Shared Oil and Mixing Grades

[Gene K]

1. 2015 F150 4x4 2.7L Ecoboost (5W30 SN GF5)
2. 2014 Mustang GT 5.0 Roush R2300 Supercharger 700 bhp (Roush says follow Ford Manual, 5W20 SN GF5) - No Warranty

Mustang has 170F thermostat and sees dragstrip passes with oil temps of 160-180F. Street head temps are normally around 190F and oil temps average around 195F with peak of 230F beating on it on a curvy road.

My thinking is given the oil temps it should be okay on 20 grade but I'm currently running Pennzoil Platinum 10W30.

I would like to share oil between the two vehicles sort of. I want to buy QSUD 5W30 for the F150 and mix QSUD 0W20(5) + 5W30(3) on the Mustang. This would allow me to buy 3 x 5 qt jugs and fill both vehicles with one qt of 5W30 left for top offs.

Thoughts?

 

[Panzerman]

I think your way over thinking this. The oil viscosity is such a small minute difference. I know you hear people on here comparing it to apples and oranges, in reality. It's orange juice and Apple juice. Just buy 5w30 and run it in both or better yet 10w30 in run it in both. Neither will be able to tell and the engines will long outlive all the other components on the vehicles.

 

[4WD]

I ran. 7w-24

 

[Shannow]

Just run the 5W30 in all.

230F (sump temp I'm presuming) could be 280f in the rod big ends easily.

 

[Gene K]

I just have a thought the oils a touch thick at the strip. Blueprint the bearings should be 10C hotter but given tolerances 5-20C hotter.

I have a little OCD.... Oil must be 10.0 cSt in the bearings 6.9 seconds into a 10.9 second pass... That's a joke!

 

[BrocLuno]

So Gene, just backing up and taking the long view ...

Just so you know how I think they build oils; they start with a base stock that equals the winter temp requirements. Then they use long chain polymer additive(s) to get the operating temp "Grade" they want - say 30. Those long chain polymers are not oil. They mix with the oil, but they actually displace a fair percentage of the oil, the actual lubricant, maybe 18% ...

And they shear down as the engine beats on them. So all said and done, when you look at an oil, under worst case (w/o fuel dilution) if the oil is all sheared down (beat up) and heated and what not, it will come down close to the winter grade base oil. If it was a 10W-30, it would drop (worst case) to a 10 grade oil. Is that what you want in a run-hard boosted motor? I wouldn't...

Some synthetics can get to the same viscosity range w/o so much long chain polymerization, but still ...

The truck uses 5W-30 and has a warranty. The Mustang does not have a warranty, so you can run anything you want. I see you want to use a USA synthetic. That's better than a common blend or a dino as described above. But I'd still be looking for robust under load and hot.

I'd be looking at the technicals on Redline 30wt race oil (which also rates 10W-30 for street use) and try to match those properties in a more readily available product

http://www.redlineoil.com/product.aspx?pid=14&pcid=1

I'm not saying QSUD will not do, but I'd want more film strength and initial viscosity, especially when the piston crowns start getting up there and the skirts are having a hard time shedding the heat. Boosted motors can really beat on oils (low RPM high bearing loads and high RPM high heat loads)...

 

[Gene K]

It just got me to thinking when M1 5W30 gets the job done in 1200 bhp turbo cars and my buddies GT500 builder recommends 5W30 for strip, 0W-40 for street and 15W-50 for track.

Roush actually recommends 5W20 for my car at the standard 575 bhp. But mines 100+ rwhp north of the standard setup.

I've been running 10W30 Pennzoil Platinum because I assumed it had minimal VII.

 

[dew]

I'd probably use the QSUD 5w30 in both vehicles, the mowers, tillers, etc.

My OCD would prevent me from mixing any 20 grade in for fear of of weakening the additive package/performance. Seems like the QSUD 30 grade should be light enough anyway.