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Stock Car Mafia

Stock Car Mafia's '78 280z LS2 Build

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Over the last few weeks I was able to sell off my stock tires, all A/C stuff, gas tank, stock hood, mirrors, and some miscellaneous CBR bike parts I had laying around.  It is nice to soften the blow of the new motor.  


I still have had little time to spend any time on the car except for driving it to and from work.  We did find a free power wheels jeep for the 4 year old and I ended up buying 2 decent batteries so we could get her juiced up to 24 volts.  She loves having something to drive :)


One concept I've had a tough time wrapping my head around is making sure my wideband O2 sensor is not only calibrated but dialed in to read accurately in HPTuners.  From just the gauge reading alone, I could tell the AFR reads a little high but there was a difference between the gauge and the output signal for the AFR...I read up on a plan to videotape both the gauge, HP Tuners reading and graph them to derive a new slope for the AFR range, and then a voltage offset.  




The equation that is built in for the WEGO III in HPT is:


AFR = (Volts/0.543478261) + 10.3  


Based upon my data below I am probably going to use the equation:


AFR = (Volts/0.5004) + 9.94


I eliminated some data that fell out of speck to come up with this.  I have yet to test it using a user defined math parameter in HPT but I am feeling more confident with this calculation.  I hopped the power wire to input #2 as well so I could see just straight voltage.  


I think the next steps I will take to practice more with the HPT scanning software is to swap on the motor the new 102 FAST intake, 102 mm Throttle body, and possibly the new ID850 injectors I got.  I think this would be a good experience before I dive in full scale with the new motor.  


After I get the new motor tuned in on 93 octane, I ended up buying a flex fuel sensor that I plan on installing.  I found out the E40 red headed step child computer I have does have functionality for flex fuel and ethanol fueling.  I am excited to learn this aspect as well but also protect the motor from detonation and burn a cleaner fuel.  


Other than that, I am taking it one day at a time.  I really hope to accomplish all of this by the middle of July.  



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I forgot to mention, I had to build a custom tune to get the AFR to scale while I changed the RPM from 1,000 to 4,000.  I had to disable the MAF and a few other things to allow the system to stay in open loop.  From there I set the PE enrichment to range from 1.420 (AFR of 10.35) at 1,000 rpm to 0.918 (AFR of 16.01) at 4,000 rpm.  This allowed me to get the AFR to change from an otherwise static 14.7 in closed loop.  

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