5w-30 to 5w-50 on na 5.0

[MAT1955]

Use full synthetic 5w-30. You should not be running 5w-50 with your set-up.

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[krisk]

I’m the same way I want to go more towards track and I just would rather be safe then sorry

So I finally broke down and after much researching, ordered the Motorcraft 5w-50 Full Synthetic. I didn't find any definitive answer on the S650 and using 5w-50 on track, but for sustained high RPM driving at high temperatures, I just don't see where running 5w-50 would be worse than 5w-30. (My opinion) I did research multiple brands and wanted to be sure whatever oil would be at least the WSS-M2C931-C specification used for prior years and found that WSS-M2C931-E1 is the updated spec which supersedes the prior one.

The only oils I found with the new spec were 1. Castrol Edge 5w-50 S, which I can only find a PDF spec sheet on and cannot locate this oil on their website, and I cannot seem to locate anywhere to purchase it except a single website, or 2. Motorcraft 5w-50 (XO-5W50-QGT). Most everywhere you look to purchase the Motorcraft lists it as a WSS-M2C931-C API SN spec, but the Motorcraft Chemicals and Lubricants data sheet shows it as WSS-M2C931-E1 API SP. I ordered two cases from Rockauto.com, so hopefully the bottle lists the updated specs because the image on their website shows the old spec. I'm not too worried, because the same thing occurred when buying the Motorcraft 5w-30 oil, where the website showed an image of a bottle with the old spec, but what was actually delivered was the new spec. The old and new spec 5w-50 oil do appear to be slightly different as the data sheets list viscosity differences between the two.

Keep in mind, my car is a track only vehicle. If I were daily driving, I would probably stick with the 5W-30 even with an occasional track day. The 2023 and older vehicles which specified 5W-50 for track use said to replace with 5W-30 after track driving.

 

[MAT1955]

@krisk ...... IMO a wise choice. Tracking using a 5W-50 is wise. We always recommended higher viscosity oils on automotive and race engines we built. BTW my uncle a chief researcher for a major oil company (not Ford) said Ford FULL synthetic oils tied or beat every oil they tested for flashover and bearing shear tests. Ford uses top base oils and the best available VIs (viscosity improvers) in the industry. The worse the stressors the better the Ford oil performed.

 

[Junkyard Dog]

The only issue I can foresee, if it even is an issue, is that the inferred oil temperature displayed will no longer be accurate, but read artificially low.

Probably not that big of a deal, since you already know what the temperature was before on track, and you have experience, so you are unlikely to be heating it up much more in the future than you were previously.

 

[LouG]

The only issue I can foresee, if it even is an issue, is that the inferred oil temperature displayed will no longer be accurate, but read artificially low.

Probably not that big of a deal, since you already know what the temperature was before on track, and you have experience, so you are unlikely to be heating it up much more in the future than you were previously.

Inferred oil pressure? Not a physical pressure sensor?

 

[robvas]

Would love to see different oil weights on a Coyote on the dyno. And while we're at it, windage tests, does an extra quart or removing a quart make more power, etc.

 

[Junkyard Dog]

Inferred oil pressure? Not a physical pressure sensor?

Temperature.

Pressure is measured with a sensor.

 

[MAT1955]

@Junkyard Dog ..... if I was tracking my Mustang most of the time I'd get a second set of gauges. That's what I used to do.

 

[RLE55]

if I was tracking my Mustang most of the time I'd get a second set of gauges. That's what I used to do.

Did the same thing, was one of my first additions once I got serious about road racing.

 

[krisk]

WSS-M2C931-E1

I can confirm the Motorcraft 5w-50 Full Synthetic from Rockauto is the Ford WSS-M2C931-E1 specification and API SP oil, despite the image on their website displaying a bottle with the older API SN spec.

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