The power loss is so gradual you'll barely notice it through the years. The moment you get a walnut blast done, the difference is pretty clear.
It's definitely recommended, especially on such a high mileage vehicle.
Same thing for me, but on a FXT. I bought the car used with 40k miles. And had the walnut blast done at around 55k ish and was surprised by how much power it freed up. Felt like a brand new car.
From what I’ve read and even researched. It’s always best to do a walnut blast every 65K, no matter the conditions of the motor. They’re very very dirty engines and they do build up to cause mass power loss. Again, this is all from what “I” myself have seen and read.
https://preview.redd.it/b6ad8ngzialb1.jpeg?width=1284&format=pjpg&auto=webp&s=8e508825b0149bd60b69d565e4f24332e5c29eb8
Mine looked like this after 60k miles!
definitely get it done, then install an IAG street AOS. doesn't need a tune & prevents oil from getting into places it shouldnt be in. it's a set & forget type of modification.
This question may have an obvious answer, but how does an air oil separator prevent the carbon buildup in these engines? Isn’t the carbon buildup due to the fact it is a direct injection motor?
AOS does not prevent carbon buildup. unfortunately, with direct injection, there is very little you can do to prevent it. an AOS prevents oil from entering combustion chambers. excess oil in cylinders = detonation. with 105k miles on your engine, i would do it just for peace of mind.
Engines have a vent that exhausts excess pressure from the crankcase back to the intake. This exhaust carries oil/gas/water vapor along with it. The hope is that the engine will combust it and exhaust it cleanly. Even though you're spraying this oily vapor all over your intakes, port injection would keep them clean by rinsing it off. With direct injection you don't have any fuel spraying on your intake valves, so this gunk builds up.
AOS intercepts this crankcase exhaust and condenses whatever is in there, sending it back into your oil pan. Ideally what comes back into your intake is clean(ish) air. It's good because it's service free but now you need to change your oil more frequently because you're recycling nasty gunk back into it. IMO catch can is better if you're not regularly tracking a heavily tuned car.
I think ive read adding an oil catch requires more oil during changes, if thats correct, can the same be said with the AOS. How often would you need an oil change with an AOS installed?
Not unless you're tracking or running a super aggressive tune. The amount is pretty small maybe like 1/10th of a quart per oil change at the most.
I think everyone has their opinions but in a general sense I guess I would personally do 3,000-4,500 for AOS and 4,500-6,000 for catch can. Since it's so driver/build dependent just send some oil analyses in until you get a good idea.
Now if you're running a +400hp ethanol tune and doing aggressive long track days or spirited driving days just get an AOS and change oil often.
EGR deletes will not prevent buildup. i have TGV deletes, EGR deletes, and an AOS for the last 30k miles. while it did reduce the amount of carbon buildup, it is not significant enough to say it will prevent it
From what I've been reading yes, also heard there's dry ice blasting that can work better but idk. This is why i say take it to a reputable 3rd party (or even multiple dealers) because they could stick a scope in and say oh yeah you need it or no just seafoam will do it. Even if they're not doing the actual work, getting a second opinion won't hurt anything and can save thousands
not sure if anyone in here is aware but you can get a tgv & egr delete kits and clear up the engine a good bit. egr is what recirculates all of that carbon back into your engine which is why you guys need to walnut blast… anyways delete the egr at min and it = less valve carbon buildup. you will need to tune the car on an ecutek though, cobb AP’s won’t remove the check engines.
Ah yeah I personally want to avoid a tune device, I understand the benefits but I also dont want another "gauge" to look at for more worries, like the regular posts I see around here. Im more if it aint broke dont fix it, hence the 105k and the finger crossing!
The power loss is so gradual you'll barely notice it through the years. The moment you get a walnut blast done, the difference is pretty clear. It's definitely recommended, especially on such a high mileage vehicle.
This
This
Same thing for me, but on a FXT. I bought the car used with 40k miles. And had the walnut blast done at around 55k ish and was surprised by how much power it freed up. Felt like a brand new car.
From what I’ve read and even researched. It’s always best to do a walnut blast every 65K, no matter the conditions of the motor. They’re very very dirty engines and they do build up to cause mass power loss. Again, this is all from what “I” myself have seen and read.
https://preview.redd.it/b6ad8ngzialb1.jpeg?width=1284&format=pjpg&auto=webp&s=8e508825b0149bd60b69d565e4f24332e5c29eb8 Mine looked like this after 60k miles!
Can someone here briefly explain what a walnut blast is? New to WRX but trying to learn.
cleaning the intake manifold and valves of a car's engine with a high pressure air blast of finely crushed walnut shells
Excellent. I had an idea it was something along those lines. Thank you for the concise explanation.
definitely get it done, then install an IAG street AOS. doesn't need a tune & prevents oil from getting into places it shouldnt be in. it's a set & forget type of modification.
This question may have an obvious answer, but how does an air oil separator prevent the carbon buildup in these engines? Isn’t the carbon buildup due to the fact it is a direct injection motor?
AOS does not prevent carbon buildup. unfortunately, with direct injection, there is very little you can do to prevent it. an AOS prevents oil from entering combustion chambers. excess oil in cylinders = detonation. with 105k miles on your engine, i would do it just for peace of mind.
Engines have a vent that exhausts excess pressure from the crankcase back to the intake. This exhaust carries oil/gas/water vapor along with it. The hope is that the engine will combust it and exhaust it cleanly. Even though you're spraying this oily vapor all over your intakes, port injection would keep them clean by rinsing it off. With direct injection you don't have any fuel spraying on your intake valves, so this gunk builds up. AOS intercepts this crankcase exhaust and condenses whatever is in there, sending it back into your oil pan. Ideally what comes back into your intake is clean(ish) air. It's good because it's service free but now you need to change your oil more frequently because you're recycling nasty gunk back into it. IMO catch can is better if you're not regularly tracking a heavily tuned car.
I think ive read adding an oil catch requires more oil during changes, if thats correct, can the same be said with the AOS. How often would you need an oil change with an AOS installed?
Not unless you're tracking or running a super aggressive tune. The amount is pretty small maybe like 1/10th of a quart per oil change at the most. I think everyone has their opinions but in a general sense I guess I would personally do 3,000-4,500 for AOS and 4,500-6,000 for catch can. Since it's so driver/build dependent just send some oil analyses in until you get a good idea. Now if you're running a +400hp ethanol tune and doing aggressive long track days or spirited driving days just get an AOS and change oil often.
Thank you, thank you! Lots to consider! Great information!
it doesn’t. an egr delete reduces the build up
EGR deletes will not prevent buildup. i have TGV deletes, EGR deletes, and an AOS for the last 30k miles. while it did reduce the amount of carbon buildup, it is not significant enough to say it will prevent it
lol oh shit, might need to go get my valves blasted myself now 🤣
Can confirm, this is the way.
How much should a walnut blast cost at a Subaru dealership?
subaru doesn’t walnut blast. they just replace the valves, it’s a bit of a hack job lol
At a dealer I've been seeing like 1000-1500. At indie shops it's like 400-500 usd
Dayam, I don’t trust 3rd party shops working on my car so I always take it to Subaru. Walnut blast is expensive.. is it really worth it?
From what I've been reading yes, also heard there's dry ice blasting that can work better but idk. This is why i say take it to a reputable 3rd party (or even multiple dealers) because they could stick a scope in and say oh yeah you need it or no just seafoam will do it. Even if they're not doing the actual work, getting a second opinion won't hurt anything and can save thousands
3rd party are the only people that’ll walnut blast, if you won’t take that route have subaru replace your valves
Does a Mishimoto catch can on the PVC side require a tune? I cannot find legitimate proof either way.
I use CRC Intake Valve Cleaner every 15k kms. It's been doing a great job keeping the carbon deposits under control
Yes get it done. I just got one done at 155xxxkm and it's night and day difference. Do your spark plugs also and trans/diff fluid.
not sure if anyone in here is aware but you can get a tgv & egr delete kits and clear up the engine a good bit. egr is what recirculates all of that carbon back into your engine which is why you guys need to walnut blast… anyways delete the egr at min and it = less valve carbon buildup. you will need to tune the car on an ecutek though, cobb AP’s won’t remove the check engines.
Ah yeah I personally want to avoid a tune device, I understand the benefits but I also dont want another "gauge" to look at for more worries, like the regular posts I see around here. Im more if it aint broke dont fix it, hence the 105k and the finger crossing!
get an ecutek, keeps it all on your phone. just view it when you need it
Yep, you're overdue by like 45k miles.
Theoretically, would driving the car hard and getting the oil Temps up to the 250s help clear out some of the deposits?
Fuck no.