gumpy added a topic in Engine & DrivetrainBefore oil threads start, read this.Revenge of the Nerd - Nissan in the sump with diamonds?
By Mike Kojima
The new Nissan 370 and the Infiniti G37 with the VQ37VHR engine has been plagued with issues regarding high oil temperatures in severe use since their launch making debate on oil a big topic on internet forums. The conversations on oil temperature issues leads to Nissans recommendations for Genuine Nissan "ester" based oil and the super expensive oil service.
Posts on forums indicate that some Nissan dealers are charging up to $300 for an oil change for the special oil that is mandatory for use on the 370z and its VQ37VHR. Is this oil expensive? Yes, does it have significant value? Yes, is it mandatory for your warranty or to insure long engine life? No. Is it important if you are the type of driver that wants the best for your engine in terms of fuel economy, life and performance? Yes. Is the "special" oil market hype intended to enrich Nissan's coffers? It’s up to you to decide, we will attempt to explain whats going on with the oil so you can decide for yourself.
Standard DLC coating is very slippery and reduces friction considerably but does not attract oil
Nissan's oil was developed in a push to greatly reduce friction in an engines valvetrain. The valve train is the second biggest contributor to the total amount of an engines mechanical friction, the piston rings being the biggest contributor. Usually on most engines the valvetrain produces 15-20% of the total friction of an engine. An engine with a complicated valvetrain like the VQ37VHR is probably on the high end of this figure.
The latest info that we have derived from Nissan white papers on the VQ37VHR's VVEL drivetrain is that contact pressures and stresses in the cam follower area are very high when the engine is working at wide open throttle at high rpm and the VVEL system is at maximum lift and duration. These high stresses heat the oil significantly. This is why any 370Z or G37 goes into limp mode for high oil temp in just a few laps on the track with a fast driver. Normally the high lift and duration modes are only a small part of the engines duty cycle so its not an issue, but for track driving they are the norm.
Nissan's special oil and their newly developed hydrogen free DLC coating on cam followers reduces the amount of friction produced by the valve train by a huge amount. This can make a considerable difference in fuel economy, power output and perhaps even heat generation.
What is Nissan's special oil? The oil was developed to complement Nissan's Hydrogen free DLC coating used on the cam followers in the QR25DE engine, the VQ35HR and the VQ37VHR engines. DLC stands for diamond like coating, which is an amorphous layer of carbon crystals with hard smooth properties much like diamond. Most of valve train friction is created by the interface between the cam follower and the cam lobe. DLC is very slippery stuff and Nissan uses it to reduce valvetrain friction to improve fuel economy, reduce emission and increase power.
Nissan's hydrogen free DLC coating has a strong molecular attraction towards Nissan's special nano particle ester oil. This reduces friction to unheard of levels
Nissan figured that eliminating the hydrogen molecules in the DLC coating would make it an attractor of polar molecules like those found in hydroxyl compounds. A hydroxyl molecule is highly polar hydrocarbon molecule. The polarity makes it a good solvent so it mixes well with other fluids, like oil. Nissan chose ester hydroxyls, part of the alcohol family, probably because the properties of esters in motor oil are well understood as esters have been used as friction modifiers in motor oil for decades. Nissan chose an ester called PAO; an ester often found as a friction modifier in oil. By adding PAO so it would be around 10-15% of the oil, when combined with the hydrogen free DLC coating, Nissan created oil that would be attracted to the cam follower on a molecular level.
In studying the various technical white papers and patents for Nissan’s super oil, we are not exactly sure of its exact composition in terms if its is considered a synthetic or not. Nissans patents and technical documentation are very broad when describing the make up of the super oil, probably to protect against patent infringement and to make it hard for a competitor to make the exact same stuff. We can ascertain that the technology is compatible to most known base oils, be they synthetic, mineral or a blend and we do know that esters are synthetic compounds so at least the oil is probably considered a semi synthetic at the least. The Nissan oil's bottle lable says petroleum oil under contents, a bottle of Mobile One doesn’t say this. The Nissan oil smells like PAO ester oil used in AC systems charged with 134A.
The next unusual thing about Nissans oil is its innovative use of nano technology. To help lubricate areas of extreme pressure and friction in the engine, the biggest of which is the interface between the cam lobe/VVEL finger follower and cam follower, engine oils have traditionaly used what are called extreme pressure friction modifiers. These typically are compounds that have a slight molecular attraction to metal and usually have a slippery metallic element to them. These are compounds such as zinc diphosphate, molybdenum dithiophosphate and molybdenum dithiocarbamate. These friction modifiers work pretty well for preventing metal to metal contact in an engine but they have some issues. One is that they don’t burn completely when they get past the piston rings and valve guide seals and create ash; this can end up being a hard but sticky deposit in your engine’s combustion chamber and valves that can stick rings and valves, raise compression to cause detonation, and create porous hydrocarbon traps in the combustion chambers, valve and ports that screw up emissions and reduce flow, hurting power. These chemicals can also contaminate catalytic converters making them lose their effectiveness. These friction modifiers also are prone to shearing down and wearing out over time, losing their effectiveness.
Nissan, in their search for improving oils frictional properties, figured out a way to substitute ultra hard nano particles for the normal chemical friction modifiers adding some interesting molecular twists. Again due to the convoluted nature of Nissan’s white papers and patents, its hard to guess exactly what the nano particles are but they are definitely an ultra hard industrial abrasive or bearing type ceramic and probably at least in part, nano particles of industrial diamond!
Nissan's hydrogen free DLC coating uses molecular attraction and the bearing action of likely attracted nano particles to reduce friction to previously unheard of levels, Nissan's treatment is significantly slicker than super slick coatings like titanium nitrate and standard DLC coating as shown in this chart
Why would Nissan put abrasives or chunks of bearing material in its oil? Well, you have to consider some things about nano technology. The unit of measure here is called a nanometer or one billionth of a meter, that’s pretty darned small. A nanometer sized particle is much too small to be seen by the naked eye. For instance, a water molecule is somewhat less than one nanometer. A typical bacterium is just less than 1000 nanometers and a hair is 100,000 nanometers thick. In the world of physics, weird things happen when particles are this small. The particles of the diamond/ceramic are so small they mix with the oil and stay suspended as they are hardly affected by gravity and molecular forces called van der waals forces keep them apart. They also are undetectable to the naked eye and the oil still looks clear.
Nissans super oil is around 0.5% nano particles by weight. The particles are probably around 10 nanometers in diameter, really very small! A certain percentage of the nano particles have to be carbon based, preferably single crystal synthetic diamond. The carbon content helps make the nano particles attracted to the low hydrogen DLC coating. Instead of making a slippery metallic film on bare metal parts like traditional friction modifiers, the nano particles act like atomic level miniature ball bearings, preventing metal to metal contact and reducing friction to previously unheard of levels. These nano particles are ashless if they find there way into the engine, making the oil low deposit forming for lower emissions. The Nissan super oil does most of its friction reduction in the valvetrain but it still helps in other parts of the engine, particularly in areas were metal to metal contact might occur.
Nissan's ester nano particle oil reduces friction in these parts of the engine as well, wherever there is the potential for metal to metal contact, it will help
In lab testing of test coupons, the Nissan Super oil with hydrogen free DLC coating had the friction reduced by 60-75 percent over conventional oil with no coating. This equated to a around a 40% reduction in total valvetrain friction in a real motor and a 20-25% reduction in total friction of the motor! This is a significant result which should show real gains in fuel economy and probably something like 1-1.5 hp per cylinder at high rpm over an uncoated valvetrain with conventional oil. If this is worth something to you then yes, the expense of the oil is worth it! Now the DLC coating still works at reducing friction with regular oil just not as amazingly well. Not using the Super oil will not cause you engine to wear out prematurely or anything like that but it probably will wear slightly more, particularly in the valve train, probably at a level that doesn’t matter much.
Nissan's nano particle oil when combined with low hydrogen DLC coating reduces total engine friction by 25%. This helps fuel economy, reduces emissions and help free up several horsepower in the 370Z and G37. The QR25DE engine used in the Sentra SE-R Spec-V and Altima, The Maxima, and the FX56 all use this technology
This leads to the next issue that has arisen with the VQ37VHR. When the engine was first introduced in the G37, there were complaints about a ticking noise coming from the engine, particularly after the first oil change. As common, particularly in these hard economic times, dealerships sometimes offer promotional oil changes at a very low price to help bring customers in the door. Typically these oil changes are a loss leader promotion were the dealerships might actually lose money just to attract customers. Naturally this results in the car getting the cheapest possible oil in the changes. If a G37 had low quality oil put into it, a customer might notice a very slight ticking noise eminating from the engine later. The noise is so slight that it can usually only be noticed when driving with the window open, close to a reflective surface like a hard wall. More G37 customers complain than 370Z customers probably because the G37 has superior NVH (quietness) to the 370Z and an Infiniti customer is pickier.
It has been determined that the noise is caused in part by not using the super oil. The VQ37VHR engines VVEL system uses a reciprocating shoe that wipes back and forth across the cam follower instead of rotating like a cam lobe. This wiping action makes it difficult to establish a hydrodynamic film of oil in the interface between the shoe and the cam follower. Low hydrogen DLC coating is used here to both reduce friction, improve wear in this more difficult to keep lubed interface and to attract the super oil.
The super oil’s attraction to the cam followers helps cushion them hydraulically against the slapping action of the VVEL shoe, thus damping out the noise. Nissan’s TSB for the noise involves switching to the ester super oil and reflashing the engines ECU. Nissan has determined the revving the VQ37VHR without load helps contribute to the noise. What the reflash does is if you free rev between 1500-4500 rpm, the engines ECU will slowly return the engine to idle. If you free rev above 4500, the engine will return to a lower speed more aggressively. The noise is harmless and doesn’t affect engine life; just some people find it annoying. We haven’t been able to hear this noise ourselves in a 370Z’s that didn’t have super oil in them so it must be pretty minor, although these Z’s had intake and exhaust systems. Perhaps the best solution if you are bothered by this noise is to turn on your radio!
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gumpy added a topic in IntroductionsHey everyone
Just like to say hi as a new member.
I'm from Sydney, and am a proud owner of a white manual 370z which I took possession in Nov 09.
My first car was a Polo GTi, had the thing for 3.5 years. It was a fantastic car that served me well, it was sporty and practical but I needed to get in on the rwd manual scene before the car companies decided shut this niche off.
My car needed to not only be a rwd manual that drove fantastically but also had to fit golf clubs. On first viewing of the car I dismissed it's ability to take fit a golf bag into boot but to my amazement, they fit.
The Z was in a tight battle with the 135i coupe and being a German car fan, I really did think the 135i was going to be the winner, but the value equation of the z was the key. The only options I needed to add for the z were parking sensors... 135i I could have added another 10-15k. Furthermore, styling the z wins hands down.
I plan to keep my car stock and one day I would love to show my grandkids what a petrol rwd manual was back in the day =)
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Majestik added a topic in IntroductionsMy name is Ronnie & I'm a ZedaholicHi All,
My name is Ronnie and I'm a Zedaholic.
I'll be receiving my 2nd 370Z in a year - which is a 40th Quartz 370Z - by the end of the month (April) along with a few bits and pieces that I have ordered from the US for it. Before I begin, I thought I'd give you a 'not-very-brief' run-down of my Zedventure so far...
My Zediction began nearly a year and a half ago in January 2009. I was finally sick of my then beloved S15 Aero and decided to jump onto the Z bandwagon by purchasing an '09 350Z Roadster Track. Around this time they were having a clearance of the 350Z's in preparation for the May launch of the 370Z so the $65,000AU price tag was a steal. Over the next few months I really got to enjoy the open-top driving and to also detest the shite clutch of the 350. By the time the 370Z started going on show Down-under, I was at a point where I was sick and tired of clutch issues (leaking master cyclinder) and could not convince myself anymore that the 370Z was an 'ugly' car.
At the start of April 09 I contacted a friend of mine at my local Nissan dealership and decided to trade up, with only a minimal loss of around $4,000 on my 350Z and a $9,000 difference. I was given the opportunity to get their dealer model which was about to be delivered (even though black wasn't my first preference), and I took it mainly for the sake of being exclusive for a few weeks (as the launch of the 370Z in Australia was around May'ish).
My April 21st 09 registered 370Z AT7 was awesome! The difference between the 350Z was like night and day - especially now that I had gone with the 7AT. Over the last year, I have loved every moment of driving the Z, meeting my fellow Z-mates for cruises and getting gauked at by passer-bys.
Around February though, I was started to get a little upset with a few things. It seems that my hesitant decision of getting a black car was starting to get justified by the amount of sand-blasting, chips, swirls and other blemishes the paint was getting. I could even put a 'dent' in the rear paint with slight pressure of my fingernail! Fortunately as luck would have it, these worries we soon to be replaced with other ones...
On March 6th, Melbourne was host to an epic storm with many suburbs flooding and hail stones the size of tennis balls. My wife and I were at a shopping mall when the worst part of the storm hit and we decided to leave the moment that the freak hail storm subsided. The rain was still very heavy and several parts of the road we were travelling on had deep puddles. Driving in the right-most lane, I saw a shallow puddle ahead and decided to accelerate through it, chuckling as I created a huge wave that buffetted the car next to me. Ahead of us I saw (what I thought was) another shallow puddle. I recall asking my wife - with a smirk on my face - if I should go through it, to which she replied "Don't You Dare!". As all of you with partners will agree, when your other half tells you "Don't you Dare", what do you do? Well, I stepped my foot on the accelerator and attempted to gun it through the water! Unfortunately the water in the 'puddle' was deep enough to cover my headlights and the next thing we know, the engine cuts out and the car is bobbing up and down, and floating forward from the momentum... and the guy that I had just splashed, drove past whilst showing me his finger...
Storm Brings Chaos to Melbourne
Now, I'm insured with RACV for an agreed value of $77,990 but due to the 10,000+ storm related claims, my wait for the assessment was a long and gruelling one. The next 2.5 weeks I was stressed out, not knowing if it was a Hydro-locked write-off or a repair job. Along with this, I became the butt-end of every water based joke from my 370Z comrades..
As you have all figured out by now, RACV paid me out 77K (after costs) and I went back to my Nissan mate and ordered myself a 40th QuartZ MT6 for $64,000AU Drive Away. An added and probably the biggest bonus was that the 2010 Z also gets the 19" Sports Wheels standard!!! Anyway, after clearing off some credit card debts, I decided to spend the remaining 9K on performance and cosmetic mods.
Please feel free to PM me if I can help you out in anyway and I look forward to being part of the growing 'ZClub' community!
Ronnie - Unreformed.
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Marz added a topic in Off Topic LoungeUnderbelly: The Golden MileUnderbelly is back with a brand new series,The Golden Mile. Underbelly: The Golden Mile premieres Sunday April 11th 2010 with an incrediable two-hour telemovie premiere.Underbelly: The Golden Mile is set in King Cross in 1988-1999, where bent cops, straight cops, cool criminals and colourful characters all converged to make their mark. But by 1995 the Wood Royal Commission had put the “black empire” under threat of collapse as strong and honest police fought to take back control of the most infamous strip in Australia.
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