another OIL weight thread. honest questions.
5w30
10w30
15w50
what are you using and why?
I've worked on LS engines that have raced in Grand Am, SCCA world challenge, SCCA trans am, and NASCAR K&N. All of those engines run with 30 weight oil and a proper oil cooler. My personal track car has always run 30 weight with a cooler, and that LS1 has seen 70k miles of abuse at autocross and the road course.
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I've worked on LS engines that have raced in Grand Am, SCCA world challenge, SCCA trans am, and NASCAR K&N. All of those engines run with 30 weight oil and a proper oil cooler. My personal track car has always run 30 weight with a cooler, and that LS1 has seen 70k miles of abuse at autocross and the road course.
30 weight will turn into water under that much stress and prolonged heat. The grand-am/scca challenge and nascar cars are POOR candidates to evaluate oil weight on - those engines last a season at best, and 30wt is a power consideration, NOT a wear one. If you want the thing to last, use thicker oil. The 15-50 M1 also has high ZDDP levels, it's the last of the M1 that does. Great oil.
30 weight will turn into water under that much stress and prolonged heat. The grand-am/scca challenge and nascar cars are POOR candidates to evaluate oil weight on - those engines last a season at best, and 30wt is a power consideration, NOT a wear one. If you want the thing to last, use thicker oil. The 15-50 M1 also has high ZDDP levels, it's the last of the M1 that does. Great oil.
For a completely stock LS, it's usually 5W30, the "30" weight being rated at 100C (212F). If your oil temps at the track are 270F, for example, you should run a thicker oil so that the viscosity isn't too thin at those temps. You can tell if this is an issue because your oil pressure will be too low. If oil pressure is too low, you can lose the "hydrodynamic wedge" that the bearings are floating on, and will result in increased bearing wear. But that thicker oil will be too thick at lower temps on the street.
Long story short, unless there is something weird about your engine or you're running in extreme temperatures, run the factory recommended 5W30. If it's a built engine run what the builder recommends. At the track, if your oil temps are high and your pressure is too low, run a thicker oil just for track use.
Also, look at the actual viscosity rating specifications for the oil, not just the xWxx numbers. The actual viscosity of two 5W30 oils can actually be quite different.
For a completely stock LS, it's usually 5W30, the "30" weight being rated at 100C (212F). If your oil temps at the track are 270F, for example, you should run a thicker oil so that the viscosity isn't too thin at those temps. You can tell if this is an issue because your oil pressure will be too low. If oil pressure is too low, you can lose the "hydrodynamic wedge" that the bearings are floating on, and will result in increased bearing wear. But that thicker oil will be too thick at lower temps on the street.
Long story short, unless there is something weird about your engine or you're running in extreme temperatures, run the factory recommended 5W30. If it's a built engine run what the builder recommends. At the track, if your oil temps are high and your pressure is too low, run a thicker oil just for track use.
Also, look at the actual viscosity rating specifications for the oil, not just the xWxx numbers. The actual viscosity of two 5W30 oils can actually be quite different.
also to everyone else, improved racing are amazing people and their tech service has been the best.
For a completely stock LS, it's usually 5W30, the "30" weight being rated at 100C (212F). If your oil temps at the track are 270F, for example, you should run a thicker oil so that the viscosity isn't too thin at those temps. You can tell if this is an issue because your oil pressure will be too low. If oil pressure is too low, you can lose the "hydrodynamic wedge" that the bearings are floating on, and will result in increased bearing wear. But that thicker oil will be too thick at lower temps on the street.
Long story short, unless there is something weird about your engine or you're running in extreme temperatures, run the factory recommended 5W30. If it's a built engine run what the builder recommends. At the track, if your oil temps are high and your pressure is too low, run a thicker oil just for track use.
Also, look at the actual viscosity rating specifications for the oil, not just the xWxx numbers. The actual viscosity of two 5W30 oils can actually be quite different.
Based on prior research on the BITOG forum, for street driving on stock bearing clearances any 5W30 should be fine. If you have higher than stock valve spring pressures, an oil with extra ZDDP wouldn't hurt. As IR pointed out, look at the actual specs on the oil, such as cST, and not just the "xx W YY" generic label.
But personally for street use I'd go with one of these:
M1 0/40
M1 5/30
Redline 0/40
Redline 5/20
Pennzoil Ultra 0/40
Joe Gibbs LS30
For track use, get an oil cooler such as a Setrab TOC-300 oil/water heat exchanger. Also look into Mobil1 Race 0W30 or 0W50 oils ($15/qt).













