Guest |202| Posted October 5, 2009 Report Share Posted October 5, 2009 Hey Ray, In the software I see two timing patterns for LS1 motors. LS1 5/10 and LS1 3/12. What are the differences between the two? Also, are these for North American based LS1's or patterns from Holdens...if there is a difference? Long story short, I need some sync info for a '98 LS1 from a Camaro for a V88 install. Quote Link to comment Share on other sites More sharing options...
rayhall Posted October 5, 2009 Report Share Posted October 5, 2009 There are two trigger patterns for the LS1 engines, and both are supported. The crank pattern on these engines is very complex. I cannot describe in words exactly what is like. One version of the engine has a crank sensor that outputs two signals. The cam sensor also outputs two signal. The two cam signals are mirror images of each other. The rear crank sensor signal has a rising edge that is evenly spaced and produces 24 signals per engine cycle. Ray. Quote Link to comment Share on other sites More sharing options...
Guest |277| Posted March 23, 2010 Report Share Posted March 23, 2010 So... Which pattern did you use for that -98 LS1? 3/12? Did you have same reluctor wheel that on left side? http://chevythunder.com/24x_and_58x_reluctors.jpg Quote Link to comment Share on other sites More sharing options...
rayhall Posted March 23, 2010 Report Share Posted March 23, 2010 That trigger wheel has 24 teeth with all falling edges evenly spaced on the rear trigger disk. The trigger can be setup as multitooth. Ray. Quote Link to comment Share on other sites More sharing options...
Guest |277| Posted March 28, 2010 Report Share Posted March 28, 2010 Are you sure that it's evenly spaced? To me it doesn't look like that... :?: Quote Link to comment Share on other sites More sharing options...
rayhall Posted March 28, 2010 Report Share Posted March 28, 2010 Sorry rising edge. If you look at the front edge of this pattern you will see they are evenly spaced. Ray. Quote Link to comment Share on other sites More sharing options...
rayhall Posted March 29, 2010 Report Share Posted March 29, 2010 Just looked at one of my old maps and I was correct the first time. The falling edges are even. Ray. Quote Link to comment Share on other sites More sharing options...
Guest |277| Posted March 29, 2010 Report Share Posted March 29, 2010 Yes you're right. 8-) Still I don't get it why GM made that? What's idea? Quote Link to comment Share on other sites More sharing options...
rayhall Posted March 30, 2010 Report Share Posted March 30, 2010 I believe GM does this so the engines start faster. The ECU can quickly work out the position of each cylinder by the pattern. Aftermarket ECU like the Vipec and others, need the engine to turn about one revolution when starting to find cylinder positions. Ray. Quote Link to comment Share on other sites More sharing options...
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