Killer B Motorsport 2022+ FA24 BRZ/GR86 Oil Retention Baffle Development

[KillerBMotorsport]

Killer B Motorsport 2022+ FA24 BRZ/GR86 Oil Retention Baffle

Goal:

Improve Oil Control in the Sump, to reduce the probability of oil starvation.


FA24 Sump Design:

The FA24’s engine design uses a 2-piece sump design. The lower piece is made from stamped steel, has no baffle, and holds less than half of the engine’s oil capacity.





The upper piece is made from cast aluminum, has oil drain-back accommodations for the rear of each head, a flat plate baffle near the crankshaft to reduce aeration and reduce crankshaft induced turbulence that can impact PCV, and holds most of the oil. The drain backs are baffled, unlike previous Subaru engines that have head drains that were open to the sump. This is a good step forward in improving oil control; oil surge back-feeding into the heads during cornering.





The engine’s Timing Cover is attached to the front of the engine and upper sump. It is a large piece with a lot of open area. There are some PCV provisions, and there are no baffles or other features to control the oil. There is a large opening from upper sump into the timing cover. The argument could be made that the timing cover is also part of the ‘sump’ because any amount of oil above the minimum level dipstick dot, is also held in the timing cover.






Hypothesis:

In motion, oil in the sump is dynamic. Oil is flowing off the crankshaft, from the drains in each head, and moves around via slosh or surge as acceleration and lateral forces change. The lower sump has a shallow wedge shape at the front. This shape makes it very easy for oil to ramp forward and upward into the upper sump and into the timing cover cavity. Oil from the heads drain from the bottom of each head into the upper sump, through some ‘baffle’ features. ‘Baffle’ features because these are not specific baffle components but cast in design features that create direction changes in the same manner as a baffle. While not perfect, this is a decent advance from previous Subaru engines where the head drains were unobstructed from oil slosh causing backflow into the heads. The timing cover is a large open space that contains the cam timing components, sprockets, and chain. The sides of the timing cover have low spots that trap oil. Under high RPM the chain can rope oil causing more oil to be drawn from the sump area as well.


Theory of Operation:

Any slow-down caused by throttle lift or braking causes a significant amount of oil to surge into the timing cover reducing oil level in the sump. With a cornering motion following, the oil in the timing cover then moves into the side of the timing cover and will stay there until the end of the corner and acceleration resumes.

The Killer B Motorsport Oil Retention Baffle restrict oil from freely flowing into the timing cover, thereby increasing the level available in the sump. A one-way flap valve allows any oil that does flow into the timing, easily able to flow back into the sump as acceleration resumes.





Questions, comments, and feedback welcomed.

[pandafabrications]

So, when can I buy? Pulling my pan soon, would love to toss this in.

[BioRebel]

I've been waiting to pull my pan until all this stuff has been sorted since I don't want to do it more than once.

What evidence/data do you have to support your theories and solution? (I know we've seen in the other thread the telemetry of pressure dropping in right hand "over crest" scenarios)

[STIconvert]

Looking forward to seeing this come to fruition, will 100% be a customer when this is released.

[DarkSunrise]

Thanks for the detailed pictures and analysis! Would love to see the results if any testing/validation has been done on this product (internally or 3rd party).

[NoHaveMSG]

Originally Posted by KillerBMotorsport

The Killer B Motorsport Oil Retention Baffle restrict oil from freely flowing into the timing cover, thereby increasing the level available in the sump. A one-way flap valve allows any oil that does flow into the timing, easily able to flow back into the sump as acceleration resumes.

That is a really good idea.

[gnarjunkie]

Super cool. Definitely very interested to see testing and data from this.

Question because I'm curious... why would that opening into the timing cover be present / large / unbaffled to begin with?

IE... could there be any unintended consequences to blocking that off?

[nomtimesthree]

Any idea what the expected service life is of those rubber(?) trap doors? I'd prefer a solution that is zero long term maintenance even if the performance isn't as good.


Either way this is exciting and can't wait to learn more

[dsc_pat]

without before and after track oil pressure log, there is no product

[blsfrs]

Just curious, with an engine on a stand, could you simulate braking and lateral G's by tipping the engine up and forward a few degrees? Then, with a borescope, look in the timing cover, valve cover, and/or pan to see where the oil is going and how long it takes for it to flow back to the pan once you re-level the engine.

[jes]

I am wondering the same thing myself

[KillerBMotorsport]

Originally Posted by pandafabrications

So, when can I buy? Pulling my pan soon, would love to toss this in.

We don't have a production date yet. The hope was to start with Alpha testing soon, but I've run into a health issue that is going to cut my availability to do this

Originally Posted by BioRebel

I've been waiting to pull my pan until all this stuff has been sorted since I don't want to do it more than once.

Can't say I blame you. Not that it's hard, but it is a mess pain in the butt.

Originally Posted by BioRebel

What evidence/data do you have to support your theories and solution? (I know we've seen in the other thread the telemetry of pressure dropping in right hand "over crest" scenarios)

At this point, our experience with boxer engines: EJ, FA, and 911s. We have done more testing on these engines than anyone else in the industry. With that experience, we have a good understanding for where oil goes under various conditions. Although, that in no way means you skip testing I would bet $1,000 that this part will definitely not make things worse

Originally Posted by STIconvert

Looking forward to seeing this come to fruition, will 100% be a customer when this is released.

Thank you for the support!

[KillerBMotorsport]

Originally Posted by DarkSunrise

Thanks for the detailed pictures and analysis! Would love to see the results if any testing/validation has been done on this product (internally or 3rd party).

Absolutely. I always say, don't take the word of the guy selling the product. Which is why we do 3rd party testing before making a product available. Not only does it verify performance (or not), it's also valuable feedback for installation as well.

Originally Posted by NoHaveMSG

That is a really good idea.

Thanks! We think so too!

Originally Posted by gnarjunkie

IE... could there be any unintended consequences to blocking that off?

Great question, and we've pondered it too. The baffle doesn't block it 100%, it's not a perfect seal. Oil can still get in there, the level will still read correctly, but the effects from surge and slosh into that area will be significantly reduced.

[KillerBMotorsport]

Originally Posted by nomtimesthree

Any idea what the expected service life is of those rubber(?) trap doors? I'd prefer a solution that is zero long term maintenance even if the performance isn't as good.

Good question! We use an advanced TPV material that is far superior to the silicone pieces, and the overseas stuff. It's OEM level of material and should last 100K miles without issue.

Another thing to note, is that this style flapper valve (originally designed and used by BMW) was made for installation on vertical baffles. Never in a horizontal application. The aftermarket got a hold of it and right or wrong, put them on everything. If you look at horizontal installs, they sag open. Not only that, but because they sag open and are installed incorrectly on a horizontal surface, the heat causes them to take a set, in the open position. This can happen after only a couple of heat cycles, rendering the flap valves functionally useless. When used correctly on a vertical surface, they only open 1-2mm.

Originally Posted by dsc_pat

without before and after track oil pressure log, there is no product

Agreed.

Originally Posted by blsfrs

Just curious, with an engine on a stand, could you simulate braking and lateral G's by tipping the engine up and forward a few degrees? Then, with a borescope, look in the timing cover, valve cover, and/or pan to see where the oil is going and how long it takes for it to flow back to the pan once you re-level the engine.

We have gimbal plates that we use for this exact thing, but they are for EJ engine/pan testing. We tip up to 60°, a few degrees doesn't really do anything. The lateral loads need to be REALLY high to actually surge into the heads.

Originally Posted by jes

I am wondering the same thing myself