What oil to use? 2003 sti
 

Hi, I need to do an oil change and want to do it myself rather than paying garage prices.

Just need to know what oil I should use and peoples preferences,

The car is 2003 sti standard running 275

Most of the time it is used on motorway but I still like to give it a good run out and would like to do a track day soon

Also best places to purchase the oil from??

Cheers guys:thumb:

Try www.opieoils.co.uk mate. Millers fully synthetic 10-60w is what goes in mine :-)

Is that not bait thick for normal fast road driving, I'm sure I only had 10 w 40 last time it was serviced?

5w40 fully synthetic here, you may want to go 10w50 if your doing a track day but it all depends object how long you are staying out, would avoid the 10w60 as its pretty thick for a subaru

Tony

Cheers think I mite go for 40 grade again, although does the 50 grade protect ur.engine a lot more??

Is the only downside to the thicker oil slight loss in power???

If cars engine is protected more with the 50 I mite put that in instead???

Wat do you think

10-60w is o.k for a highly moddified car on a track day & if you have a moddified oil pump & performance oil filter, but for a road car I would choose a fully synthetic 5w-30, 10w-30 or 10w-40 of a reputable brand.

10w 50 Silkolene is what I use.

Wat make should I go for? Castrol shell millers??

Read above ^^^^ :thumb:

Motul ;) though I do use shell helix ultra also :D

Tony:D

why does everybody go 10/40? manual say's 5/40,more power than yes,10/50 etc but on a road car with standard BHP???

Manual says 10w40 semi or 5w40 fully synthetic, it probably also says 5w30 fully synthetic also, but im not too keen on running that really.

Tony:)

I just use what I was advised to ON HERE.

Hi

I would use a 5w-40 synthetic and you will find those through the link below.

http://www.opieoils.co.uk/c-656-5w-40.aspx

Out of those, the best ones are the Fuchs/Silkolene Pro S, Millers CFS, Motul 300V, Redline and Gulf Competition. The Motul 8100 X-Cess, Millers XFS, Fuchs Supersyn, Shell Helix and Mobil Super 3000 are good, cheaper alternatives.

In a 275bhp Impreza, a 10w-50 is a bit thick, not too bad though, but a 10w-60 is way too thick and can lead to problems. Using a thicker oil doesn't give more protection, using the right grade and quality gives the best protection.

Cheers

Tim

So shouldn`t I be using a 10w 50 in my 340bhp Blob?

10w 50 is fine mate don't worry about it. What you must understand about oil is you're trying to strike a balance between hot and cold protection. Cold protection is generally the same for all Imprezas (so a 5 or 10w is fine) it's the hot protection that's critical. This will depend on power output, how the car is driven (gently/thrashed), where it is driven (road/track). These factors should influence the hot protection. A standardish car driven gently will be okay with 5/10w 40. A tuned Impreza driven hard (as most Impreza are) on the road will be okay with 10w 50. A tuned Impreza driven on the track will be best with 10w 60 (and uprated oil pump).:)

If it's getting tracked, then the 10w-50 will be fine, but without track use, I'd go for a really good 5w-40 instead. I wouldn't worry too much, your car is on the verge of wanting a 10w-50 anyway.

Cheers

Tim

Ok, thanks, that makes sense :thumb:

It doesn`t get tracked. Why is it on the verge of wanting 10w 50 :wonder:

From the power output. Everything is running a little bit harder and getting a little bit hotter. This means your hot protection needs have gone up slightly. Oilman doesn't always give a clear and simple explanation.:D

As it's running a bit more than standard power, the engine is going to be running hotter than normal, making the oil become thinner than normal. If it gets too thin, it won't be giving enough protection and can lead to more oil being burned off, so that is when a thicker than normal oil is needed. In post 2000 Imprezas, the oil tends not to get too hot for a good 5w-40 to be effective until about 400bhp. As yours isn't that far off, a 10w-50 is nothing to worry about.

Cheers

Tim

Tim

Isn't it also true that if the base stock is the same, more additives to increase its viscosity to 50 over 40 could result in more deposits in your turbo, and that the need for "thicker" oil is dictated not by the power your car has, but how hot you run the car.

For someone who is not tracking the car, and not getting the engine regularly hotter than average, a 50 oil may actually do more harm than a 40 oil made from the same base stock.

Conversely, a lower power car that is regularly tracked and driven hard having sustained high temperature use will benefit from a 50 over a 40 oil.

0w-5w-10w is only a reflection of the oils pouring point low temperature and how fast it flows at that lower temperature, 0w is slightly different in that instead of it's viscosity, the 0w represents that it will pour at a lower temperature than say a 5w or 10w. A 10w oil may offer no more protection than a 0w oil, but the 0w will crank easier and put less strain on the battery and the starter at low winter temperatures.

People need to differentiate, like Einstein RA said, not with the power they run, because that power may only rarely be used, resulting in no overall increase in average temperature or oil thinning, but how the car is driven and the temperatures the car is driven in.

At the moment there is a lot of assumption that a 60 oil will provide more protection than a 50 oil or even a 40 oil on a car driven gently at road speeds, and that is a fallacy. If the car is not driven to the higher operating temperatures, it could actually be detrimental to fuel economy, and in the case of some oils, the viscosity modifiers may end up stuck to your turbo bearings.

I agree with the latter part 100% but the deciding factor being the power rather than how you drive the vehicle is incorrect imho.

You're right, it is due to temps, I just try to keep things simple and so many people that we deal with have absolutely no idea how hot their oil is getting. If someone lets me know oil temps, I base my answers on that. I did say if the car is getting tracked a 10w-50 would be better, a 5w-40 for road use and that is due to temps.

If an oil is made to be thin when cold and thick when hot, a lot of additives are needed. The action of the engine cuts (shears) the polymers used and the viscosity gap is reduced, ie a 5w-50 is likely to become a 5w-40 or 10w-40 quite quickly, same with a 10w-60. The most stable oils have a small viscosity gap, so if a car wants a SAE50 when hot, I'd tend to recommend a 10w-50 for mainly road use and a 15w-50 if it's mainly a track car.

Cheers

Tim

I think I`ll just use what I used last couple of times :thumb:

Motul 300v 15w50 here :)

Think I will go with the 10 40 that I had last time as is mainly motorway driven at 70 80 and thrashed prob once a month for 20 mins max

Although I do fancy a track day so would I be ok still using this 40 oil or would it be best to put 50 grade in then swap. Back after the track day??

Also is it best to swap the oil after a track day anyway???

If you go for a really good oil, it will cope with the normal road use, blasts and some track use without needing to change for a trackday or affecting the service schedule.

http://www.opieoils.co.uk/c-657-10w-40-engine-oil.aspx

The Millers CFS, Redline, Gulf Competition and Motul 300V are all top end oils and will be ideal for what you need.

Cheers

Tim

Having good clean oil is always recommended.:thumb:
That said it needs to be tempered with economics and convenience. For one track outing 10 40 should be fine, an oil change after a track day sounds like a good idea. The punishment your oil takes inside an engine is quite something.

Ok thanks for that.... I can get it serviced at scoobyworld for £100 they say they use shell helix 10 40.... Do u think it's worth changing it myself or is it worth paying the bit extra and having them do it ......

I do usually do all maintenance repairs on all my cars although this seems cheap??

Forget that iv just seen how much cheaper can get it on the link oilman has given

Defo thinking do myself again!!

Plus are standard filters ok or upgraded such as k n .... Or are they a waste of money which I'm thinking

Is the shell helix any good?? I'm asking as it's over half the price of the millers???