VVT and viscosity

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Are VVT systems really effected by different viscosity oils?

At a car show at the Peterson Museum I talked with a Honda tuner that turbocharges Honda B20 (I hope I've got the model correct) engines and several other models. He said the stock engine runs 0w-20 oil and they've mapped the stock continuously variable cam timing profile on the dyno. They run a 5w-50 oil in the high powered turbo versions that retain the VVT stuff and the stock valve timing pattern remains the same with their modified cams. He said that it appears that the viscosity does not effect the system enough to measure.

I'm asking this because a Honda dealer told a co-worker that he had to absolutely use a 5w or 0w-20 oil or it would cause poor performance and could damage the engine camshaft system and would invalidate the warranty on the engine.

The tuner did a burnout behind the museum in his Honda and when he got off the gas a neat looking flame shot out the back with a loud pop. That motor was producing a lot of power, nothing like a stock Honda. The work under the hood looked like a space ship. Everything was absolutely clean and neat. I especially liked the transparent blue tinted lexan air box that contained the air filter and the same style transparent valve cover so you could see the oil flowing while the engine ran. The turbo and NOS systems were impressive as well.
 
The USA/Canadan Mazda CX5 stipulates that 0w20 must be used but, the same engine requires 5w30 in Mexico. I think in Mazdas case it is the CAFE mileage requirement. Ed
 
I'd like to have a transparent valve cover.

More on topic, I didn't notice much difference with different oil weight in the "primitive" vvt system in my Barchetta (only affects the admission camshaft with some sort or variable timing...more like an on/off system with two positions to me, but not sure at all).
Of course I'm talking oil at operating temperature, and I only compared light 40 to 60 grades. No sensible difference to me in performances, or when the systems engages/disengages (it works between ~2000 and 4000 rpm and over 25° coolant temp). When cold, different viscosity made for sure a difference, but I suspect it is because the system is not very "fresh" and rattles when oil pressure is too high (10Wxx or 15Wxx grades when cold or level above max).

I'm not sure this experience can correlate in a much more modern vvt system designed with much more "finesse"...but I think oil grade can make a difference in an hydraulic system...just don't know what difference.


Edit: never seen much difference in the Forfour wich has vvt too, ran 0W30 to 5W50.
 
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I doubt there'd be much if any difference between any of the 0/5W-20-30 or 40 grade oils frequently mentioned here.
 
BMW spec'd 5w30 and 10w-60 for the same VANOS systems. Dodge does the same with 5w-20 and 0w-40. They really aren't viscosity sensitive. If they were as sensitive as some think they wouldn't work in the winter where viscosity is massively higher than just the difference between grades at operating temperature.
 
Originally Posted By: OVERKILL
BMW spec'd 5w30 and 10w-60 for the same VANOS systems. Dodge does the same with 5w-20 and 0w-40. They really aren't viscosity sensitive. If they were as sensitive as some think they wouldn't work in the winter where viscosity is massively higher than just the difference between grades at operating temperature.

They are sensitive to viscosity, just not the way the brainwashed think. The new SAE J300 addresses this. The new SAE 16 minimum viscosity is higher than the old SAE 20 minimum. This was done at the request of manufacturers concerned that too thin an oil would interfere with VVT operation.

Ed
 
I have not done this myself, but someone logged the VVT system on an Expedition while running 5W20 and 0W40 to see if it made a difference. It didn't. Of course, that's just one car and one guy. I can't remember where I saw this, sorry, or I'd link to it.

robert
 
Originally Posted By: edhackett
Originally Posted By: OVERKILL
BMW spec'd 5w30 and 10w-60 for the same VANOS systems. Dodge does the same with 5w-20 and 0w-40. They really aren't viscosity sensitive. If they were as sensitive as some think they wouldn't work in the winter where viscosity is massively higher than just the difference between grades at operating temperature.

They are sensitive to viscosity, just not the way the brainwashed think. The new SAE J300 addresses this. The new SAE 16 minimum viscosity is higher than the old SAE 20 minimum. This was done at the request of manufacturers concerned that too thin an oil would interfere with VVT operation.

Ed


To quote Honda R and D Technical Paper "Effects of Low-Vicsosity Engine Oil on fuel Economy and Wear"

Originally Posted By: Honda R and D
In addition, there are concerns that simply lowering the engine oil viscosity may result in increased wear at high temperature, lower operating performance of hydraulic devices, and increased oil consumption.
 
VTEC kicked in, yo?
Wife's VTEC Civic gets specified 5W-20 because Honda engineers are pretty sharp imho.

Doubt it actually makes much difference at viscosity (and HTHS) naturally varies contingent upon myriad factors.

Makes zero VVT difference in GM Gen-IV V8s ot Chrysler Hemi variants (per SteveSRT8).
 
I wouldn't hesitate to go 1 grade thicker than recommended with VVT. My Fusion recommends 5W-20 & I know at least 3 quarts of the next oil change will be MaxLife full synthetic 5w30. Still contemplating whether to use MaxLife Blend in 5w30 or 5W-20 for the other 3 quarts.
 
IIRC the Honda B20 did not come with VTEC, but it is a common build to add a VTEC cylinder head from another B series engine. These use VTEC, not VVT, and it isn't continuously variable it's a switch from one cam profile to another. This is activated by hydraulically-actuated pins that lock together the rocker arms above the cams, so the only oil effect is the small stroke of some pins. This is switched by an electrical solenoid and uses pressurised oil from a spool.

Knowing how it works give an insight into what the oil effects might be. In this case the only possible effect of viscosity could be the sluggish response of the pins if the visc was too high, but given the temperatures and pressures this is unlikely to be discernible or even real. Elsewhere in the world Honda specified 10W-40 for B series VTECs, so go figure.

The biggest issues should be deposits that could interfere with the actuation, but I have never seen it (in 5 years of ownership and 15 years of moderation of a Honda forum). In reality the solenoids fail or the seals leak or some other issue in the engine logs a fault with the ECU which then locks out VTEC activation.

Elsewhere, BMW introduced new valvetrain wear requirements when they launched Valvetronic as the components needed wear protection, but this is more a chemistry effect and less about viscosity.
 
Originally Posted By: OneEyeJack
... I especially liked the transparent blue tinted lexan air box that contained the air filter and the same style transparent valve cover so you could see the oil flowing while the engine ran. The turbo and NOS systems were impressive as well.


Neat. Now please tell us how many minutes that thick 5w50 oil took to reach the top of the engine. It should be helpful to the crowd that always worries about cold oil flow.
 
B series did not come with VVT, a.k.a VTC.

VTEC and VTC are totally different things. I doubt he knows what they mean.
 
Originally Posted By: splinter
VTEC kicked in, yo?
Wife's VTEC Civic gets specified 5W-20 because Honda engineers are pretty sharp imho.


You mean the same sharp gang who couldn't build an automatic transmission to save their souls, or the ones who came up with the various incarnations of their infamous VCM systems? They are like the friggin gang that couldn't shoot straight.
VVT works fine on anything from 0w20- 10w60.
 
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I run a 10w30 in a dual VVTI. I don't by in to the "You MUST!". My logic is simple: My Pennzoil Platinum 10w30 is thinner at the dead of winter where I live at 208.363 mm2/s(roughly) than Mobil 1 Advanced Fuel Economy 0W20 in the dead of winter in Saskatoon at 1461.651 mm2/s (roughly). A 1200 difference during the warm-up phase (and people drive their cars with this stuff!) vs I fail to recognize the logic. Correct me if I'm wrong.
 
My Genesis coupe has the oil temp sender right at the Oil Control Valve for the cams. It limits their action when the oil is under 150f I believe.
 
Originally Posted By: Trav
You mean the same sharp gang who couldn't build an automatic transmission to save their souls...

lol obviously they have no souls or conscience.
Witness the millions of Honda's vehicles subject to NHTSA recalls.
Already got a 'free' transmission replacement under the auspices of 'goodwill.' Never put 5W-20 in its transmission, though.

Bloody thing torque steers so badly I can skip wrist curls' circuits at the gym after driving it.

Upside is its NA HQ remains in Torrance after Nissan and Toyota bolted. I work for some of their six-figure VPs and suits.
smile.gif
 
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