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GammaE < 100% ?; What is deltaT?
Posted: Tue Apr 18, 2006 1:10 am
by Philip Lochner
Some datalog questions:
1) What might cause GammeE to be < 100% (I spotted GammaE going to 98% in my datalogs but I can't explain it)
2) What is the "deltaT" parameter that appears in the datalog?
3) What exactly is "TPSacc"? I can see it has something to do with accel enrichment but what determines its value and duration?
Re: GammaE < 100% ?; What is deltaT?
Posted: Tue Apr 18, 2006 1:56 pm
by grippo
Philip Lochner wrote:Some datalog questions:
1) What might cause GammeE to be < 100% (I spotted GammaE going to 98% in my datalogs but I can't explain it)
GammaE is the product of several enrichments (warmup, dcel, baro and air temp). Each enrichment can be < or > 100% (= no enrichment).
2) What is the "deltaT" parameter that appears in the datalog?
This is the time between tach inputs as measured in the processor timer - its accurate to well under a microsecond and is provided as a means to measure relative horsepower during a WOT acceleration run. You can calculate how fast the deltaT is decreasing at each rpm (average a few numbers around even rpms like 1000, 1200, 1400, .... The reciprocal of each of these is proportional to the hp in the sense that the faster the times decrease the more horsepower there is. So if you make a run and plot these points, then make another run with everything richened by say 2%, you can see at what rpms the richening helped and hurt and use the data to tune. A poor man's dyno.
3) What exactly is "TPSacc"? I can see it has something to do with accel enrichment but what determines its value and duration?
Acceleration is handled by adding tpsacc to the calculated pulsewidth rather than multiplying by a % increase - like a carburetor provides extra shot for a certain amount of time. (There is also extra volume, but this enrichment is automatically provided by the MAP factor). TPSacc is a function of tpsdot and mapdot, and is decreased at higher rpms if desired.