daville_pits

iTrader: (9)

i have a 1997 trans am with a Vortech V-1 supercharger.. I was told to run 15-20 in it and i have been but i was wonderin if u can run lighter oil in it and be ok anyone got any ideas??

buffman

iTrader: (9)

15-20. Never heard of such as weight. 20w50 is a oil weight. Is your engine stock? A good synthetic in a 30 or 40 weight would do just fine if the engine is stock.

SlowestTransAm

Sorry to hijack the thread but are you guys using 5w30/40 or 10w30/40???
Went to go pick up some Royal Purple at Advance Auto the other day and they only had 5w30

z_speedfreak

iTrader: (3)

im approaching 100k miles so I stepped up to the 10w30 last oil change

96capricemgr

iTrader: (1)

10w30 is NOT necessarily thicker than 5w-30.

A 15w-20 oil if it existed would be very thin not thick, would almost be like a straight 20 weight.

The amount of BAD very BAD info you will get about oil on these forums is FAR greater than the amount of good and frankly I still feel I understated that.

Here is a place to get good oil information. http://www.bobistheoilguy.com/forums/ubbthreads.php

Some of the thickes Xw-30 oils are actually 0w-30 I know that flies in the face of what you all thought you knew but the thing is that the first number is not that important, it is just a cold temp number the second number is for a hot running engine which is the important one. a 0w/5w/10w-30 ALL fall into the RANGE that means at 100c they are 30 weight some of the popular stuff like M1 tends to be at the very thin end of that range with the 10w-30 being thinnest for a long time while oils like German Castrol Syntec 0w-30 and Amsoil 0w-30 tend to be at the thick end of that range, while the 0w-30 M1 you could get has sometimes be VERY nearly a 0w-20. The formula periodically change too, at one point the above questioned Royal Purple was a poor choice for a street car, it didn't last, it has gotten better but I stuill wouldn't waste my money on it. Now don't mistake that for being a bad product a race oil has different things to cope with than a street oil and a perfect race oil may be completely inappropriate on the street.


I have not kept up on the most current trends for all the oils so maybe the M1 that used to be a mediocre choice at best in these engines has gotten better, what I do know is when I kept current on all that it was VERY thin and resulted in high iron wear numbers. That brings me to another point, opinions from Buffman and myself and a relatively FEW others around here are based on UOA, Used Oil Analysis where they take oil used in an actual engine under actual street conditions and then measure wear metal content and how the oil has held up. Important to look for information about YOUR ENGINE under similar use. The M1 5w-30 I wouldn't use if given to me is great in other engines, just not that appropriate in this one despite popular myth, still a quality product though.

daville_pits

iTrader: (9)

my question is what weight to run with a supercharged lt1

Formula350

iTrader: (3)

15w-20 is not a common weight, and I wouldn't be surprised if it wasn't even considered a consumer weighted oil. 15w-30 isn't common either, and 15w-40 is what the majority of us are familiar with, due to it being the most common Diesel weight.

So now the big question is: Who told you to run 15w-20, and are you 100% sure they said 15w-20?

You could always try getting in touch with Vortech too...
http://www.vortechsuperchargers.com/contact.php

buffman

iTrader: (9)

well see what vortech recommends. If the engine is a stock build, a 30 or 40 weight oil will give you what you need for the engine. A good synthetic will be recommended because of the SC.