FA20 Engine Oiling, Bearings, and Starvation

[Element Tuning]

Originally Posted by mike the snake

Not sure if it's been asked, but what about running a pump like the AVO pump, driven by the cams, and plumb that to the mains?

Wouldn't that increase pressure to the mains? A small resevoir might also help in times of scavenging.

You mean this dinky thing? That's a scavenge pump only and a very small one at that. No that won't help. We are talking multiple gallons per minute at 80 psi.

[mike the snake]

DOH!

Ahh, I see.

[Element Tuning]

Originally Posted by mike the snake

DOH!

Ahh, I see.

Ha ha. It's all good

[bimmer635csi]

Originally Posted by Element Tuning

Thanks but oil consumption doesn't really have an impact on oil pressure unless you burn up all your oil. LOL!

I just thought it might fit in the thread title "FA20 Engine Oiling, Bearings, and Starvation". It wasn't specific to the "pressure" sub-thread.

[Element Tuning]

Originally Posted by bimmer635csi

I just thought it might fit in the thread title "FA20 Engine Oiling, Bearings, and Starvation". It wasn't specific to the "pressure" sub-thread.

Well you weren't very convincing in your first post that it belonged here I basically said its not relevant because it's a news story about a lawsuit and there's no technical information there even about the oil consumption.

I will tie in some personal knowledge and experience about oil consumption here. There are certain oils that have very good anti-burn off properties compared to others (there is a technical term for this but it eludes me right now). We have tested this back to back with various oils and the difference can be dramatic! The Red Line and Amsoil burn off very little compared to an off the shelf Mobil 1 product. I urge anyone that has some abnormal oil consumption that isn't from a damaged engine to try one of those oils as a comparison.

[Brzzee]

Thank you for taking time from your busy day to thoroughly respond to my questions.

While I had thought to use the 2qt sized Accusump attached as you have done, I did have concerns about oil vent overflow. I am using a Crawford AOS now. Your comments illustrate that I have more study to do before moving forward with oiling system upgrades.

[Calum]

How do you accommodate having an oil system that will transfer 60% of its oil from one storage location to another where it will sit mostly unused? That leaves very little oil in the sump, causing much less dwell time, higher oil temps, and a much bigger chance of needing that accumulator.

[Brzzee]

Additional oil perhaps 2.5 QTS are added to the OEM quantity with the sized unit I am investigating. One adds more oil with an accumulator, the condition with which you have concerns does not happen.

[Calum]

Originally Posted by Brzzee

Additional oil perhaps 2.5 QTS are added to the OEM quantity with the sized unit I am investigating. One adds more oil with an accumulator, the condition with which you have concerns does not happen.

An accumulator has either a diaphragm or a piston in it. On one side will typically be pressurized nitrogen and on the other side will be the oil. The nitrogen is there to maintain pressure in the system when the main oil feed pressure decreases. As the engine oil pressure increases the volume of oil in the accumulator will increase as it fills the accumulator and further pressurizes the nitrogen, and as the engine oil pressure decreases the volume of oil in the accumulator will decrease as the oil is forced out of the accumulator and into the system. When your car is at idle and the engine oil pressure drops the oil in the accumulator will come rushing out until the volume of oil in the accumulator is small enough to balance the engine oil pressure against the pressure of the nitrogen on the dry side of the accumulator.

If you do have a remote valve and you close it before you shut the car off, you're still only isolating a small amount of oil. But while the engine is at high rpm and the valve is open, you're going to have ~2.5 qts of oil in the accumulator. Those 2.5 qts, or most of them, are going to reside in the oil pan when the motor is shut off, but are going to move from the oil pan to the accumulator when the engine is at high rpm. As a compete wild ass guess I'm going to say there's probably 1 qts of oil in the system while the engine is running. So of the ~5 qts of oil that were in the oil pan while the engine was shut off, only about 1.5 are left to dwell (cool, deaerate, and allow particulate to settle), and keep the oil pickup submerged while the engine is running at high rpm. That doesn't seem like a good idea to me.

As you said, running an extra 2.5 qts of oil should overcome this. But then the oil level will certainly be too high for anything other than high rpm/high oil pressure use. If that oil level, during lower rpm driving, isn't enough to cause the crank case to over pressurize, possibly causing a catastrophic failure (these aren't pretty, I've witnessed one on a 16 cylinder 1400 kw diesel engine) it will certainly be enough to partially submerge the crankshaft. This will cause the crankshaft to further aerate the oil, which could also cause catastrophic failure.

I guess if you know the oil pressure vs. engine rpm curve you could calculate the accumulator oil volume vs. engine rpm. Add in oil sump volume vs. fluid height and you could figure out a safe minimum operating rpm for the engine. But the oil pressure will vary a fair amount as the oil temperature changes. So you'd have to create a minimum safe operating rpm curve based on oil temperature.

Clearly there's got to be a better/simpler way. Hence why I asked my question.

[Element Tuning]

Ok first let me say for the first time ever I have 70-75 psi of oil pressure to 8500 RPM with the Element Tuning Pro Comp motor with internal oiling modifications, Hydra EMS, Perrin oil cooler, and the oil accumulator. This is after a 35 minute commute in stop and go with about 50% highway, AC on the entire time, some mixed hard pulls where I could squeeze them in, and then the final test of 2 WOT runs from 3-4th gear, and then another 1st through 4th (essentially all back to back and I'm at about 400hp). About 5 minutes later I pulled into my driveway with idle oil pressure at 20 psi. I call this a win!!!!!

The accumulator doesn't work like has been described by others. The initial pressure in the system is set to about 7 psi which is easily overcome by normal idle oil pressure. We had to add 3+ quarts so you don't lose oil but you have to add! There is a process to do this by overfilling a little and slowly craxking open the accumulator while watching engine oil pressure. Shut while running, tuen off engine, and check the oil level and add as needed. Repeat until the oil pressure is stable and your oil level is full.

I would think any vent into intake catch can (that isn't massive like mine) is a really bad idea in this application. While under normal conditions it's not a problem, when the accumulator is really needed (during pressure drop) it will push the reserve oil into the engine bearings and back to the pan where it will momentarily be too full. So if you remember my earlier post, even with our engine mods and the oil cooler we still had high rpm pressure drop. I do not have this now which means the accumulator is doing it's job and forcing more high pressure oil into the mains.

It's a simple device that has it's place but has some shortcomings which with the right company can send you off with very little downsides. A dry sump is superior but comes with a superior price tag and has its own shortcomings for street cars.

We have figured out a solution with our internal engine mods and when coupled with some off the shelf products like a Perrin Oil Cooler and an accumulator (lots of brands) I can sell engines with a clear conscience now.

Next an external oil pump for more serious racing and HP users (keeping AC is my goal) prior to going dry sump.

Thanks,
Phil Grabow

[Grip Ronin]

So say if I did ported heads and valvetrain would the stock oil pump be safe to 8k? I noticed you said after 8k it drops

[Element Tuning]

That is not at all the correct conclusion. Read more of the thread as all the details are there.

There is no easy way out as I wish there was but what we do to the engine is internal and part of our build spec. Without the internal modifications it's a lost cause and an external oil pump will be required over the HP and RPM limits I've discussed.

If you're NA follow the external bolt ons we've done and thicken that oil! For high power boosted guys my positive results are a function of our engine build. Hopefully we can develop a bolt on external oil pump solution for guys who don't need/want an engine build but it's going to be expensive if keeping the AC is a requirement.

In my current configuration I should be able to push 600 whp reliably in street, drag, or autocross configuration. I still have my concerns road racing due to the extended thermal loads so I'm just going to have to see how the oil pressure holds up under those conditions.

[mike the snake]

Would you recommend running thicker oil on medium HP turbo applications?

I'm around 300WHP and running mainly on the street. Presently running Motul 0-20.

[Element Tuning]

Originally Posted by mike the snake

Would you recommend running thicker oil on medium HP turbo applications?

I'm around 300WHP and running mainly on the street. Presently running Motul 0-20.

Absolutely!