Best oil for high boost turbo car?

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Feb 15, 2022
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I’ve been researching online, and have found a full range of answers by “internet professionals”……but I thought that for a reliable answer backed up by people who actually know what they are talking about, this would be the best place to ask the question.

Long story short….I’ve got a twin turbo BMW N54 Inline 6 in my “weekend” car. I’ve always ran Rotella T6 5w-40 in it with a Mann filter, and change it out every 3K miles (oil is cheap, motors aren’t). The car has around 100K miles on it now, and over the winter I’ve been doing some work on it….bigger turbos, and running on e85 now. The new turbos will make around 27psi boost, and should make close to 650+ hp at the crank. It doesn’t really spin crazy high rpms (shift at 7K), but it makes a lot of torque (550+ ft/lbs)…..so these motors are typically hard on rod bearings.

As far as oil goes, am I’m ok to keep running the T6, or would I be better off looking at some of the boutique oils out there? I saw that Amsoil has a “boosted” series of oil for turbo cars. Liqui Moly, Motul, and Redline also make some oil that they market towards turbo cars. After all the money I invested in parts, I don’t mind spending a little more on oil if it’s actually going to help protect the motor a little more.

Any info would be great! Thanks!
 
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IMO the operational environment matters as much if not more than the amount of power. On a 3k OCI you could probably use any 5w40.
Remember oils are measured by their performance over time. A PCMO of the same weight and rated for 5k miles won't perform worse than an oil rated for 10k miles if the OCI is 3k miles.
 
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T6 is a good oil, but, pushing that much torque through stock internals, on that engine, is opening a whole new chapter for it and it won't be a very long one...
That said, moving up a grade (RedLine 5W50) and monitoring oil and coolant temps along with a good tune that does NOT unleash full 550 ft/lbs torque before 4000rpm, should give you some boost filled weekends to come :)
 
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I’ve been researching online, and have found a full range of answers by “internet professionals”……but I thought that for a reliable answer backed up by people who actually know what they are talking about, this would be the best place to ask the question.

Long story short….I’ve got a twin turbo BMW N54 Inline 6 in my “weekend” car. I’ve always ran Rotella T6 5w-40 in it with a Mann filter, and change it out every 3K miles (oil is cheap, motors aren’t). The car has around 100K miles on it now, and over the winter I’ve been doing some work on it….bigger turbos, and running on e85 now. The new turbos will make around 27psi boost, and should make close to 650+ hp at the crank. It doesn’t really spin crazy high rpms (shift at 7K), but it makes a lot of torque (550+ ft/lbs)…..so these motors are typically hard on rod bearings.

As far as oil goes, am I’m ok to keep running the T6, or would I be better off looking at some of the boutique oils out there? I saw that Amsoil has a “boosted” series of oil for turbo cars. Liqui Moly, Motul, and Redline also make some oil that they market towards turbo cars. After all the money I invested in parts, I don’t mind spending a little more on oil if it’s actually going to help protect the motor a little more.

Any info would be great! Thanks!
I would contact HPL via PM, this is a very specific application that may benefit from a very specific high end oil.

 

Astro14

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If you want the very best.

I would message @High Performance Lubricants and ask directly. Depending on other factors, he might have a different recommendation.

Yes, you’ll pay more. But you will absolutely have the best, much better than other options suggested so far.

Edit: simultaneous post with Trav. Great minds think alike! 😊
 
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Before giving advice, I would be interested in seeing what the oil is doing in the car. So, I would first pick a good oil that is reputable (Mobil, Castrol, Pennzoil) in an xW40, do a run, do a UOA, and see what it looks like. That will give you the best starting point to see where you need to go next. That's just my .02.
 
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Isnt that engine very similar to a 2jz toyota inline 6?
They make crazy power on stock internals and run normal oils.
I'd go with 0w50 m1 or something similar but a 0/5w40 should work.
Id definitely do an uoa on the t6 to make sure nothing looks wonky.
 
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In our turbocharged road race cars, we typically used M1, 15W-50. A commonly available oil with an HTHS of (at least) 4.5. In some circumstances, 15W-50 was replaced with M1, V-Twin 20W-50, with it's more robust HTHS of 5.9 and complete lack of VII's.

In essence, the only time the 15W-50 was inadequate was with poorly managed oil temperatures. Which brings up a really important point. We now understand how to run very thin oils in race engines, and the secrets include very careful management of oil temperature and generally a dry sump oil system that produces adequate flow and pressure under all conditions. The dry sump system can be designed to help immensely with oil temp management. It is not unusual for production based race engines, with limited RPM, using 0W-20 oils to limit oil temperature to 180°F.

As a very general rule, 0W or 5W (40-50-60) oils contain significant levels of VII's and are more likely to shear. Some even believe they don't quite match the performance of similarly rated oils with heavier base stocks. I tend to avoid 0W-anything for my turbocharged engines.

Consider what happens in simple systems, when turbochargers drain 350°-400° oil into the sump, where it is then mixed with already very hot sump oil and picked up by the oil pump and fed directly into the engine.

Even way back in the 1980's we could reliably produce 600++ HP from 1.7 to 2.1L 4 cylinder turbocharged road-race engines.

mustang-gtp-027.jpg
 
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IQraceworks

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Isnt that engine very similar to a 2jz toyota inline 6?
They make crazy power on stock internals and run normal oils.
I'd go with 0w50 m1 or something similar but a 0/5w40 should work.
Id definitely do an uoa on the t6 to make sure nothing looks wonky.
Yep....that's the motor. It's pretty much BMW's version of the 2jz. It's pretty common (and easy) for guys to get 600-700hp out of them on all stock internals....and they last for a very long time. When people start pushing them past 800hp...that's when things start breaking. A lot of it is how you tune them......that can make a massive amount of torque at low rpms, and you don't really want that....so if you can keep the boost low until higher up in the rpms, that really seems to help them live longer at those crazy power levels.

I sent Blackstone an oil sample last year, and they said everything looked fine...I will see if I can dig up the report.

From what everyone is saying...I don't think T6 is a bad choice, so maybe I will just stick with that.
 

IQraceworks

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In our turbocharged road race cars, we typically used M1, 15W-50. A commonly available oil with an HTHS of (at least) 4.5. In some circumstances, 15W-50 was replaced with M1, V-Twin 20W-50, with it's more robust HTHS of 5.9 and complete lack of VII's.

In essence, the only time the 15W-50 was inadequate was with poorly managed oil temperatures. Which brings up a really important point. We now understand how to run very thin oils in race engines, and the secrets include very careful management of oil temperature and generally a dry sump oil system that produces adequate flow and pressure under all conditions. The dry sump system can be designed to help immensely with oil temp management. It is not unusual for race engines using 0W-20 oils to limit oil temperature to 180°F.

Consider what happens in simple systems, when turbochargers drain 350°-400° oil into the sump, where it is then mixed with already very hot sump oil and picked up by the oil pump and fed directly into the engine.
In our turbocharged road race cars, we typically used M1, 15W-50. A commonly available oil with an HTHS of (at least) 4.5. In some circumstances, 15W-50 was replaced with M1, V-Twin 20W-50, with it's more robust HTHS of 5.9 and complete lack of VII's.

In essence, the only time the 15W-50 was inadequate was with poorly managed oil temperatures. Which brings up a really important point. We now understand how to run very thin oils in race engines, and the secrets include very careful management of oil temperature and generally a dry sump oil system that produces adequate flow and pressure under all conditions. The dry sump system can be designed to help immensely with oil temp management. It is not unusual for race engines using 0W-20 oils to limit oil temperature to 180°F.

Consider what happens in simple systems, when turbochargers drain 350°-400° oil into the sump, where it is then mixed with already very hot sump oil and picked up by the oil pump and fed directly into the engine.

My oil temps usually stay in the 215-235f range depending on how hard I'm running the car. Aside from a few runs down the dragstrip every now and then, it's primarily a street car. From everything I read online, the guys who are racing these cars on the track for long periods of time spend good money on aftermarket lol cooler setups to manage the oil temps.
 

Zee09

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T6 should do well as you are using it.
I doubt throwing another $100 at it every oil change will make much of a difference.
 

Astro14

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T6 should do well as you are using it.
I doubt throwing another $100 at it every oil change will make much of a difference.
He’s got several thousand in engine modifications, and it’s far from stock HP and operating conditions, so, in his shoes, I would absolutely spend a few $$ more at every oil change to get the best.

I really think the extra $50 for an oil change with HPL is a good idea in his case.

He is exactly the use case for a company like HPL.
 

Zee09

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He’s got several thousand in engine modifications, and it’s far from stock HP and operating conditions, so, in his shoes, I would absolutely spend a few $$ more at every oil change to get the best.

I really think the extra $50 for an oil change with HPL is a good idea in his case.

He is exactly the use case for a company like HPL.
I have no issue with HPL and I did read the full post.
I used to spend big on everything but now if it meets or exceeds approvals I am good but unlike most here I have no issue with others choices.
Whatever works is the right decision eh.....
 

IQraceworks

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Thanks for all the info, I will reach out to HPL and see what they say. Do they make custom blends? Or do they just have some higher end oils that they stock? I have never heard about HPL.....can someone give .e some info on them?
 
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A lot of it would depend on use.
Track car might get M1 15W-50 (Relatively high oil temps)
Strip car might get M1 EP 0W-20 (Relatively low oil temps)
Street car might get M1 0W-40 (Moderate oil temps).

Our 1400 hp turbo car (strip) has M1 EP 5W-30 in it right now.

The specific requirements for that engine's bearings would lead me to consult with someone familiar with getting that engine to live in your specific appplcation.
 
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