Oil Recommendation for 2006 Infiniti G35 Coupe

[Trav]

Originally Posted By: CATERHAM
Originally Posted By: OVERKILL


If an engine is spec'd for a 40-weight and it generally runs the oil around 14cSt when hot, and this is the recommended grade by the OEM, this would be relatively close to "optimum" for the engine as defined by the OEM. Of course there's going to be a bit of leeway in either direction but generally, let's say that in the range of 12-16cSt is "optimum" for this particular engine.

No, a 40 grade oil (12-16cSt) is way heavier than optimum @ 100C
oil temp' for any engine. In fact most engine oil pumps will still be in bypass at that temp' with a 15-16cSt oil.
An oil's optimum viscosity in HTHSV terms will be somewhere in the 3.5-4.5cP range at all oil temp's if such a lubricant could be invented. (I'll be posting on recent developments in that regard when I find the time).

A 2.6cP HTHS rated 20 grade oil has a HTHSV of around 6cP at 100C so it's still thicker than optimum at that temperature for all engines.
It's the reason more and more manufacturers are specifying that grade and lighter. So aside from availability issues with 20 grade oils, 30 and 40 grades are spec'd to deal with viscosity loss associated with very high oil temp's, fuel dilution and one oil shear.


How can you say that?
Engines designed to run on xw20 are different from an xw40 engine. To run xw20 reliably the engines needs extra block and crankshaft rigidity, this usually requires a forged crank and extra block webbing along with more main bolts.

The xw40 engine probably has a cast crank and not so rigid block, this flexing will will cause bearing clearances to reduce at high RPM/stress loads.
With a xw20 this flexing would be disastrous to the engine resulting in damages to the crank and bearings.
The crank bearing contact will happen long before your oil pressure gauge could even register it and for you to do something about it.

Over the years 4 bolt mains and forged cranks have been used in some engines to increase the rigidity, but the block itself was still lacking the necessary addition webbing.
A xw40 is not too heavy in these engines.

The oil pressure gauge is basically useless in detecting block/crank flex because it will wont show it if only one or two bearings make contact at any given time.
Advising peope to use gauges to determine the optimal viscosity is quackery.

 

[Shannow]

Trav,
Have tried repeatedly to get across similar points that while the pressure gauges tell you the viscosity of the oil on the entry side of the bearings, they tell you absolutely nothing about what the oil is doing in the loaded part of the bearing.

That, temperature rise across the bearing (again not measured by the oil pressure viscometer) are discounted as "technical obfuscation".

 

[Trav]

Some people will never get it, they don't want to. Their bias that drives them not facts.

 

[CATERHAM]

Originally Posted By: Shannow

That, temperature rise across the bearing (again not measured by the oil pressure viscometer) are discounted as "technical obfuscation".


(I normally try to ignore your nonsense and that of your followers so this response if for anyone else that may read this thread.)

And in that same thread you got called out for lying by another member.

In a high performance engine when the oil can be pumping through at a rate of 12 gallons/minute, how much will the oil temp's rise on a single pass though a crankshaft? A fraction of the 60 degrees you've claimed in the past.
Besides it doesn't matter, the oil viscosity in every part of an engine correlates to sump oil temp's when the oil is flowing at it's maximum rate. An OP gauge reading is a proxy for that sump oil viscosity at the pick-up point. Once it has been established what minimum reading represent a sufficient minimum viscosity that's all one need know.

The concept of operational viscosity is not a difficult one to grasp, so you're either not that bright or are just deliberately espousing misinformation.

One can run a light 0W-20 oil in any engine spec'd for a 30, 40 or heavier grade with no problem whatsoever if maximum oil temp's are contained even for track use as I have proven as have many other members and oil formulators for that matter.

And while we don't have anything lighter than a SAE 20 grade at present to use in a street oil, in racing much lighter oils are used.
For example, a 1000 hp engine that requires a 4.5cP HTHSV 50 grade oil when lapping on a circuit track with 150C sump oil temp's will only require a 0W-2 (3cSt, est' 1.3-1.4cP HTHSV) oil with maximum oil temp's of 50C at a sprint event. Source Joe Gibbs Racing.

 

[chrisri]

Internet expert at it's best. Good man drives his BMW with oil of HT-HS of 2.8 cP on a TRACK, without any issue.Bearing size, maximum load, bearing clearance, temporary oil share, crankshaft twisting, all this means nothing.
All we need is OP gauge, preferably Chinese, those work best.

 

[il_signore97]

This is absolutely ridiculous. I just can't sit back and read this anymore without putting my 2 cents in...

Firstly, to answer tawheed (OP) and his question about his new-to-him Infinity VQ-engined vehicle, I would not hesitate to use any 0W40 European-style oil in your new car year-round. GC/BC 0W30 is also good, but as others have stated, you can find much better deals on the 0W40's in large jugs rather than quart/liter bottles. Also, understand that there is very little difference between GC 0W30 and Mobil or Castrol 0W40. They all have HTHS values of 3.5-3.8 cP, and are operationally very close in an engine.

Furthermore, this advice comes from someone with ACTUAL experience with your particular engine, having owned one for many years and having worked on many of them. Other members here have also shared with you their first hand experience with these engines, and their preference (in some cases) for a European style oil (HTHS > 3.5 cP). This engine family has certain issues, which include poor timing chain components, oil usage, very high oil temperatures when driven spiritedly, VTC component issues, and in some cases, richness issues (causing oil degradation). These issues combined support the use of a 40 grade oil in your car, and also, to those that say "Use the recommended grade of oil", 10W40 was listed as an alternative grade in almost all VQ engined vehicles up to a certain point (2008 I believe). So this means that the OP's 2006 Infinity can absolutely use a 40 grade oil according to Nissan.

And Caterham, your view that any oil that is not in the optimal viscosity range will cause engine damage is simply not true. Stop with the assertions if you can't provide proof. Don't repeat the same old things again and again and expect them to be true. Don't personally insult me and other members saying that we don't understand. YOU don't understand, clearly, the principles of engine lubrication.

I don't know how many times the other very knowledgeable members here can explain the same things to you before you actually get it. An engine operating with the oil pump relief valve cracked opened is simply illustrating the fact that the oil system cannot except any more oil flow at what has been determined to be the maximum oil delivery pressure by the manufacturer. That means that every part, every bearing, every cam journal, every oil squirter, is flowing the most that it possibly can given the oil's viscosity and the maximum design pressure of the oiling system. PERIOD. It doesn't need any more flow, otherwise the manufacturers would have designed a higher relief valve opening pressure (as they HAVE in some engine families). The positive displacement pump will generate infinitely high pressures to obtain the required oil delivery until something were to break, had it not been for the relief valve being able to crack opened and allow the excess delivery flow from the pump to vent back to the pan.

Also, the above notwithstanding, you clearly have no idea what mechanisms affect start-up wear in a cold engine. I suggest you read up on the MANY SAE papers that were written on the subject. Most have found the same things that other members have already discussed here. Start-up and warm-up wear is mostly comprised of mechanical wear due to poorly fitting parts, improper tolerances, and most importantly, corrosive wear (in the case of cylinder walls, which typically suffer the most from start-up wear). Acids from cold combustion temperatures coupled with excessive fuel wash on cylinder walls causes microscopic corrosion of the cylinder walls, contributing to wear. Please tell us here how ANY oil will help to control these wear mechanisms???

Please stop spreading incorrect and incomplete information. It is not the point of this forum, and causes new members to be quickly uninformed.

 

[Trav]

Originally Posted By: Caterham
One can run a light 0W-20 oil in any engine spec'd for a 30, 40 or heavier grade with no problem whatsoever if maximum oil temp's are contained even for track use as I have proven as have many other members and oil formulators for that matter.


Oh no, here we go with the speed racer funny business.

Simple question. If thats the case why do the engines that have xw20 in their spec sheet have reinforced webbing in the block, forged cranks and more than likely multi bolt main bearing caps?
If it really doesn't matter why are they going to that additional expense (and a real expense it is)?

what is it about the most basic block and crank design elements that alludes you?
Go and try xw20 in an old M3 that needs 10w60 to stay in one piece, you wont get oil mist on your racing goggles there will be a deluge coming out the back.

 

[Oil Changer]

I can't wait to read CATERHAM's upcoming post when he has time to write it (source: his words). I'm hoping it includes a detailed discussion on the maladies imposed by a positive displacement pump bypassing a fraction of oil once the engine has accepted all that it needs. Should be fascinating.

 

[demarpaint]

Originally Posted By: il_signore97
This is absolutely ridiculous. I just can't sit back and read this anymore without putting my 2 cents in...

Firstly, to answer tawheed (OP) and his question about his new-to-him Infinity VQ-engined vehicle, I would not hesitate to use any 0W40 European-style oil in your new car year-round. GC/BC 0W30 is also good, but as others have stated, you can find much better deals on the 0W40's in large jugs rather than quart/liter bottles. Also, understand that there is very little difference between GC 0W30 and Mobil or Castrol 0W40. They all have HTHS values of 3.5-3.8 cP, and are operationally very close in an engine.

Furthermore, this advice comes from someone with ACTUAL experience with your particular engine, having owned one for many years and having worked on many of them. Other members here have also shared with you their first hand experience with these engines, and their preference (in some cases) for a European style oil (HTHS > 3.5 cP). This engine family has certain issues, which include poor timing chain components, oil usage, very high oil temperatures when driven spiritedly, VTC component issues, and in some cases, richness issues (causing oil degradation). These issues combined support the use of a 40 grade oil in your car, and also, to those that say "Use the recommended grade of oil", 10W40 was listed as an alternative grade in almost all VQ engined vehicles up to a certain point (2008 I believe). So this means that the OP's 2006 Infinity can absolutely use a 40 grade oil according to Nissan.

And Caterham, your view that any oil that is not in the optimal viscosity range will cause engine damage is simply not true. Stop with the assertions if you can't provide proof. Don't repeat the same old things again and again and expect them to be true. Don't personally insult me and other members saying that we don't understand. YOU don't understand, clearly, the principles of engine lubrication.

I don't know how many times the other very knowledgeable members here can explain the same things to you before you actually get it. An engine operating with the oil pump relief valve cracked opened is simply illustrating the fact that the oil system cannot except any more oil flow at what has been determined to be the maximum oil delivery pressure by the manufacturer. That means that every part, every bearing, every cam journal, every oil squirter, is flowing the most that it possibly can given the oil's viscosity and the maximum design pressure of the oiling system. PERIOD. It doesn't need any more flow, otherwise the manufacturers would have designed a higher relief valve opening pressure (as they HAVE in some engine families). The positive displacement pump will generate infinitely high pressures to obtain the required oil delivery until something were to break, had it not been for the relief valve being able to crack opened and allow the excess delivery flow from the pump to vent back to the pan.

Also, the above notwithstanding, you clearly have no idea what mechanisms affect start-up wear in a cold engine. I suggest you read up on the MANY SAE papers that were written on the subject. Most have found the same things that other members have already discussed here. Start-up and warm-up wear is mostly comprised of mechanical wear due to poorly fitting parts, improper tolerances, and most importantly, corrosive wear (in the case of cylinder walls, which typically suffer the most from start-up wear). Acids from cold combustion temperatures coupled with excessive fuel wash on cylinder walls causes microscopic corrosion of the cylinder walls, contributing to wear. Please tell us here how ANY oil will help to control these wear mechanisms???

Please stop spreading incorrect and incomplete information. It is not the point of this forum, and causes new members to be quickly uninformed.


Well written. This tends to get old real fast.

 

[Shannow]

Originally Posted By: CATERHAM
(I normally try to ignore your nonsense and that of your followers so this response if for anyone else that may read this thread.)

And in that same thread you got called out for lying by another member.


CLAPTRAPHAM, you are one class act ...

I'll be a little less generous when calling you out from now on.

 

[Shannow]

Originally Posted By: CATERHAM
In a high performance engine when the oil can be pumping through at a rate of 12 gallons/minute, how much will the oil temp's rise on a single pass though a crankshaft? A fraction of the 60 degrees you've claimed in the past.


I take it you've taken the licence of converting it to F for poetic licence.

Again, you are demonstrating your absolute lack of understanding of hydrodynamic lubrication, and a pig headedness to refuse to learn, as it doesn't suit your mantra...I've tried, and tried, but you reject it as "technical obfuscation"... is that code for "I reject facts" ?

The oil does not "pick up" heat as it flows through the bearings, heat is generated by the shearing of journal against oil doing work against the oil...same mechanism that generates the hydrodynamic forces that keep the journal and bearing separated.

That heating is in the hundreds of watts range for a crank assembly, and YES, the oil temperature rises significantly across this interface, higher, much higher than the coolant temperature ... there's a reason why HTHS is 150C.

(In my Caprice, after 15 min at 2,000 RPM on the highway, the oil in the dipstick location is 105C, with a bulk oil temp of 90C...the dipstick location being where the oil has come from the crank/cam bearings and draindown...4,000 RPM at the same engine load for 10 mins, and it's been 135C).

Your pet theory only works when the oil is "picking up heat" from combustion, not functioning hydrodynamic lubrication.

As I've repeatedly offered, go here

http://www.tribology-abc.com/calculators/c9_3.htm

Put in the dimensions of your Astra engine bearings, clearances, an HTHS of 2.6, 3,000 RPM, and you will see instantly that there's 10K temperature rise across the passage through the bearing, 6,000 RPM, and there's 20K/C, with 125W of heat generated by the hydrodynamic process WITHIN the bearing...on the other (loaded) side to your oil pressure viscometer.

 

[Merkava_4]

Anybody know which oil the OP eventually went with?

 

[53' Stude]

Nope

 

[tawheed]

Originally Posted By: Merkava_4
Anybody know which oil the OP eventually went with?

To be honest, I still haven't decided

 

[Trav]

Shannow, is there any correlation between a cast crank and lightly reinforced block that are subject to flexing and this..
Quote:
Hydrodynamic journal bearings become unstable with small shaft eccentricity. It's the reason that high speed or relatively low loaded hydrodynamic bearings are to be designed less stiff.


Would the slight flexing be considered eccentricity?