Honda oil req. & power density

[randomhero439]

Interesting thought: Recently Honda bases their oil weight requirements based on power density.
2002-2005 Civic Si: 80hp/L, 5w-20
2006-2011 Civic Si: 99hp/L 5w30
2012-2013 Civic Si: 84hp/L 0w-20
RSX base: 80hp/L 5w-20
RSX-S: 101hp/L 5w30
Honda S2000: 120hp/L 10w30 or 5w-40
Acura RDX Turbo: 104hp/L 5w30
Acura RDX V6: 78hp/L 0w-20

Hyundai Genesis
2.0T I4: 105hp/L, 5w30
3.8 V6: 81hp/L, 0w-20

Thoughts on this?

 

[brandini]

What about torque/L?

 

[Eddie]

Interesting observation. I too would be interested in a plot showing torque in foot pounds/liter vs oil weight.
My CX5 has 184 HP and 185 ftlbs torque with 2.5L =74ftlbs and 0w20 oil in US or 5w30 elsewhere.

 

[OVERKILL]

As is the case for MANY manufacturers. I posted about this correlation some time ago and posted a number of examples of it at that time.

The ability for an engine to heat an oil directly relates to its power density. This assumes one can operate at 100% load of course.

This also plays into manufacturer sump sizing and oil cooler fitment. An engine of modest power density with a large sump and factory oil cooler is going to be able to get away with running a thinner oil than an engine with the same power density but a small sump and no oil cooler.

I also find it interesting that Ford did some "playing" with Coyote:

1. F-150 5.0L: 360HP@5,500RPM, 380lb-ft@4,250RPM
2. Mustang 5.0L: 420HP@6,200RPM, 390lb-ft@4,250RPM

Yet they are essentially the same engine....... They did the same thing with the 4.6L back in the day too.....

Both of these engines spec 5w-20. Yet it is obvious that the truck, being derated by a solid 60HP is going to heat the oil less. And considering the usage profile of the truck.......

And then we have the Roadrunner (BOSS 302) derivative of the 5.0L at 444HP calling for 5w-50 and ALSO sporting an oil cooler, LOL! Because of course Ford EXPECTS the BOSS 302 to be tracked.

And on top of all of this, Ford fitted them with oil temperature castration mechanisms to cut power if the oil gets too hot. Though I imagine that the lower power output of the F-150 essentially guarantees one would NEVER encounter it in service. On the other hand, SteveSRT8 witnessed a Mustang go into thermal protection on one of the race tracks he frequents.

There's a great deal of planning that goes into what ends up being spec'd for a particular engine and these things all play into that.

 

[dailydriver]

^^^Does the 'Roadrunner' derivative use different (ported) heads/bigger valves and cams, and higher compression than the garden variety Coyote in the GT, or just a better intake/plenum?

Did they keep the piston oil squirters in the latest versions of the Roadrunner, or dump them as in the Coyote?

 

[Shannow]

Not a bad concept for a discussion...

Torque is probably more representative of average pressure (force) levels inside the cycle, when looking at applied pressures to bearings...more pressure needs more viscosity for a given required minimum film thickness.

 

[randomhero439]

Originally Posted By: Shannow
Not a bad concept for a discussion...

Torque is probably more representative of average pressure (force) levels inside the cycle, when looking at applied pressures to bearings...more pressure needs more viscosity for a given required minimum film thickness.


This logic sounds correct, however the TQ vs Visc does not follow the same pattern has Hp vs Visc.

 

[donnyj08]

Here's and interesting one. Mazda rotary engine 183hp/L 5w20 oil recommended.

 

[brandini]

Doesn't count, it should be a 2-stroke.

 

[Shannow]

Also, the rotary doesn't have pistons, big ends, and main bearings in the traditional sense, so it's similar to saying that a GE frame 5 Gas turbine runs on the equivalent of 10W

 

[jrustles]

2.3L DISI
119hp/L
121ft-lbs/L @ 3500
5w30

Originally Posted By: brandini
Doesn't count, it should be a 2-stroke.

But there are still 4 strokes.... ??

 

[Ken2]

Originally Posted By: brandini
What about torque/L?
Torque is just the twisting force on the crankshaft. A "high torque" engine is likely a high pressure, slow turning engine. This puts more load on the bearings (with the hydrodynamic oil wedge being somewhat speed related), so adequate lubrication may require bigger bearings or higher viscosity oil.

The engine makers know the PSI on the bearings. Because (other things remaining equal) heavier viscosity oil has higher film strength, the pressure on the bearings determines the required film strength. The fuel economy engineer says "use lighter oil to improve CAFE." The engine design engineer says, "you'll need bigger bearings to reduce the psi, then you can have the lighter oil."

 

[brandini]

Originally Posted By: jrustles
2.3L DISI
119hp/L
121ft-lbs/L @ 3500
5w30

Originally Posted By: brandini
Doesn't count, it should be a 2-stroke.

But there are still 4 strokes.... ??

Nah it's about oil delivery and in the best sense it's the fuel's job to hit the apex seals. Best thing I saw for it was a replacement OMP and you could adjust the flow of 2-stroke from a separate reservoir and then you were free to finally run synthetic in the sump.

 

[Shannow]

Originally Posted By: Ken2
Originally Posted By: brandini
What about torque/L?
Torque is just the twisting force on the crankshaft. A "high torque" engine is likely a high pressure, slow turning engine. This puts more load on the bearings (with the hydrodynamic oil wedge being somewhat speed related), so adequate lubrication may require bigger bearings or higher viscosity oil.

The engine makers know the PSI on the bearings. Because (other things remaining equal) heavier viscosity oil has higher film strength, the pressure on the bearings determines the required film strength. The fuel economy engineer says "use lighter oil to improve CAFE." The engine design engineer says, "you'll need bigger bearings to reduce the psi, then you can have the lighter oil."


Nice work...very concise and clear.

 

[Nederlander75]

Originally Posted By: Shannow
Also, the rotary doesn't have pistons, big ends, and main bearings in the traditional sense, so it's similar to saying that a GE frame 5 Gas turbine runs on the equivalent of 10W


Could you elaborate or school this one please?

 

[Shannow]

The rotary is a completely different design, not pistons, cracks and rods...different animal to the discussion.

 

[Nederlander75]

Sorry Shannow, I should have been more elaborate as I get what you saying in that regard. I thought you were making inference to difference in loads being less given the design but that thought was generated by an overall lack of familiarity in the subject.

 

[OVERKILL]

Originally Posted By: dailydriver
^^^Does the 'Roadrunner' derivative use different (ported) heads/bigger valves and cams, and higher compression than the garden variety Coyote in the GT, or just a better intake/plenum?

Did they keep the piston oil squirters in the latest versions of the Roadrunner, or dump them as in the Coyote?


The heads are the same castings, but I believe they might be cleaned up a bit more and it also has different cams. Valves are the same size.

I believe the non-oil squirter pistons originally came from the BOSS 302, so I would assume that's what the last iteration of it had.

 

[jrustles]

Originally Posted By: brandini
Originally Posted By: jrustles
2.3L DISI
119hp/L
121ft-lbs/L @ 3500
5w30

Originally Posted By: brandini
Doesn't count, it should be a 2-stroke.

But there are still 4 strokes.... ??

Nah it's about oil delivery and in the best sense it's the fuel's job to hit the apex seals. Best thing I saw for it was a replacement OMP and you could adjust the flow of 2-stroke from a separate reservoir and then you were free to finally run synthetic in the sump.


The rotary's lubrication needs are kind of a hybrid situation. The apex seals (tip seals) never see crankcase oil. They are constantly in the combustion area and are totally dependent on injected oil or 2T oil for lubrication. Totally unique in that regard.

But there are still many more ;conventional' lubrication points;
-stationary gears in which the rotors eccentrically rotate around
(shearing/HTHS nightmare #1)
-main e-shaft and rotor bearing, and side seals which see crankcase oil on one side.
bearingsthey are relatively large sized, but see far more combustion heat conduction through the rotor vs a crank bearing would see conducted through a rod. Bearing HTHS nightmare #2 This is why rotaries have HUGE OIL COOLERS.

This is also why I find it laughable, the 5w20 recommendation from Mazda North America in Irvine, CA (a daft bunch on many fronts if you ask me, they're also responsible for poor market gearing decisions)

Guess which area that standard rotaries have the shortest lifespan? Not in Japan! Not in Europe!