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willclarke

Deciding on Oil Weight

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I know there's a tonne of info out there on oil weights for these so apologies, but I often come away reading threads even more confused from varying opinion, so perhaps this wont help me, but here goes.

I'd like help deciding on the grade of oil to switch to at next opportunity. N/A car used daily, with currently no oil cooler and perhaps 5 trackdays a year.

I've struggled with oil temperatures on track (e.g bedford in 25C heat, got to 125C oil temp in a little over 1 lap!) and I realise the lack of pressure up to these temps can be a major issue here , so oil cooler will be on the cards at some point soon, O2A or O2W i'm also undecided  on.... but anyway, with that in mind:

0W-20 - Good Quality such as millers nanodrive which im currently using. Perhaps this would be okay with an oil cooler even in 25C heat, if temps would stay around the 115-120 mark? I realise not many who track this car stick with this oil weight, but I'd be inclined to think that Toyota/Subaru have done their testing, and they wouldn't expect a car like this to be nanny'd around but still chose this weight? (emissions/economy play a part here too i realise)

0W-30 - I believe Rogue recommend this for @will300 and @Deacon  (both N/A) but correct me if i'm wrong. Sounds like a good compromise as you're still having similar low temperature viscosity to oem, but with better pressures on track. However, I've read that the bigger the number gap between the two..er 'numbers?' means there are modifiers in the oil to create this versatility, which are prone to breaking down when used on track?

5W-30 Again, correct me if i'm wrong I believe Abbey Motorsport have recommended this (amongst many other places i'm sure) for some who are N/A and use on track (e.g Michael Chan). Clearly this is thicker than oem and has better pressures when hot, so could be more appropriate. This weight is also stated in the manual as an 'temporary' alternative, or used at high speeds/temps (unsure on the balance of it also being daily driver here). I know this is a common alternative for many of you who track the car, but are there any downsides, such as increased engine wear when 'cold' being a 5W, and is the british climate cold enough to matter against 0Wxx?  

And we could go onto heavier however I think for me, its probably one of the above to go with for now staying N/A and the use of the car. The ultimate of course would be switching oils before and after trackdays, or switching through winter/summer months - but it'd be ideal to have something to use all the time. 

Any help deciding would be appreciated!

Thanks 

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You ask a very opinion driven question Will.
Trying to share my thoughts in parts
1. 5W vs 0W - I have attached the manual page where it shows both oils can go below -18C , so the UK winters are not cold enough and this should not worry you, which ever oil you choose.
2. 0W -30 vs 5W-30 - you are right in theoretically stating that the wider the viscosity gap , the more the viscosity modifiers that are used. I will say with the fantastic quality of oils now , it does not matter that much in practise.

3. Using a quality oil - Millers Nanodrive is a quality product. 5W-30 is almost always a lot cheaper than 0W oils as it is the most commonly used oil in petrol engines and hence you could replace it more often , every 5K miles instead of 10K, if you track it. Bear in mind though, it will be ever so slightly less fuel efficient on daily driving compared to 0W-20

4. I haven't seen many , if any posts around catasteophic engine failures on NA state in this car though many track it. Not everyone is as considerate and researching as you , so i would expect then engine is safe. There were a couple of oil starvation issues but I think they were on wider tyres and sticker rubber hence pulling more g forces and would've probably benefitted with a baffled sump. So if you use regular size tires 215/45 tyres and not some fancy semi slicks, you should be fine on that front.
Your engines first wear sign is oil consumption ( or its increase if it already consumed a little) and if it is not showing any such sign, I would not worry about changing the oil type.

Not sure if toyota oil temps are higher than subaru due to bumper design and hence air flow as I do not remember seeing such high temps in just 1 lap of bedford in summers. I use nanodrive or fuchs race oil 0w20. How do you measure it? Torque via OBD11 slot or a dedicated gauge tapping elsewhere?
20180806_191651.jpg

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PM me your e mail id or mobile and I will share my millers used oil analysis which says with 10K miles and 2 track days, no wear metals and oil can be used for another 5k miles. That will give you scientific peace of mind.

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Thanks for the very detailed answer! Some good info there

So that example at Bedford last year, it was very hot ambient to be fair, and I'm using torque with obd2 (is this taken from the hottest point in the oil system?), and yes within 2 laps I was slowing off as I'd set an alarm at 125...perhaps I should of left it even longer to cool off before going back out but the temps seem to drop quickly on these.

I have the moroso sump baffle so should be good from that viewpoint although probably won't be going wider than 215 anyway.

Are you running an oil cooler?

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I do around 10 track days a year. I have only 1x oil change done per year and its done by Toyota using the standard oil they recommend for these cars.

I have a Cosworth baffled sump but no oil cooler and I drive the car hard - but I never do more than about 10 minutes of full on hard driving.

I come in for a cool down on a regular basis. But I check the oil before and after every track day. The level never goes down and its always as clean/clear as the day it goes into the engine.

I think Toyota designed the cooling/oil system on these NA cars to be more than tolerant to the amount of abuse you can give them on track. But I just stay mindful that too many hard laps without a break is bad for any car.

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@willclarke as you said I'm running Miller's Nanodrive 0w30. I'm usually doing about 6-8 trackdays a year and about 5k road miles. I run an oil cooler, Cosworth sump baffle and have the vents on the bonnet uncovered on trackdays. I can happily run sessions of 30-40 minutes without the oil going above 125°. @will300 runs the same cooling set up as me except the bonnet and comparing our temps on track last year the vents were worth around a 10° reduction in oil temps.

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1 hour ago, willclarke said:

Thanks guys

Any thoughts on why rogue prefer 0W-30 to say 5W-30 for your car@Deacon?

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I asked Matt at Rogue and he said:-

"In all honesty a 5W 30 should be fine. We use the 0W 30 because this oil will give you the same characteristics from cold as the standard 0W 20, but the 30 side of it gives you a little more temperature range when on track."

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Ok.

So I'll probably be looking at 5w-30 or 0w-30, as it doesn't sound like there'll be that much difference. I'd probably just more conscious of changing the oil sooner after trackdays if using the 0w30 due to the risk of the modifiers breaking down from track temps, but I imagine as Millers nanodrive do this grade (high quality), and pairing with an oil cooler to keep temps down, could be a good move

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My car gets the same usage as you and I have always run it on Shell 0w-30 without issue.

Although the car currently has 5w30 in it as its back from its recall and that is all Toyota would put in other then 0w20.

I would happily run a good quality one of either but if both were side by side on the shelf I would take 0w30

 

Although I am in the same boat as you and looking to get an oil cooler dropped in this year to be super safe :)

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He may know his stuff but I am not too sure on what he is saying....

 

Is he basically saying as the OP gave no info on his spec and usage there is no right or wrong answer? but his oil choice is too thick and others are ok depending on the intended use.?

In which case I agree if I only drove mine as a road car I would stick 0w20 in it.

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Sorry I was trying to highlight his comments on the oil weight used by Toyota/Subaru and bearing clearance. I've now circled this section. 

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Interesting point. So if thinner oil is necessary there, but we don't want too thin to lose too much pressure with track abuse at high temps (with 0w20), would mean an oil cooler would be the best thing to do here to keep it at a certain viscosity range which would satisfy both arguments? (perhaps the 0w30 would also be a good approach to this)

 

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19 hours ago, willclarke said:

Interesting point. So if thinner oil is necessary there, but we don't want too thin to lose too much pressure with track abuse at high temps (with 0w20), would mean an oil cooler would be the best thing to do here to keep it at a certain viscosity range which would satisfy both arguments? (perhaps the 0w30 would also be a good approach to this)

 

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From reading that and @will300 pointer to the correct section he was referring to I read that as something with 0w is ideal for the tight clearances. But increasing the oil to 0w30 will give you higher temperature stability too so win win. And as 5w30 is in the handbook Toyota must be happy with this one too.
But 10w40 as the OP put is overkill and too thick at cold to get into the tight clearances.

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