View single post by t4brew
 Posted: 11-03-2011 01:48 am
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Joined: 03-11-2010
Posts: 12
StevenD57 wrote: t4brew wrote:I had the same reaction to that system.  So far I have acquired the ECM, chip, harness, throttle body, fuel rail, manifold, injectors, fuel pressure regulator, TPS, IAC valve,MAP sensor, coolant sensor, knock sensor, crank trigger wheel, trigger sensor and 02 sensor for $800.  I also spent $20 for a chip definition file so I can modify the settings on the chip. I have already made changes for things like the fuel cutoff RPM, fuel return RPM, radiator fan temp on, radiator fan temp off, injector pulse constant for the S4S injectors and the speed sensor conversion. The GM ECM is very tunable. Tuning the VE and spark advance tables will take some time. The Quad 4 W41 spark advance table seems to be very close to the Lotus 912 advance curve.  The VE tables may take some time to get right but should not be too difficult. I still have to purchase a high pressure fuel pump and the additional fuel line.  Hopefully I can stay under $1000 for the complete system.
The TunerStudio software for the Megasquirt ECU has an autotune feature that I have found to be very helpful for dialing in everything except the WOT part of the VE tables.
I looked into the Megasquirt ECU and saw the autotune feature, that will save you a bunch of time.  To tune the GM ECU I will need to need to drive and datalog the 02, MAP, RPM, and advance values and based on those modify the VE tables.  It would be much easier if the GM ECU had an autotune feature.