Cadillac XLR LH2 Tuning – Tune 7B Less Timing low, Lean

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I am glad that I am running 2 tests on every setting now, as I am seeing some variability.

[Click to zoom images, back to return]

XLR Tune 7B Hp Torque 2 runs

Tune 7B reduced the timing low, included some knock reserve where we were seeing KR, kept the timing high, and put piston protection back to 8192 instead of 6000 rpm.

Both the runs on the graph are tune 7B same day, same roadway, so same conditions.  The graph shows calculated HP at the top, degrees of advance in the middle, and degrees of KR at the bottom.  What happens is the 2nd run gets a knock event around 5500 rpm and loses 2 points of advance that it never seems to recover.

XLR Tune 7B run-to-run and 7A

Throw in 7A as well, which had all the advance and a lot of KR, and you can see that 7B-0236 basically emulates 7A but via timing table not knock retard.

Tune 7B Virtual Dyno Compare w 7A 6G S3

I am focusing on the calc HP/torque and not the Virtual Dyno for now, but the Virtual Dyno loved these tunes — except it shows some huge variability it could not smooth out.

XLR Tune 7B-0502 weather

Weather Calc for 7B: https://wahiduddin.net/calc/calc_hp_dp.htm

I hope to gather more sample data for Tune 7B next.

 

Cadillac XLR LH2 Tuning – Tune 7A Timing

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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 https://wahiduddin.net/calc/calc_hp_dp.htm

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.