grubinski

GM recommends 15W-50 for these engines on the track. I use 5W-30 on the street. When I do pre-track-day oil changes, it's probably 10-11 quarts of oil, because I change it twice on the theory that my oil cooler and associated plumbing still has the lighter weight oil in it. If I change back after the track day, that's another 10-11 quarts of oil I'm buying ... so like $200 for oil at current pricing for good oil.

I **could** run 15W-50 all the time. I'd rather run something that was a little thinner on the street. So I'm thinking Castrol European 0W-40 or 5W-40 for both street and track usage.

Does anybody here have experience good/bad/indifferent running a 40W oil on the track?

NSFW

If you can keep oil temperatures under control I don't think it makes sense to use super thick oil. I ran M1 0w40 in my C5 when it had the stock engine. It's inexpensive and readily available, which are nice for frequent oil changes. Oil temps initially peaked at 245, but venting my hood got the peaks down to 235 and I felt pretty good about that.

Then a valve dropped and all hell broke loose, but I don't think the oil caused that problem.

grubinski

I have now gotten that advice from several people. I have a cooler on the car. The 15W-50 only got to 250 degrees, and I was told it would actually run hotter than a thinner oil, which was true on the street, by 10-20 degrees.

So I’m guessing I’d be fine with a super premium 5W-30 like Redline or Amsoil. I’m still waiting on a few queries I have out, but it’s leaning that way.

Thanks for your input!

Che70velle

iTrader: (6)

Very true sir. A thicker (higher viscosity) oil will not transfer heat as well as a thinner oil.

grubinski

Decided on 5W-30 Redline.

Dian

i very strongly doubt that. and if it were not to "tranfer heat", why would it get hotter?

sae xw-50 grade super thick oil? keep in mind oils fall one viscosity class with each temp rise of about 30°f. also inexpensive and readily available doesnt match well with trackday use (at least not in my book). frequent changes are neccessary only if oil has seen 300°f+ for considerable time (even good pao-ester oils, btw). otherwise a good trackday oil shoud be good for 2k miles. and to change it twice doesnt make any sence at all, i never heard of anyone doing that.

SAPPER

iTrader: (10)

An outstanding oil will not be bothered by heat. Also, if the oil is hotter than normal, then it's doing its job. One of it's jobs is to pull heat from the engine while still maintaining it's viscosity. This is where a good oil cooler comes into play.
If you run a top of the line oil and still have factory clearances in your engine, the recommended weight oil is all you need. I only run one brand of oil in all my cars/trucks. Don't believe any hype about the words "FULL synthetics". That only requires 24% synthetic base stock. There's only ONE true 100% synthetic oil.
Cheers.

01CamaroSSTx

iTrader: (3)

https://www.amsoil.com/p/dominator-1...cing-oil-rd30/

Yep and it's called Amsoil. Been wanting to make the switch but Redline 5W30 is a little cheaper.

SAPPER

iTrader: (10)

Get what you pay for. A few dollars more for oil vs internal wear and damage???. I'll pay the small difference.

wannafbody

iTrader: (2)

I'd run Amsoil Z Rod or Dominator. 10W40 would probably be more shear resistant than 5W30.

01CamaroSSTx

iTrader: (3)

Totally agree..Signed me up!

​​​​​​​https://www.amsoil.com/cart

Che70velle

iTrader: (6)

Boundry layer. The thinner the oil (lower number) the thinner the boundry layer. The thinner the boundary layer, the better heat transfer.

01CamaroSSTx

iTrader: (3)

Now that's what I call quick service.

wannafbody

iTrader: (2)

There has to be more to it than just that or everyone would run 0W20 at the track. Oil tends to shear and thin with use.

Che70velle

iTrader: (6)

Nope. If your building a dedicated race engine, set it up for the lighter oil. Free hp. Pro Stock guys are running a 0w3 oil. Obviously this is toooo thin for an endurance build, but for a drag engine set it up for the thin stuff. Street engines are a different story.

Dian

of course. in the engine oil acts as heatsink and in the oil pan/cooler as heat source. whats the balance? its true that thicker oil will create more heat in a hydrodynamic bearing. is this effect not negligible in view of the heat picked up from pistons, cylinder walls and valve train? its even questionable if thin oil will circulate faster. my best guess is oil temp depends on the cooling capacity of the system. iv seen reports of thicker oil running hotter and vice versa.

(just a few thoughts.)

wannafbody

iTrader: (2)

Yes, drag strip is slightly different than road course.

Dian

i came accross a paper on heat transfer into engine oil and thought i would share what in sais. v8 pushrod engine at 2000 (in parentheses) and 4000 rpm/wot:

heat input from piston crown 72% (76%)
from (all) bearings 19% (13%)
from oil pump 8% (8%)

total input was around 11 kw. squirters increased sump temp by 14°c and decreased rings by 57°c, undercrown by 75°c.

and i was wrong above, no heat from the rings/cylinder wall into oil.

(sae 2001-01-1073)