
This notion fascinates me.
It's the ol' they don't make them like they used to.........
The notion that a major performance auto manufacturer would knowingly endorse substandard product and allow that substandard product to remain on it's approved lubricants list is laughable. This actually made me laugh out loud.

Third, the majority of oils are 0w40s and almost all guys with my generation of car agree that you will absolutely have cold start issues with such a low winter rating oil.
Not sure what you're getting at here. It would seem that a 0w-xx oil would be an advantage in cold start situations. Can you elaborate and discuss the failure mode a 0w-xx would produce?
 

MolaKule

Staff member
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...The RP maxgear does not contain the sulfur compounds which become acidic at high temps. My gearbox has quite a bit of bronze in the synchros and will not tolerate that formulation. I never realized it was because of the EP additives until reading specifically about this, so many thanks for the knowledge!...

Unfortunately, most turbo manufactures don't actually endorse a specific brand or weight of oil! The company line is "use high quality oem recommended oil for your motor"...
So the turbo manf. recommends an "engine" oil rather than a gear oil, but do not specify a specific grade? That makes no sense to me.

Unless you do a VOA on RP MaxGear with an additional 'sulfur' analysis you will not know how much sulfur is really in the RP Maxgear. Phosphates are used as AW chemistry and can decompose into phosphoric acids.

As stated in the paper I referenced, you'll want a system that pressurizes the oil to about 29 psi and with a minimum volumetric oil flow rate of 1.9L/min (0.5 Gal./min). If you are going to tap off the engine's oiling system, you might consider an engine oil cooler if it does not currently have one.

In addition, more frequent oil and filter replacements would be in order.
 
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18,141
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Kschachn - the issue with the list is several fold - first, it is a paid endosement of sorts. You have to pay porsche on a regular basis to be put on that list. A lot of guys aren't ok with that idea. Second, some of the oils listed (like mobil 1) aren't the same quality they once were but are still on the list. Third, the majority of oils are 0w40s and almost all guys with my generation of car agree that you will absolutely have cold start issues with such a low winter rating oil. lastly, a lot of guys especially track guys, run oils - both weight and brand - that aren't on that list and have fantastic results in terms of running temp, pressure, and lack of other oil related "complications".
Oh my, you and the guys really know a lot about oils and approvals as well as how the winter rating works. That's really something.

Where did you get all this learning? Down in the pits with the boys?
 

OVERKILL

$100 Site Donor 2021
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I am actually a certified garrett installer (not bragging here, it's quite a joke of a process to obtain that certification) and trust me when I say that I have tried every way I know to get this info out of them (and BW) but no go.
Clearly, the subject of "you don't lubricate turbos with gear oil" didn't come up during the training eh?
As for the A40 list, I will say one thing - a lot of things about porsche are great, but there are plenty of things that are total garbage. I am a pretty outspoken about porsche's flaws, the company makes far from perfect vehicles. The A40 list is no exception to this. While motor oils are debated pretty heavily in the boxster and 996 forums, the one thing that most agree on is nature of that list.
A40 is a test sequence, and a very robust one at that. Most gearheads don't know much about lubrication. This thread is an example of that with the contemplation of using a gear lube in something that reaches temperatures gear oils are never meant to hit; an application a gear lubricant is in no way designed for.

Here are the details of A40:
This test will last 203 hours.
The engine, and the oil, will go through:
- 4 times the simulation of 35 hours of summer driving,
- 4 times the simulation of 13.5 hours of winter driving,
- 40 cold starts,
- 5 times the simulation of 1-hour sessions on the “Nürburgring” racetrack,
- 3.5 hours of “running-in” program

Measurements on the engine and on the oil will be done at regular intervals, and the following parameter will be taken into account to grant the approval or not:
- torque curve (internal friction),
- oxidation of the oil,
- Piston cleanliness and ring sticking,
- Valve train wear protection. Cam & tappet wear must be less than 10 μm.
- Engine cleanliness and sludge: after 203 hours, no deposits must be visible.
- Bearing wear protection: visual rating according to Porsche in-house method.

There's nothing garbage about that test sequence. What you are likely seeing is the confusion of opinion, conjecture, brand championing and ignorance as factual evidence from which opinion is made.
 
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8,953
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If you must use your cooler and pump setup, install an oil tank and lubricate the turbocharger separately.

Gear oil is a no-go.

If you want to mitigate oil starvation in high-g turns, install an Accusump.
 
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1,084
Location
New York
The oil you use will not matter. Just find a good niche repair facility on the internet when it seizes like my brother's did. It's a rather good cottage industry actually. Note that it may take almost a year to get it back. Other than that, good luck and Godspeed!
 
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pa
turbos require CLEAN oil + of course REAL synthetic Ester oils tolerate the most heat without issue. my hotted up daily driven journal bearing turbod 1.8T went 200 thou without issue on REAL synthetic 10-30, no track days for sure as xtra heat from them would prolly be better with a higher viscosity. if my memory serves me i believe ball bearing turbos oil requirements are a bit less, love those "hair dryers", big boost = big power with proper gas + tuning + todays DI cools so it deters knock. a 100 HP comes easily on a 2.0 VAG volkswagen auto group easily via an APR tune + 93 octane, add 100 octane for another 40!!! big torque as well if everything else is up to it!
 
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@OVERKILL Hit the nail on the head in post #31. Porsche A40 is a strict test, and not any oil can pass it.

On a different note - I don't see this mentioned yet, but 75w90 Gear oil is a similar viscosity to a 10w30-10w40 Motor oil. I'll include the graph below for reference.

ISOchart.png

Screenshot_20210413-222435_(1).jpg
main-qimg-056baad156d8640bf110df22281020cb.gif
 
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Ike84

Thread starter
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11
Thanks again for all the replies. After understanding more about gear oil additives, I'll cross this off the list. There are so few manual transmissions anymore that detailed discussion about the stuff rarely ever comes up.

Sorry for talking out of turn on the oil list, I didn't mean to tick anyone off. The list is fine, and the testing behind it is great. If you start running a 20year old 986 though, please come to the forum and read what a lot of really experienced guys have to say about some of these.

The cold weather issue is pressure related. 0w40 mobil 1, for example, will give you a lifter tick in cold weather. Porsche actually redesigned the pressure release valve to combat this issue in later models, but a lot of people (me included) found that 10w eliminated the issue. Kinda crazy that they would redesign an engine part rather than change the recommendation, but that would tick off the company that paid to have their emblem stamped in the trunk since they only offer a high mileage version and a motorcycle version of 10w.

Speaking of mobil 1 (putting fire suit on now), the comment I made was based on info from this site. I'm not a "back in the good ol day" person, the comment was based on base group iii being the mainstay of their formulas. My understanding of oils (yes it is basic) is that it's better to start with better base group and need fewer additives then to just rely on additives to meet the needed specs. Please correct me if this is not accurate though.

The oil starvation issue - that's a doozy. People have tried everything under the sun and still have failures - accusumps, deep sumps, improved baffles. You could write a book on the issue, but the problem is purely mathematical - over 6k rpm the oil pump is moving over 20L per min and when the scavenge pumps cant get the oil back to the pickup during a long sweeping high g turn (porsche cheaped out and only put scavenge pumps in two corners of the case instead of all 4 and remember that this is a horizontal setup so gravity doesn't factor in) there's nothing that will save you.

Anyway, thanks again for all the replies!
 

Ike84

Thread starter
Messages
11
@OVERKILL Hit the nail on the head in post #31. Porsche A40 is a strict test, and not any oil can pass it.

On a different note - I don't see this mentioned yet, but 75w90 Gear oil is a similar viscosity to a 10w30-10w40 Motor oil. I'll include the graph below for reference.

View attachment 54032
View attachment 54034 View attachment 54033
Vladiator! Where did you find these charts! Holy **** I have looked for weeks trying to find this information! Tranny oil is back in the list! Now just gotta find a gear oil that will jive with the 01a and not eat a turbo from the inside out...

Seriously, if you're ever in the lake cumberland area PM me and I will buy you a beer (or 6 lol)
 
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