Jump to content
SAU Community

Recommended Posts

Pressure is directly proportion to viscosity, the thicker it is the higher is the pressure. This also mean higher pressure will have lower flow rate. You need both flow rate and pressure to fully optimize the operation of the oil system. IMO 50wt oil is just too thick for most application except racing or autocross....

Rather than start an argument I would rather pose a question.

First things first what you have said is partly correct. A higher viscosity fluid will create a larger pressure difference when measured from one end of the pipe it is being pumped in to the other. This means a higher output pressure at the pump is required to achieve the same flow rate.

BUT

There is more than one type of pump. For a centrifugal pump (like your water pump) the output pressure has a huge effect on the flow rate of the pump. For a positive displacement pump it has ABSOLUTELY no effect.

So what type of pump is your oil pump?

Rather than start an argument I would rather pose a question.

First things first what you have said is partly correct. A higher viscosity fluid will create a larger pressure difference when measured from one end of the pipe it is being pumped in to the other. This means a higher output pressure at the pump is required to achieve the same flow rate.

BUT

There is more than one type of pump. For a centrifugal pump (like your water pump) the output pressure has a huge effect on the flow rate of the pump. For a positive displacement pump it has ABSOLUTELY no effect.

So what type of pump is your oil pump?

It does when the bypass is wide open; in essence the thicker oil creating high pressure also causes a huge effect on the flow rate of the pump as it has to dump a lot more oil to hold its specified oil pressure.

With a 5w40 I see ~90-95psi of oil pressure over 3500rpm.

Nah i'll never take the odometer reading as gospel hehe. I just want to know if its a safe things to use. Ive been going through this thread and man ive got a headache and I just want to know what oil to buy tonight when i go down to supercheap. I just want something good quality and something quietens down my lifters abit during start up thats it. any suggestions for my 1996 R33?? Im sure its not rocket science but after reading a few pages im like damnnn oil choice is a massive decision.

yeah, you've asked quite a few times :(

I've answered with Mobil 1 a few times as well :P

0w40 in my car, took a little less than 5 litres i think. As i've said before, RB lifters are fairly noisy anyway, but the Mobil 1 did quiet them down a little, for me. NEO R34, don't know if that makes a difference.

i can't say anymore than what i've already said. I've got 0w40 in my car, and yes it made the lifter less noisy.

can't answer your question any more straight forward than that. And if people like Trex101 are telling you it's fine, that it's 100% cool. They're the sorts of people in this thread that i made my oil choices from. Trex101 and khunjeng, etc...

that's cool :(

mate, i was exactly the same, worrying about which oil to put, concerned about this and that. But some of guys in this thread REALLY know their oils. Mobil 1 is a good starting point, at a reasonable price and having 0w40 is fine. Then you can go German Castrol, Redline, Motul after that if you're keen.

i know exactly what it's like to be paranoid bout the car, especially with the oils. I also did my gearbox and diff at the same time, so i was 3 times as paranoid! haha

Maybe just PM Trex101 or khunjeng with your EXACT concerns and worries, and grab their opinion :P

nope, will still be cheaper i'm pretty sure :rofl: Even melb people have to pay for postage. The difference isn't that great between posting here or interstate.

ah okay yeh ive found those rates they aint that bad...

Pretty keen on the royal purple stuff for that price, anyone using this in theyre cars?

Guys,

Was just enquiring about gearbox oils at the Outlaw Speed Shop here in Adelaide, and got to talking about engine oils too. I was passed on this article to read/keep and had to share with everyone as it has some REAL eye openers.

I will more than likely be using the Royal Purple next, far and above the others for value for money I reckon. Almost makes me want to dump the Motul 8100 excess in there now!. However got to say that the Valvoline shocked me!

Cheers

Lee

Oil_Compar.pdf

Well I didnt get a price from Outlaw, but the listed price in the comparo is $79.99 compared to $92.99 for the Motul 8100 Excess, which you can get for cheaper than that.

By value for money, i meant for similar dollars to Motul, get far better protection for a full synthetic.

For a Semi synthetic, seems the Valvoline durablend is the go.

Its all in the PDF I attached to my post ;)

Edited by Hotwire
Guys,

Was just enquiring about gearbox oils at the Outlaw Speed Shop here in Adelaide, and got to talking about engine oils too. I was passed on this article to read/keep and had to share with everyone as it has some REAL eye openers.

I will more than likely be using the Royal Purple next, far and above the others for value for money I reckon. Almost makes me want to dump the Motul 8100 excess in there now!. However got to say that the Valvoline shocked me!

Cheers

Lee

This article from StreetCommodore is very misleading, this Timken test are only good for grease, not oil. The editor has admitted the test is flawed and not representatives of actual engine condition.

StreetCommodore reply:

http://www.streetforce.com.au/news/01_oils_aint_oils.php

Wow,

Thanks for pointing that out. So the verdict is still out then LOL

You know, i can get better wear reading with head and shoulder shampoo then all these oil tested. The chorine in there are a very good extreme pressure additives, it just that when you include it in your engine oil combine with moisture, you will form hydrochloride acid.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • That is surely the biggest gathering of Stageas in North America, ever!
    • Remember kids - if you can't afford to buy 2 GTRs......
    • I know people cry at the price of the Getrag 12-14k for a conversion now, but it really is a nice mid point. Not going to get change from 10k on a gearset installed.  $30k++ for sequential.   I know you run the risk of a damaged used one and parts are hard to get but as a street car gearbox its really hard to beat. If you enjoy a more traditional manual, its the choice no question.     
    • Time to decide what’s more import, your power level or your budget because you’re going to struggle to keep both 
    • Our Southern Highlands Cruise is proudly registered with “R U OK?” Day.  Sometimes the best way to check in on your mates is by getting out for a drive together. Sharing a common passion like cars creates the perfect space to chat, connect, and support each other.  A simple “R U OK?” can make all the difference. Let's enjoy the drive, the company, and look out for one another. PLEASE WEAR YELLOW FOR “R U OK?” DAY Sunday 14th September 2025 9:30AM Meeting Crossroads Homemaker Centre 10:00AM Cruise Departure Via Old Hume Hwy 11:45AM Arrival at Mittagong RSL Club Meet Location: Crossroads Homemaker Centre Final Destination: Mittagong RSL Club *Disclaimer* There will be a lead and follow car so no one should get lost. If you would like to attend or bring others along please put your name down and a +1 as numbers will be needed prior! This is NOT a race and we will all be adhering to all road rules. If this is what you want please come to one of our many track days. This is an official SAU:NSW event and will be run under a CAMS permit. One of the things that really sets our club apart is our commitment to being true enthusiasts. When on normal roads we strive to maintain good relations with the authorities as well as the public in general. When attending one of Skylines Australia NSW events please try to: • Be aware of surrounding environment and act accordingly. • Drive courteously on the state’s roads as a true enthusiast should. • Understand how important it is to maintain the good name of SAU NSW and thus, treat others accordingly. • Any misbehavior will not be tolerated and you will be asked to leave.
×
×
  • Create New...