10w50 or 5w40 for sti engine running 400bhp ?
19 July 2009, 09:41 PM
#1
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10w50 or 5w40 for sti engine running 400bhp ?
I've been using Silkolene Pro s 10w50 in my classic sti engine for a while but after speaking to Opie oils i've ordered 5w40. The reason for this is the car is used everyday to and from work and the 5w40 will give me better protection from cold.
After reading a few posts on here i'm worried that 5w40 maybe too thin !
Anyone got any ideas if it'll be ok for me ?
After reading a few posts on here i'm worried that 5w40 maybe too thin !
Anyone got any ideas if it'll be ok for me ?
19 July 2009, 09:51 PM
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Personally I think the 5w-40wis fine and is what I use only running 340bhp tho but there are some very high grade oils about that will cope easily.
If you are still concerned how about running the 5w-40 in the winter then changing to the 10w-40 in the summer
every ones a winner 
If you are still concerned how about running the 5w-40 in the winter then changing to the 10w-40 in the summer
every ones a winner
19 July 2009, 09:58 PM
#5
i got 10w in my car at mo but going to go for 15w as the engine is gonna be running hotter. 5w is good for warming up quickly but just warm your car up that little longer and will be fine
19 July 2009, 10:07 PM
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On the other hand i've been told that a 15w is too thick !
I don't want to start another massive oil thread as there's been enough of them
I don't want to start another massive oil thread as there's been enough of them
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19 July 2009, 10:09 PM
#8
The thing is, 10w is the cold end, When cold the thinner the better, Flows around the engine more quickly, Once hot & using 5w40, You have the whole spectrum upto 40, so you are protected from 5 upwards Etc...
Dean
Dean
19 July 2009, 10:16 PM
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So the next question is will the 40w be good enough to cope with the heat associated with running the power that I am ?
19 July 2009, 10:23 PM
#11
Cheers
Dean
19 July 2009, 10:30 PM
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I cannot remember what the Temp is that 5w40 starts to break down/shear but opie will tell you im sure, I also think that if your oil temps are exceeding that, You really need to invest in a futher External Oil Cooler !! & i doubt that is the case, I was running 330 /300 on a classic for best part of 30K miles, No issues.. You really need to know what your Oil temps are, That is the concerning factor ..
Cheers
Dean
Cheers
Dean
19 July 2009, 10:30 PM
#14
If you don't want to be bothered with changing from one grade to another from winter to summer, then a quality 10w/40 such as Millers CFS will be fine all year round.
JohnD
19 July 2009, 10:38 PM
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The "W" refers to the cold performance end of the grade, so you won't get a 40w - that would be like treacle when cold!
If you don't want to be bothered with changing from one grade to another from winter to summer, then a quality 10w/40 such as Millers CFS will be fine all year round.
JohnD
If you don't want to be bothered with changing from one grade to another from winter to summer, then a quality 10w/40 such as Millers CFS will be fine all year round.
JohnD
It's not really the weather that's the issue. It's mainly that within a couple of minutes of leaving home i'm on the motorway and the same when leaving work. Just thought the 5w would give me better protection than the 10w that i'm currently using.
The cars pretty loud so can't wait around for it to warm up before leaving !
20 July 2009, 07:29 AM
#16
Hi mate I just serviced my classic impreza turbo 2000 103k on the clock with silkolene pro s 5w40 ester based oil based on opie oils recomendations.
the car runs fine but I hear more noise now so i think Im gonna change to a ester based 10w40 dont think it will matter much to me 5w40 is a bit of overkill in my std engine and we dont really see thetype of cold temps to benifit from using a 5w40
so a 10w40 ester based is next on my list and should be a good compromise between the 5w40 and 15w50 think im gonna use motul v300 ester based for the win. Its a bit more expensive but we are prepared for the cost when u drive an impreza!
the car runs fine but I hear more noise now so i think Im gonna change to a ester based 10w40 dont think it will matter much to me 5w40 is a bit of overkill in my std engine and we dont really see thetype of cold temps to benifit from using a 5w40
so a 10w40 ester based is next on my list and should be a good compromise between the 5w40 and 15w50 think im gonna use motul v300 ester based for the win. Its a bit more expensive but we are prepared for the cost when u drive an impreza!
Last edited by ScoobyNudge; 20 July 2009 at 07:45 AM.
20 July 2009, 04:38 PM
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I used to run 5w-40 silkolene pro s in my 95wrx , found it a bit to thin and had more engine noise , now run same oil but 10w-50 , runs well and oil temp rarely goes above 90
20 July 2009, 05:39 PM
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Right,I have no idea whether to put the 5w40 in my car now or not 
Opie oils definately recommended it to me after asking what mods/style of driving etc and bearing in mind it's not tracked.
Opie oils definately recommended it to me after asking what mods/style of driving etc and bearing in mind it's not tracked.
20 July 2009, 06:38 PM
#20
10w40 or 50 is a safer bet in a higher milage car. my car never gets tracked just daily driver.
20 July 2009, 09:12 PM
#23
Also known as daz
Been running silkolene pro s 10w50 since i've owned the scoob 3 years ago, it's now done 97k miles and engine is sweet as, hardly drinks the stuff, typically 0.5 litres between 7500 miles.
Scoobs like being warmed up and cooled down gently anyway, don't listen to gossip and hearsay too much just listen to your engine when the stuff is in.
Scoobs like being warmed up and cooled down gently anyway, don't listen to gossip and hearsay too much just listen to your engine when the stuff is in.
21 July 2009, 02:24 PM
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i use 10w 60 fully just to really upset the apple chart lol and ive bene using it for a long time now im running 350bhp/340 fast road i always let my car warm up for 6-7 minutes before driving it and subaru tell you to do it in there hand book to, as your piston are horizontel and gravity will pull on them and the crank will be pulling them in another direction so you want some good oil pressure with some good oil temps lubing them up,
21 July 2009, 04:01 PM
#25
If worried about prolonged high revs (therefore oil getting very hot/thin), then a 10W-50 (a '60' hot weight isn't recommended) such as Silkolene Pro R should be able to comfortably handle road and trackday work.
Last edited by joz8968; 21 July 2009 at 09:07 PM.
