BigMonkey73

LS3, assume healthy engine, 75K+ miles, external oil cooler in place

​​​​Assume good oil e.g. Motul 300V

When running 5W30, oil temps stay under 260

When running 10W40, oil temp rises as high as 290

Actual temperatures may vary, but always under 300 for either.

For track, ​​​​​​​which oil weight do you choose? Is lower temperature results the obvious desired weight to choose?

ipuig

5w-30

froggy47

Certainly the best way to figure it out & you have your answer lower = better.

ZZebes

I run straight Mobil 15W-50 in my tired LS1 and temps stay under 300 in Texas July heat

seamus2154

15/50 here in Fla most of the year. Now it's getting cool like 70-80s so 0/40.

chpmnsws6

I run 5w-50 Amsoil.

conradb

Your oil additives will break down above ~240F for extended periods.

Get your heat management under control first. I had to daisy chain a second double pass mishimoto oil rad on to my Ron Davis alum rad with integrated oil cooler. I think I fixed the over-heating issues now.

I'm using Amsoil 10W-30 racing oil. I recommend it since it's formulated for more punishment and stress. It costs a bit more, but they made it for our application.

bigmackloud

I run Rotella T6 full synthetic, 5w40. Just added a stand alone oil cooler. In 95* heat at VIR, I hit a max of 252* oil temps. Previously I was hitting 275* in cooler weather (Nov/March). I'll be at VIR tomorrow and Friday, so we'll see how it does in slightly cooler weather with the oil cooler.

I will say I'm surprised that a 5w30 vs 10w40 made a 30* temp difference. I assume the weather and track conditions were similar?

Dan H.

I'm running 15-50 in my ls6. I have a DRM stand alone cooler and hit the 260's on the track

BigMonkey73

Similar weather, different track actually. My home track is Cresson, and the first time with new thicker oil weight was at Eagles Canyon where the top speed can get higher.

However, I will be going to my home track at Cresson MSR this Saturday and I'm keeping the 40 weight oil in there to verify that the track wasn't an influence. I suspect the temps will still be high.

The immediate following Saturday I will be going back to Eagles Canyon and I will change the oil back down to 30 weight and that should complete the comparisons. I'll post my results here after each event.

rkdc5z06

I use 10w30 or mix in 15w50 w 10w30 about 5:2 ratio. I get about 275 oil temp by the end of session with DRM oil cooler.
I am on my stock radiator but took out the A/C condenser so Radiator is only blocked by oil cooler.
Usually my brakes /tire go out before I have to worry about my cooling/temp since I got the Oil cooler. I am planning to make better ducting for radiator and install hood vents to lower under hood temp and reduce lift in the nose.

l98tpi

Lucas 20-50 Racing Oil High Zinc

rfn026

I asked this question of Joe Gibbs Racing last year. Their response was "Use what the owner's manual says to use."

If you have a real race car then ask your engine builder what oil you should use. Remember that very few of us here have real race cars though. Some of us think we do - but we don't.

Those are the two options: Your engine builder or your owner's manual.

JGR then discussed the idea that oil is very similar to religion. People have beliefs and nothing will change that.

I've given up trying to write an article about oil. It would be similar to writing an article about the existence of God.

In the meantime I use what the owner's manual says I should use.



Richard Newton
Garage Lights

Bill Dearborn

Here is something to think about. Over the years GM has changed their recommendations on what should be done for cars that are used on the track. From 08 to 09 the OM recommendation on diff maintenance changed even though there was no change in the actual assembly. From 13 to 14 with the C7 the engine oil recommendation changed. With the C7 they now recommend 15W50 any time a car is being run on a track. Yes, I know the LT1 and LT4 are new Vs the LS engines but there are still a lot of similarities and I suspect GM's recommendation has a lot to do with lessons learned through warranty repairs on both the C5 and C6. What is interesting is what Tadge says about 15W50 oil and why they don't recommend it for the street. Or actually it is what he doesn't say. He doesn't say it will damage the engine. He does say it will reduce gas mileage and increase warranty replacement of the cats if used on the street for prolonged periods of time.

I do know with the 15 starting weight the oil will definitely work in cars that see ambient temps down into the 40s. If the ambient temps fall below that then switching to 5W30 during the cool months would be a good idea. Switching the weight of the oil based on ambient temps is something we all did back in the 60s and 70s.

Bill

FASTFATBOY

Geez some of you guys run cane syrup in your cars!

I run Mobil 1 0-40 Euro, but I only run in the winter months down south. No oil cooler, I see 280* oil temps consistently. Rarely is it "cold" at Nola or Barber.

I change it every 2 weekends.

Im running a C5 Z06

Joshboody

I run 0-40 mobile 1 also with 260-ish temp with oil cooler. My thinking on oil is thinnest without loosing oil pressure. This is what I remember after much reading on bobtheoilguy website.

chpmnsws6

My reason for the 5w50:

In the Ford circle, the Boss 302 which is designed as a more track oriented car runs 5w50. The same engine runs 5w20 in the GT which is a more emissions friendly street car. I care far more about engine longevity more then an extra .2mpg.

zrtman1

Mobil 1 5w30 dex. C5 with forged tight clearance 6.2 with ported lsa pump so I have plenty of volume/pressure. 240max temp 45 psi idle 75@6800 with 72 row cooler c6 style. Good Blackstone's.

SouthernSon

Don't go to a different grade of oil to increase the pressure. Use this, I do:

http://store.katechengines.com/oil-pump-shim-p80.aspx

froggy47

This is track use right? And your oiling system is stock? Radiator stock? Those are good #'s I was over that at Fontana on the Roval, had to slow down. That was b4 the DeWitt radiator.