wrx sti dd and autocross / 300v vs ?

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I have a 2020 wrx sti that has intake, exhaust and custom tune. It’s a dd for me but, it also sees 1-2 autocross events per month (I live in california where we’re lucky to have almost a year long autocross season).

It also has an aftermarket oil cooler, aos, the killer b oil pan, pickup and baffle. It also has the cylinder 4 cooling mod for any Subaru geeks that might be wondering if I took ALL the protective measures possible up front (I did everything I could think of).

The question comes down to what oil should I run for a combo of dd (I wfh now so it doesn’t really see a daily commute anymore. Just occasional trips to places for errands) and autocross. I changed to Motul 300v 5w-40 from the factory. Should I stick with the 300v or would it be best to move to something like Castrol 0w-40?

I have gone through a bunch of the other wrx sti threads but most of them look like they’re just dd’s and I’m wondering if the monthly autocross events are enough to make a difference in what oil I should run.
 
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60-80 seconds at a time at full clip isn't enough to stress the oil that much. Usually by the time you idle up to the start gate and idle back to the grid, you've got warm up/cool down covered. You're running a good oil, probably not going to take much more life out of it than you would if you were standing on it getting on an on-ramp.

I never found AX to be that stressful on my cars, now track days on the other hand.....
 

KJH

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Depends on how hard you drive at autocross and how long/intense the courses are setup, and how many runs you get. If you drive 75% at a 45 second parking lot course and get 5-7 runs, normal maintenance(harsh conditions in manual) should be fine even at 2x a month year round. If its cones on a road circuit/long course 1:30+ min runs autox and you are pushing it 100%, high quality euro(castrol or mobil 1 0w-40 etc) with a 3-4k interval. The latter example is what the events around me tend to be and thats what I do, and maybe extra for you since you are turbo. I'm sure subaru has optimized their cooling systems for the flat-4, but that is a alot of hot stuff crammed into a tiny space in that cali heat.
 

dustinh

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Thanks everyone. Our events usually are around 60-80 seconds, 5 runs. The catch is, during summertime the temps are often close to 100* if not over that. Is there any reason not to run an oil like 300v as a dd? I thought I read something a while back about higher zinc oils causing issues with catalytic converters. I haven’t checked what the zinc level is in 300v compared to other oils but this may also be a non-issue?
 
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Thanks everyone. Our events usually are around 60-80 seconds, 5 runs. The catch is, during summertime the temps are often close to 100* if not over that. Is there any reason not to run an oil like 300v as a dd? I thought I read something a while back about higher zinc oils causing issues with catalytic converters. I haven’t checked what the zinc level is in 300v compared to other oils but this may also be a non-issue?
Does it burn significant amounts of oil? If not, then it doesn't matter. 300v is very good oil, the only reason to not run it is price or warranty concerns.
 
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Run motul xcess 5w40. You arent getting out of 2nd gear or putting a real heavy load during an auto cross event. Even if oil temps see 240 thats nothing.
X-cess is a good choice and most any high SAPS xW-40. I’m a firm believer in high SAPS oils in an EJ25x. X-cess is what IAG specs in their built EJ’s. If you feel like saving some money go with any other high SAPS Euro xW-40 (Pennzoil, M1, Castrol, etc.)

The Killer B oil pan gives you about an extra quart capacity, correct? You sound like you’re making a lot of smart decisions so kudos for that. Lot of folks get a bro-tune and are surprised when they have issues.
 

dustinh

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X-cess is a good choice and most any high SAPS xW-40. I’m a firm believer in high SAPS oils in an EJ25x. X-cess is what IAG specs in their built EJ’s. If you feel like saving some money go with any other high SAPS Euro xW-40 (Pennzoil, M1, Castrol, etc.)

The Killer B oil pan gives you about an extra quart capacity, correct? You sound like you’re making a lot of smart decisions so kudos for that. Lot of folks get a bro-tune and are surprised when they have issues.
How does the X-cess line compare to 300v?

The killer b does give some extra capacity. I’m not sure if it’s a full quart but definitely some extra.

My goal for the car was to protect the engine as much as possible and just get a bit of extra power especially as much low end torque that I could have the tuner get. I’m lucky to have a great tuner down the street from my house although California has made it illegal now to tune cars. Not sure what I’ll do in the future.
 
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Motul 300v 5W-40 is factory fill for the S209 and IIRC, from another thread, someone had pointed out that they are classified as “racing oil” and therefore, no official manufacture approval rating or API rating. Anyway, they are great oil and you can stay with 300v if you wish, just expensive and not readily available. Personally, I use Mobil 1 0W-40 in my STI.
 
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How does the X-cess line compare to 300v?

The killer b does give some extra capacity. I’m not sure if it’s a full quart but definitely some extra.

My goal for the car was to protect the engine as much as possible and just get a bit of extra power especially as much low end torque that I could have the tuner get. I’m lucky to have a great tuner down the street from my house although California has made it illegal now to tune cars. Not sure what I’ll do in the future.
300v is a race oil. It "can" be used as a daily driven oil but thats not its intent.
5w40 xcess holds:
MERCEDES-BENZ MB-APPROVAL 229.5, MERCEDES-BENZ MB-APPROVAL 226.5, PORSCHE A40, VW 502 00 505 00
The porsche A40 spec sees thousands of hours actual track time from the porsche guys across the world.
My built sti was tuned by Cobbs head tuner Mike G. After the build and tune he sent me off with motul xcess 5w40.

Edited to add credibility
 
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What's your actual oil temp in the summer? What peak engine speed?
I'd tend to use M1 0W-40 or any Euro xW-40 with Porsche A40 approval
or Porsche C40/VW 511 00 if this engine is DI. Btw, what's 'aos'?
 
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You can go 300V but you don’t have to. Everything depends on your oil temperatures and lenght.
Here is Castrol Edge 0W40 with track day and 5k OCI. 47 lap long session without break. Only modification is added oil cooler. Granted no turbo. 5k is 0W40, 4.6k is Castrol 0W30 with no track time, winter driving though.
175D9330-2505-4478-B4B5-B693C39F7A7A.jpeg
 

dustinh

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I haven’t installed an oil temp sensor yet (on the list of to do). Ironically, my 2018 wrx came with one stock. On the hottest days of autox oil temps in the wrx would get to about 245*. I expect the sti should be a little bit lower than that since I’m running an oil cooler. Peak engine speed is 7k rpm.

I think I’m gonna give the Motul Xcess a try. I’ll also see if I can post a Blackstone report from my 300v. It’s been in the car quite a long time (has about 3k miles on it but it’s been in the car going on 10 months now). Has also seen a couple of autox events in that time so I’m curious what the Blackstone numbers look like.
 
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Hate to say this, but no matter what you use - it's just a matter of time before cylinder #4 starts singing its song. Not an IF, but a WHEN. So I'd stick with Castrol 0W40, and use saved money for future rebuild fund.
 
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I would echo what others have said. While 300V is excellent it seems unnecessary in your situation.
Motul Xcess is a good choice.

Here is a recent thread that might be helpful, which includes a link to what Motul had to say about it.
 

dustinh

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Hate to say this, but no matter what you use - it's just a matter of time before cylinder #4 starts singing its song. Not an IF, but a WHEN. So I'd stick with Castrol 0W40, and use saved money for future rebuild fund.
Yeh, I also did the cylinder 4 cooling mod. Car only has 6500 miles on it so hopefully cylinder 4 will hold out a while :)
 
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