Best Engine Oil for Road Course Racing & Weekend Driving?

[BaylorCamaro]

X25, I too recently spend A LOT of time over at Bobistheoilguy.com and I too think sticking with a 5w-30 should be OK or maybe a 0w-40. If I add a dedicated oil cooler and NOT use the engine coolant I think that will solve a lot of my problems.

[Camaro Dude]

I'm using 10/30 on Sledge, because in a nutshell, for that particular brand oil I'm using, the 10/30 is a hair more stable at high temps than the 5/30. Don't forget, generally speaking in simple talk, an oil with less variation in its viscosity numbers, will need less additives than something with a wide margin ratio like say a "0w/50", to make it work. I try to keep away from wide ratio's like that, even if they sound feasibly perfect for street and track from marketing perspective.

I also elected to use a 10/30 and not a 5, because I'm using a slightly more aggressive cam.

[Merc]

Nothing but Redline for Pumpkin.

[Camaro Dude]

Originally Posted by Merc

Nothing but Redline for Pumpkin.

Is this because of the Group V base stocks?

[X25]

I tried 5W-30 (replacing 0W-40) on my supercharged Miata today, combined with removed thermostat, and my oil temps stabilized at about 20-30 degrees lower, around 250-260 degrees F. I'm not sure which one helped more, but I am definitely pleased.

On my way back, I was monitoring my truck's oil temp and pressure, and especially the pressure was definitely way too high. At 2000 RPM, it was already making about 55 PSI, and it doesn't climb much higher than that (perhaps up to 65 PSI or so), suggesting I am just recirculating oil through bypass valve at as low as 2000+ RPM! Per Bob, 20 PSI at 2000 RPM is perfectly fine. Since the pump flow is linear to the RPMs, you expect a somewhat linear increase in oil pressures as the RPMs climb. If it doesn't, it means the oil is just flowing through bypass valve, lubricating nothing, and heating itself. It also hit as high as 240 degrees F during the uphill section. It is obviously not alarmingly high for a truck that is towing, but I wonder if I can reduce that. The oil in use is Rotella T6 5W-40, which is actually significantly thicker than gas 5W-40 oils. Does it do its job? It probably does; Rotella never let me down on any car. Is it optimal? Far from it. The user manual calls for 5W-20, and that's what I will switch to next week (Mobil1 5W-20 EP to be exact). I am looking forward to towing my car again, and checking how oil pressures and temps fare. I also expect a measurable (1+ MPG) fuel economy with the change.

In short:
RAM 1500 Hemi --> Mobil1 5W-20 EP
Supercharged Miata --> Mobil1 5W-30 EP
Camaro 1LE --> Mobil1 5W-30 EP

I have a stockpile of 3x5-quart Mobil1 0W-40. I can sell them for $20 each if anyone is interested, though I suppose I'm not the best salesman by stating I think 5W-30 is the better choice :P

[keith.wilkinson.10]

This web site is incredible....

https://540ratblog.wordpress.com/201...-test-ranking/

Since most synthetics have excellent wear protection almost any will do but since you will be running at high engine temps I'd be weighing more heavily on the info I have pasted on thermal breakdown. Side note thicker isn't better; aeration of thick oils will contribute to inadequate lubrication.

SYNTHETIC GASOLINE ENGINE OILS:

10W30 Amsoil Dominator Racing Oil, synthetic = 300* F

10W30 Amsoil Z-Rod Oil, synthetic = 300* F

5W30 Joe Gibbs Driven LS30 Performance Motor Oil, synthetic = 290* F

0W30 Mobil 1, API SN, Advanced Fuel Economy, synthetic = 290* F

0W30 Castrol Edge with Syntec (black bottle), API SL, European Formula, synthetic, made in Germany and sold in the U.S. = 290* F

0W40 Castrol Edge with Syntec (black bottle), API SN, European Formula, synthetic, made in Belgium and sold in the U.S. = 290* F

10W30 Lucas Racing Only, synthetic = 290* F

5W50 Mobil 1, API SN, synthetic = 290*F

5W30 Motul 300V, Ester Core 4T Racing Oil, synthetic = 285* F

0W40 Mobil 1, API SN, European Formula, synthetic, made in the U.S. = 285* F

5W30 Royal Purple XPR, synthetic = 285* F

5W30 Mobil Super Synthetic, API SN = 285*F

10W30 Joe Gibbs XP3 NASCAR Racing Oil, synthetic = 280* F

5W30 Pennzoil Ultra, API SM, synthetic = 280* F

5W20 Castrol Edge w/Titanium, API SN, synthetic = 280* F

0W30 Mobil 1 Racing Oil, synthetic = 280* F

5W50 Motorcraft, API SN, synthetic = 275* F

0W50 Mobil 1 Racing Oil, synthetic = 270* F

5W30 Mobil 1, API SN, synthetic = 265* F

0W40 Pennzoil Ultra, API SN, synthetic = 260* F

5W30 Oil Extreme Motor Oil, API SM, synthetic = 255* F

5W30 PurOl Elite Series, synthetic = 255*F

0W Mobil 1 Racing Oil, synthetic = 210* F, and this is NOT a typo

Sent from my SAMSUNG-SM-G890A using Tapatalk

[Nick S]

Originally Posted by X25

I tried 5W-30 (replacing 0W-40) on my supercharged Miata today, combined with removed thermostat, and my oil temps stabilized at about 20-30 degrees lower, around 250-260 degrees F. I'm not sure which one helped more, but I am definitely pleased.

On my way back, I was monitoring my truck's oil temp and pressure, and especially the pressure was definitely way too high. At 2000 RPM, it was already making about 55 PSI, and it doesn't climb much higher than that (perhaps up to 65 PSI or so), suggesting I am just recirculating oil through bypass valve at as low as 2000+ RPM! Per Bob, 20 PSI at 2000 RPM is perfectly fine. Since the pump flow is linear to the RPMs, you expect a somewhat linear increase in oil pressures as the RPMs climb. If it doesn't, it means the oil is just flowing through bypass valve, lubricating nothing, and heating itself. It also hit as high as 240 degrees F during the uphill section. It is obviously not alarmingly high for a truck that is towing, but I wonder if I can reduce that. The oil in use is Rotella T6 5W-40, which is actually significantly thicker than gas 5W-40 oils. Does it do its job? It probably does; Rotella never let me down on any car. Is it optimal? Far from it. The user manual calls for 5W-20, and that's what I will switch to next week (Mobil1 5W-20 EP to be exact). I am looking forward to towing my car again, and checking how oil pressures and temps fare. I also expect a measurable (1+ MPG) fuel economy with the change.

In short:
RAM 1500 Hemi --> Mobil1 5W-20 EP
Supercharged Miata --> Mobil1 5W-30 EP
Camaro 1LE --> Mobil1 5W-30 EP

I have a stockpile of 3x5-quart Mobil1 0W-40. I can sell them for $20 each if anyone is interested, though I suppose I'm not the best salesman by stating I think 5W-30 is the better choice :P

X25, What does the "EP" signify in your oils listed above? Is that for the European Blend?

Also as I've been reading through these oil threads and taking in the discussion about oil pressures it seems to me that if we just look at the type of pump that the oil pump is, it starts to also shed light on why higher pressure does not mean better lubrication. Oil pumps are usually a gerotor style which are I believe are positive displacement pumps. Link below describes how gerotor pumps work and specifically states "Constant and even discharge regardless of pressure conditions"

http://www.pumpschool.com/principles/gerotor.asp

Given how positive displacement pumps operate they are going to pump out the constant flow rate (i.e. volume) at a given pump speed no matter the pressure (until something breaks at a high enough pressure which is why they have a bypass valve).

So a higher pressure just indicates a higher resistance to flow. A lower pressure means a lower resistance to flow. This has been something I have questioned for a while when everyone says how they are happier with a higher oil pressure at idle after switching oil grades. To me all that tells me is the new grade of oil is harder to move through the oil flow passages thus creating more backpressure on the pump and a higher oil pressure.

Obviously you don't want to see "0 psi" for oil pressure as there should always be some oil pressure when the pump is working. But again to me higher pressure just means harder to pump.

Also pumping a constant volume of oil (which is what positive displacement pump will do at a given speed) but at a higher pressure just means you are putting more heat into the oil from pumping alone. This seems counterproductive as we are always trying to minimize the heat gain in the oil.

I guess that is just my engineering thoughts on this whole issue. I did not read the Bob The Oil Guy pages to learn more about how the different viscosity's work but just looking at fluid pumping principles with positive displacement pumps by itself I have not always believed that higher pressure = better oil lubricating.

[X25]

Originally Posted by Nick S

X25, What does the "EP" signify in your oils listed above? Is that for the European Blend?

Also as I've been reading through these oil threads and taking in the discussion about oil pressures it seems to me that if we just look at the type of pump that the oil pump is, it starts to also shed light on why higher pressure does not mean better lubrication. Oil pumps are usually a gerotor style which are I believe are positive displacement pumps. Link below describes how gerotor pumps work and specifically states "Constant and even discharge regardless of pressure conditions"

http://www.pumpschool.com/principles/gerotor.asp

Given how positive displacement pumps operate they are going to pump out the constant flow rate (i.e. volume) at a given pump speed no matter the pressure (until something breaks at a high enough pressure which is why they have a bypass valve).

So a higher pressure just indicates a higher resistance to flow. A lower pressure means a lower resistance to flow. This has been something I have questioned for a while when everyone says how they are happier with a higher oil pressure at idle after switching oil grades. To me all that tells me is the new grade of oil is harder to move through the oil flow passages thus creating more backpressure on the pump and a higher oil pressure.

Obviously you don't want to see "0 psi" for oil pressure as there should always be some oil pressure when the pump is working. But again to me higher pressure just means harder to pump.

Also pumping a constant volume of oil (which is what positive displacement pump will do at a given speed) but at a higher pressure just means you are putting more heat into the oil from pumping alone. This seems counterproductive as we are always trying to minimize the heat gain in the oil.

I guess that is just my engineering thoughts on this whole issue. I did not read the Bob The Oil Guy pages to learn more about how the different viscosity's work but just looking at fluid pumping principles with positive displacement pumps by itself I have not always believed that higher pressure = better oil lubricating.

Nick you're exactly right. Due to this, you need to make sure you don't create too much back pressure since once the bypass valve opens due to too much pressure, you're no longer flowing all the oil through engine, and it is the flow, not pressure that ultimately lubricates the engine!

If your pressure climbs somewhat linear to your RPM, you know that the flow is increasing linearly, too, and bypass is not engaged. If the pressure platoes, then bypass valve is opening up.

[Nick S]

Originally Posted by X25

Nick you're exactly right. Due to this, you need to make sure you don't create too much back pressure since once the bypass valve opens due to too much pressure, you're no longer flowing all the oil through engine, and it is the flow, not pressure that ultimately lubricates the engine!

If your pressure climbs somewhat linear to your RPM, you know that the flow is increasing linearly, too, and bypass is not engaged. If the pressure platoes, then bypass valve is opening up.

So what does the "EP" in the oils you listed above stand for? European Blend?

Thanks.

[X25]

Originally Posted by Nick S

So what does the "EP" in the oils you listed above stand for? European Blend?

Thanks.

Oops, forgot to reply to that. It stands for Extended Performance, where Mobil1 guarantees engine protection for up to 15,000 mile intervals, not that the warranty applies to track use.

[Nick S]

Originally Posted by X25

Oops, forgot to reply to that. It stands for Extended Performance, where Mobil1 guarantees engine protection for up to 15,000 mile intervals, not that the warranty applies to track use.

Thanks for the clarification!

[wakespeak]

I still think HTHS is the best measure rather than viscosity because it is a shear or film strength test. My Pennzoil ultra Euro L is 5w-30 with an HTHS of 3.68. I use this track and street.

[Camaro Dude]

Originally Posted by wakespeak

I still think HTHS is the best measure rather than viscosity because it is a shear or film strength test. My Pennzoil ultra Euro L is 5w-30 with an HTHS of 3.68. I use this track and street.

I'm a lil rusty on my oil talk and suffering from information over load as well, so pardon my asking, does HTHS consider extreme high temps as well in the protocol?

[wakespeak]

Originally Posted by Camaro Dude

I'm a lil rusty on my oil talk and suffering from information over load as well, so pardon my asking, does HTHS consider extreme high temps as well in the protocol?

Hths = high temp high shear. This is a pretty good explanation of the tradeoffs http://www.hddeo.com/hthsarticle.html.