Cadillac XLR LH2 Tuning – Tune 7A Timing

Today’s test was to add 2 degrees of timing advance in the mid-range except in knock-sensitive areas, and up to 4 degrees near redline.  This builds the timing to be closer to the MBT table.

XLR Tune 7A-0348 Comparison to Tune 6G-0312

The result was more KR in the midrange, which is not good.  Overall today’s test came out as lower calculated HP/Torque than the prior 6G-0312 test except in the 6000-6400 range where it gained 5 hp.

XLR Tune 7A Weather Corr

Weather correction data table

XLR Tune 7a-0348 HpTuners

Uncorrected HPtuners output at peak HP.

Reviewing 7A, in a classic ‘Don’t do two things at once’ mistake I took the AFR 0.5 richer at 6400 rpm, so that could impact the tip-over in today’s run.  I will take that out, and look at the spark level desired at 6800 rpm.  I also plan to re-test AFR at 12.8:1 instead of current 12.5:1.  I tested that in Tune 2 but I want to recheck.

XLR Tune 7A-0348 to 6A-0312 Timing


This chart shows the LOSS of timing due to KR for 7A by increasing the timing, except above 6000 RPM.





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