Oil Pressure Instability
05-19-2021, 08:45 AM
#1
Race Car
Thread Starter
Oil Pressure Instability
I posted this vid in my thread but thought the topic itself and follow on discussion deserving of its own thread.
I have brought up what I saw through the factory gauge as oil pressure instability on track previously. Over the winter I put a data logger on the car to allow what I was seeing to be quantified and better evaluated.
Now, as NickL points out, maybe it’s an issue with scavenge pumps or just more broadly, a mechanical issue specific to my car. Or, maybe it’s an inherent often discussed issue that many have when running the engines on track and is inherent to the design of the oil system.
In any event, I think it’s good to put data into a context that’s easy to digest and understand and I hope the video does a good job of that.
Driven XP 9
LN 2QT Deep Sump & Baffle
LN Spin on Filter and Napa 1042
Both Oil Pressure and Temp taken from ports on an oil filer adapter using AIM sensors
Data logged at 20HZ Oil P and 10HZ Oil T
Oil is filled to 1/4 up the dip stick, about 10QTS
Water temp is not shown but was 200F and steady
Oil Pressure is the bar graph on the right, it is shown as TEMP - But is configured to show pressure.
Oil Temperature is the bar graph on the left
I thought may be interesting to the group.
Porsche 996 Oil Pressure Instability on Track
I have brought up what I saw through the factory gauge as oil pressure instability on track previously. Over the winter I put a data logger on the car to allow what I was seeing to be quantified and better evaluated.
Now, as NickL points out, maybe it’s an issue with scavenge pumps or just more broadly, a mechanical issue specific to my car. Or, maybe it’s an inherent often discussed issue that many have when running the engines on track and is inherent to the design of the oil system.
In any event, I think it’s good to put data into a context that’s easy to digest and understand and I hope the video does a good job of that.
Driven XP 9
LN 2QT Deep Sump & Baffle
LN Spin on Filter and Napa 1042
Both Oil Pressure and Temp taken from ports on an oil filer adapter using AIM sensors
Data logged at 20HZ Oil P and 10HZ Oil T
Oil is filled to 1/4 up the dip stick, about 10QTS
Water temp is not shown but was 200F and steady
Oil Pressure is the bar graph on the right, it is shown as TEMP - But is configured to show pressure.
Oil Temperature is the bar graph on the left
I thought may be interesting to the group.
Porsche 996 Oil Pressure Instability on Track
Last edited by zbomb; 09-09-2021 at 11:16 PM.
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Popular Reply
04-22-2023, 01:12 PM
I hope this comes across with the positive and mature tone with which it is intended.
I'm excited to see some of the upcoming data.
It sounds like @Porschetech3 will have some more good data soon after the recent revisions. Hopefully the medical delays are over and everyone is better! It will be very exciting to see that!
And @Slakker will also have some good 996 data soon. That is just as exciting!
I'm not sure why people seem to have split into factions here, but all let's step back and appreciate that @zbomb started one of the best threads here to actually collect DATA on the oil instability problem in order to clear away the marketing.
Can we acknowledge that there may be room for multiple improvements to this problem, especially at different price points? They may differ in level from "band-aid" to "solved", but with data, we will all see, and we can each evaluate our own personal cost/benefit ratio. This thread has already shown things that DON'T work.
Let's just appreciate that very hard work is still going into our 20+ year old cars, and that there is progress which seems to be promising.
Thank you EVERYONE for your contributions.
I'm excited to see some of the upcoming data.
It sounds like @Porschetech3 will have some more good data soon after the recent revisions. Hopefully the medical delays are over and everyone is better! It will be very exciting to see that!
And @Slakker will also have some good 996 data soon. That is just as exciting!
I'm not sure why people seem to have split into factions here, but all let's step back and appreciate that @zbomb started one of the best threads here to actually collect DATA on the oil instability problem in order to clear away the marketing.
Can we acknowledge that there may be room for multiple improvements to this problem, especially at different price points? They may differ in level from "band-aid" to "solved", but with data, we will all see, and we can each evaluate our own personal cost/benefit ratio. This thread has already shown things that DON'T work.
Let's just appreciate that very hard work is still going into our 20+ year old cars, and that there is progress which seems to be promising.
Thank you EVERYONE for your contributions.
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05-19-2021, 09:56 AM
#3
Nordschleife Master
So after watching the video im not sure whare the problem is. Looked like pressure was responding to throttle input and the temp stayed under 240*. Was there a partucular moment in a curve that i missed?
05-19-2021, 10:52 AM
#4
Race Car
Thread Starter
Multiple pressure drops to 15PSI above 3.5K RPM.
And that’s with cool oil, under 250.
I would much prefer to not see the pressure drops every time G force is introduced.
And that’s with cool oil, under 250.
I would much prefer to not see the pressure drops every time G force is introduced.
05-19-2021, 11:13 AM
#5
I'm not an expert here but from watching the video it seemed like right hand turns exhibited bigger drops in pressure, especially at the initial turn it when pulling more g forces but there were also some dips at left hand turns. Makes me wonder, if having the oil pick up a bit lower to ensure that it is more often submerged in oil during hard cornering be of any help... 
05-19-2021, 12:01 PM
#6
I'm not an expert here but from watching the video it seemed like right hand turns exhibited bigger drops in pressure, especially at the initial turn it when pulling more g forces but there were also some dips at left hand turns. Makes me wonder, if having the oil pick up a bit lower to ensure that it is more often submerged in oil during hard cornering be of any help...
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plpete84 (05-19-2021)
05-19-2021, 12:05 PM
#7
Rennlist Member
Cross posted from the main thread...
The display is awesome. Great data. Having this video along with graphs from the data logger is quite powerful. It seems there are some pressure drops on left hand turns as well, just not as dramatic. What is an expected amount of drop? Let's say, straight line, WOT to no throttle for 2 seconds, then back to WOT, how much pressure drop would there be? But this is not really the issue. The issue is pressure drop on a right hand turn under power. Maybe a different parameter is needed. Something like Pressure/Load/G or Pressure/RPM/G
Really nice work.
The display is awesome. Great data. Having this video along with graphs from the data logger is quite powerful. It seems there are some pressure drops on left hand turns as well, just not as dramatic. What is an expected amount of drop? Let's say, straight line, WOT to no throttle for 2 seconds, then back to WOT, how much pressure drop would there be? But this is not really the issue. The issue is pressure drop on a right hand turn under power. Maybe a different parameter is needed. Something like Pressure/Load/G or Pressure/RPM/G
Really nice work.
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05-19-2021, 12:57 PM
#8
Race Car
Thread Starter
I'm not an expert here but from watching the video it seemed like right hand turns exhibited bigger drops in pressure, especially at the initial turn it when pulling more g forces but there were also some dips at left hand turns. Makes me wonder, if having the oil pick up a bit lower to ensure that it is more often submerged in oil during hard cornering be of any help...
Cross posted from the main thread...
The display is awesome. Great data. Having this video along with graphs from the data logger is quite powerful. It seems there are some pressure drops on left hand turns as well, just not as dramatic. What is an expected amount of drop? Let's say, straight line, WOT to no throttle for 2 seconds, then back to WOT, how much pressure drop would there be? But this is not really the issue. The issue is pressure drop on a right hand turn under power. Maybe a different parameter is needed. Something like Pressure/Load/G or Pressure/RPM/G
Really nice work.
The display is awesome. Great data. Having this video along with graphs from the data logger is quite powerful. It seems there are some pressure drops on left hand turns as well, just not as dramatic. What is an expected amount of drop? Let's say, straight line, WOT to no throttle for 2 seconds, then back to WOT, how much pressure drop would there be? But this is not really the issue. The issue is pressure drop on a right hand turn under power. Maybe a different parameter is needed. Something like Pressure/Load/G or Pressure/RPM/G
Really nice work.
05-19-2021, 01:31 PM
#9
To me, it seems the only way to lose pressure is for the oil pump pickup to become in contact with air. So there is only a couple causes, not enough oil in the system overall, or, oil is pooling somewhere and not returning to the sump fast enough.
Likely the second issue would be my thoughts - which match the comments about scavenge pumps and such. Also, any drainback limitations that exist, thicker oil will just make it worse.
-Tom
Likely the second issue would be my thoughts - which match the comments about scavenge pumps and such. Also, any drainback limitations that exist, thicker oil will just make it worse.
-Tom
05-19-2021, 04:10 PM
#10
Rennlist Member
Watching your video literally ties my stomach in a knot !!!
Very nice data, and great display (needs more G-force definition), shows the issue very well. But watching it is a love/hate thing..
Very nice data, and great display (needs more G-force definition), shows the issue very well. But watching it is a love/hate thing..
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Ratchet1025 (06-02-2021)
05-19-2021, 04:16 PM
#11
Race Car
Thread Starter
Then, I look at the video and it’s like... ****.
Im still working out some details in how I want to format the videos, the inner circle was set to 1.5G but something looks wonky in how it came out because it’s showing around there all the time, which I’m not.
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Ratchet1025 (06-02-2021)
05-19-2021, 04:47 PM
#12
Rennlist Member
At least your pressure is really good up top. Above 5k rpm you have good pressure up to 80psi.
The instability is between 4-5K, with the major dips occurring at below 4K.
It would be really telling to see the delta between RPM and Pressure (where it counts) as related to G-Force. (where the problem lies).
I credit your driving style to surviving this instability !!! Someone who downshifts too early, goes into a turn too hot at too an high RPM/G-force, cornering at a lower gear ,will not be so luckly. Your smooth driving style and taking care of the equipment is paying off. If I were a Race Car Owner, you would be the kind of driver I wanted..
The instability is between 4-5K, with the major dips occurring at below 4K.
It would be really telling to see the delta between RPM and Pressure (where it counts) as related to G-Force. (where the problem lies).
I credit your driving style to surviving this instability !!! Someone who downshifts too early, goes into a turn too hot at too an high RPM/G-force, cornering at a lower gear ,will not be so luckly. Your smooth driving style and taking care of the equipment is paying off. If I were a Race Car Owner, you would be the kind of driver I wanted..
05-19-2021, 04:53 PM
#13
Race Car
Thread Starter
At least your pressure is really good up top. Above 5k rpm you have good pressure up to 80psi.
The instability is between 4-5K, with the major dips occurring at below 4K.
It would be really telling to see the delta between RPM and Pressure (where it counts) as related to G-Force. (where the problem lies).
I credit your driving style to surviving this instability !!! Someone who downshifts too early, goes into a turn too hot at too an high RPM/G-force, cornering at a lower gear ,will not be so luckly. Your smooth driving style and taking care of the equipment is paying off. If I were a Race Car Owner, you would be the kind of driver I wanted..
The instability is between 4-5K, with the major dips occurring at below 4K.
It would be really telling to see the delta between RPM and Pressure (where it counts) as related to G-Force. (where the problem lies).
I credit your driving style to surviving this instability !!! Someone who downshifts too early, goes into a turn too hot at too an high RPM/G-force, cornering at a lower gear ,will not be so luckly. Your smooth driving style and taking care of the equipment is paying off. If I were a Race Car Owner, you would be the kind of driver I wanted..
Let me know and I can send you some screen shots of whatever combo you want to see.
Or, If you or anyone else wants to download the race studio 3 software I can send out the full logs and you can view whatever you want.
https://www.aim-sportline.com/en/sw-fw-download.htm
Its really pretty intuitive to use and fun to play with.
I ran lawn mowers and plow trucks for my youth Skip... taking care of the equipment is engrained in me.
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paddlefoot64 (05-19-2021),
Porschetech3 (05-19-2021)
05-19-2021, 05:08 PM
#14
To me, it seems the only way to lose pressure is for the oil pump pickup to become in contact with air. So there is only a couple causes, not enough oil in the system overall, or, oil is pooling somewhere and not returning to the sump fast enough.
Likely the second issue would be my thoughts - which match the comments about scavenge pumps and such. Also, any drainback limitations that exist, thicker oil will just make it worse.
-Tom
Likely the second issue would be my thoughts - which match the comments about scavenge pumps and such. Also, any drainback limitations that exist, thicker oil will just make it worse.
-Tom
05-19-2021, 11:17 PM
#15
Rennlist Member
OK i got the race studio downloaded, now i need that file to look at..