AOS or catch can for track use - Page 2 - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

mhiscott · 07-02-2018, 11:40 PM

I've got 50,000 kms (just over 30k miles) with oil changes every 3k kms. I don't buy that there'd be significant enough delta in ring condition etc to make a measurable difference this early in the engine's life when it's been well maintained.

Regardless of the engine will deal with a pressurized crankcase because it's physically more tight and in "better condition" doesn't take away from the fact crankcases don't like being pressurized as a rule, regardless of if it will take it at this point.

While I was originally leaning towards going back to VTA because numerous tuners and folks have suggested it, I almost wonder if it's just the safer advice to give people because it's easy to screw up a sealed system install if it isn't done correctly.

I also have a 2018 STI. It has a boost rated oem pcv valve which blocks intake charge air from getting into the crankcase. It's something like 3/8th NPT iirc. I don't see why I shouldn't be able to order a replacement STI valve at the dealer, thread it into a female NPT to male barb adapter, and put it in line with a sealed can on the PCV side. I could keep the OEM pcv in the block too, even if it's sort of redundant.

I don't see why the above setup wouldn't work a valve known to be reliable for multiple hundreds of thousands miles on OEM Subaru applications (insert joke here about no boosted EJ25 cars making it that far lol).

CSG Mike · 07-02-2018, 11:44 PM

You're the one asking, I'm providing real world feedback. If you want a check valve or AOS, by all means! It won't negatively impact the performance of the car at all.

mhiscott · 07-03-2018, 12:24 AM

I think it must be something else about our setups that must be different, but I can't think what it could be. Your PCV valve must be working well, it would be interesting to see how it seals up with various psi values on a test bench with compressed air.

I am leaning towards trying a sealed setup with a FI proven OEM valve. Worst case scenario, I could convert them to VTA if I have issues. I realize VTA is a safer bet, but I feel strange discounting sealed setups without explicit reasoning for why VTA is a better option than a properly setup sealed can. This is assuming a reliable boost isolation method is used.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
FS: Hawk track brake pads, DTC-30 front/HP+ rear, 90% life left, best track day combo	tampaSi	Brakes, Suspension, Chassis	4	05-27-2017 03:31 PM
MVP Track Time 2013 Great Lakes/Midwest Track Dates	Feffman	Great Lakes	5	09-07-2013 02:39 PM
Track Day: Upcoming Joey G Open Track Day for ADVANCED Drivers, Aug 20 NJMP Lightning	AZP Installs	NY / NJ / CT / PA	11	08-21-2012 12:31 AM
Track Day: Upcoming Joey G Open Track Day for ADVANCED Drivers, Aug 20 NJMP Lightning	AZP Installs	Tracking / Autocross / HPDE / Drifting	0	08-14-2012 07:46 PM
Element Tuning Track Tested and Track Proven FRS Video	Element Tuning	Tracking / Autocross / HPDE / Drifting	47	07-17-2012 05:12 PM

07-02-2018, 11:40 PM	#15
mhiscott Senior Member Join Date: Dec 2013 Drives: 2013 FRS Location: NL, Canada Posts: 190 Thanks: 37 Thanked 39 Times in 29 Posts Mentioned: 6 Post(s) Tagged: 0 Thread(s)	I've got 50,000 kms (just over 30k miles) with oil changes every 3k kms. I don't buy that there'd be significant enough delta in ring condition etc to make a measurable difference this early in the engine's life when it's been well maintained. Regardless of the engine will deal with a pressurized crankcase because it's physically more tight and in "better condition" doesn't take away from the fact crankcases don't like being pressurized as a rule, regardless of if it will take it at this point. While I was originally leaning towards going back to VTA because numerous tuners and folks have suggested it, I almost wonder if it's just the safer advice to give people because it's easy to screw up a sealed system install if it isn't done correctly. I also have a 2018 STI. It has a boost rated oem pcv valve which blocks intake charge air from getting into the crankcase. It's something like 3/8th NPT iirc. I don't see why I shouldn't be able to order a replacement STI valve at the dealer, thread it into a female NPT to male barb adapter, and put it in line with a sealed can on the PCV side. I could keep the OEM pcv in the block too, even if it's sort of redundant. I don't see why the above setup wouldn't work a valve known to be reliable for multiple hundreds of thousands miles on OEM Subaru applications (insert joke here about no boosted EJ25 cars making it that far lol).

07-02-2018, 11:44 PM	#16
CSG Mike Join Date: Jul 2012 Drives: S2000 CR Location: Orange County Posts: 14,562 Thanks: 8,942 Thanked 14,211 Times in 6,854 Posts Mentioned: 970 Post(s) Tagged: 14 Thread(s)	You're the one asking, I'm providing real world feedback. If you want a check valve or AOS, by all means! It won't negatively impact the performance of the car at all.

07-03-2018, 12:24 AM	#17
mhiscott Senior Member Join Date: Dec 2013 Drives: 2013 FRS Location: NL, Canada Posts: 190 Thanks: 37 Thanked 39 Times in 29 Posts Mentioned: 6 Post(s) Tagged: 0 Thread(s)	I think it must be something else about our setups that must be different, but I can't think what it could be. Your PCV valve must be working well, it would be interesting to see how it seals up with various psi values on a test bench with compressed air. I am leaning towards trying a sealed setup with a FI proven OEM valve. Worst case scenario, I could convert them to VTA if I have issues. I realize VTA is a safer bet, but I feel strange discounting sealed setups without explicit reasoning for why VTA is a better option than a properly setup sealed can. This is assuming a reliable boost isolation method is used.

User Name		Remember Me?
Password