Jump to content
SAU Community

Recommended Posts

I'm running Silkolene Pro-R 15W-50 (race oil) and most of the other oils I've seen used are around 15W-50 motorsport oils. My pressure is good (+4 whilst driving) and the temp (with the same oil cooler as you) is around 1/4 on the gauge.

When I first had it I used 0w-40 and it ran too thin and leaked past the turbo seals causing blue smoke etc.

franks the reason higher powered cars or circuit cars need higher viscosity oil is due to needed oil to be there when its needed eg when the oil gets damn hot. having a higher viscosity will mean the oil will be there instead of not being there if the oil was too thin

generally as far as my knowledge goes, to worry about that u should be looking at the last number, a higher number will give greater protection when its needed

u can run something like what IanH has, i did and my car ran like a dog cos it was too thick, would take longer to start and forever to get goin

just my thoughts

but the other side of the argument is how much strain a thicker oil will put on an engine compared to a thinner oil

obviously an older engine will need thicker oil because it will just blow too much by the rings

a thicker oil will put more strain on bearings, piston rings etc. but if ur fine with that then go ahead.

i think a balance between the 2 would be more justified. thats prob y nissan suggests using a 7.5w30 oil

the 30 being due to the colder conditions in japan tho

The two numbers are a representation of how think the oil is, when its cold hence your "0" and when its hot "50" which is very thick (good for keeping hot engines cool). Mobil 1 is expencive for a reason, it covers a wide range of temp.

The thickness changes with temp, ie gets thicker when hotter. There for Mobil 1 being 0W-50 will cover a wider range than 15W50. The only thing you want to be carefull of is that the oil is not too thin when starting (cold) as rb engines can develop leaks (mine is fine). On a cold mornings (Canberra/winter) you would want as thin as possible for starting so it has oil in it quick, if its too think when cold it will take ages to get up to the heads and you risk running the engine with next to no oil in it = bad. (dont flog your car when cold).

I stand by mobil 1 for road use for these reasons although I dont drive on the track (yet)and havent had much experiance with track cars, but I would assume the oil princiles are the same, but being the cars will be running hotter for longer you would want a thinker oil to cool the cylinders and stop ceasing. I belive redline make a track engine oil but I dont know its viscosity.

Things to keep in mind:

- When oil gets older it looses its viscosity (not as effective), and should be replaced

arround 5000kms in tough conditions = boost.

- If the car temp is out side the oils capability it will break down and not be effective.

- If the car is cold you shouldn't give it any till the temp needle is atleast off cold so you

know the oil is inplace.

- Oil is not only a lubricating substance but also a cooling substance.

Change your oil regularly... Car will love you long time for it..

If I am incorrect in any place's pls correct me..

hks make an oil, i think its 15w40 so that would give us an idea to what redline would be making.

changing oil is very important, we just retuned a tx3 turbo only to realise the oil was gone (only bout 3000kms) n it sounded like a tug boat. so we put it up on the hoist, changed it. sounded like gold again

moral : change ur oil all the time, its almost as important as insurance

btw stirlo i think u hit the nail on the head

0w50 is prob better than 15w50

hmmm wheres sydneykid when u need him? :):)

The first figure in multigrade oil refers to how it passed its viscosity testing at winter temperatures, thus the W - this has nothing to do with the hot weight, which is the latter of the two figures.

So 5W50 will have the same viscosity at 100 DEG celcius as 15W50 - it is SAE 50, regardless of the 'W' rating.

The 'W' measurement is conducted to SAE standards for winter use, ie it has been tested and passed for use at 0 deg F - the lower the number the thinner the oil will be.

So 5W oil will be thinner (more viscous) than the 15W at 0 deg F, but the hot rating is the second figure. The two are measured and rated differently, so the figures dont have a direct relationship to each other in that sense.

The lower the first number, the thinner the oil will be when cold, the higher the second number the EDIT: thicker the oil will be when hot.

Stirlo_GTR how can oil "gets thicker when hotter" oils get thinner as they heat up. The trick with multi grade oils is reducing how much the oil thins so it doesnt end up thinning so much that oil pressure drops too low, and the shear resistance of the oil (which is related to viscosity) is depreciated so far it becomes useless.

If you have ever changed your oil after warming the engine, you will know that it thins as it warms.

Sorry if I have confused, I just re-read my post and it doesnt make a heap of sense, so I will try and simplify

Viscosity - the higher the number, the thicker the oil

SAE test their oil for viscosity at 100 DEG celcius

W rating means it is suitable for use in winter - from what I understand this is tested by pouring oil through a specific size hole at 0 DEG celcius, so a 5W will be thinner than a 15W, as higher numbers indicate thicker oil (as for viscosity)

But remeber a 50 weight oil will always be thicker than a 40 weight oil which will be thicker than a 30 weight oil

AND the 'W' means winter suitable, not the oil weight

Hope that makes sense.

Something else of interest, is that whilst the higher the number the thicker the oil, the 50, 40, 30 etc are not actual measures of viscosity but EQUATE to ranges of viscosity, viscosity itself is measured in stokes.

Also, gear (diff, trans) oil ratings are different to engine oil ratings, for example SAE 75 weight gear oil is actually thinner than SAE 50 weight oil (at 100 DEG celcius)

Bobby^, I would suggest you speak to your local performance shop (that you trust) and ask what they recommend.

I use MOTUL 300V 15W/50, it was recommended to me by people who swear by it, and also it is used by NISMO in their cars - so it cant be bad.

How extreme are the temperatures where you live?

0W-40 is pretty thin for the track. probably fine on the street altho the winter rating is still very thin and not needed in temperate climates. I've run 15W-60 synthetic on the track (warmer weather) and also 5W-40 on the track (cooler weather) and had no troubles at all. I only tend to do a few hard laps and then give the car a breather though... it's a daily driver after all not a racecar.

There are a few other just as important factors though - how fresh is the oil, to what level was the oil filled, and how was the car being driven. Old oil = no brainer. Level - you want as much oil as you can safely put in ie right up to the high marker on the dipstick. If you thrash the hell out of an engine for 20 minutes then your oil temps are going to climb and eventually you'll hit the point where the oil stops working. Granted this will be different for a 40 weight vs a 60 weight but if you don't have an oil cooler you shouldn't be asking that much of your car. Also are the other engine components OK with being run that hard for that long... and does the car have sump baffles :P

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

    • I know why it happened and I’m embarrassed to say but I was testing the polarity of one of the led bulb to see which side was positive with a 12v battery and that’s when it decided to fry hoping I didn’t damage anything else
    • I came here to note that is a zener diode too base on the info there. Based on that, I'd also be suspicious that replacing it, and it's likely to do the same. A lot of use cases will see it used as either voltage protection, or to create a cheap but relatively stable fixed voltage supply. That would mean it has seen more voltage than it should, and has gone into voltage melt down. If there is something else in the circuit dumping out higher than it should voltages, that needs to be found too. It's quite likely they're trying to use the Zener to limit the voltage that is hitting through to the transistor beside it, so what ever goes to the zener is likely a signal, and they're using the transistor in that circuit to amplify it. Especially as it seems they've also got a capacitor across the zener. Looks like there is meant to be something "noisy" to that zener, and what ever it was, had a melt down. Looking at that picture, it also looks like there's some solder joints that really need redoing, and it might be worth having the whole board properly inspected.  Unfortunately, without being able to stick a multimeter on it, and start tracing it all out, I'm pretty much at a loss now to help. I don't even believe I have a climate control board from an R33 around here to pull apart and see if any of the circuit appears similar to give some ideas.
    • Nah - but you won't find anything on dismantling the seats in any such thing anyway.
    • Could be. Could also be that they sit around broken more. To be fair, you almost never see one driving around. I see more R chassis GTRs than the Renault ones.
    • Yeah. Nah. This is why I said My bold for my double emphasis. We're not talking about cars tuned to the edge of det here. We're talking about normal cars. Flame propagation speed and the amount of energy required to ignite the fuel are not significant factors when running at 1500-4000 rpm, and medium to light loads, like nearly every car on the road (except twin cab utes which are driven at 6k and 100% load all the time). There is no shortage of ignition energy available in any petrol engine. If there was, we'd all be in deep shit. The calorific value, on a volume basis, is significantly different, between 98 and 91, and that turns up immediately in consumption numbers. You can see the signal easily if you control for the other variables well enough, and/or collect enough stats. As to not seeing any benefit - we had a couple of EF and EL Falcons in the company fleet back in the late 90s and early 2000s. The EEC IV ECU in those things was particularly good at adding in timing as soon as knock headroom improved, which typically came from putting in some 95 or 98. The responsiveness and power improved noticeably, and the fuel consumption dropped considerably, just from going to 95. Less delta from there to 98 - almost not noticeable, compared to the big differences seen between 91 and 95. Way back in the day, when supermarkets first started selling fuel from their own stations, I did thousands of km in FNQ in a small Toyota. I can't remember if it was a Starlet or an early Yaris. Anyway - the supermarket servos were bringing in cheap fuel from Indonesia, and the other servos were still using locally refined gear. The fuel consumption was typically at least 5%, often as much as 8% worse on the Indo shit, presumably because they had a lot more oxygenated component in the brew, and were probably barely meeting the octane spec. Around the same time or maybe a bit later (like 25 years ago), I could tell the difference between Shell 98 and BP 98, and typically preferred to only use Shell then because the Skyline ran so much better on it. Years later I found the realtionship between them had swapped, as a consequence of yet more refinery closures. So I've only used BP 98 since. Although, I must say that I could not fault the odd tank of United 98 that I've run. It's probably the same stuff. It is also very important to remember that these findings are often dependent on region. With most of the refineries in Oz now dead, there's less variability in local stuff, and he majority of our fuels are not even refined here any more anyway. It probably depends more on which SE Asian refinery is currently cheapest to operate.
×
×
  • Create New...