0W20 vs. 5W30 Test Data

[Calvin27]

Originally Posted by bem75

So, where is the sweet spot for a race engine? We ran the 15W-50 and temps climbed rapidly. I've also been advised by others in the know that they would never run a 50wt oil in the FA20. For stock clearances, I would agree with that. For a built engine, I tend to go with what the builder recommends.

As a note, a fellow racer with the exact same setup as mine ran a full season with Torco 5W-30 and had no issues. So, for a stock engine with FI, I'm interested to know the differences, under racing conditions, between 5W-30 and 0W-40. Any thoughts?

The Toyota 86 race series (Australia) runs a x-60 oil for stock internals. A few boosted guys that do circuit/track run 10-40 but hard to say what the impact here is as basically all forced induction will run oil coolers, compared to the stock configuration without one.

[TRAKRAVN]

With using that calculator would it not be possible to work out a recommended oil weight for an operating temperature? For example if you see 220F sustained at the track you should use X weight. If you see 240F sustained at the track you should use an X weight?

[cueball89]

Originally Posted by TRAKRAVN

With using that calculator would it not be possible to work out a recommended oil weight for an operating temperature? For example if you see 220F sustained at the track you should use X weight. If you see 240F sustained at the track you should use an X weight?

I suppose you could get a rough idea, there would be many variables I'd imagine.

Dezoris has good data here. http://www.ft86club.com/forums/showthread.php?t=76760 With his car, using the viscosity calculator, the lower limit on the viscosity across the 3 grades for what he deemed adequate oil pressure at varying temperatures is ~8.0-8.5.

My plan for my car and autox is bump up an oil grade, 30wt, and monitor the oil pressure and temperature changes. If I don't like the results I'll try a light 40wt or get an oil cooler. I don't think I need more than a 30wt oil as its just autox.

[Calvin27]

A bit of a bump here. Oil cooler is now in, do you guys recommend 0-20 with the oil cooler or still 5-30?

I'm thinking if you can keep the 0-20 relatively cool then it's properties should be ok. The reason for going back to 0-20 would be to maintain greater pressure than 5-30 to somewhat compensate for the oil cooler.

[GSpeed]

Originally Posted by Calvin27

A bit of a bump here. Oil cooler is now in, do you guys recommend 0-20 with the oil cooler or still 5-30?

I'm thinking if you can keep the 0-20 relatively cool then it's properties should be ok. The reason for going back to 0-20 would be to maintain greater pressure than 5-30 to somewhat compensate for the oil cooler.

For hardcore track use 5W30 would be better, but everyday use should be fine with 0W20. Especially if you've got a thermostat in the oil cooler adapter.

[zdr93523]

Originally Posted by Calvin27

The Toyota 86 race series (Australia) runs a x-60 oil for stock internals. A few boosted guys that do circuit/track run 10-40 but hard to say what the impact here is as basically all forced induction will run oil coolers, compared to the stock configuration without one.

I run 10W-60 Liquimoly as required by the GT-86 Cup car owner's manual in my FI race car.

[BuffDriver]

Originally Posted by GSpeed

For hardcore track use 5W30 would be better, but everyday use should be fine with 0W20. Especially if you've got a thermostat in the oil cooler adapter.

So I have a 10 row cooler and a thermostatic adapter plate (all -10, fittings not banjos).
I am scheduled for my first driver training and track day 3/7/17 and am still uncertain whether to keep the OEM oil or go 5W30. I have a case of it in my garage as it's what I run in my truck.

My question is what exactly you mean by 'hardcore track use'? Does one day qualify as hardcore for the oil or do you mean multiple track times?

[Calvin27]

Originally Posted by BuffDriver

So I have a 10 row cooler and a thermostatic adapter plate (all -10, fittings not banjos).
I am scheduled for my first driver training and track day 3/7/17 and am still uncertain whether to keep the OEM oil or go 5W30. I have a case of it in my garage as it's what I run in my truck.

My question is what exactly you mean by 'hardcore track use'? Does one day qualify as hardcore for the oil or do you mean multiple track times?

Last track day without a cooler I ran 5-30 on a 30C day (hot) and even with 15 min sessions and a cooldown lap in between oil was getting real hot. Fast forward to oil cooler with 185F thermostat and I basically ran 30 minutes straight with no cooldown on 5-30 in 32C heat. In the end it was the tyre and brakes that couldn't keep up.

[GSpeed]

Originally Posted by BuffDriver

So I have a 10 row cooler and a thermostatic adapter plate (all -10, fittings not banjos).
I am scheduled for my first driver training and track day 3/7/17 and am still uncertain whether to keep the OEM oil or go 5W30. I have a case of it in my garage as it's what I run in my truck.

My question is what exactly you mean by 'hardcore track use'? Does one day qualify as hardcore for the oil or do you mean multiple track times?

It wouldn't be a bad idea to change the oil after your track day whichever you choose, but you've got nothing to lose by running 5W30. It shouldn't be too warm out, but periods of extended high-RPM and high load on the engine can still get oil temps up.

Basically, we never recommend people run 0W20 on track. Odds are your engine will be fine, but based on what we've see with sensors, 5W30 is likely safer for the engine.

[OND]

Originally Posted by GSpeed

It was within a few degrees, I'd consider that a normal variance between two sessions. If you were to average several sessions together that gap would likely disappear.

That is the part that doesnt make sense though. All things being equal, an increase in oil viscosity will always increase oil temperatures. If you see lower or same max oil temps when going from 0w20 to 5w30, that leads me to believe that the testing conditions were more favorable for 5w30.

[Icecreamtruk]

Originally Posted by OND

That is the part that doesnt make sense though. All things being equal, an increase in oil viscosity will always increase oil temperatures. If you see lower or same max oil temps when going from 0w20 to 5w30, that leads me to believe that the testing conditions were more favorable for 5w30.

Will it always be the case? Purely speculating here, but would it be possible the oil is not lubricating enough and its getting some more heat into from generated friction and increasing viscosity increases lubrication and the heat gained from the extra pressure is offset by the less heat generated in friction?

Im just speculating here, just trying to keep the discussion going in a sane/interesting direction.

[CSG Mike]

Originally Posted by Icecreamtruk

Will it always be the case? Purely speculating here, but would it be possible the oil is not lubricating enough and its getting some more heat into from generated friction and increasing viscosity increases lubrication and the heat gained from the extra pressure is offset by the less heat generated in friction?

Im just speculating here, just trying to keep the discussion going in a sane/interesting direction.

"not lubricating enough" = touching metal surfaces (no film) = dead engine.

[OND]

Originally Posted by Icecreamtruk

Will it always be the case? Purely speculating here, but would it be possible the oil is not lubricating enough and its getting some more heat into from generated friction and increasing viscosity increases lubrication and the heat gained from the extra pressure is offset by the less heat generated in friction?

Im just speculating here, just trying to keep the discussion going in a sane/interesting direction.

That makes sense in the "boundary lubrication" regime, which is where you dont want to be due to the vicious cycle of thinning-->more heat-->more thinning... I think once you get to that point, you'll end up with a spun bearing in no time and I dont think that condition applies to this case.

Check out Stribeck curve (Fig 14) here:

http://edge.rit.edu/edge/P14453/publ...l_Bearings.pdf

[ApexEight]

Originally Posted by zdr93523

I run 10W-60 Liquimoly as required by the GT-86 Cup car owner's manual in my FI race car.

What oil temps and pressures do you see with the 10W-60 during cold starts and also during race conditions?