Group IV -vs- Group V heat resistance in turbos?

[LateArrivalforLSU]

Is there a link out there that provides the heat that different oils can withstand? I've narrowed my oil choice down to Delvac 1 5W-40 or Red Line 15W-40 in a turbo diesel application.

I'm concerned with oil coking in a turbo application. I know Red Line can withstand the extremes, but can the Group IV Delvac 1?

I like the fact that Mobil 1 Turbo Diesel Truck can be had locally (Delvac 1) -vs- having to mail order it like Red Line. Any input is appreciated.

 

[TooSlick]

I happen to think that Delvac 1 is the better product and certainly a better value overall. You won't have any turbo issues caused by D1....

TS

 

[SSDude]

It is rumored that D1 is 25% group V.

 

[ebaker]

I'd use Delvac for the higher TBN.

 

[SteveD2]

Quote:

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It is rumored that D1 is 25% group V.

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So ummm. Is Delvac 1 is still considered a group 4 oil?? I always thought group 5 was added for seal swell.