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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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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! |
Originally Posted by johnsopa
(Post 15832568)
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? 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 |
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. |
Originally Posted by 2BWise
(Post 15839678)
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. |
Originally Posted by 2BWise
(Post 15839678)
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. I am 😕 |
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! https://cimg4.ibsrv.net/gimg/rennlis...9fe0b40ef4.jpg |
Interesting, thanks.
Was the blue run a much warmer day/run? Seems like the pressures are lower all around. |
Originally Posted by 924RACR
(Post 15841692)
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! https://cimg4.ibsrv.net/gimg/rennlis...9fe0b40ef4.jpg |
Originally Posted by Jabs1542
(Post 15841777)
I wish I could do this with VBox :banghead:
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Originally Posted by ProCoach
(Post 15841786)
You can, but use their higher level analysis tool, VBOX Tools. Also easy in Excel.
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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 :) |
Originally Posted by 924RACR
(Post 15841692)
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! https://cimg4.ibsrv.net/gimg/rennlis...9fe0b40ef4.jpg |
LOL... have another look:
https://cimg6.ibsrv.net/gimg/rennlis...93087e02b6.jpg 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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