Best Engine Oil for Road Course Racing & Weekend Driving?

[SPCBA]

Originally Posted by BullF-16

My motor is no where near stock, not a single part actually. But, i have chosen Amsoil Dominator 15w50 for track days, swapped out promply to either Amsoil ZRod 20W50 or Valvoline VR1 20w50 synthetic for the street due to the anti corrosion additive package.

Nice choices in terms of zinc phosphorous and sheer. The dominator for others is a track only type of fluid dyed red with next to no detergents.

[wakespeak]

Originally Posted by hcsi99

I see the new C7 Corvette recommends 15W50 Mobil One for track use. Would that be a good oil for the Camaro for track use?

That is interesting information but I wouldn't assume same for the LS3 unless the LT1 has the same oil pump bypass value (50psi) for starters. There may be other design considerations. Regardless I would drive like granny until the oil temp is up to 200F with such a thick oil.

The thread with the guy using forced induction got much worse results with 15w-50 vs 5w-40 for street use.

Higher viscosity creates more friction and heat, along with reduced start up lubrication. I would estimate 2-3% drop in hp with 15w-50 unless the oil temp is > 220F. With the C7, is that recommendation with the Z51/dry sump or the wet sump LT1?

I would like to see more of us send in samples to Blackstone for testing instead of guessing. I will send in my current oil with 4000 miles and 2 track days soon. Will post results.

Edit: BTW is there a track oil recommendation for the Z/28?

Found this on the c7:

Corvette Track Prep

15w-50, DOT4, race alignments, and rotor cooling rings. Can we get those for our Brembos?

Still don't know if 15w-50 is right for the LS3 except possibly strictly for track use, but a 40 grade is sounding like a good idea.

[White_SS/RS]

Originally Posted by wakespeak

That is interesting information but I wouldn't assume same for the LS3 unless the LT1 has the same oil pump bypass value (50psi) for starters. There may be other design considerations. Regardless I would drive like granny until the oil temp is up to 200F with such a thick oil.

The thread with the guy using forced induction got much worse results with 15w-50 vs 5w-40 for street use.

Higher viscosity creates more friction and heat, along with reduced start up lubrication. I would estimate 2-3% drop in hp with 15w-50 unless the oil temp is > 220F. With the C7, is that recommendation with the Z51/dry sump or the wet sump LT1?

I would like to see more of us send in samples to Blackstone for testing instead of guessing. I will send in my current oil with 4000 miles and 2 track days soon. Will post results.

Edit: BTW is there a track oil recommendation for the Z/28?

Z28 recommends 15w50 for track use. Seems heavy IMO

[X25]

Originally Posted by White_SS/RS

Z28 recommends 15w50 for track use. Seems heavy IMO

I did not read its manual, but it probably also recommends draining/replacing the oil after track use, so they wouldn't have to care if it's too thick for street use.

I agree that it's too thick, and would not protect the engine enough in the long term in street use.

I think 5W-40 is the best compromise among the engine oil weights available to us. The fact that Rotella T6 does not provide its HTHS value really spooks me, and in between Mobil1 5W-40 TDT and 0W-40, I'd go with the 0W-40, especially considering they made it more resistant to shear after reformulation.

Other than expensive specialty oils (like Class 5 Motul oil, etc.), I don't see much available. I like Amsoil as a company, and I use its products on my transmissions and differentials, but 10W-30 just doesn't feel good enough.

[White_SS/RS]

Originally Posted by X25

I did not read its manual, but it probably also recommends draining/replacing the oil after track use, so they wouldn't have to care if it's too thick for street use.

I agree that it's too thick, and would not protect the engine enough in the long term in street use.

I think 5W-40 is the best compromise among the engine oil weights available to us. The fact that Rotella T6 does not provide its HTHS value really spooks me, and in between Mobil1 5W-40 TDT and 0W-40, I'd go with the 0W-40, especially considering they made it more resistant to shear after reformulation.

Other than expensive specialty oils (like Class 5 Motul oil, etc.), I don't see much available. I like Amsoil as a company, and I use its products on my transmissions and differentials, but 10W-30 just doesn't feel good enough.

I haven't read the z28 manual I just saw the one page of the manual posted recommending the 15w50. Most of the z28 guys are also complaining about oil temps as well. Could be a relation to the heavy oil. I know running the Mobil 1 5w30 will result in lower oil pressure at idle when hot. I'll try the 0w40 next oil change and see if idle pressure is improved by 5 or so psi.

[X25]

Originally Posted by White_SS/RS

I haven't read the z28 manual I just saw the one page of the manual posted recommending the 15w50. Most of the z28 guys are also complaining about oil temps as well. Could be a relation to the heavy oil. I know running the Mobil 1 5w30 will result in lower oil pressure at idle when hot. I'll try the 0w40 next oil change and see if idle pressure is improved by 5 or so psi.

I will do so, too. After a literally disgusting negotiation (I said I'll walk away if they don't give me a fair price, dealer flat out threatened to keep the deposit, I said I'll call my lawyer, then they said let's split the difference, I said I'll spit their split, which was a deal) which was quite stressful, I locked in the price and will be picking up the car tomorrow! Here is hoping they don't back out on their trade-in offer.

I'll be trying it out with stock oil cooler + DeWitts radiator.

[wakespeak]

X25, interested in your results with the larger radiator.

I use this oil: HTHS 3.68 in a 5w-30: Pennzoil Ultra Euro L 5w-30. Has every European car certification you can get. About $7/qt shipped.

There is also a 5w-40 of same oil (HTHS of 3.88) on Amazon.

[X25]

Originally Posted by wakespeak

X25, interested in your results.

I use this oil: HTHS 3.68 in a 5w-30: Pennzoil Ultra Euro L 5w-30. Has every European car certification you can get. About $7/qt shipped.

There is also a 5w-40 of same oil on Amazon.

http://www.epc.shell.com/Docs/GPCDOC...30123090_5.pdf

Looks pretty good. Why did you not go with the -40 variant? Its HT/HS value is 3.88

[wakespeak]

Hi guys got a report back. The numbers are really good for a GM V-8. I changed the oil prior to 2 track days in April (temps mid 80s- low 90s), then drove for about 4000 miles into mid-August. The oil use monitor was at 54% remaining. The oil was Pennzoil Ultra Euro L 5w-30. The interesting thing is the oil tested thicker than a 30, so the European spec may come into play here. Pennzoil states the HTHS is 3.68. (Also the miles on the car are 24K not 74K).

The other item to point out is the low silicon. This means very little dust in the oil. In the years I have been doing this, dirt has proven to have the single largest affect on wear. Oil types and use are a very distant second. Using the factory intake w/ZL1 filter.

: An older report with no track days and regular Walmart Pennzoil Platinum

[White_SS/RS]

So 4000 miles and 2 track days and the oil look great! Zinc levels are almost that of new oil. I believe this confirms that you can use your oil for more than 1-2 track days.

[Camaro Dude]

Originally Posted by wakespeak

Hi guys got a report back. The numbers are really good for a GM V-8. I changed the oil prior to 2 track days in April (temps mid 80s- low 90s), then drove for about 4000 miles into mid-August. The oil use monitor was at 54% remaining. The oil was Pennzoil Ultra Euro L 5w-30. The interesting thing is the oil tested thicker than a 30, so the European spec may come into play here. Pennzoil states the HTHS is 3.68. (Also the miles on the car are 24K not 74K).

The other item to point out is the low silicon. This means very little dust in the oil. In the years I have been doing this, dirt has proven to have the single largest affect on wear. Oil types and use are a very distant second. Using the factory intake w/ZL1 filter.

: An older report with no track days and regular Walmart Pennzoil Platinum

Thank you for sharing!

[BaylorCamaro]

Originally Posted by wakespeak

Hi guys got a report back. The numbers are really good for a GM V-8. I changed the oil prior to 2 track days in April (temps mid 80s- low 90s), then drove for about 4000 miles into mid-August. The oil use monitor was at 54% remaining. The oil was Pennzoil Ultra Euro L 5w-30. The interesting thing is the oil tested thicker than a 30, so the European spec may come into play here. Pennzoil states the HTHS is 3.68. (Also the miles on the car are 24K not 74K).

The other item to point out is the low silicon. This means very little dust in the oil. In the years I have been doing this, dirt has proven to have the single largest affect on wear. Oil types and use are a very distant second. Using the factory intake w/ZL1 filter.

: An older report with no track days and regular Walmart Pennzoil Platinum

Great info, thanks for sharing! I have one track day on my oil so far and maybe 1,000 miles. I am going to do one more track day on it and then send it in for a sample. Last sample (~1,500 miles and 1 track day) should normal wear. I think a good quality oil will last at least a few track days.

[X25]

I've been discussing this with many at the Miata forums (for my supercharged Miata that overheats despite having an additional air-to-oil cooler with Mobil1 0W-40), and also ended up reading the whole oil university section of Bobstheoilguy.com. In short, my attitude is now changed a bit regarding oil pressures at the track.

Long story short, it is the flow that is most important, not the pressure. When we do a cold startup, we see very high oil pressures not because the oil is everywhere in the oil, lubricating the engine beautifully, but on the contrary, because the oil is too thick to go through the oil lines (especially the small ones in the engine), and it is creating a massive back pressure, creating those oil pressures we see and running most of the oil through the oil pump's bypass line, not through the engine.

There is currently no oil in the market which is thin enough for a cold start - NONE. Thinner oils will obviously come to enough flow faster, so the engine wear, most of which happens at the cold starts, will be less. Now, the question becomes, what should we do for the track duty?

The goal viscosity is actually 10 cSt. This is the target viscosity for 30 grade oil at operating temp, 212 degrees F. Now, when we get to 302 degrees F, 30 weight oil becomes around 3 cSt, while the 40 weight oil will hit around 3.7-3.8. You might say that it is 20+% more viscosity, but it is still just 1 cSt; they are actually almost identical! The significance of 1 cSt does not become 10x as important just because you have a very low value in hand. Granted, the best oil would stay at 10 viscosity across the board, but there is no such oil at the moment.

Assuming we use same base as GM recommends, i.e. 5W-XX oils, should we use 40 or 30 for track? 5W-30 will have marginally lower viscosity at 302 degrees F, but it will actually reduce the friction, reduce the likeliness of oil bypass valve (which opens up at 50 PSI?), and you will hit lower overall temps. It depends on the engine, but higher grade oil usually ends up increasing the PSI without necessarily increasing the actual flow of the oil.

Bob's recommendation in this regard is to observe the oil pressure at different RPM levels. If you hit 10 PSI at 1000 RPM, 20 at 2000, ... 50 PSI at 5000 RPM, then you're good. If you see higher, then you should consider trying a lower weight oil. I believe oil pressure relief valve opens up at 50 PSI, so there is no point in testing above 50 PSI; it will be misleading with the bypass circulation added to the equation. Actually, just so you know, if you hit 50 PSI at as low as 3000 RPM, then you will start circulating more and more oil above those RPMs, so you're doing pretty poorly. If you see very low PSI at idle at the track right when the engine is very hot, it is not the end of the world. After all, the oil is flowing without any resistance at high temps, and the engine does not need much protection at low RPMs anyway.

I intend to try 5W-30 next time at the track. If a ZL1 with its supercharger can survive 24 hours of torture at the track with this oil, so can my car at a simple track day. What's more, 5W-30 used oil reports have never raised any concern, and I will have reduced temps and better flow of oil when it's needed most as the advantage. I highly recommend reading Bob's oil university chapters.

[Camaro Dude]

X25, this is pretty much what Dave at Redline Oil told me years ago, after I asked him which oil viscosity should I use, right after I turbocharged my stroked 3.0 inline 6 and used as weekend track duty.

Many guys were using Mobil 15/50 in normally aspirated guise, even my engine builder recommended it for the most part, but I went against the grain thanks to Daves 10/40 approach. He predicted cooler oil operating temps than even over their very own 15/50. He asked about my psi and oil temps, and this was the basis of moving down in viscosity, and working our way up again if need be, as opposed to the other way around.

FWIW, I have never have blown, burn, coked a turbo, to this day.