#Cadillac XLR LH2 V8 Tuning – Tune 9B #Tuning #VirtualDyno

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Tune 9B removes IAT multipliers below 6000 RPM from Tune 9A to keep them from causing KR.

XLR Tune 9B and design for tune 10

Tune 9B tests ran almost no KR, so removing the IAT adders helped there.  The totals were good at 317-320 2nd gear HP.

XLR Tune 9B VirtualDyno with 9A

Both 9B runs were pretty wavey but overall 9B made at least as much WHP as 9A.

In the first graph it is clear that Tune 9B is running MORE timing than the MBT table.  For Tune 10 I am zeroing out PE/COT timing adder and touching up the base timing to pull timing down to the MBT timing shown in gold.

Cadillac XLR LH2 V8 Tuning – More Tune 9a

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Tonight I had cooler weather so I re-tested Tune 9a for baseline comparison.

XLR Tune 9A2 Comparison Calc HP

The 9A2 runs showed some KR spikes at 4150 rpm and 5000 RPM. This appears to relate to a high IAT advance multiplier at those RPMs, which I will zero out for Tune 9B.

XLR Tune 9a2 to 9a comparison

The Virtual Dyno for 9a2 was equivalent to 9a1, which is good news (same tune, different day).

Tune 9B will also reapply the MAF 2% touch up around 8,000 hz since there are some signs of running lean there.

XLR Tune 9A2-0139 HPTuners

The issue of KR due to multiplied IAT advance at lower temps could be why the XLR has consistently run better at high temps (which is counter-intuitive). In the next tune I will change the multipliers below 6000 RPM/below 104F for IAT advance to 0. The alternative would be to zero out IAT advance adders at cooler temps, but there may be some value in keeping them at higher RPMs.

Because the KR doesn’t go up at higher RPM it may be false knock?