Subaru STi race engine, RP XPR 5W/30, 3hrs

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Subaru 2.5L (EJ25) Dual AVCS, 4-cyl Turbo, race motor, track use, 7,500 RPM, 430 WHP, BW EFR turbo.
OIL TYPE & GRADE: Royal Purple XPR 5W/30
HR on Oil: 3 Hours
Total HR on engine: 6 hours
I am using 32 ounces of TORCO per 5 gallons of premium 93 octane, the maximum amount of Torco octane booster additive, in my
fuel.
The other thing I did, which may be inappropriate, is I drained the oil cold and collected my sample after a quart or so ran out. Could that cause volatiles (fuel) to be missed?
I have no hint of impending doom. No excessive blowby for a race engine.
Engine is conservatively tuned so A/F ratios are fairly fat.
Oil pressure is good. 60-80 PSI. Nine quart capacity. I use K&N HP 3001 filters. Race engine bearing clearances of 1.5 on mains. ACL racing bearings.
Any thoughts on the high lead number? Should I continue to use the oil (for more hours)?

ALUMINUM 6
CHROMIUM 3
IRON 24
COPPER 4
LEAD 125
TIN 1
MOLYBDENUM 104
NICKEL 0
SILVER 42
TITANIUM 0
POTASSIUM 2
BORON 41
SILICON 10
SODIUM 7
CALCIUM 2496
MAGNESIUM 11
PHOSPHORUS 980
ZINC 1527
BARIUM 0

SUS Viscosity @ 210°F 56.2
cSt Viscosity @ 100°C 9.13
Flashpoint in °F 360
Fuel % TR
Antifreeze % 0
Water % 0
Insolubles % .1
 
Tuned WRX's and STis tend to be run on thicker oil in the UK.

5w40 is now pretty much the usual oil, usually Shell Helix Full Synth.

Some specialists used to use even thicker oil, 5w50 if memory serves.
 
xw30 is too thin for the EJ25 engine, especially if it is driven hard. That would be the reason for high lead number.

You should use at least 40 weight in that car, even some Subie drivers in the middle east use 10w60.

I'd change it with Rotella T6 5w40 and take sample again, and see if lead gets lower.

By the way, what do you mean by "fat" A/F ratio? Do you mean is it rich or lean? If it is lean, detonation might be the reason for high lead number.
 
What are your oil temps? Pretty sure you need something thicker in there. 5w40 or 5w50 come to mind.
 
Maybe XPR uses lead as an additive!? No idea. That's a lot though. I would certainly run something thicker. Somewhere in the 14-17 cSt range for KV100.
 
Originally Posted By: 1JZ_E46
Maybe XPR uses lead as an additive!? No idea. That's a lot though. I would certainly run something thicker. Somewhere in the 14-17 cSt range for KV100.


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They are using TETRAETHYL LEAD, (C2H5)4Pb as the antiknock compound and of course to raise the octane level.
 
Originally Posted By: MolaKule
Originally Posted By: 1JZ_E46
Maybe XPR uses lead as an additive!? No idea. That's a lot though. I would certainly run something thicker. Somewhere in the 14-17 cSt range for KV100.

thumbsup2.gif

They are using TETRAETHYL LEAD, (C2H5)4Pb as the antiknock compound and of course to raise the octane level.

Is there any way of quantifying how much could get into the oil? How it could affect the numbers? Blackstone wondered if it was the Torco. A quart per five gallons...
Also, I've run Royal Purple XPR before without the high lead numbers, but also with only 12 fluid ounces of Torco.
When I say "fat" I do mean rich. At boost I am at 11:1.

Originally Posted By: Rand
What are your oil temps? Pretty sure you need something thicker in there. 5w40 or 5w50 come to mind.
My oil temps are great. Often below 200 and never over 210. My engine has never run hot. I also have a big racing radiator.

I will add that I thought I could run a lower viscosity oil because of my unique oil system. I don't know how much you can compare it to stock and Subaru recommendations. I've done the obligatory radiusing, enlarging and matching of galleys that many race engine builders do. I am running a 12mm ported pump with deep back. This gives me lots of volume. I run an external, adjustable oil pressure relief valve. I started out with over 150 PSI! I dialed it down to 85 PSI. It seldom sees below 70 PSI on the track. It has dropped some and I have raised it back and I went with 10-40 RP when I took the tested oil out. Of course, I am concerned that I may have some bearing wear issues. The engine was dyno'd at 470 WHP and 391 FPT, but I have yet to race it at that max power level.
 
You're reasoning seems sound for running a thinner weight, especially given your low oil temps. Only another UOA will be able to tell you if you have a bearing issue. Maybe do a quick flush dino oil and then re-fill with your RP of choice (although I'd recommend Redline 30 or 40 weight racing), turn the boost down a bit, run without the octane booster, and re-analyze. If the lead is still high, you may have a bearing issue.
 
I appreciate the comments. However, like i said, I have just put in 10-40 and will try that on my next track days which will give me three plus hours on the engine. I'll then have it analyzed and it will have the same run time on it as the first sample.
It's not so easy for me to change my boost settings and mess with other factors. The engine was dyno'd for three performance levels; all using the same Torco enhanced fuel or 105 octane (so I could use 105-110 racing fuel if I needed to). I cannot modify the maps. Yes, the 385 WHP setting could run on pump gas but it's not as much fun as 430... (and it was tuned on 105 octane). I could possibly reduce the Torco, but not eliminate it, for 430 if I keep a close eye on my EGT readings. I guess I don't see much point in doing anything different until I see how the more viscous oil does.
I am skeptical as to making an oil brand change when Royal Purple has served me well with two previous Subaru race engines. No bearing failures and no extreme wear. One bottom-end could have easily kept going had I not burned a valve from lash being too tight. I generally ran 10-40 in it when ambient temps warmed up.
I may well have bearing wear issues but I don't suspect the oil is at fault. Another Subaru racing buddy put an ungodly number of track hours on one engine using RP and he didn't have the enhancements I have had.
One thing I have learned, as I have built subsequent Subaru race engines, is that the cases and journals can move around and must be always be measured and machined in an "as run" assembled condition, meaning torque plates to simulate heads being in place, etc. Otherwise, you just luck out if it lasts in a high power, high RPM environment. I didn't do everything on this engine to the "Nth degree" when I set up the bearings. I hope it doesn't come back and bite me in the [censored].
 
Originally Posted By: Scargo
]My oil temps are great. Often below 200 and never over 210. My engine has never run hot. I also have a big racing radiator.


Hmm, maybe you are overcooling your oil? Tape off the oil cooler? Are you running a thermostat?
 
Originally Posted By: Brons2
Sheared to 20wt. You need a thicker oil period, full stop.

What do you mean by "sheared to 20wt"? How do you come up with that?
I have run over two hours on the engine since I last posted and it is a screaming mother!
I am running 10-40 RP. Highest oil temp I saw was briefly 230°F. In a 20 minute session it climbs to 215-220°F usually with water temps a lot lower, not exceeding 180 in the same period.
Pressures, measured at the pump's output (post external relief valve) and at the rear of the right side galley run 70-90 and 40-60 PSI, respectively. I am shifting between 7,000 and 7,500 RPM. My cut seems to come in around 7,800.
I have a Borg Warner EFR 8374 turbo, so no bearing metal in it to contribute to the metals in the oil.
I get about two ounces of diluted oily liquid, which might smell of fuel(?) in my catch can after my air/oil separator after about two hours of running. No smoking and very low oil consumption. Perhaps half a quart.
So far the engine is performing great and my question would be: How many hours should I put on the oil? When should I pull it and send it off for analysis?
Recent video made at new Club Motorsports in New Hampshire.
 
Originally Posted By: Scargo
Originally Posted By: Brons2
Sheared to 20wt. You need a thicker oil period, full stop.

What do you mean by "sheared to 20wt"? How do you come up with that?


Because you posted:

cSt Viscosity @ 100°C 9.13

And according to SAE J300:
SAEJ3002009.JPG


That puts it within the range for a 20-weight, being below 9.3cSt.
 
Yep 9.13 is a 20 grade so it's good you're running a 40 now. That will probably end up a 30 grade. Not sure how long to leave oil in a race engine. Out of my depth there. I suppose a sample can be taken when you get some serious hours on the oil and that will tell you how much it has or has not sheared, along with everything else.
 
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