Originally Posted by Irace86.2.0 (Post 3220982)

Thanks. That paper helped my understanding.


I think the data he posted is clear that increasing the diameter of the inlet should raise pressures, and the evidence suggests that this should decrease cavitation. If that translates to a reduction in the occurrence of oil starvation is still up for interpretation, and really, is yet to be seen, but regardless, it is definitely a solution to a potential inadequacy.


I'm still bugged by the fact that the output side didn't show an equally dramatic improvement in pressure. Here is an analogy:


--Imagine we had a water wheel in a river, and instead of being driven by the flow of the river like they typically area, it was being driven by a machine spinning the wheel in order to pass the water into an output pipe. Now, say the river level was variable and inadequate (maybe a beaver was clogging it upstream) then the wheel's fins or buckets were never getting filled completely. This would cause low flow to the output pipe.
--Farmers decided to remove the dam and the river's levels rose. Now the buckets are getting filled completely, and the output pressure/flow rate increases.
--Now say the output needs to be increased, so the farmers turn up the machine to spin the wheel faster and when they do they get more output.
--Now say the output needs to be increased more, so the farmers turn up the machine more, but there isn't more output. Why? As the bucket is spinning, it is spinning so fast that the bucket doesn't have time to fill (I'm a hospital worker, and we see this in the hospital with high heart rates when there is inadequate time to fill the chambers, ie, preload drops).
--The next day it rains and suddenly the river is flowing faster, so the buckets are able to fill completely once more, even at the fast speed, so pressure/flow increases at the output pipe (this is analogous to having the body respond with better vascular tone and muscle pump to increase preload, just to continue that analogy of this analogy lol).


So, where am I going with this? If the output pressure isn't increasing with an increase in inlet pressure then perhaps the scoops or buckets of the pump are already picking up all they can; ie, there isn't an inlet inadequacy. Perhaps the inlet inadequacy could decrease cavitation, but maybe the pump is already scooping up all the oil it can fit in the space of the pump.

Originally Posted by Horrid_Funk (Post 3221019)

The inlet and outlet pressures of the pump go up approximately the same amount in his data. At 5000 RPM it looks to be approximately 0.1 bar.

Originally Posted by CSG Mike (Post 3220978)

I recommend you pursue a solution, rather than keep trying to fix the symptoms.

Originally Posted by CSG Mike (Post 3220978)

I recommend you pursue a solution, rather than keep trying to fix the symptoms.

Originally Posted by Capt Spaulding (Post 3221056)

I have to confess Mike, that I don't quite understand your point. It seems to me that addressing the symptoms would be using thicker oil, weird additives or something of that sort. It seems to OP is exploring the structural/design causes of the oiling problem itself and proposing/testing solutions. Am I missing something?

Originally Posted by solidsnake11 (Post 3220957)

https://www.crossco.com/blog/prevent...ing-pump-inlet

https://www.machinerylubrication.com...avitation-wear

Originally Posted by Capt Spaulding (Post 3221056)

I have to confess Mike, that I don't quite understand your point. It seems to me that addressing the symptoms would be using thicker oil, weird additives or something of that sort. It seems the OP is exploring the structural/design causes of the oiling problem itself and proposing/testing solutions. Am I missing something?

Originally Posted by ETM_Shaman (Post 3221045)

Please do elaborate!

Originally Posted by ETM_Shaman (Post 3220926)

I would absolutely recommend to get the Killer B oil pickup!

I was going to use the one I ordered straight up, but then I noticed I couldn't because length and orientation where different in the GT86 FA20 and the WRX FA20DIT. At the time I ordered, Killer B didn't have a GT86 option. From the pictures I thought there were the same but go figure :bonk:.

As I had to modify Killer B's pickup anyway, I chose to go with the 1" tube that gave me an inner diameter that better matched the rest of the intake galleries I had improved.

If there's a real improvement between a 3/4" or 1" tube is up for discussion.
Even if it existed, it'd be far less of an improvement than going from stock (18mm, bent, restrictive mesh) to Killer B (3/4", straight, much better mesh).

I've contacted Killer B and Chris has been kind enough to offer to send me one of their new GT86 FA20 oil pickups to make a test in my car: stock vs 3/4" (Killer B) vs 1" (Killer B modified by us). We'll see how it goes, but I'd recommend to anyone with the stock pickup to get Killer B's asap.

The 3/4" vs 1" discussion is better suited to rebuilt engines with looser tolerances and higher flow, so even the objective results from the test we'll do will have to be interpreted correctly and probably won't apply to a stock engine.

Originally Posted by CSG Mike (Post 3221119)

The thicker weights are band-aid fixes for a symptom (cavitation). What is causing the cavitation? The increased pressure differential from the enlarged passages.

There seems to be a consensus that these engines have crank oiling problems. Element Tuning has apparently spent a bit of time and money developing a solution to it and are, rightfully, keeping it close. Looking at the pictures the OP posted I get the impression the cavitation had been going on for a while. If the inlet side of the pump was restricting the flow to the impeller and cavitation was resulting all the while and, in turn restricting pressure and raising temps. Some other posters have confirmed the cavitation problem in engines that have not been modified suggesting opening the outlet side is probably not responsible for it.


Are the enlarged passages even necessary? While my engine is only one data point, it is a very strong data point, given the number of hours on my engine, as well as the power level which may be comparable to the OP.

The necessity of enlarging/de-restricting the oil passages is not clear. If I recall my undergrad physics restricting flow reduces pressure on the downstream side of the restriction. In some situations that may be desirable. Again, a lot of people have problems with these engines grenading. The culprit seems to have something to do with low oil pressure to the crank. If removing or reducing restrictions increases pressure at the crank that goes some distance toward addressing that particular problem.

I've intentionally been running this until it fails, to see what ACTUALLY fails, when prepped to the best of my ability.

I don't have any of the issues the OP is having, and I believe many of the issues are self induced.

This is certainly possible, but the OP's problems appear to predate his modifications.


I run 0W20 and 5W30, depending on ambient temps, and my oil temps never exceed 230F. My turbo is oil cooled.



A flat 4 struggles with oil return; without a dry sump, I don't think increasing oil flow volume is a good idea; you'll just drain your pan faster without refilling it under cornering.

I'm not convinced that a global increase in oil flow is what he's shooting for or getting. He restricts flow to the driver side head to what appears to be the same orifice as the passenger side. If the overall flow in the system is increased, it will still face the restriction going to heads, increasing pressure on the upstream side which may pay dividends in the form of crank bearing survival.

Originally Posted by CSG Mike (Post 3221119)

The thicker weights are band-aid fixes for a symptom (cavitation). What is causing the cavitation? The increased pressure differential from the enlarged passages.

Are the enlarged passages even necessary? While my engine is only one data point, it is a very strong data point, given the number of hours on my engine, as well as the power level which may be comparable to the OP.

I've intentionally been running this until it fails, to see what ACTUALLY fails, when prepped to the best of my ability.

I don't have any of the issues the OP is having, and I believe many of the issues are self induced.

I run 0W20 and 5W30, depending on ambient temps, and my oil temps never exceed 230F. My turbo is oil cooled.


A flat 4 struggles with oil return; without a dry sump, I don't think increasing oil flow volume is a good idea; you'll just drain your pan faster without refilling it under cornering.

Originally Posted by CSG Mike (Post 3217670)

I run a stock radiator, with a fully ducted cooling stack, upgraded intercooler from JDL using a Garrett core, a GReddy (ducted, divorced) oil cooler, and Trackspec hood vents, along with a CSG fan shroud with SPAL fans and relays.

Originally Posted by solidsnake11 (Post 3221160)

Please inform people why you never exceed 230f.
Because when I first read it I was like wow but then I found this. You are also running a higher cst than a thicker oil at higher tempatures.