Race Capture - Podium Live

[steved0x]

Very cool video, that graphically answers a lot of questions I have seen folks ask about an accusump and how it works. Also like you said, interesting the pressure differences between the oil pressure measured down at the oil pump vs measured in the valve cover way at the end of the oil path.

Nice driving too BTW

[AZ986S]

And here are a couple graphs.

The first graph shows the distribution of the time it takes from Valve Open (discharge) to Valve Close (refill). The avererage time is 822 msec. The second and third graphs show how much time it takes for engine oil pressure to increase by >=2 psi (average 213 msec) and >=5 psi (average 518 msec) from the time the valve opens. On some Accusump events, the valve closes before there is even a 5 psi increase in oil pressure. One thing to note is that it is difficult to separate the effect of the Accusump from the effect of the RPM fluctuations during the time the Accusump triggers, but since this is a fairly short event, it is assumed the oil pressure increase is due to the Accusump. What I mean is that with higher RPMs, oil pressure increases ever so slightly.

Not shown on graphs:

Average Lateral G force @ valve open: 0.85
Average Lateral G force @ valve close: 0.53

Generally speaking, the oil pressure did not ever dip below 25 psi, and even then, for very short periods of time (msecs). So my take is that I'll keep this setup, as it seems to me like it has a positive effect on protecting this engine. It would have been beneficial to have a comparison with the Accusump turned OFF, but I didn't want to take the risk, especially after having lost an engine last season...

Obviously, this data combines a lot of different conditions, and is specific for this track, my car, my setup, my driving technique, the oil used etc... but in general, the oil temperature gets hotter as the session goes on, and the Accusump triggers much more frequently on the second half of the session. Also, since we were running CCW on this track, there were more left turns than right. I did not notice any significant pressure dips/accusump triggers during hard braking prior to entering a left turn. This may not be true for a right turn though... Driver smoothness of input seems to minimize the accusump triggers, and the opposite seems true: quick, jerking steering inputs seem to increase the accusump triggers.

So it'll be off to COTA in 9 days (Feb 23rd) with MVP TrackTime (yes it's a 950 mile drive). I'll be data logging this fast, long track and hope to be able to report progress.

[AZ986S]

Originally Posted by steved0x

Very cool video, that graphically answers a lot of questions I have seen folks ask about an accusump and how it works. Also like you said, interesting the pressure differences between the oil pressure measured down at the oil pump vs measured in the valve cover way at the end of the oil path.

Nice driving too BTW

Thanks Steve. Now that I think about it, adding the pump oil pressure could have shown even more dramatic pressure dips graphically...

[AZ986S]

Here's the updated YouTube video for Session #3 with Accusump and Oil pressure data overlay.

https://youtu.be/RznjhpiZHbc

I added the Oil pressure at the pump (pre-filter) to have a better graphical representation of the magnitude of the oil pressure drop spikes and how the Accusump helps to smooth out the resulting oil pressure at the valve cover location.