Rudolph

iTrader: (1)

I was wondering if the 15w40 was a good choice for our cars?

Thanks for any input!!

StrongWS6

Do you mean 15w-50? Thats what I have used since I got my car, it now has 21,000 miles. During the winter I changed it to 10w-30.

Rudolph

iTrader: (1)

Not really, is right! i was talking about 15w40!!

Damian

iTrader: (89)

Not a bad idea at all. Especially if you've over 50K miles. I recommend AT LEAST 10w30 to anyone after break-in periond on LS1's. They do not like thin oil for very long. After 50K, 15w40 would be just fine. If you're under that, just stick with 10w30 or 10w40 until then.


josh

Patman

15w40s are generally "fleet oils" which means they are dual purpose gas/diesel oils. Often they don't have the necessary antiwear additives for hard driven cars.

Plus the viscosity at 40c is pretty high usually, so you'll get more engine wear when you first start your car.

If you need a thicker oil, go with 10w40 (Redline or Amsoil preferrably, but Mobil 1 0w40 is also a pretty good choice)

Rudolph

iTrader: (1)

Thanks everyone.

Also, thanks a lot Pat, for the replay in here and the other forum!!! Thanks!!

bigSS

Patman - How does engine RPM and horsepower effect engine oil selection?

sawedoff

iTrader: (3)

I've been running Neo-Synthetic racing oil in the 0w-5 weight range, and I haven't had any problems. No oil consumption problems,etc. The factory owner's manual specifies using 5w30. I don't understand why you guys think you need to run these ridiculously heavy viscocity oils.

StrongWS6

Right now I am using 15w-50 oil, and have been since I bought the car new. Should I go back to factory specs? I am reving the car to 6600 rpms does that matter at all?

Patman

Higher horsepower engines need an oil that is more durable for sure, one that won't shear back under stress, which is why I recommend Redline and Amsoil for very hard driven and higher horsepower cars. But what Sawedoff said is correct, the thicker oils are not necessary for these engines, those 50wt oils will just rob you of power and create unneccessary heat. The ideal viscosity is found through oil analysis, something I highly recommend people start doing if they are curious about how their oil is performing. Otherwise it's all just speculation.

sawedoff

iTrader: (3)

You really don't need that thick of an oil, in engine like the LS1. You will definitley do yourself a favor by going to a 5w-30 sythetic. You'll free up some power, and improve your mileage. The bigger numbers philosophy of "more is better doesn't apply to picking an oil." It all comes down to application. If you had to pick between Amsoil or Redline, I'd go with Amsoil, personally. If you can get oil in a range of 5w-20, take it.

sawedoff

iTrader: (3)

Patman is 100% correcto! I just wish that someone publish a pamphlet or some sort of info that would clarify what those numbers mean about oil in a simple manner, so that folks would undrestand how to choose a proper oil. Patman post that URL to that site that you use.

Patman

Redline makes a 5w20 now that I'd love to see someone try out in an LS1 and do oil analysis. It would have to be someone who doesn't burn oil though. You'd get awesome oil flow and make more horsepower too.

Patman

Here it is:

http://theoildrop.server101.com/ubb/ultimatebb.php

StrongWS6

I saw an oil that was not full synthetic 5w-20. Will that be good?

Patman

Probably not. The only 5w20 I would even consider trying out would be Redline, since it's HTHS numbers are so much higher than other 5w20s (which means it'll protect better) Most 5w20s have an HTHS of only about 2.6 while Redline is 3.1, higher than many 5w30s!

StrongWS6

Where do you find the HTHS #? On the bottle?

WS6 RULES

I'm using Mobile 1 10w-30 right now but I just picked up 4 Gal. of Delvac 1300 Super 15w-40. Got it at a discount store called Sams Club. $1.35 a quart. It passes every spec there is. It's a Mobile product. They e mailed me about it, passes Japanese valve train, any diesel, any gas motor. I'm goin to try it this summer and go back to the syn in winter.

Patman

Nope, it'll be listed in the technical specs page on the website of the oil manufacturer.

StevieZ

iTrader: (3)

This is suposed to be a GREAT oil. The oil formulation engineer who bought my 1st Viper from me swears by this oil and has used it for 40K miles since he bought my car. He works designing additive packages for oil at Texaco.