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Old 03-22-2012, 11:41 PM   #1
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monkecmonkedo's Avatar
Join Date: Mar 2005
Location: Manchester Center, VT
Default High speed data logging fun

For kicks and grins I used a Labjack U6, which is capable of 50kHz data streaming, to see what's going on with my car during WOT runs. I figured I'd start with the AMM and got the following results for my 016. For the record, the car is a '92 245+T AW70 running pretty much stock except a 15g @15psi and a 954 ECU with Mike's chip (EZK chip too).

This is a 0 to ~80mph run collecting data at 2kHz (20 data points per crank rotation at 6000 rpm). At first glance, I thought all the "noise" was due to using unshielded wires, but no... you can actually see the air moving into each cylinder (pics 2 [idle] and 3 [WOT])! While I didn't measure RPM directly, I used the peak and valley of each intake pulse to calculate engine RPMs in pic 1. The response time of the hot wire in the AMM is pretty amazing. I assume that the ECU sees only the maximum of this signal, since I seem to be maxing out my AMM at ~3500 rpm (my AFRs peg at 10 and I've got no boost leaks).

Once I get my 012 AMM installed I should be able to calculate VE using the intake volume for each pulse (the area under the curve) plus the AMM transfer function.

I think there's lots of interesting things to note about this high speed data and I'm curious to hear people's thoughts.

1993 245 Classic
1992 245+T (DD) Build thread here.
1976 66GL
1975 164E
1972 P1800E Chassis number 39412 (Doesn't exist according to Volvo)

Feedback thread here.
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