Subaru EJ205 Stroker motor (2.1) Oil weight Q

[rwenz]

Recently had a stroker motor built for my 02 Subaru WRX
Changes from stock included:

EJ257 Crankshaft
11mm oil pump
92.5mm stroker pistons

Clearances were:

Mains:
.0015
.002
.002
.002
.0015

Rods:
.0018

Car was broken in on 10w30 break-in oil. Oil pressures were within stock pressures based on data from forums (idle ~20psi; cruising 70-75psi @3500 rpm).

From what I have read, these clearances on my build are within Subaru spec - likely on the loose side. I'd like to run a thicker weight oil. My engine builder suggested Valvoline VR1 or Brad Penn oils (car does not have cats). He gave me a wide range of oil weights I could run - just wanted opinions. Should I try thicker viscosity oil and just monitor oil pressures (FYI stock EJ205 is 5w30)?

I have been leaning toward a 5w-40 or 10w-40 at this time.

Thanks in advance.

 

[Rand]

Yes even the stock version of that engine does very well on a 5w40.

One of the most popular oils for that engine is rotella T6 5w40.

It may have a higher amount of additives vs regular pcmo oils but I haven't seen a VOA in years.

 

[901Memphis]

Mobil 1 High Mileage 10w40 is thick and loaded, with a 3.9 HTHSV and meets API SN + ACEA A3/B3 . Since it's a 40 grade it has the higher ZDDP limits too.

If you are going to be looking at different viscosity to monitor oil pressure make sure you are paying attention to HTHSV, which is the best way to determine overall viscosity of the oil inside your engine; especially a hard working turbo one.

Oil temperatures are also important, maybe make some notes about temperature/pressure/viscosity and report back.

 

[Olas]

Redline 5w30

 

[bluesubie]

Any 5W-40, Mobil 1/Castrol 0W40 or perhaps Mobil 1 High Mileage 10w40 if you track it or for summer.

Do you plan to track it? What weights did your builder say were fine? VR1 or BP would be good as well, although you could probably run something from Walmart if that's what you want to do. How often do you plan to change the oil?

 

[rwenz]

Originally Posted By: bluesubie

Any 5W-40, Mobil 1/Castrol 0W40 or perhaps Mobil 1 High Mileage 10w40 if you track it or for summer.

Do you plan to track it? What weights did your builder say were fine? VR1 or BP would be good as well, although you could probably run something from Walmart if that's what you want to do. How often do you plan to change the oil?

Thanks!

No plans to track it at this time. Looking to swap this engine into the Factory Five 818C in a couple years which could alter my thoughts on tracking this engine, but no plans at this time.

Engine builder was pretty vague about oil weights - he was a bigger advocate of brand (BP/Mobil 1 race oil). He said I would be OK with a 30W oil, but at this point in my build, I feel as though I will be the best judge of oil viscosity as I log the pressures, UOA, and oil temperatures since this is not a stock build (nor was it common for a customer to request a stroker build).

Looking to change the oil at 5,000 mile intervals. Will send analysis and see what they say. The hardest I drive this car is during 1-2 WOT logs a month from 2500-7000 rpms to try to tune this 2.1.

At this point, I am between Mobil 1 High Mileage 10w40 and Rotella T6 5W-40 (Rotella based on what I've read on NASIOC and both oils are readily available). Heck, I feel like mixing the two just so I could get something in-between.

 

[901Memphis]

I wouldn't mix the two as you may throw off the additive package balance, if you want to mix try Redline which uses a similar additive package throughout the lineup although I'm sure you can get exactly what you want with one off the shelf product.

If you do find you have excessive oil pressure I would try Pennzoil Ultra 5w30 which is what they use in the 1200+ HP Hennessy venom.

 

[Garak]

As was already mentioned VR1 in 10w30 might be a reasonable option. It may have a higher HTHS than a normal ILSAC 10w30, since it doesn't have to meet any ILSAC requirements. Of course, I don't know for sure, since HTHS isn't on their data sheet. Perhaps Ashland may answer that question if posed to them.