Vacuum based tables in L03 TBI bin
#1
Vacuum based tables in L03 TBI bin
I'm using TunerPro RT to work on the tuning of a '91 L03 engine in a '91 Caprice. I've done a little logging and data tracing just to get a feel for the system and its all working pretty well now, thanks to some help from Mark Mangus to get the .ads file for the Caprice working right.
I'm trying to get an understanding of all the tables in the bin, and I was surprised that there are a couple of tables based on engine vacuum rather than MAP, for example the table:
TCC Locked Spark Correction Vs. RPM Vs. Vacuum
Vacuum is not a variable sent back in the logging, so I'm assuming I have to calculate it as:
Vacuum = 100 - MAP
Correct?
Anybody know why they had these tables based on Vacuum rather than just basing them directly on the MAP?
Thanks,
Paul T.
I'm trying to get an understanding of all the tables in the bin, and I was surprised that there are a couple of tables based on engine vacuum rather than MAP, for example the table:
TCC Locked Spark Correction Vs. RPM Vs. Vacuum
Vacuum is not a variable sent back in the logging, so I'm assuming I have to calculate it as:
Vacuum = 100 - MAP
Correct?
Anybody know why they had these tables based on Vacuum rather than just basing them directly on the MAP?
Thanks,
Paul T.
#2
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Re: Vacuum based tables in L03 TBI bin
I'm using TunerPro RT to work on the tuning of a '91 L03 engine in a '91 Caprice. I've done a little logging and data tracing just to get a feel for the system and its all working pretty well now, thanks to some help from Mark Mangus to get the .ads file for the Caprice working right.
I'm trying to get an understanding of all the tables in the bin, and I was surprised that there are a couple of tables based on engine vacuum rather than MAP, for example the table:
TCC Locked Spark Correction Vs. RPM Vs. Vacuum
Vacuum is not a variable sent back in the logging, so I'm assuming I have to calculate it as:
Vacuum = 100 - MAP
Correct?
Anybody know why they had these tables based on Vacuum rather than just basing them directly on the MAP?
Thanks,
Paul T.
I'm trying to get an understanding of all the tables in the bin, and I was surprised that there are a couple of tables based on engine vacuum rather than MAP, for example the table:
TCC Locked Spark Correction Vs. RPM Vs. Vacuum
Vacuum is not a variable sent back in the logging, so I'm assuming I have to calculate it as:
Vacuum = 100 - MAP
Correct?
Anybody know why they had these tables based on Vacuum rather than just basing them directly on the MAP?
Thanks,
Paul T.
I am going to take a stab at the fact that Vacuum is fairly constant, where MAP will vary some due to weather, altitude, etc.
#3
Re: Vacuum based tables in L03 TBI bin
Fast355, what you said makes sense, but on this ECM it doesn't have a baro sensor (I don't think so anyway, '91 Caprice with L03 and 16136965 ECM) so I guess it must estimate the vacuum using the MAP value.
If thats what they are doing it still seems like it would have been less of a hack for the tables just to directly use the MAP value instead of this "fabricated" vacuum amount.
Paul T.
If thats what they are doing it still seems like it would have been less of a hack for the tables just to directly use the MAP value instead of this "fabricated" vacuum amount.
Paul T.
#4
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iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
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Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: Vacuum based tables in L03 TBI bin
Fast355, what you said makes sense, but on this ECM it doesn't have a baro sensor (I don't think so anyway, '91 Caprice with L03 and 16136965 ECM) so I guess it must estimate the vacuum using the MAP value.
If thats what they are doing it still seems like it would have been less of a hack for the tables just to directly use the MAP value instead of this "fabricated" vacuum amount.
Paul T.
If thats what they are doing it still seems like it would have been less of a hack for the tables just to directly use the MAP value instead of this "fabricated" vacuum amount.
Paul T.
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