[thescreensavers]

Originally Posted by PinHead

Adjusting Oil Lubricity for maximum performance.

GM Engineers want the least amount of internal engine friction to achieve maximum performance.

I believe it's mentioned in my Oil, Oil and more Oil post.

High viscosity oil causes more "drag" that's why eco cars are using 0W20 and now 0W16, reason for 15W50 is most likely for protection of the bearings, higher the viscosity = higher load capability.

We can deduce for ZL1 and SS,SS1LE (and it's just an opinion) For a 30min hpde session 5W40 dexos2 is good but for longer stints I'd use 15W50 which is acceptable per manual. Though at least for SS it is required to be removed after track day.

[CarFlow1]

Originally Posted by thescreensavers

Just as Redline, Amsoil does not have a dexos2 certificate but "meets" requirements, they did not pay for the certification like Motul X-clean or Valvoline MST for example. So it does not have manufacturer approval.

So take that fwiw.

Right, I noticed that too when I looked on the site. Many of the Dexos2 oils are much more expensive as well. For example, Amalie Elixir Euro Full Synthetic is what I've been researching.

[soceur77]

Originally Posted by Johnbgood1

at 7,000 miles

Not true i got my first at 500 and my second at 1500. They asked if I was sure at 500 and really didn't want to at 1500 as they didn't see a need, but I insisted and they performed the 2nd free oil change.

[unavailablezl1]

Originally Posted by Inspector 17

I track mine so I am currently running Valvoline Synpower MST 5W-40 per the high performance driving supplement. I bought it on sale and took it with me to the dealer when they did the oil change. I will probably just stick with that in the car since I do a few track events per year. I buy 10 quarts when I see it on sale so I have it handy when I need to do a change.

I have used 20w50 Castrol GTX in all of my cars since 1980. They all go well over 100,000 miles and run like new when I sell them. I think it is kind of a scam really with they weight of oil. I know the 0w30 or 5w30 gets better gas mileage. But really, the 20w50 in 100 degree weather is better.

I know BMW M cars use 10w60 Castrol GTX. $17.00 a bottle. But it is very high quality and it is not "race" quality, but closer.

[unavailablezl1]

Originally Posted by Stephen12ZL1

Amsoil Euro spec 5w40 is Dexos 2 and appropriate for street & track. GM recommends 15w50 for track only and return to 5w30 after an event. I am going to swtich to Amsoil after 1500miles and a PF64 filter.

I think down the road I will get a better filter like K&N. I think they are really close to the best.

[Mr. Wyndham]

Originally Posted by SliChillax

What if I'm not tracking the car and still use 5W-40?

Then you're not following the owners manual, technically. There's nothing wrong with it...supposedly you may lose some fuel economy due to higher viscosity...

[thompstl1]

Originally Posted by SliChillax

What if I'm not tracking the car and still use 5W-40?

I think that more significant than the slightly increased viscosity, the Dexos2 has additional zinc (over that of Dexos1) which is an anti-wear additive for metal to metal contact at extreme pressures.

The additional zinc isn't needed for typical driving, and the zinc is a catalyst poison for your catalytic converters. Day to day use can cause a plugged converter.

Personally, I'm not going to try and outsmart the folks who designed my engine. I plan to use exactly what they specify, in exactly the way they specify it.

[Ray_Dogg]

Originally Posted by soceur77

Not true i got my first at 500 and my second at 1500. They asked if I was sure at 500 and really didn't want to at 1500 as they didn't see a need, but I insisted and they performed the 2nd free oil change.

Did you do your rear diff fluid at 1,500 miles as well? What did they charge for that?

I'm quickly approaching 1,500 miles. Can I get heavy on the peddle a little before I can get the car in for service?

[unavailablezl1]

Originally Posted by Ray_Dogg

Did you do your rear diff fluid at 1,500 miles as well? What did they charge for that?

I'm quickly approaching 1,500 miles. Can I get heavy on the peddle a little before I can get the car in for service?

Onstar keeps track of all speeds above 80mph and hard starts

[Smuuth]

Redline Euro-Series 5W30 and 5W40 both meet GM Dexos2® specifications.

[msawyer110]

Ya im running amsoil also!

[soceur77]

Originally Posted by Ray_Dogg

Did you do your rear diff fluid at 1,500 miles as well? What did they charge for that?

I'm quickly approaching 1,500 miles. Can I get heavy on the peddle a little before I can get the car in for service?

i was but decided to wait until it needs the service as I don't track the car and mainly because its an auto. I believe had i gotten a manual i would have done it before hand. If GM engineers didn't feel the need for me to do one early, i can sleep well at night not doing it.
As far as getting on it, depends on what heavy is, I had to drive my car from NJ to MD during that time after 100 miles, I pushed it to about 5500 rpms maybe more a few times, but never any hard starts until after 1000mi, but as i mentioned i also got an oil change at 500mi. I say dont straight rape her and u will be fine!!

[gblaue]

Originally Posted by Johnbgood1

at 7,000 miles

They did mine at 2500 and 5500 miles.

[gblaue]

Originally Posted by unavailablezl1

I have used 20w50 Castrol GTX in all of my cars since 1980. They all go well over 100,000 miles and run like new when I sell them. I think it is kind of a scam really with they weight of oil. I know the 0w30 or 5w30 gets better gas mileage. But really, the 20w50 in 100 degree weather is better.

I know BMW M cars use 10w60 Castrol GTX. $17.00 a bottle. But it is very high quality and it is not "race" quality, but closer.

Try starting your ZL1 with 20W50, up here in the Northeast, in February. IF your motor turns over, it won't last 100k miles.