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Question about oil filters and oil for modified wrx.

3K views 7 replies 5 participants last post by  MainFrame 
#1 ·
So greatest news of all first in getting my wrx with a fresh new ej255 block and can't wait. The guy who I had do it told me after 400 miles change oil and use the wicks oil filter. I was just curious how much of a difference does it make if I use wicks or just use a Generic brand like fram.
 
#4 ·
The main thing to look at when picking a filter is the bypass pressure. MANY oil filters don't have the same bypass pressure as the OEM filter.. does that make a noticeable difference? I doubt it, but you may end up with more oil bypassing the filter than what the engine was designed for, and that could mean dirtier oil over a period of time. For what it's worth, WIX filters do have the correct bypass pressure.. and when compared to most other brands the internal construction and filtration level is superior (internally WIX and NAPA Gold filters are identical as far as I know). WIX is what I run on all of my vehicles.


As far as oil, turbo charged engines kind of need synthetic. You could run conventional (I wouldn't), but turbos are hard on oil and I would expect it to shear rather quickly. If it's a stock block (OEM clearances), then I would run the weight which is recommended in the owner's manual (typically 5w-30). If you are going to be driving the car hard, and/or live in an unusually hot climate I would run 5w-40 (or 10w-40). When it comes to the brand you're not going to notice a ton of difference (you can compare used oil analysis data on bobistheoilguy.com). There have been several reports of Mobil 1 5w-30 synthetic performing poorly in turbo Subaru engines (abnormally high shear over a relatively short period of time.. other weights of the same brand don't have this problem), so I would avoid that. Also, the regular line of Royal Purple oil has some issues with it (frothing being one) which I would also avoid. Other than that it's mostly up to personal preference. The vast majority of brand name synthetics will have similar performance and should be plenty sufficient for normal driving. As for myself, I run Castrol Edge 5w-30 in three of our vehicles, and Motul 300v Chrono 10w-40 in my modified WRX. I have also used Amsoil in the past with good results.
 
#6 ·
The main thing to look at when picking a filter is the bypass pressure. MANY oil filters don't have the same bypass pressure as the OEM filter.. does that make a noticeable difference? I doubt it, but you may end up with more oil bypassing the filter than what the engine was designed for, and that could mean dirtier oil over a period of time. For what it's worth, WIX filters do have the correct bypass pressure.. and when compared to most other brands the internal construction and filtration level is superior (internally WIX and NAPA Gold filters are identical as far as I know). WIX is what I run on all of my vehicles.


As far as oil, turbo charged engines kind of need synthetic. You could run conventional (I wouldn't), but turbos are hard on oil and I would expect it to shear rather quickly. If it's a stock block (OEM clearances), then I would run the weight which is recommended in the owner's manual (typically 5w-30). If you are going to be driving the car hard, and/or live in an unusually hot climate I would run 5w-40 (or 10w-40). When it comes to the brand you're not going to notice a ton of difference (you can compare used oil analysis data on bobistheoilguy.com). There have been several reports of Mobil 1 5w-30 synthetic performing poorly in turbo Subaru engines (abnormally high shear over a relatively short period of time.. other weights of the same brand don't have this problem), so I would avoid that. Also, the regular line of Royal Purple oil has some issues with it (frothing being one) which I would also avoid. Other than that it's mostly up to personal preference. The vast majority of brand name synthetics will have similar performance and should be plenty sufficient for normal driving. As for myself, I run Castrol Edge 5w-30 in three of our vehicles, and Motul 300v Chrono 10w-40 in my modified WRX. I have also used Amsoil in the past with good results.
I'll be in Las Vegas for majority of the time with this next oil cycle. Would you reccomend 5w-40? Temps can reach up to 120.
 
#5 ·
I have never and will never use anything other than Subaru oem oil filters on my car. The two performance shops I have dealt with (IAG performance and Agile automotive) use nothing but Subaru oem filters. Even on their big hp builds.
 
#8 ·
From what I've seen, Subaru has used various manufacturers throughout the years, with vastly different levels of internal quality. You might be using nothing but OEM filters, but that doesn't mean you've been using the same filters every time.



I'll be in Las Vegas for majority of the time with this next oil cycle. Would you reccomend 5w-40? Temps can reach up to 120.

I would.. that's not to say that it probably wouldn't be alright with 5w-30, but I feel like a 40 weight gives you a little extra piece of mind when the temperatures are >100ºF. I know when I was running Rotella 5w-40 in my WRX it would still get pretty thin when stuck in stop and go traffic here in TX when it was >100ºF outside, despite being 40 weight. I don't know how hot my oil was actually getting, but the oil pressure at idle would fall to around 11-12psi, when under normal conditions it would run 18-19psi fully warmed up. Oil pressure would have gone even lower had I been running 5w-30.



Here's a copy of the oil page from the owner's manual for a 2010 WRX.. Las Vegas summers would fall under "severe driving conditions".

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