OEM FD Wet Sump limits
 

I have a 13brew in my 818 kit car. It’s a MR layout with the engine behind me. Car is 2000lbs, has wide tires and aero. Similar cars running Subaru motors suffer from oil starvation on long sweepers as they often see 1.5-1.7g’s.

I have the engine out for rebuild (failed oil line) and I’m wondering if I should build a pan. If I build one, it would use a baffle/windage style top plate and trap door hinges to keep the pickup in oil. However maybe all that work is unnecessary and FD oil pan baffling is adequate. I know there’s been 25 years of FD’s on track, so I’m sure the limits are known, just not easy to google.

Raceonly over here said they were getting loss of pressure on braking on one of their customer cars and installed an accusump.... I do wonder if this was related to a past jacking error on the pan rather than something intrinsic on a fairly basic aero car.

The 124 Fiat here, recently went from a 20b lump to a turbo REW set-up and probably pulls similar G (assuming you're talking sustained rather than spikes), it runs just a baffle plate.


If there's any development of the car, a dry sump has to be the answer!

In my opinion the biggest issue is the nuisance of oil climbing up the oil fill neck and filling your catch can under boost with the stock FD pan.

On my FC I used 7qt Mazda Motorsports pan with RB baffle pattern welded in (RB baffle was a sandwich plate, twice the potential for leaks).

On my FD I went with the Winchester Metals/Bacon trap door baffled 7qt pan. Im running 305s or 295s DOTRs on 18x11s and it keeps the catch can pretty dry.

Dry sump would let you lower your engine and trasaxle that extra 3" (assuming your ring gear doesnt hang down) so, it would be worth it just for that 400lbs 3" lower...

If you want to go nuts on the engine there are a bunch of oil mods one can do (which I did on my FC).

Will start with pan and circulate back to pan.

Can bellmouth/velocity stack the oil pick-up tube and ditch the screen, can port the oil pump cavities in the front iron smooth, can plug front cover oil exit and tap area where plug is in oil pump exit galley for straight shot to oil cooler (eliminates two blind 90deg bends), can put in MFR oil pressure regulator (120psi), can use biggest stationary gear bearings and taper the ends, can run loop line from oil filter housing to front iron stationary gear bearing to eliminate three blind 90deg turns, can drill eccentric shaft rear oil entry for two entries (one stock to balance pressure drop to the two in front fed through three blind 90deg turns), can tear drop eccentric shaft oil entries for more pick-up and reverse tear drop oil exits to rotor bearings, can use largest rotor bearings or race rotor bearings, can put in smaller Mazda Motorsports rotor cooling oil jets for more rotor bearing oil pressure at high rpm and can eliminate eccentric shaft's cold oil bypass for the rotor cooling jets.

Thanks guys! I did port/smooth out the oil pump housing, I have the RB race regulator and I’m eliminating the Eshaft bypass. Currently I have -10 vents from the filler neck and rear turbo drain going to a catch can. Should I consider venting the front cover too?

Dry sumps are sweet, and the best option once sorted, but they’re expensive and often complicated. I also can’t lower my engine due to my transmission height and diffuser. I can however go a little deeper with my pan.

I’m either going to cut my own sandwiched baffle plate 1/4” or 3/8” aluminum (with matching pickup spacer) and use the FD pan, or fab my own with hinges. No “big” tracks in my area with long sweepers or double apex turns, and a local road racer got back to me saying he’s never had an issue with the FD pan yet.

Mazda Factory Race dry sump is really simple.

Its a new front cover and everything mounts internally. Worth looking at just to drool!

You really need to log oil pressure to see if you experience any sloshing issues. I personally don't think momentary loss of pressure is a big problem. That said, I'm putting in a baffled pan for insurance. IMO, sloshing gas is a bigger issue than sloshing oil

Most annoying issue with the tin can stock one, at least in my opinion, is sealing, especially with ethanol. This homemade one, just cut out on the bandsaw, used no fancy O ring seal, just good sealant (3 bond), stock gasket and it's been oil tight for 5 years......I did follow up and fly cut it after welding to correct a bit of distortion, it's 1/4" 6061 and carries an extra litre of oil.

I don't see the advantage of the RB reg over the stock FD one and most here retain the thermo pellet - there might be a tiny percentage of failures in high mileage cases, hasn't been observed here as a significant issue in track cars.

We run a -12 from the filler neck to a baffled catch can with largest external vent that fits, then a drain back to the sump (one way valve). I wouldn't worry about an extra breather, but you do want the oil sitting in the engine, absolutely no use if you're flogging it and the oil is sitting in a can.
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After looking at the dry sump kits, it’s definitely not an option for as I have zero room in front of the engine. Running a single pulley and it’s less than a 1/2” from the firewall.

I do log oil pressures as I’m using a AEM Infinity for tuning, and have their digital dash as well which has warning lights/screens I’ve programmed for low pressure at 1000rpm intervals.

I’m not a fan of draining catch can oil back into the engine, especially if using E85. Lots of fuel vapours, condensation, etc in there. But it’s a weekend/track car, I can keep the oil topped up.

I’m leaning towards the stock pan with a baffle plate, increased oil isn’t needed as I’ve got two 19row oil coolers in the front of the car with about 30ft of -10 line so it already holds about 7 litres.

You should be okay under 8000- 8500 rpm and boost under 14 psi. WITH High boost and rpm the oil will pour out of the oil filler to the tune of 1-2 plus litres for a 30 minute race . I went dry sump and still have excessive engine oil blowby ( fresh motors) and ended up putting the sump tank in the engine bay with the engine breather going into it. At least the oil ends up where it belongs. No oil ever leaves the sump tank which has a small catch can breather.

wb

So I made up a baffle plate out of 1/4” aluminum. I traced the open areas on the top of the stock pan and drilled tapered holes where it was open. My thinking is that it’s open enough to “drain” normally but isn’t as free to slosh up the front cover or up the filler neck side. I say “drain” because I’m not sure how much lower the oil level sits with the engine running as the dipstick full level is above it.
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Tapered for “drainage”
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Full level above plate


I also chose to incorporate the oil pickup spacer into the plate. I’m undecided if I’ll use a gasket between the plate to iron and the plate to pickup or silicone one. I’m using 6mm x 30mm studs, and the aluminum threads will pull out at around 200in/lbs (tested on trashed housing). FSM says max 104in/lbs, but I think I’ll go to 150.

Now in looking at the OEM FD pan the baffles are not sealed. The drivers side has a rubber plug in the top of it (mazdatrix website says it uses 4 but I only found 1) and two drain tubes. The passenger side one seems to just have the one hole (correct size for the plug)


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Based off them saying there’s supposed to be 4, there being 4 holes (albeit 2 would use a different size plug), and looking at the design I’m thinking these are meant to be sealed with air in them. Makes sense as their purpose would be to prevent slosh.

But why not let them fill with oil? If allowed to fill from the top (remove the one plug and drill a hole on the top of the other one) then when turning left the oil would drain from the drivers side baffle right at the pickup, and vice versa.

Thoughts?

I used the RB baffle plate on my FC before I remade it out of steel and welded it into Mazda Comp pan - as I stated earlier.

The issue with the baffle plates is you have twice the sealing surface for oil pan leaks and even worse, the return oil from the engine runs across the top of the baffle and out to the edge where the seal to the engine is.

So, the RB always always caused leaks on my FC till I integrated the baffle into the oil pan. The FD is notorious for oil pan leaks without any help...

Anyone here bother chucking baffles and hinged gates on the underside of their slosh plates?

I'll update my findings once I get the car on track later this year, but I wanted to add my latest video to this thread as I go into detail on what I believe will work for baffling.

i run accusump with wetsump and external pump on 4 rotor at 800hp on track is loses pressure under hard braking going into left hand turns, and lowest i've seen it drop is 35psi on 60w oil for approx 1.5 seconds, this dip occurs one time per lap at barber motorsports, and once at Road atlanta going into 10a, i dont see it being a problem, 100+psi everywhere else. Before accusump, at Road Atlanta, during testing, it hit engine protection dropping to nearly zero for 3s in turn 10a

accusump is the way to go

I’ve always heard mixed reviews on accusumps. I think it’s a case of guys with it are happy with it, and guys with dry sumps see it as a bandaid.

Do you have any pics of inside your wet sump? Seems almost every 4 rotor is dry sump so I’m really curious.

i'm currently planning to keep my 4 rotor a wet sump. Will be a little bit before it's running but can try and remember to update this thread later if you are interested.

Yeah for sure, it’s always good to follow up on threads. Too many times I’ve searched old threads and they end up being dead ends with no updates.