: Mobil 1 15w50 "Red Cap"



Me Wanna A V
03-17-11, 06:41 PM
Before I start, I must state that I know this is a "touchy subject" due to all the posts over at LS1tech, CorvetteForum, and every other LSX Forum. I know GM states to use 5w30 in the LSA and most of their motors, whether it's for the "tight tolerances" or maybe perhaps fuel economy reasons, which are the two main arguments as to why a person should "only" use what GM states on the oil cap.

My concern is the fact that we all know supercharged engines (as well as turbocharged) run very hot and require "more protection" than a naturally aspirated motor.

In my previous 609 rwhp 1995 Cobra 347 R302 block (forged) with Vortech S-Trim, I ran it with 15w50 with no issues what so ever.

The 15w50 is "specially formulated" for high performance vehicles with turbos and superchargers- as per the bottle and their website.

Also, it's been stated that Lingenfelter actually specifies to use 15w50 ( in the summertime) with all their Maggie Supercharger installs on LS3 Camaros. I found this info over at Camaro5 forums.

Another tricky issue is the LSA's have "piston oil squirters" and maybe this would require the use of the thinner 5w30 as the 15w50 might be too thick for the squirters to properly function.

There's been many posts on this forum about Amsoil vs Mobil 1, but not much if any discussion on this subject. I can't be the only person who is kind of skeptical about using 5w30 especially for the people who live in Florida, California, and Arizona, like myself, where the summers are brutal.

I understand that using anything other than 5w30 could have "warranty implications", so there's no need to mention that. I'm sure the 5w30 is just fine, but like I previously stated, I can't be the only one skeptical.

Thoughts - Opinions?

Gary

dvandentop
03-17-11, 08:20 PM
i used 15w50 in my road road z06 all summer long now for 2 years no issues at all

jzchen
03-17-11, 09:18 PM
There is a concern about startup where the engine is cold and oil is down in the pan. You are sucking up a more viscous oil to start off and most damage is done at this time. I haven't been up to date but have people been reporting damage to the engine from the concern you are talking about? It doesn't really seem like it.

baabootoo
03-18-11, 12:36 AM
There is a concern about startup where the engine is cold and oil is down in the pan. You are sucking up a more viscous oil to start off and most damage is done at this time. I haven't been up to date but have people been reporting damage to the engine from the concern you are talking about? It doesn't really seem like it.

This is EXACTLY the reason for "thinner" oil; startup. I have considered using sythetic 5W-40, IN A FEW SUMMER MONTHS ONLY, for the extra protection at extreme temperatures. I'm talking about running on road courses with temperatures over 90 or hotter all day long.

6speeder
03-18-11, 09:36 AM
The synthetic 5w30 has been shown to survive high 200's temps. I wouldn't change to a heavier weight oil for normal use. If your road racing, and seeing very high temps, then either change more often or change to the 15w50 for the racing events, and change back for daily use.

JMHO

Life@60
03-18-11, 10:49 AM
Porsches use 0w40 and 0w50 in there cars The lower number is good for oil to get about sooner but the higher number is for miliage. My self I use 0w40 and I have never had a problem with any of my vehicles. I used it year round.

wait4me
03-18-11, 11:39 AM
Oil is simple. Stick to what the manufacturer says... You can tear apart an engine at 50,000 miles and the bearings still look nice, Just stick to it and change the oil and filter..

The first number on the oil is the rating on how thin it is at 0deg F. So say 5w-30 oil is a 5 W at 0F and the oil gets thicker as the temp increases. So the second number means as the oil hits 212 degree F the oil is now thicker and is a 30W.


Back in the older days, oil used to have a chart on it. And depending on the ambient temp outside is what you would target for your oil weights.. In cold weather like 30 down, they prefer you use a 10w or less. On 60 and higher F, they prefer you use a 20 or higher. An oil that is to thick is hard on parts, especially the oil drive system. So in -10F degree weather and 20W50 would be REALLY hard on the oil system at startup. But in 90deg F for a low and 120F for a high ambient temps, a 20w50 would be just fine.

David Nicholas
03-18-11, 11:53 AM
Again, I don't know why anyone would want to second-guess the engine manufacturer. They could have specified any viscosity they thought best. There is no way other racers or modifiers have as much historical data as GM or Eaton. They both have the same goals - performance & reliability. (I would normally include fuel consumption, but I suspect that was not high on the list).

Caddy Wagon
03-18-11, 02:35 PM
Manufacturers spec certain weight oils for various reasons. Usually the tighter the tolerances on rod/main bearings, etc., the lower the viscosity that is spec'd. I wouldn't run heavier oil unless my engine builder recommended it.