Oil Temp Rise and Viscosity

[alcyon]

Originally Posted By: SR5
Not sure what 30 grade oil to try next. Probably not a synthetic, as I'm experimenting a little and changing early.

Thinking either
Caltex / Chevron Delo Silver SAE 30 (API CF/SJ) monograde mineral
KV 40 = 90 cSt, KV100 = 11.5 cSt,

Or
Castrol Magnatec 10w30 (API SN, ACEA A3/B4) semi-synthetic
KV 40 = 84 cSt, KV100 = 12.4 cSt

Both should have a HTHS of around 3.5 to 3.6 cP (I assume).
The Magnatec is the sensible option, but I'm itching to try a HDEO mono-grade if it's not too silly an idea.

Right now I'm running
Castrol GTX 15w40, (API AN, ACEA A3/B3) mineral
KV 40 = 113 cSt, KV100 = 14.5 cSt, HTHS = 3.95 cP

What do you think, a multigrade 10w30 or a mono-grade SAE 30 ??



Interesting KV40 and KV100 values for the Magnatec, loaded with VII ? how does the VI value factor in here since both the DELO SAE 30 and Magnatec 10w30 has almost similar KV values. What I mean of course is the so called high VI of the XW oil.

 

[zeng]

Originally Posted By: Jetronic
Originally Posted By: Shannow
And here's a pic from a paper on accelerating engine warmup, which mentions.

Pic shows the internal heating that's generated within the oil in the warm-up phase, and includes comparison to heat conduction into the oil through piston crowns et al.

It's only a little 1.7L donk, but there's 4KW of oil heating taking place early in the warmup...this heat also goes into heating the coolant and the metal surfaces, by passage through the main bearings and bulkheads...but that 4KW is just over 5hp worth of fuel burned at that point.

A higher VI oil will result in less heating there, and a slower warmup, as per the quote you used...will also use less power.

The Japanese, in papers, state that's the primary driver for the ultra high viscosity index oils, to reduce fuel consumed in the warmup periods, particularly in hybrid situations that don't establish full oil temperature in many cases.


at 33% efficiency, wouldn't that be 15 hp worth of fuel? and 5 hp less power?

This 15hp/5hp is instantaneous power draw...... in seconds..... during engine start-up.
Average shown in chart is 1120 watts in first 14 minutes upon starting up, however power draw at steady state operation could be 200 watts or so.