Need your thoughts on 5w-40 Motul

[WildHorse]

That’s my story and I’m sticking to it.

Good for you.

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[galaxy]

If I didn't use what I currently use, I would most likely be using Motul for everything on the car!

 

[Cory S]

Yes. Gets to the operating temp quicker than thinner oils for sure.

I believe this is because when it's thicker, it creates more clearance friction until up to full operating temperature. Lighter viscosity oils do in fact transfer/dissipate heat faster. Same principle as water vs. 50/50 coolant, with straight water being the best heat transfer/dissipation over mixes/additives.

 

[GregO]

Same principle as water vs. 50/50 coolant, with straight water being the best heat transfer/dissipation over mixes/additives.

Exactly
Heat exchanger 101

 

[WildHorse]

Exactly
Heat exchanger 101

Straight water runs hotter than a 50/50 mix. But cools quicker as well. In my experience, it's a yoyo effect with straight water. It never seems to find that equilibrium.

 

[GregO]

Straight water runs hotter than a 50/50 mix. But cools quicker as well. In my experience, it's a yoyo effect with straight water. It never seems to find that equilibrium.

I think the YoYo effect is due to your location being on the north side of the Northern Divide….

 

[WildHorse]

I think your

Show all the charts you want. Try it. I'll wait.

 

[K4fxd]

I agree 5W-40 being a bit too thick, do feel the sluggishness.

I doubt it takes an extra 5 hp to pump 40 weight.

 

[GregO]

I went from Castrol Professional 0W-20 to Castrol Euro 0W-40. Car still tach’s out like a Hayabusa and that’s in normal mode.

 

[thunderstrike]

Hey guys My 17GT PP has about 23k mikes on the clock. Ive always used Motul 5w-30 and last week I changed my oil and used Motul 5w-40 now I feel like this oil is too thick for the coyote motor. My car feels sluggish and hesitates when I get on throttle. Car is full time E-85 24/7. Is 5w-40 too thick? Keep in mind I drive this car HARD high rpm (7,600) about twice a week.

I made posts 10W-30 and 5W-40 appear too thick, feels sluggish accerlating. 5W-30 seems just right. Someone answered my post "pacebo". I'd say you and I can feel the car better than some folks.

 

[robvas]

Internet dyno says there is a couple hp difference in oils... but it's not going to feel "sluggish"

 

[thunderstrike]

Internet dyno says there is a couple hp difference in oils... but it's not going to feel "sluggish"

So, that's what 2 horsepower difference feels like.

 

[shogun32]

So, that's what 2 horsepower difference feels like.

Are you seriously suggesting your butt Dyno can suss out 2hp?

The coyote is a 15 year old engine. What was the oil spec back then? 10w30.

With the fancy heads and variable timing I could see 10w being a little thick on startup for a few seconds, but not enough to really matter. At operating temps -30 or -40 would have no effect.

Your "sluggish" has other causes.

 

[K4fxd]

Your "sluggish" has other causes.

Yea, like DA. I can tell when it is -300 compared t +3500 Car feels like a rocket ship, then feels like a turd.

 

[Cory S]

Yea, like DA. I can tell when it is -300 compared t +3500 Car feels like a rocket ship, then feels like a turd.

That’s about a 10% HP change. Yep.

About 50hp on a 500hp engine.

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