Oil pressure dropping to critical levels under hard braking (Headscratcher)

[sldghmr]

At least for me this is a head scratcher....braking from 100-135 down to about 45 and my oil pressure drops from 90ish to 14-25psi. Seems to me that the oil pickup is getting uncovered....
My setup:
Gen 2 coyote w/GT500 oil pan, GT500 oil pump, -12 lines, Earl's Ultra Pro 34row oil cooler (834-16ERL), OEM 5.0 windage tray/oil pan gasket, FR remote oil adapter (M-6881-M50A), FRPP Control pack, Watson Racing radiator, 170deg thermostat

Don't have oil temp readings but ECT does not go beyond 200deg. Have OEM radiator ducting. Seems to do it even when not running hard....attaching a pic of datalog for some clarity. Can datalog also...

Any thoughts??? Thanks in advance..

 

[Mad Hatter]

Thats sounds a little scary. Are you sure your oil pickup is compatible with your GT500 oil pan and pump setup?? Its does not seem to be something you hear about often.

I see the Ford Kit has a pick up included.

 

[JAJ]

At least for me this is a head scratcher....braking from 100-135 down to about 45 and my oil pressure drops from 90ish to 14-25psi. Seems to me that the oil pickup is getting uncovered....
My setup:
Gen 2 coyote w/GT500 oil pan, GT500 oil pump, -12 lines, Earl's Ultra Pro 34row oil cooler (834-16ERL), OEM 5.0 windage tray/oil pan gasket, FR remote oil adapter (M-6881-M50A), FRPP Control pack, Watson Racing radiator, 170deg thermostat

Don't have oil temp readings but ECT does not go beyond 200deg. Have OEM radiator ducting. Seems to do it even when not running hard....attaching a pic of datalog for some clarity. Can datalog also...

Any thoughts??? Thanks in advance..

View attachment 95728

I might be missing something obvious, but the oil pressure doesn't make any sense in respect of the RPM profile. Yes, it's low on braking and cornering in T1, but then as you bring the revs up onto the T2 straight, it's flat for a while and then when the revs drop as you're shifting, the oil pressure starts to climb without any visible changes as the RPM rises and falls on T2 straight. And it's low again in T3, bumping up after you exit the turn.

It's hard to guess about the cause of the flat spots, but it sure looks like air in the oil system coming from somewhere. The GT500 pan-pump-pickup tube combo solves that problem on the GT500, so it should work on a regular Coyote just as well. One possibility that occurred to me, but it seems unlikely, is that something is trapping the oil in the upper gallery area (cylinder heads) and the pan is running low enough that it starves on cornering. Seems far-fetched, but maybe early 2015 era Coyotes have smaller oil drains from the heads to the sump or something. I know that the Voodoo/Predator blocks have enlarged drains, so maybe it's something like that. Thing is, 2012 Boss 302 blocks didn't have this problem, so why would a 2015? Makes no sense.

 

[sldghmr]

@Mad Hatter - yeah, we used the pickup that came in the kit. Just 'baffling' where 12-13 qts of oil is going.....when braking that is....

@JAJ - TY for catching the flat line oil pressure (when rpm climbing)...I've stared at this stuff for quite a while (obviously TOO LONG) and I completely missed that. I feel that the 'air pocket' makes sense, I just don't understand how it would "stay" in the system with a catch can [ I neglected to list that I have a Motion Raceworks oil catch can w/breather ]. I would think that after a min or so of running, the oil pump would purge any air from the system. I get why it's recommended that oil cooler connections be faced up (so oil cooler stays full of oil), but wouldn't [even] that cause a small air pocket? Doesn't the oil in the lines to the radiator drain back when engine is not running?

There has to be someone on here that can confirm or provide some insight as to the oil draining differences in the coyote gen's? I really want to figure this out....pockets are getting light from throwing $$$$ at this car!

 

[JAJ]

@Mad Hatter - yeah, we used the pickup that came in the kit. Just 'baffling' where 12-13 qts of oil is going.....when braking that is....

@JAJ - TY for catching the flat line oil pressure (when rpm climbing)...I've stared at this stuff for quite a while (obviously TOO LONG) and I completely missed that. I feel that the 'air pocket' makes sense, I just don't understand how it would "stay" in the system with a catch can [ I neglected to list that I have a Motion Raceworks oil catch can w/breather ]. I would think that after a min or so of running, the oil pump would purge any air from the system. I get why it's recommended that oil cooler connections be faced up (so oil cooler stays full of oil), but wouldn't [even] that cause a small air pocket? Doesn't the oil in the lines to the radiator drain back when engine is not running?

There has to be someone on here that can confirm or provide some insight as to the oil draining differences in the coyote gen's? I really want to figure this out....pockets are getting light from throwing $$$$ at this car!

Maybe an Accusump? It's only just a little bit more money.

 

[GAR944]

Going back to basics and because i have never seen one of these up close and personal.

When it was installed, were the flaps free to swing cleanly. And i mean full range of motion multiple times as the shaft moves. They appear to be a really basic pin style hinge but pretty crude in production quality.
Train of thought was if say the front one was sticking open partially, the boxed section for the pickup would potentially be worse off than no baffles at all as the sides are effectively removed from the oil supply (at least delaying effective filling) leaving the centre section to drain quicker.
Spent time on your data log relating longitudinal acceleration, specifically braking, to the onset of pressure drop soon after.

Next left field thought, and i don't really think its this, have you logged voltage on your data setup. Are you getting false data from a fluctuating voltage supply due to a potential myriad of other issues. Electrics suck big time on modern cars.

And last though caus once again haven't seen one. Is the dipstick the same between setups and maybe giving a higher reading therefore under filling the sump? Out there but lets tick it off the list of basics.

Have been looking at doing exactly this to my GT also as i'm paranoid about spinning bearings due to track loads. Hope you can find a definitive solution soon.

 

[sldghmr]

Maybe an Accusump? It's only just a little bit more money.

Again....probably shouldn't be posting after midnight (senior moments tend to increase and what-not).... have a 2qt Accusump plumbed in the system as well. Don't know if it makes a difference or not, but it's plumbed in on a -10 line which tees into my -12 lines.

@GAR944 - Thank you very much for grounding me. You bring up some good points. I didn't assemble motor, but can only assume that the door flaps were swinging correctly. Pan will be coming off shortly so will verify. Voltage seems okay...reading from 14.5v - 14.9v throughout whole lap. Now the dipstick is another issue....I didn't find anything definitive about if the GT and the GT500 use the same dipstick. So I did use my original one. I put oil in it until it showed on the stick (11qts) then fired it up to fill the cooler and all, then added another quart and a half to get it back on the stick, low, but on there (bottom of the 'ok' area). "If" the stick was 'short' I should be a little overfull, but I know I only put 12.5 qts in it. I read oil change info on the 2020 GT500 saying it is a 11.5 qt oil change, so I should be good .... right? What scares me is, even if I'm a quart low....can this setup be THAT sensitive to being low one quart? Where do these engines hide 12 quarts of oil, even for a couple of seconds? When I pull the pan off, I'm going to fill it w/water and measure it myself, and then add one quart for cooler, lines, etc and see where it lands on the stick.

Just has a brainfart.... did all of my initial filling of oil w/out Accusump in the system. Could Accusump be stealing two quarts???

 

[sldghmr]

Another thought....could this wiz-bang superhero of an oil pump be pumping TOO MUCH OIL??? Seems like the harder it's run the less oil pressure (overall) it has..... is there something to oil not flowing back fast enough?
(I probably really should go to bed...not sure if I'm making any sense....apologies)

 

[TMSBOSS]

Is the low pressure we are seeing, the oil being pumped from the Accusump? With the same thought as you, anre you actually 2ish quarts down when the Accusump fills.
is it possible to manually shut off the valve at the Accusump and then check your oil fill level after running and the Accusump tank full?

 

[GAR944]

https://blog.cantonracingproducts.com/blog/importance-of-accusump-valve-selection-how-to-choose
After reading all this series of articles, can you draw a picture of how your system is plumbed up. Might give a clearer picture given we now have GT500 sump, oil cooler lines and take off fittings as well as an accusump in the system.
Also was all this together before the GT500 sump was added and working fine? Trying to get a clearer picture of what has changed that could be the cause. The more we can concentrate on what is new to the system the better suggestions everyone can offer. I don't like the idea of bandaids after the fact but want to find the root cause and eliminate it at the source. It may also help when I potentially do this so I'm invested.

 

[sldghmr]

Is the low pressure we are seeing, the oil being pumped from the Accusump? With the same thought as you, anre you actually 2ish quarts down when the Accusump fills.
is it possible to manually shut off the valve at the Accusump and then check your oil fill level after running and the Accusump tank full?

Unfortunately not able to check this as we've already pulled the motor out. The datalogs that I've been posting are from the 3rd event (5th & 6th days) that the car was running like this. Had a little boo-boo resulting in the driver's side cylinder head getting 'ventilated' [#7 hole]

 

[sldghmr]

Okay....nobody laugh at my elementary school diagram!

This entire oil system is 'new to the car' with the exception of the Accusump and accompanying -10 line. Previous system was a Mishimoto cooler w/sandwich plate on top of the factory oil cooler/coolant piece. I (used to) think ' the more the merrier', and it all fit w/a FL820S oil filter. Thought I was sooooo slick, until I came here and learned that all of my oil system needed to be upgraded for what I am trying to do.
Gotta run and do home stuff [right now, before I get in trouble], but will lay out a more complete history of my flubs later....

 

[TMSBOSS]

If mama ain’t happy…………

Good luck.

 

[SMGDHG]

At least for me this is a head scratcher....braking from 100-135 down to about 45 and my oil pressure drops from 90ish to 14-25psi. Seems to me that the oil pickup is getting uncovered....
My setup:
Gen 2 coyote w/GT500 oil pan, GT500 oil pump, -12 lines, Earl's Ultra Pro 34row oil cooler (834-16ERL), OEM 5.0 windage tray/oil pan gasket, FR remote oil adapter (M-6881-M50A), FRPP Control pack, Watson Racing radiator, 170deg thermostat

Don't have oil temp readings but ECT does not go beyond 200deg. Have OEM radiator ducting. Seems to do it even when not running hard....attaching a pic of datalog for some clarity. Can datalog also...

Any thoughts??? Thanks in advance..

View attachment 95728

Looking at the "main straight" column:

I see your oil pressure steadily drops from "x" high value down to "16.5psi" minimum value. I also noticed your rpm trace has two blips in it; are these from you heel toe downshifting?
I am trying to get an idea of how long (time) of a braking zone this is, and how long this steady decrease in oil pressure lasted.

I have found that the engines have two things working against them with regards to oil pressure and braking:
1.) High RPM is usually experienced at the beginning of a braking zone. High RPM = high oil pump speed which means LOT's of oil being pumped OUT OF the sump. This is significant because the oil does not necessarily drain back into the sump at the same rate as which it gets pumped out of the sump.
2.) And then of course you have the "sloshing" forward of the oil itself under braking. Depending on your tire compound and how much G' force your car pulls under braking, I imagine the oil would use the front of the pan as a ramp and fly up into the timing cover area, get flung around by the timing chain/crank, etc.

The above two items have represented the biggest deficiency I have found with the stock oil pan. In nearly every other scenario, I have been fine with the stocker, but will be upgrading soon.

Are you certain you are running enough oil (you should be way above the factory fill quantity due to the larger pan, lines to the cooler and the cooler itself). For reference; I have to run my car with an extra 1.45qts just from the oil cooler setup alone. In actuality I run an extra 2 quarts (stock 4.6L is 6qts, I run 8qts) because I have a similar issue to you; under braking the pickup tube seems to suck air in. To combat this I run 8qts total and the issue has gone away.

I believe this is part of the reason why ford kept increasing oil capacity for the 5.0L over the years (aren't they up to like 12 qts. now?!), to try and ensure there is reserve oil within the sump at all times.

 

[sldghmr]

@SMGDHG - You are absolutely right my friend....those rpm blips are downshifts.

Two things working against engines (oil pressure & braking):
1) Yeah, @JAJ brought up the drain back thought and I'm inclined to agree w/you two...but I also feel like this might be more of a me problem since I've not heard about something like this until now. I'm pretty sure I messed something up or a piece in my puzzle ain't quite fitting correctly....
2) I've got the GT500 oil pan (see @Mad Hatter post #2 picture)...completely baffled pan..."should" keep oil in it from climbing the walls...Toyo RR's and about 1G of braking

2015 GT (Gen 2) - 8.5qts oil change
2018 GT (Gen 3) - 10qts oil change
2020 GT500 - 11.5qts oil change
2024 GT (Gen 4 [?]) - 'you sure you want to buy ONLY one case of oil??'

I put 11qts in...ran it...checked the oil....added 1.5qts to get in on the stick. So 12.5qts total (well above both my 2015 factory fill and a little above the GT500 fill). Oil was on the stick but towards the low end.... My buddy has dug and found out the (new to me) cooler holds almost a whole quart. I need to get off of my butt (or maybe on my butt) and do the research to find out if the GT500 oil dipstick is the same as my stock oem 2015 dipstick. I'm really thinking now that between the larger oil cooler, larger lines, larger pan, and the Accusump, I may have been short on oil even though I had it on the stick...but still with 12.5 qts??? Mind boggling!!

 

[JAJ]

@SMGDHG - You are absolutely right my friend....those rpm blips are downshifts.

Two things working against engines (oil pressure & braking):
1) Yeah, @JAJ brought up the drain back thought and I'm inclined to agree w/you two...but I also feel like this might be more of a me problem since I've not heard about something like this until now. I'm pretty sure I messed something up or a piece in my puzzle ain't quite fitting correctly....
2) I've got the GT500 oil pan (see @Mad Hatter post #2 picture)...completely baffled pan..."should" keep oil in it from climbing the walls...Toyo RR's and about 1G of braking

2015 GT (Gen 2) - 8.5qts oil change
2018 GT (Gen 3) - 10qts oil change
2020 GT500 - 11.5qts oil change
2024 GT (Gen 4 [?]) - 'you sure you want to buy ONLY one case of oil??'

I put 11qts in...ran it...checked the oil....added 1.5qts to get in on the stick. So 12.5qts total (well above both my 2015 factory fill and a little above the GT500 fill). Oil was on the stick but towards the low end.... My buddy has dug and found out the (new to me) cooler holds almost a whole quart. I need to get off of my butt (or maybe on my butt) and do the research to find out if the GT500 oil dipstick is the same as my stock oem 2015 dipstick. I'm really thinking now that between the larger oil cooler, larger lines, larger pan, and the Accusump, I may have been short on oil even though I had it on the stick...but still with 12.5 qts??? Mind boggling!!

I looked at the oil pressure trace and RPM again with the thought of the Accusump in mind. Whatever is dropping the oil pressure has to run the Accusump out of oil in the process. If the Accusump is static-pressurized with 10PSI air, then at 90 PSI, a 2.5 quart unit will hold about 2.2 quarts of oil. If the oil supply from the pump stops, and the pressure drops to 15 PSI, it'll only be holding about 0.9 quarts, so 1.3 quarts of oil will have released back into the engine. That, combined with whatever was in the sump before the pump pressure loss, is a lot of oil that's disappearing somewhere in the system.

This leads me to a couple of questions - first, what static air pressure do you run in the Accusump? That's the pressure on the air side when the oil side is empty. Second, what type of valve do you have on the Accusump feed line? Electric or manual? And, do you shut the valve with reasonably high oil pressure so the Accusump is full and under lots of pressure when you start the engine?

 

[steveespo]

Odd issue. I have run this pump and pan on three different engines since it came out in late 2020 and have never seen any oil pressure drops in the data, nor evidence of oil starvation even after 2 engine failures. I have a remote filter that runs the FL-1A pattern, Setrab 960 and -12 lines. Capacity is 13.5 quarts total. I have used both the GT500 and OEM dip sticks. The fill level for both is the same. The relationship for the dipstick is dependent on what top of cam cover position is used. The GT500 has a swan neck tube that gets the handle out from under the tower brace, the GT version just goes straight into the cam cover. You cannot use a GT500 dipstick without the extension tube being installed in the cam cover. It would be too long and you wouldn't have enough oil in the sump. This is not the problem in your case. where are you picking up the oil pressure data? Are you sure that information is accurate? I would love to see you have a mechanical gauge with a GoPro pointed at it to verify the issue. Also what is the fill procedure for the Accusump? If it holds 2.2 qts and you only have 12.5 in the system total then you are at least 2.2 quarts low on oil when running. Maybe I am figuring wrong but that may be a place to start.

 

[sldghmr]

@JAJ - Accusump has a manual valve for open/closing. To be honest, not sure what the static air pressure is, but will measure tomorrow.
@steveespo - Good to know that you haven't had any issues w/this setup. I firmly believe that you (and others) are correct....I essentially was running low on oil. I'm guessing about 1-2 qts low....
My oil pressure sender is located in the small port of the M-6881-M50A Ford Racing Remote Oil Filter adapter. TBH, I am unsure if this port is connected to the 'in' side or the 'out' side. It is right in the middle of both, but obviously can't bridge them. Thank you for saving me some time w/the dipstick info. I'll continue to use my oem 2015 dipstick. Putting a mechanical gauge in there somewhere with a camera is a good idea. My setup is an X05PSA00010B18K AIM 0-10bar sensor in the previously mentioned port wired to my MXL2 dash logger.

UPDATE: What I did find out this evening is that my check valve is not CHECKING! Any amount of liquid or air that we ran at it (backwards), went through. So, even if my Accusump/system was filled correctly, oil would be pumping from the Accusump in both directions instead of just towards the engine inlet.

 

[steveespo]

@JAJ - Accusump has a manual valve for open/closing. To be honest, not sure what the static air pressure is, but will measure tomorrow.
@steveespo - Good to know that you haven't had any issues w/this setup. I firmly believe that you (and others) are correct....I essentially was running low on oil. I'm guessing about 1-2 qts low....
My oil pressure sender is located in the small port of the M-6881-M50A Ford Racing Remote Oil Filter adapter. TBH, I am unsure if this port is connected to the 'in' side or the 'out' side. It is right in the middle of both, but obviously can't bridge them. Thank you for saving me some time w/the dipstick info. I'll continue to use my oem 2015 dipstick. Putting a mechanical gauge in there somewhere with a camera is a good idea. My setup is an X05PSA00010B18K AIM 0-10bar sensor in the previously mentioned port wired to my MXL2 dash logger.

UPDATE: What I did find out this evening is that my check valve is not CHECKING! Any amount of liquid or air that we ran at it (backwards), went through. So, even if my Accusump/system was filled correctly, oil would be pumping from the Accusump in both directions instead of just towards the engine inlet.

Oil pressure port in the line adapter is measuring outlet pressure but that is fine as it is the same as the factory oil filter adapter reads. 2 quarts low would definitely uncover the pickup in high negative g situations. Isolate the accusump and ensure the oil level is just below the upper dot on the dipstick. Run a short session (I don't think you need the Accusump anyway) and check your data. If that check valve is not functioning the oil pressure from the accusump would be sent in both directions, toward the inlet side of the oil galleys, but also towards the outlet side of the pump, which would just repressurize the cooler and lines taking oil and pressure that could be going fully to the bearings during the low pressure events. Are you sure it isn't installed backwards? Seems odd that the check valve wouldn't hold in one direction unless the flapper was damaged or missing. Good luck with the new engine. BTW 1 quart of oil is 57.75 cubic inches, which occupies a space 3.8"x 3.8"x 3.8". As you can see 2 quarts would occupy a good area inside the sump.
Steve

 

[JAJ]

Oil pressure port in the line adapter is measuring outlet pressure but that is fine as it is the same as the factory oil filter adapter reads. 2 quarts low would definitely uncover the pickup in high negative g situations. Isolate the accusump and ensure the oil level is just below the upper dot on the dipstick. Run a short session (I don't think you need the Accusump anyway) and check your data. If that check valve is not functioning the oil pressure from the accusump would be sent in both directions, toward the inlet side of the oil galleys, but also towards the outlet side of the pump, which would just repressurize the cooler and lines taking oil and pressure that could be going fully to the bearings during the low pressure events. Are you sure it isn't installed backwards? Seems odd that the check valve wouldn't hold in one direction unless the flapper was damaged or missing. Good luck with the new engine. BTW 1 quart of oil is 57.75 cubic inches, which occupies a space 3.8"x 3.8"x 3.8". As you can see 2 quarts would occupy a good area inside the sump.
Steve

I'd expect that if the check valve was both working and installed backwards, he'd have lots of oil pressure at the sensor which is upstream of the valve and none in the engine which is downstream. As you say, though, if the pan has enough oil, he shouldn't need the Accusump. Maybe a test drive with it switched off is in order - a lap or two working up the speed and g's to see how the pressure goes.