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Some time ago we back to back tested Castrol FR 5W30 and 10W60 in a race engine (not an RB) on the dyno. Sure the race engine was built “loose” compared to a brand new “standard” road engine, but probably no looser than a 100,000ks’ old road engine. On the dyno there was very little difference in power output at all rpm ranges, with the 5W30 slightly ahead. But in real world conditions I don’t think you would ever notice the power or fuel consumption differences.

So I have continued to use the 10W60 in my road cars (and race cars) for the temperature safety margin it gives me.

:kiss: cheers :rofl:

PS; I didn't notice any significant oil pressure differences at normal operating temperatures, the oil pressure relief valve controls that.

Edited by Sydneykid

With the 5w40 Motul gear, over 3500rpm its a smidge under 6kgcm2... I should walk out to the car and have a look what units the std guage use.. lol

SK, to back up what you are saying I have seen on the net somewhere a dyno back to back with different oils in a subaru turbo thing, the castrol 10w60 actually made more power than some of the other lighter weight oils (splitting hairs type results, but none the less it wasn't less power), if I remember correctly better than the majority of 5w40/5w50 oils with the only one beating it being the mobil 1 0w40.

I would have kept running the 10w60 but was concerned with such high oil pressure, I must admit fuel economy is the same between oils.

Just cruising at 100km/h it was sitting damn close to 6kgcm/2 vs the 5w40 that sits on roughly 4.5..

Busky2k, I remember when whatsisname was running the motul 300v 10w40 in his close to 300rwkw rb25, he ended up moving to the 300v 15w50 as the 10w40 was not cutting it, how he knew this im not sure.

PS; I didn't notice any significant oil pressure differences at normal operating temperatures, the oil pressure relief valve controls that.

Yes very true , but it really depends on the engine too. Some go into relief just off idle. Others don't until 5000rpm etc. So different viscosities behave differently between engines. For example a 10W60 might go into relief at 4000rpm, but a 10W30 in the same motor might not go into relief until 6000rpm. So the latter oil would provide more flow for the same pressure.

Whilst the fuel economy benefits between thick and thin are small, they are definitely there but we're not talking say a trend you could see just over 1 tankful. For example, an ILSAC GF-4 rated oil must show 2% (IIRC) better fuel economy than a refererence fully synthetic 10W30. Moreover, many manufacturers in the USA are moving to 5W20 purely for fuel economy reasons. I believe people who would benefit the most from a thinner oil is one who does frequent short trips, where the cold viscosity differences between a 10W60 and a 10W30 are very large.

However I wouldn't say a thick oil would make you loose power compared to a thin on the dyno as the differences are down to the margin of error.

Cheers :D

Edited by Busky2k

Ive been using castrol R 10w 60 in my 33 since compliance...its only had 1 oil change so far at 5000kms ( due for the next 1 in about 2-3000km).

on startup, the pressure is at 3/4 of the stock gauge (6). when its warmed up and driving, it sits right on 4, and when stopped at the lights etc, it goes to 2.

None of that means anything to me, just thought i'd put it up for those who know what they're talking about.

justin911 uses the same oil, and his gauge shows those same readings in his 33 as well :D

personally i think 5000kms is too many between changes. but i am a catious mofo when it comes to maintenence as i punish the ring out of my cars i like to look after them as best i can in every other respect.

  • Like 1
Ive been using castrol R 10w 60 in my 33 since compliance...its only had 1 oil change so far at 5000kms ( due for the next 1 in about 2-3000km).

on startup, the pressure is at 3/4 of the stock gauge (6). when its warmed up and driving, it sits right on 4, and when stopped at the lights etc, it goes to 2.

None of that means anything to me, just thought i'd put it up for those who know what they're talking about.

justin911 uses the same oil, and his gauge shows those same readings in his 33 as well :D

My oil pressure is quite a bit higher than that, my oil pump is 'supposed' to be an rb25det pump.

First thing in the morning no matter what oil I use its up over the 8, well the only oil that was around 7.5 was the 10w30 castrol.

The idle is it sits on 2.

  • 4 weeks later...

lots of talk about pressure not much on viscosity...look at the cSt ratings of the 10W60 etc...compared with the 10W30...cold start is miles different...which is when 90% engine wear occurs.

on top of that a wide spread oil will need ot be changed more often due to the VII content to get the spread...never go past the POE stock oils such as redline and Motul 300v for example.

you op. temp visc. ratings will be similar in a 30 or a 40 60 is probably quite thick still...but the cold start is where u have a gain.

my 2 cents.

lots of talk about pressure not much on viscosity...look at the cSt ratings of the 10W60 etc...compared with the 10W30...cold start is miles different...which is when 90% engine wear occurs.

on top of that a wide spread oil will need ot be changed more often due to the VII content to get the spread...never go past the POE stock oils such as redline and Motul 300v for example.

you op. temp visc. ratings will be similar in a 30 or a 40 60 is probably quite thick still...but the cold start is where u have a gain.

my 2 cents.

for those that dont understand technical stuff, were you saying 10w 60 is good or bad?

is there any reason too high oil pressure is bad? mine is up at 85-90psi at idle when stone cold, and drops to 40-50psi at idle when warm, then hits around 80psi on full rpm under load. its a jun oil pump though, and im running the castrol 10w60 edge as well. it this just because of the relief valve spring being stronger in jun pumps?

is this a benefit ive got such good oil pressure or is there a downside to it?

Edited by CruiseLiner

I cant begin to tell you how good the formular R range is. used the 10w-60 on my GTiR and every single change on my GTR. every 3-5000kms. the 10w-60 is designed for high stress engines. wouldnt you agree that a GTR is a stressful piece of equipment.. therefore since i like pushing my GTR to 9000rpm (katimoto chipped ecu) i think ill use the formula R.

I actually put the formular R EDGE in on sunday and immediately i noticed that it became smooth and quieter again like a tammed lion. maybe its my mind talking but i think the edge is improved it does say so on the bottle. I think ill always use the 10w-60 it only costs me $55 a bottle. and i give my GTR more throttle than brakes. I highly recommend it.

Keep in mind a good oil filter is needed too. DONT USE VALVOLINE. im using a RYCO filter which cost $11 at repco (DICKHEADS). ill be using genuine Nissan Filters next time.

hope that helps u sway ur mind. BTW its not too thick IMO

Mark.

I cant begin to tell you how good the formular R range is. used the 10w-60 on my GTiR and every single change on my GTR. every 3-5000kms. the 10w-60 is designed for high stress engines. wouldnt you agree that a GTR is a stressful piece of equipment.. therefore since i like pushing my GTR to 9000rpm (katimoto chipped ecu) i think ill use the formula R.

I actually put the formular R EDGE in on sunday and immediately i noticed that it became smooth and quieter again like a tammed lion. maybe its my mind talking but i think the edge is improved it does say so on the bottle. I think ill always use the 10w-60 it only costs me $55 a bottle. and i give my GTR more throttle than brakes. I highly recommend it.

Keep in mind a good oil filter is needed too. DONT USE VALVOLINE. im using a RYCO filter which cost $11 at repco (DICKHEADS). ill be using genuine Nissan Filters next time.

hope that helps u sway ur mind. BTW its not too thick IMO

Mark.

Nissan oil filter cost me just tad over 9 bucks at dealer.

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