Big(ish) Hybrids and dropping oil pressure

What transmission?

When you “let off” are the rpms dropping back to idle?

Can you simply use the trans to brake? Use the engine rpm to slow the vehicle while applying brakes? AKA locked converter?

Essentially don’t just let the rpms drop back to idle.

Tim @ P.I.S. said:

What transmission?
When you “let off” are the rpms dropping back to idle?
Can you simply use the trans to brake? Use the engine rpm to slow the vehicle while applying brakes? AKA locked converter?
Essentially don’t just let the rpms drop back to idle.

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2 speed Powerglide, does not go to idle when I let off, RPM's slowly drop as the car slows down.

When you're going down the track, all the oil is forced backwards. When you let off the throttle, the oil rushes forward, out of the sump. Some stays to give you pressure but not enough volume.

I would try overfilling engine and see what happens. You might need to install some baffles/trap doors in the pan or make a custom pan.

Billy T.
[email protected]

Have you tryed running it a couple quarts overfull yet??

Or just run a line from the oil galley on the side of the block up to the top of the revisor .
That’s what I had to do and it solved the issues I was having after a hard run.
But then again I have twin 17* pumps with a single ipr...
It’s easy to try I guess.

gnxtc2 said:

When you're going down the track, all the oil is forced backwards. When you let off the throttle, the oil rushes forward, out of the sump. Some stays to give you pressure but not enough volume.

I would try overfilling engine and see what happens. You might need to install some baffles/trap doors in the pan or make a custom pan.

Billy T.
[email protected]

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It is pretty much a custom pan, but I thought about that. A flap to keep oil to the back would certainly help given the modified proportions of the pan.

Swaan said:

Have you tried running it a couple quarts overfull yet??

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No, been busy on weekends, and Wednesday night racing ended a few weeks ago. The track is only open 2 more Saturdays and I have plans for both days so it looks like I need to wait till next year.

KBMKVIII said:

Or just run a line from the oil galley on the side of the block up to the top of the revisor .
That’s what I had to do and it solved the issues I was having after a hard run.
But then again I have twin 17* pumps with a single ipr...
It’s easy to try I guess.

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That won't solve the issue of the LOW pressure dropping. I need to address that first and foremost before worrying about the HPOP.

DZL JIM said:

1) It's a well known pump from a well-known company, nothing special. It's just a LOT of rpm's causing it to flow a LOT of oil.

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OH GOD IT'S PROBABLY OURS
(if it is, you can post, I'm all about transparency #thanksobama - if it's not ours, please ignore!)

Wanna call and talk Tech with Bob about your oil stuff? I can probably try and have him call you if that's better.

Does the oil pan hold the same amount of oil as stock?

I was also thinking volume- over filling. BTW when I had my motor out this summer I was not able to fill the hpop res, poured 3-4 qts in and it never filled, I assumed that it was draining back to the pan, but as said before- it's pressurized. I assumed that it was draining back through the lpop- but it was just a thought.

Jennifer@Dieselsite said:

OH GOD IT'S PROBABLY OURS
(if it is, you can post, I'm all about transparency #thanksobama - if it's not ours, please ignore!)
Wanna call and talk Tech with Bob about your oil stuff? I can probably try and have him call you if that's better.

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No, it's not your pump, the Adrenaline won't support 300/200% injectors. And I already talked with Dan about what was going on. I think he discussed with Bob. I have no intention on condemning the HPOP until I know for sure it is the problem, which right now I do not, nor do I think it is.

Magnum PD said:

Does the oil pan hold the same amount of oil as stock?

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No, it holds 3 gallons not 4. Can't physically fit any larger pan between the rails, and the bottom of pan is 3 1/2" off the ground right now (sump was removed completely, pan made wider and extends forward.)

bluedge8 said:

I was also thinking volume- over filling. BTW when I had my motor out this summer I was not able to fill the hpop res, poured 3-4 qts in and it never filled, I assumed that it was draining back to the pan, but as said before- it's pressurized. I assumed that it was draining back through the lpop- but it was just a thought.

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Mine holds oil right to the plug on top, all the time.

once I fired my truck back up it holds it. I changed hpops, rebuilt oil cooler, changed injs, and resealed all the hp oil O rings when it did this, I don't know where the oil was going, but it was going somewhere. Probably doesn't help you at all. I hope you get it figured out

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DZL JIM said:

No, it's not your pump, the Adrenaline won't support 300/200% injectors.

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Fantastic!

But man tell that to this local guy who absolutely would not listen to us when I told him 300/200 was probably a bit much. Bought anyway and hes just driving around town happy as a clam... says Swamps did his tuning and it's been perfect since.
(they probably pulled back sooooooooo much - didnt have the heart to tell him)

I meant talk to Bob in general as another major enthusiast to another... theorycrafting especially about oil (low or high). Dan's great but getting Bob in here focused on this specific topic might be fun.

I am sure even a stock HPOP would work ok for 300/200%, if it was tuned as such. But we all know you'll never get all the fuel out of them at that.

Anyhow, I know Bob is a super busy guy and I really wanted to try out some things I already suspect before taking up his time with this.

If I can't hit the track in the next few weeks I will try to get to the dyno and make some 10 second hard pulls and see what happens. I can never seem to get over 3800 rpm on the dyno, though for whatever reason, and I really want to see it at track rpm.

Anyway I appreciate all of the tips and insight, I'll keep plugging away and keep y'all updated.

DZL JIM said:

I am sure even a stock HPOP would work ok for 300/200%, if it was tuned as such. But we all know you'll never get all the fuel out of them at that.

Anyhow, I know Bob is a super busy guy and I really wanted to try out some things I already suspect before taking up his time with this.

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Don't we know it! I'm sure dealing with injectors you get into that talk a lot more than us.

Seriously it's not a problem - holler any time.

Good luck with everything!

How many quarts of oil does your custom pan hold? Got a picture of just the pan?

Hpop rpm is the same as crank shaft rpm since the HPOP and crank gears are the same size.

Just for kicks, put a lpop pressure gauge in one of the ports on the block to see if the pressure is dropping across the whole lube circuit.



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My pan holds 3 gallons, sorry I don't have a picture.
The HPOP turns about 80% of crank speed, the gears are not the same from what I recall.
I have an oil psi gauge on the front driver's side port for my low pressure readings.

Ok, A little update.
I made a few runs on the dyno Saturday. The car ran fine, no issues with anything. Low oil pressure was fine across the board. Came down to idle after each run, no coughs or anything, and idled perfectly.
The only variable was that the car was sitting still and not rolling down the track.
This leads me to an issue with the pick-up and custom oil pan.
The car is put away now for the winter, so I'll pull the pan next spring and add baffles, or trap door, or whatever and see what it'll do next summer.

I want to thank everyone for all ideas and input on what might have been going on. I feel I am going in the right direction now.

Are you using rear sump?

powerstrokenstang said:

Are you using rear sump?

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...yeah, but...
It's a heavily modified pan. There is no 'sump' as you would see in a typical pan since ground clearance is an issue, but the pick-up does go to the rear of the pan. The pan was widened, and it also extends forward from oem which is really where I think the issues is. I created too much space for the oil to flow forward when I slow down immediately after a 140 mph run.

That's your problem right there. Your pan has no sump and it's all rushing forward and sucking air.

I had a milodon pan like you just described with no sump in my V8 jet boat... the pan had a ton of baffles and trap doors that kept the oil close to the pickup..

You just need more capacity and better baffling.

About time you post again Jason.