The Goods On Oils

[Rolls]

Sorry Rolls, I should have put a or something there. Yeah, in 10yrs on cars I've never seen a tangible performance increase from an oil change. Even back-to-back on a dyno - clean oil is preventative maintenance, not a performance gainer.

Haha I thought so, was just making sure that no one got the wrong idea.

On another note something I did notice when I used shell 5-30w was that it leaked quite a bit of oil daily from various seals, the motul 8100 5-40 still leaks a bit but no where near as bad, doesn't burn as much as well.

My car blows smoke if you load it up for the first minute when its cold (I try and avoid this) its not loads of smoke but I can see it from the rear vision mirror. Should I consider going a slightly thicker oil? or am I better off just accepting that its an old motor and will burn some oil and change more frequently?

(Redtop rb20det with apparently 120k on it.)

Edited June 21, 2008 by Rolls

[boostin_r33]

Just tryed some royal purpal seems to be pretty good ! idles alot better than motul turbolight!

[Cubes]

Idle better?

Do you mean engine quieter?

I've tried so many damn oils over the years and honestly.. never noticed any difference apart from a really really slight difference in valve train noise. When it comes to performance etc its all the same.

[SS8_Gohan]

i think when you first go from crap oil (ie, "don't know how it came from japan" oil), give it a good clean out, and then put some real good quality stuff in, i think there CAN be differences in idle, noise, lifters, etc...

[Rolls]

When I put 'better' oil in my 300km aus r31 (RB30E) it made it make horrid noises from the top end. Dumped the oil out and put some $15 20w50 in it and it fixed it up.

I guess it really depends on the life the engine has had.

[slidetaker]

The 7.5W30 rating came from the Gt-R manual, so I know it is correct....Most RB's have a fair amount of blow by & run rich....

Thanks for confirming these specs. This should help greatly when people are putting in new equiry. Perhaps Durablend 5W30 with shorter interval will be better than a long one with M1 0W40 then.....um..

As to where to draw the line??? All the theories will need to put into consideration in each application. So basically there is no line. Just to give an extreme example, someone could put $5 5L motor oil in a new car if it will be traded-in for another one within a couple of years. The damage is great but is too early to tell. In this case, the $5 oil works perfect for the owner.

Cubes, are you talking about sludging with Helix Utra 5W40??? how many km has it done to start sludging? Was X-cess being used similar for comparison?

[JI34GT]

I coming to my first servicing of my R34GTT and I've done about 70,000kms.

Been reading up on this oil thread, and im still really confused about oil i should be using. i gathered that motul and royal purple are good brands but can someone help me out specifically as to which one to get and which #W## thing as well?

[some_cs_student]

I coming to my first servicing of my R34GTT and I've done about 70,000kms.

Been reading up on this oil thread, and im still really confused about oil i should be using. i gathered that motul and royal purple are good brands but can someone help me out specifically as to which one to get and which #W## thing as well?

Most skylines are roughly the same if its for street driving, I'd recommend looking at the first page for a summary of group IV oils and group V oils, they are generally considered the better oils to use.

The lower viscosity the better, so if you can run 0w30 or similar try run that, don't got for something like 10w40 if your car doesn't get really hot (like 105+ degrees).

Personally I've tried Castrol but the American version off performancelub.com, anything besides 0w30 is not German

The GTR's recommended 7.5w30 when they came out but oils have changed a lot since then.

If your doing track driving my recommendations will be irrelevant to you as you'd want something with a higher temp...

Castrol SynTec 0w30 (Group III)

A minor mistake in the front page, Castrol SynTec 0w30, the German castrol is group IV. The American 5w40 or similar is group III (sometimes written as III/IV but not true group IV).

Look for posts by Trex101 and khunjeng if you want to read the thread, they are the oil experts

Regards,

Gareth

[some_cs_student]

There is alot of factors to consider when choosing oil weight and it's quite difficult to give you any good advice by your above description.

There are 2 major considerations in choosing oil viscosity,

1) Fuel dilution (fuel blowby into oil sump effectively thin down the oil viscosity)

Thicker oil can withstand more fuel dilution then thinner oil but thicker oil also causes friction drag, slower spool, higher FC and more startup wear.

For example: If you run Penrite Sin 25 25w60 in your engine, at 10’c morning when you first crank your engine, you would have effectively run 1131cSt startup viscosity. That’s like 4.5 time thicker then Mobil 1 0w40 (248.8cSt@10’c). It’s like running greases through your engine instead of oil.

2) Engine oil temp

Higher oil temp effectively thins the oil down.

For example: Mobil 1 0w40 is 14.3cSt @ 100'c but when avg oil temp raise to 120'c, it would have thin down to 9.1cSt which mean that it is effectively a 20wt oil (you do not want to run a 20wt oil when you racing down a track, do you). So if your avg oil temp are 90’c, any 30wt oil will do as it is effectively a 40wt oil at that temperature.

The key to the correct oil viscosity depends on mostly the above 2 conditions. There is no one size fit all oil.

Oh, IMO some brand of oil are known to withstand quite abit of fuel dilution before thinning down. Redline & German Castrol is one of them. That’s why it’s highly recommended in BITOG for track or high hp muscle car usage.

Just thought I'd re-quote that for anyone who doesn't understand the oil ratings, I had trouble finding that, it was in response to one of my questions

Also there is a discussion of 5w40 Fuchs Synthetic Oil which is not mentioned in the lists here.

[XcileD]

What oil would you guys recommend for an R33 gts-t going onto 160,000k's?

Mods (from what I can tell so far, just picked it up a couple of days ago) are: front mount intercooler, bigger injectors, exhaust, fuel pressure gauge in the engine bay?. It also looks like they had to remove some parts to get a RWC to sell it.

Cheers

[slidetaker]

What oil would you guys recommend for an R33 gts-t going onto 160,000k's?

Mods (from what I can tell so far, just picked it up a couple of days ago) are: front mount intercooler, bigger injectors, exhaust, fuel pressure gauge in the engine bay?. It also looks like they had to remove some parts to get a RWC to sell it.

Cheers

For stock and average mileage, it is recommended to stick with 0W30 or 5W30.

With your engine on higher boost (I am guessing because of the mod) and high mileage, I think it is suitable to run 5W40. Motul X-cess is popular and gives many positive results. Valvoline SynPower is another one that is readily available in most auto retailers.

It would be a good idea to test the condtions of the engine like compression and whether it is burning any oil.

Hope this helps.

[XcileD]

Thanks.

I found some Valvoline SynPower, 5w40 (5L) for around $55. Does that price sound about right?

And would this suit (taking into account the k's etc), or would I be better off with the 10w50?

[some_cs_student]

Thanks.

I found some Valvoline SynPower, 5w40 (5L) for around $55. Does that price sound about right?

And would this suit (taking into account the k's etc), or would I be better off with the 10w50?

Sounds like you haven't read the thread OR even attempted to read the first page!

Thats not in the list of known quality oils, it *might* be Group III...maybe, if you want quality oil you will be paying a bit more.

5w40 sounds ok for a rating, closer to 0w30 will be better unless your engine gets hot often.

The higher km's idea has been discussed and it was concluded you don't really need to go with a thicker oil as the engine gets older...(at least I think, double check the thread to know for sure)

[XcileD]

Thats not in the list of known quality oils, it *might* be Group III...

And that is why I asked Cheers.

I don't mean to seem like I have read nothing in this thread, but it's just a bit confusing with 45 pages and everyone's 2c chucked in...

Especially considering the fact that I have only owned a Skyline (also my first performance vehicle) for about 5 days, and I'm just trying to cram all this info in.

[slidetaker]

I found some Valvoline SynPower, 5w40 (5L) for around $55. Does that price sound about right?

And would this suit (taking into account the k's etc), or would I be better off with the 10w50?

SynPower for $55 sounds about right. It is available in Kmarts so watch for auto sales time.

It is mainly Group III, how well is refined I don't know, quality should be similar to those used in Shell and Mobil.

Redline and RoyalPurple is PAO/Esters, but mix proportion, type of esters, additive packages all unknown. These performance oils are double the price of SynPower.

10W50 is a lot thicker than OEM 7.5W30, I won't make such a decision without knowing the conditions of the engine and how 5W40 is working.

Hope this helps.

[Rolls]

Motul 8100 is only $59, also have a look for this.

[Wacky Dee]

I have an R34 GTT (1998 model) with 63k on the clock and was doing a bit of research on which oil to get and got the impression that 5w30 would be the right viscosity...

But then I just spoke to the garage where I take my car for most of the servicing (Unigroup) and they said they'd use 10W40 and that 5W30 is too thin and doesn't hold the oil pressure too well. And he said to ignore what most people are saying and that as long as I change the oil every 5000km/6months it wouldn't really matter which oil I use.

I'm a bit confused ... 10W40 sound right for a 10yo GTT ? In winter? I think he even mentioned Motul 4100

How about Motul 8100 Xcess (5W40 100% synthetic) ?

Edit: oh yeah this is a daily driver (mostly city) with no track/racing.

Edited July 17, 2008 by Delta Force

[SS8_Gohan]

then ask the garage why my oil pressure was/is always fine when running 0w in summer they learn the same old shit at those mechanic schools... old shit...

10w40 if you're doing a lot of track work.... PERHAPS....

I went to 5w30 BECAUSE i was doing some track work (Royal Purple) but will drop down to 0w30 German Castrol to see how that goes.

98, GTT, 76K km

[Cubes]

Cubes, are you talking about sludging with Helix Utra 5W40??? how many km has it done to start sludging? Was X-cess being used similar for comparison?

I changed oil at 5000km's. The Motul was used in exactly the same style and km's of driving.

At first I didn't believe it so I repeated the test with the shell and again sludge in the oil filter. Not all that happy to be honest as I would have liked to run the shell as its a fair whack cheaper @~$45.

I've ran motul for a few oil changes since so I may try for a third time with the shell just to be sure.

[1SLP80]

This information kindly provided by Rolls, some_cs_student, & trex101

When choosing oils the better the rating, generally the better the oil, and also the more expensive. Keep in mind even the Group II oils are probably still better then any oil that was made when your car was manufactured.

Basic explanation of ratings

Group I - mineral

Group II/II+ - hydrocrak (VI below 120)

Group III - hydrocrack (VI above 120, mineral derive "Fake Synthetic")

Group IV - polyalphaolefin (man made Synthetic)

Group V - Ester & other un-group fluid (Ester or Polyolester, super high grade Synthetic, good for aircraft jet engine).

Common products and their ratings.

Redline (Group V Polyester)

Motul 300V (Group V)

Motul 8100 E-Tech 0W40 (Group IV/V Blend)

Mobil 1 (Group IV)

Motul 8100 xcess 5w40 (Group IV) ~$59 - one of the best value

Castrol SynTec 0w30 (Group IV) [A minor mistake in the front page, Castrol SynTec 0w30, the German castrol is group IV. The American 5w40 or similar is group III (sometimes written as III/IV but not true group IV).]

Castrol Edge Sport 5w30 or 10w60 (Group III)

Motul 4100 Turbolight (Group II?)

Keep in mind that the 100% synthetic stickers mean jack, just means that the oil is at least Group III. As far as viscosity ratings go, this depends entirely on what temperature range your car is going to be used in and your driving style (track or street car) A decent read through this thread should help you answer that.

As far as oil filters go, get a genuine nissan one if you don't want to spend much, these are superior to ryco/cooper.

On Selecting Which Viscosity

There is alot of factors to consider when choosing oil weight and it's quite difficult to give you any good advice by your above description.

There are 2 major considerations in choosing oil viscosity,

1) Fuel dilution (fuel blowby into oil sump effectively thin down the oil viscosity)

Thicker oil can withstand more fuel dilution then thinner oil but thicker oil also causes friction drag, slower spool, higher FC and more startup wear.

For example: If you run Penrite Sin 25 25w60 in your engine, at 10'c morning when you first crank your engine, you would have effectively run 1131cSt startup viscosity. That's like 4.5 time thicker then Mobil 1 0w40 (248.8cSt@10'c). It's like running greases through your engine instead of oil.

2) Engine oil temp

Higher oil temp effectively thins the oil down.

For example: Mobil 1 0w40 is 14.3cSt @ 100'c but when avg oil temp raise to 120'c, it would have thin down to 9.1cSt which mean that it is effectively a 20wt oil (you do not want to run a 20wt oil when you racing down a track, do you). So if your avg oil temp are 90'c, any 30wt oil will do as it is effectively a 40wt oil at that temperature.

The key to the correct oil viscosity depends on mostly the above 2 conditions. There is no one size fit all oil.

Oh, IMO some brand of oil are known to withstand quite abit of fuel dilution before thinning down. Redline & German Castrol is one of them. That's why it's highly recommended in BITOG for track or high hp muscle car usage.

I did read this, and other post's on this topic.

This is my situation, i have a standerd rebuilt s1 rb25 (5000km old) Just did a track day. temp at track gets about 105 atm (will be sorting this out soon). sprited driving in the hills see about 90-95.

In example 2 of the above quote, it talks about oil thinning at higher themps...... i dont quite understand what im needing to use at these temps.

Also, what should a warm s1 rb25 oil pressure sit at when idleing? i have a apexi oil prerssure gauge, but am un sure of whats good and whats not

EDIT: After further research, i have came accross some spec's on oil pressure that say the following

RB25det KG/CM2 (bar?)

Warm engine**

Idle 1.1 kg/cm2

2000rpm 3.5 kg/cm2

6000rpm 5.6 kg/cm2

Edited July 20, 2008 by 1SLP80