04Denali

I agree with the above posts, Rick told me to wait until about 4000 miles to switch to synthetic, My question is (and sorry if it is off topic) what about the Corvettes and other High performance cars that come with synthetic from the factory?
Mark

chevyguy7802

iTrader: (3)

I always wondered the same thing.......

LowBlack99

iTrader: (3)

I have always wondered that myself? Worked for a GM dealer and never really got a clear answer? I do know that if you bring a vette in for a engine problem they can choose not to cover it if you don't run the GM recomended oil.

krambo

iTrader: (4)

Sorry to dig up an old topic however I am finishing up my 408 and will be using the Valvoline VR1 racing oil (10W30) with the break in additive (comp or GM) as per Texas Speed recommendations. I was told any conventional oil with high levels of ZDDP (Zinc DialkylDithioPhosphate), which we commonly just call zinc is suggested. There are a few "racing oils" that have the higher content as well (Joe Gibbs racing oil, Rotella etc.). The content of the metals are 0.130 units Zinc and 0.120 units Phosphorus for the VR1. The conventional oil was suggested for several thousand miles prior to switching to synthetic as well.

Some random numbers for API SM approvals:

Conventional petroleum oil…………zinc/phos .083/.076
Synthetic blend oil………………….....zinc/phos .083/.076
Full synthetic oil………………....……zinc/phos .084/.077

The "racing oils" with the higher levels of ZDDP are harder to come by due to the known issues with deteriorating catylitic converters. The lower the ZDDP in the oils, the longer the cats will last as well as reduced emissions. The issue with lower ZDDP is scuffing of pistons and rings and premature wear. I will not be running cats so this isn't even a question for me.

A google search will land you some good info as well. This was an interesting thread :

http://forums.corvetteforum.com/show....php?t=1646912

Hope this info proves useful to someone!

philntx

iTrader: (8)

BRAD PENN® PENN-GRADE 1®
Break-In Oil

SAE 30 mono-grade oil formulated specifically to meet the critical lubrication needs of new engines during break-in while allowing proper seating of rings and component ‘run-in’. Enhanced levels of “zinc” (zinc dialkyldithiophosphate a.k.a. ZDDP) and superior oil film strength from Penn Grade™ base oils offer complete anti-wear, anti-scuffing protection for even the most demanding of applications such as those presented by break-in of engines with ‘flat tappet’ cams.

viciousknid

iTrader: (8)

They are already broke in before you get them.