Corvette data from Daytona road course

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Here is some data that I downloaded from my Corvette's ECU when I did some track days at the Daytona International Speedway road course. I reviewed about 2 hours of data and found the fastest lap, which I have broken into 3 segments.

This is the infield:
[img:left][/img]


[img:left][/img]

The data of interest to BITOG enthusiasts is the oil pressure, which barely gets above 40 psi at any time, and drops to about 20 psi in long left-hand turns. No worries; the engine has been running this way since 1995. During this lapping session the oil temperature was running at ~315 F. I run Redline 5w30 with an M1 filter. The oil system is plumbed with a 2 quart Accusump. The oil system does have an air-to-oil cooler, but apparently it needs a better one. Running on shorter tracks, the hottest the oil had gotten previously was 277 F. Daytona has long periods of WOT while running on the oval.
 
Cool data. Thanks for sharing.

Why does it drop so much in the corners? Don't the Accusumps prevent that? What's the oil pan design like?
 
This is NASCAR Turn 2, the Backstretch, and the Bus Stop Chicane:

[img:left][/img]



Max speed down the backstretch was 158 mph.
On the oval, I was shifting at 5300 rpm to try and keep the oil temperature down.
 
It looks like oil pressure is generally not rising and dropping as RPMs rise and drop. Right? If so, why do you think that is?
 
And here is NASCAR 3-4, the TriOval, and entry into Turn 1:

[img:left][/img]

[img:left][/img]

Max speed through the TriOval was 168 mph with the engine taching ~5600 rpm. And that was about all it would do, as can be seen by the Vehicle Speed trace flattening out. Maybe if I had wound the engine to 5600 in the lower gears, I could have made 170?
 
Originally Posted By: dparm
Cool data. Thanks for sharing.

Why does it drop so much in the corners? Don't the Accusumps prevent that? What's the oil pan design like?


Left hand turns are worse than rights. (On the graphs, left is negative lateral G's, and right is positive.) When a car is turning at ~1G lateral acceleration, the surface of the oil in the pan will take a 45-degree angle from the horizontal. This may uncover the pickup, or at least cause the pump to suck a mixture of oil and air. Left turns are worse because windage from the crankshaft impedes drain flow from the passenger side cylinder head. This in turn causes the oil pump to suck the oil pan dry while oil is being held in the cylinder head rocker box.

The Accusump helps, but it cannot generate oil pressure. It can only store oil at system pressure, then push oil into the main oil gallery at reduced pressure, when gallery pressure falls. I have the air pressure on the Accusump set at 10 psi when empty, so if I see oil pressure drop to 10 psi, I know it has run out of oil.

I have the stock oil pump, pan, and windage tray on it. I tried out an ultra-trick road-race pan and high volume pump on it back in 1994. It had all the tricks: 7-quart capacity, wings, trap doors, expanded metal windage tray, and small-diameter pickup. But it didn't seem to maintain oil pressure in the turns any better than the stock pan, so I went back to stock. This was long, long before I had a datalogger so I could really understand what was going on with oil pressure. My method for diagnosing oil starvation back then was to look at the oil pressure warning light while exiting the turns. Based on that, the fancy pan didn't seem to work any better than the stock pan.
 
Originally Posted By: JAG
It looks like oil pressure is generally not rising and dropping as RPMs rise and drop. Right? If so, why do you think that is?


This engine reaches its maximum oil pressure at ~3000 rpm, and the minimum rpm recorded on this lap was 3200. Therefore, the engine was operating above the speed at which the pressure would fluctuate.
 
So cool, thanks for sharing.
20.gif
 
Hello, How do you extract that data?
AND
How do you effect changes in the operation of things like FUEL:AIR mixture.

I'd like to add a hydrogen generator to my car but it's little brain will get confused.
We've had great success getting my friend's old tractor to breathe hydrogen. Kira
 
Originally Posted By: Kira
Hello, How do you extract that data?
AND
How do you effect changes in the operation of things like FUEL:AIR mixture.

I'd like to add a hydrogen generator to my car but it's little brain will get confused.
We've had great success getting my friend's old tractor to breathe hydrogen. Kira


The car has an AEM ECU on it. It has internal datalogging of 16 channels. I communicate with it via an old cheapy laptop. After dowloading logger data into the laptop, I export data from the AEM Log program to Excel for more detailed analysis and plotting.

The AEM Pro engine tuning software gives me complete control of air-fuel ratio and spark timing. I have dual wideband O2 sensors on it, which are also logged, so I can review and make changes to the fuel map.
 
Originally Posted By: A_Harman
Originally Posted By: Kira
Hello, How do you extract that data?
AND
How do you effect changes in the operation of things like FUEL:AIR mixture.

I'd like to add a hydrogen generator to my car but it's little brain will get confused.
We've had great success getting my friend's old tractor to breathe hydrogen. Kira


The car has an AEM ECU on it. It has internal datalogging of 16 channels. I communicate with it via an old cheapy laptop. After dowloading logger data into the laptop, I export data from the AEM Log program to Excel for more detailed analysis and plotting.

The AEM Pro engine tuning software gives me complete control of air-fuel ratio and spark timing. I have dual wideband O2 sensors on it, which are also logged, so I can review and make changes to the fuel map.


I wonder if you have noticed the new camera and data system on the new Vettes? It sounds very good, and it would be integrated into the car so a very neat and clean simplicity is likely.
 
Yes, I've read that it has vehicle performance data overlayed on the video, so you can tell what the car was doing when you were at a specific location on a track. It's all very much further advanced than what I have. I have to do a lot of analysis to make sense of the data I get out of the logger.
 
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