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Wet sump and high G forces

 
Old 05-10-2019, 08:26 PM
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Default Wet sump and high G forces

It looks like my Radical is capable of pulling around 2.5 Gs. The engine I have is the standard wet sump 1300 Hayabusa. It looks like a dry sump system was an (finicky, somewhat problematic) option.

I've been keeping an eye on the oil pressure through the extended high G corners and the pressure seems to stay at the same level as it does when it's running straight ahead.

Hi seems to me this would indicate I don't really need a dry sump for my application.

Assuming the oil pressure sender is in a decent location, would there be situations where my conclusion would be incorrect?
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Old 05-10-2019, 10:17 PM
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Post here to the guys who run these cars

https://radicalsportscarregistry.com/radicalforum/
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Old 05-11-2019, 09:16 AM
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Baffled oil pans with swinging pickups is a pretty common setup for these cars. I went dry sump, but of course there's a weight penalty.

Then again, P2 weights just got raised, so now I'm stacking lead and steel in my car!
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Old 05-12-2019, 10:03 AM
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Originally Posted by johnsopa View Post
It looks like my Radical is capable of pulling around 2.5 Gs. The engine I have is the standard wet sump 1300 Hayabusa. It looks like a dry sump system was an (finicky, somewhat problematic) option.

I've been keeping an eye on the oil pressure through the extended high G corners and the pressure seems to stay at the same level as it does when it's running straight ahead.

Hi seems to me this would indicate I don't really need a dry sump for my application.

Assuming the oil pressure sender is in a decent location, would there be situations where my conclusion would be incorrect?
Bearing clearance, crankshaft windage causing oil aeration, and uncovered oil pump pick up tube leading to air intake produces localized low oil pressure.

The best test is to use Blackstone Lab in Ft Wayne to run an oil sample analysis to determine if bearing babbitt particles are in the oil. If significant, then the engine has issues. The test is cheap insurance
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Old 05-14-2019, 11:23 AM
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You'll never be able to accurately know what the oil pressure is by watching a gauge. The only way to confidently be sure is to pull the data afterward and look at the oil pressure signal. There exists a relationship between rpm and minimum oil pressure that should not be crossed with respect to keeping the engine alive. The best way to look at this is to plot RPM vs Oil Pressure for an entire session. It will be a cloud of data points. You'll be able to see any precarious drops in pressure at high rpm. You'll also be able to then compare that plot against each session as the oil ages. The cloud will likely fall with oil age.

Another advantage to a dry sump is that it can pull negative crankcase pressure. That can equate to increases in power.
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Old 05-14-2019, 11:58 AM
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Originally Posted by 2BWise View Post
You'll never be able to accurately know what the oil pressure is by watching a gauge. The only way to confidently be sure is to pull the data afterward and look at the oil pressure signal. There exists a relationship between rpm and minimum oil pressure that should not be crossed with respect to keeping the engine alive. The best way to look at this is to plot RPM vs Oil Pressure for an entire session. It will be a cloud of data points. You'll be able to see any precarious drops in pressure at high rpm. You'll also be able to then compare that plot against each session as the oil ages. The cloud will likely fall with oil age.

Another advantage to a dry sump is that it can pull negative crankcase pressure. That can equate to increases in power.
2B, thanks -- makes sense. I have an AiM SoloDL from my GT4/GT3 now in my Radical now but don't have any analog expansion units yet. I'll get one...
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Old 05-14-2019, 07:43 PM
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Originally Posted by 2BWise View Post
You'll never be able to accurately know what the oil pressure is by watching a gauge. The only way to confidently be sure is to pull the data afterward and look at the oil pressure signal. There exists a relationship between rpm and minimum oil pressure that should not be crossed with respect to keeping the engine alive. The best way to look at this is to plot RPM vs Oil Pressure for an entire session. It will be a cloud of data points. You'll be able to see any precarious drops in pressure at high rpm. You'll also be able to then compare that plot against each session as the oil ages. The cloud will likely fall with oil age.

Another advantage to a dry sump is that it can pull negative crankcase pressure. That can equate to increases in power.
Why does a dry sump increase HP. The dry sump pump is primary oil pressure from one pump section and scavenging oil and air for a minimum of 2 pump sections. That is more parasitic HP than just an oil pump for oil pressure.

I am 😕
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Old 05-15-2019, 08:46 AM
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An example of what Bill was saying... two different sessions - actually data from my dry-sump GSXR1000, so very relevant to the OP.

Top left is pressure vs RPM (with 1bar and 2bar ref lines), top right vs lat g's, bottom left vs. longitudinal g's, and bottom right vs. temp.

Enjoy!



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Old 05-15-2019, 09:06 AM
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Interesting, thanks.

Was the blue run a much warmer day/run? Seems like the pressures are lower all around.
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Old 05-15-2019, 09:42 AM
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Originally Posted by 924RACR View Post
An example of what Bill was saying... two different sessions - actually data from my dry-sump GSXR1000, so very relevant to the OP.

Top left is pressure vs RPM (with 1bar and 2bar ref lines), top right vs lat g's, bottom left vs. longitudinal g's, and bottom right vs. temp.

Enjoy!

I wish I could do this with VBox
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Old 05-15-2019, 09:45 AM
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Originally Posted by Jabs1542 View Post
I wish I could do this with VBox
You can, but use their higher level analysis tool, VBOX Tools. Also easy in Excel.
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Old 05-15-2019, 09:53 AM
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Originally Posted by ProCoach View Post
You can, but use their higher level analysis tool, VBOX Tools. Also easy in Excel.
This assumes I am capturing Oil Pressure, which isnĺt being picked up... yet.
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Old 05-15-2019, 09:57 AM
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I don't recall the exact circumstances - that's an old data set from 2014 and earlier. But that's why we have the oil temp curve - allows one to equate different-temp sessions, which should lie on the same curve. These are close, but not exactly the same; I suspect they are different motors.

Surprised no-one commented on the oil pressure drop-out at high negative lat g's.

I was having a surge issue in the dry sump tank (during transitions) which was uncovering the pickup, since fixed by rework of the pickup tube and improved baffling. Curves are much steadier now.

Current analog channel assignments:
oil pressure
coolant temp
gear position
FL ride
FR ride
RL ride
RR ride
oil tank temp
WBO2
TPS
oil outlet temp
brake pedal travel
fuel pressure

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Old 05-15-2019, 10:12 AM
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Originally Posted by 924RACR View Post
An example of what Bill was saying... two different sessions - actually data from my dry-sump GSXR1000, so very relevant to the OP.

Top left is pressure vs RPM (with 1bar and 2bar ref lines), top right vs lat g's, bottom left vs. longitudinal g's, and bottom right vs. temp.

Enjoy!

Good old Race-Technology! Your OEM roots are showing, Vaughn! That is/was the go-to for every GM/Ford/FCA/Tier 1 supplier engineer in club racing since it came out in 2001. Great use of the tech. Looks like your oiling system is working close to as it should.
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Old 05-15-2019, 10:54 AM
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LOL... have another look:


OK, yeah, this is showing the before/after of the fix - it's clearer with the session data plotted out on the distance scale. Red still had the surge problem, blue shows it solved (which is echoed less clearly by the first picture, with no drop-off at high lat).
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