10W60 vs 5W30 (as per manual) Oil ?
 

I see places like RCM sell oil for WRX/STI Impreza's like Castrol Edge that are 10W60.

The car manual says 5W30 is recommended.

Anyone shed any light on which to use and why 10W60 would be better?

Thanking you! :)

No expert but think 10/60 oil is more suited to high power cars that are used on track days:thumb:

I would not use any of they oils ,10w40 for standard or a 10w50 for one thats running a bit more boost than standard or does track days.

Hi

Unfortunately there are some people that are a bit old fashioned with oil recommendations, they suggest the thickest thing, thinking it protects more. Years ago, you needed thick oils in performance cars as the oils were rubbish, you'd put in a 20w-50 and it would end up a 20w-40 or 20w-30 quite quickly, so it wasn't practical to use a thinner grade. Also, older engines have larger tolerances, so larger gaps for the oil to flow around.

Modern oils are better than the old mineral oils, so if you put in a 5w-30, it's likely to come out as a 5w-30. Also, modern engines are tighter, so thick oils do not flow well around them and it's the flow that helps to protect.

As your handbook says 5w-30, that's a sensible place to start, there are guys on here that have done well over 100k on 5w-30. If lightly modified, go for a 5w-40, or heavily modified use a 10w-50.

Cheers

Tim

I use Millers 10w-50 with prodrive and a map at 330bhp. I daily it and boost it most days, does this seem the most suitable?

Hi

If it goes on track as well as the road, then that is ideal. If it's just road use, I'd go for a good 5w-40 next time.

Cheers

Tim

I was going to use 5w-40 for winter and 10w-50 for summer, as the grades to temp of those seasons make sense.

Hi

I would just stick with 5w-40 all year round, unless it gets track use in the summer.

Cheers

Tim

I was recommended Millers Nanodrive 10w60 by opieoils over the phone. I have a 411hp jdm bugeye STI, forged rods and pistons, so should I really be using 10w50?

Hi

Who was it that recommended it?

Sometimes we get someone who says 'I want a 10w-60 for my Impreza' and some of the guys that don't do recommendations sell it. If it was me ( I take most of the calls about oils) I either didn't know it was for an Impreza or there was a reason for using it (like fuel dilution). Unless your engine was either suffering from fuel dilution or high oil consumption, I would have recommended a 10w-50 in it.

Cheers

Tim

It was a freshly built engine. we were recommended and sold 10w40 mineral for running in and a few cans of 10w60, both millers. I don't know who it was we spoke to as it was back in early January. I have 2 more cans of 10w60 left and i'm literally in the middle of changing my sump to a twinscroll one, so ideal time to change oil grades. Am I not safe using the remaining 10w60?

Hi

I have no idea who recommended a 10w-60, or why they would have done. 10w-40 Millers CRO is ideal for the running in.

It's not that the 10w-60 is unsafe in yours, but a 10w-50 is better. If you let me have the order details, I'll get the two cans of 10w-60 swapped for the 10w-50.

Cheers

Tim

Nice one. I'll dig out my details and give you guys a ring at some point.

Hi,

I have a 2018 WRX STI which is stock for now, but is gonna be running around 360BHP by the end of the year. I am currently running some Motul 300V 10W60 (which I, by reading this topic, understood was a mistake). It is my daily driver and I live in the swiss Alps, therefore I regularly (5-10x/month) drive mountain passes (between 10-25 min of pretty hard driving). When I'll be running the 360BHP, it'll have an IAG competion oil pan, a mishimoto oil cooler and a koyorad radiator. With all of that in mind, what grade oil would recommend (gonna go with Motul 300V) : 5W30 ; 5W40 ; 5W50 ?

Quentin Guilbaud