5w50 CASTROL SYNTHETIC VS. 15w50MOBIL 1
 

OIL change coming up, close to 24000 hard driven miles. Should i change to heavier weight?

15W50 Mobil or 15W50 AMSOIL gets my vote if you are running your car on a road course.

Jim

Define hard driving!?!? Street or track? Typical ambient temps? Lots of cold starts?

All those factors effect whether you should run an xW-30, xW-40, or xW-50.

My vote goes for the Renewable Lubricants Inc. (RLI) 5w-40 HD. I've had excellent wear readings since switching to it in my street & track Z06.

i'm at your exact milleage looking to get away from the mobile one thinking of running royal purple i had good experiences from other engines has anyone ran RP in their Z?

If you are thinking of changing oils, Look at Valvoline 5w30 synthetic. Do some research you will see it is the only oil to be equal to Amsoil for wear resistance and it is readily available at Wal-mart and most auto parts stores.

Would be interesting to know what Katech and Lingenfelter use. A&A Corvettes in Cali used Mobil 1 15w50 in both my supercharged Vettes.

Iam leaning towards the MOBIL 1 15/50 , very hot here in S.FLA.

On Jason's recommendation, I run 15w50 in my new Katech Street Attack engine.

-Dave

If you want to stay with Mobil 1, you can run either the 0w-40 European formula (if your car is primarilly street) or the 15w-50 if you do a lot of track, or hard driving in extreme temps. I wouldn't run any 50w if you do more cold starts than hard driving though. BTW the M1 0w-40 is factory/dealer fill in Europe.

The best wear readings I've seen on my Z06 are with the RLI (Renewable Lubricants Inc.) 5w-40 I mentioned earlier. I've got even better wear readings with this oil than Amsoil or Mobil 1.

If you were going to try the Valvoline as someone posted above, the 5w-30 really wouldn't do much (if any) better than stock M1. You'd have to run their 5w-40 MST.

To the guys running 15W50, I'm assuming you run it 100% of the time, right? How many street miles do you put on your car? If your Z was primarily a daily driver, but saw a handful of track events a year, what would you recommend doing for oil?

I run Mobil 1 15W50. My car only sees track duty except to move it into the trailer. I wouldn't want to use a lower viscosity oil with my max oil temps of 310 degrees when running hard on the track.

Steve

FWIW- my M6 runs on Castrol 10w60 full synthetic from the factory. And its freakin expensive! And, it goes through a quart every 1,500 miles! Kinda like my old 01 Z06 :)

5W30 on the street and 15W50 on the track. My oil temps never get over 230-240 on the street, even in heavy mountain up hill driving.

Jim

If you are running 310 degrees you need to get some more cooling.

Jim

:iagree:

:withstupid:

i just got some m1 15w50 for my lingenfelter tank install, what is the reccomended lowest temp i should run this 15w50 oil, i am sure at the lower temps up here it will become somewhat thick

thanks

What you might consider hard running is visible on the DIC--lookup the oil temp at the end of as long a session as you typically run. If this number is below 285dF then there is every liklihood that the thinner oils will protect your engines the way GM engineered them.

The only real time that thicker oils provide better protection than the thinner oils is when the oil gets really hod, hotter than 285dF. And for about every 30-35dF hotter the oil gets, one step higher in the SAE weight scale is appropriate. Thus, one would be needing to see 320+ temps for the xx-50 weight oils to be appropriate for the LSx engines.

The whole valve train has been rollerized so there is not scuffing friction (like flat tappets), rings are better lubricatted and cooled with thin oils than with thick oils, as long as the oil film in the bearings is maintained, there is neglible advantage for thicker oils in the main and rod bearings. The engine, was designed for long life with thin oils. Thick oils will not flow as fast at cold startups adn engine wear will take place until the pressure and temperatures come up. Thinner oils protect better durring the cold start time than thick oils.

{For the paranoid in the crowd:: if you take the 285dF temperature and reduce it to 260dF, and use the 30dF-35dF for a weight grade change; even the wear-paranoid will find that for the very vast majority of your driving situations, thinner oils are more appropriate than thicker oils.

For the optimists in the crowd:: change the 285dF temperature to 302dF (where HTHS is measured) and choose your oil appropriately.}