Oil Recommendation for LS3/LS7 Engines

[phat ralph]

Guys,

 

Looking for some advice on oil for an LS3. Currently I am seeing high oil temps in the 300’ range. I am running Amsoil 5w30 synthetic. I would like to run a higher weight oil but not sure how high to go.

What do you run in your Corvette in TT? What weight? Have you seen a reduction in oil temps?

[Cobra4B]

I run Amsoil XL (the basic synthetic stuff) 10w40. I've been tracking/racing C5s for 10 years now and this has always been my oil of choice. Before I started using Amsoil I'd use the Mobil 1 European formula 5w40. IMO it provides a good balance of increased protection at higher temps without being overly thick like a 15w50. I've just never been a fan of 50wt oils. In every car I've tried them in the oil temps have gone up 20+ degrees from the increased viscosity. Increasing your oil viscosity will only make your temps go up. If you want to decrease them you need an oil cooler or a bigger oil cooler.

 

I run a DRM kit with a Setrab 625 cooler. Racing at Road Atlanta a few weeks back in 90 degree ambient temps I saw a max oil temp of 269. Normally it stays in the high 250s, but we were racing hard for 40 minutes. It never hit 270.

[yakisoba]

AMSOIL also makes a racing 1w30 oil that I'm about to try. I used their old racing oil to good effect, as well as their 10w40.

[Kubs]

AMSOIL also makes a racing 1w30 oil that I'm about to try. I used their old racing oil to good effect, as well as their 10w40.

 

 

Be careful if you drive your car on the street. The racing oil does not contain the detergents and dispersants that help keep street engines clean.

[phat ralph]

I am currently sticking with Amsoil signiture series 5w30. Looking at the Setrab 625 cooler and and aluminum radiator from CSF. I was looking at Amsoil 15w50 racing oil but was scared away because of the tight tolerances in the LS3. I may choose to go with a 10w40 but they do not offer one that is Dexos compliant. Does this matter? Also what about mixing oils like a Amsoil 5w30 and 15w50, does this equal a 10w40 with some of the Dexos andrequirements to keep the motor clean for the street. With that said I only use the car on the street to drive to the track. This is not a daily driver. If I need to change oil for the track and for the street that is fie also. But need the ability to drive the car to the track at this time and hopefully drive it home. I am in the hunt for a truck and trailer also.....

 

Thanks for the advice so far....

[Kubs]

Do not worry about the Dexos requirements for a racing application. That has to do with what the OEM wants in the car for street driving.

 

If you are adding a cooler I would stick with the 30 wt and try the Racing oil (would need to be changed out if driving on the street after the event. Ok for driving to and from):

 

Dominator 10W-30 Racing Oil

http://kahunamotorsports.com/rd30-product-page.html

 

For a good all around oil that can be driven on the street I would look at the new Z-Rod line. It has higher levels of Zinc and Phosphorus for the added protection during racing, but also includes the detergents and dispersants for street driving. The Z-Rod line is kind of a combination of the Signature 5W-30 you use now, and the 10W-30 racing oil:

 

Z-Rod 10W-30

http://kahunamotorsports.com/zrt-product-page.html

 

One of the reasons the Z-Rod does not pass the Dexos 1 requirement is because of the higher levels of Zinc and Phosphorus (ZDDP). It exceeds the min. set by the API for street use. Long term use may not be good for the cars cats or O2, but if it is not a daily driver than it won't really affect you.

 

As far as mixing goes, it wont really equal the grade in between the two. All AMSOIL motor oils are compatable with each other and as well as other brands, but the Z-Rod line is designed around what you are trying to accomplish. Mixing two oils designed for different uses wont be as good as getting one designed around your specific use.