Blog Post: Cadillac ATS-V Tune F

[Bruce Nunnally]

Changes: Overspeed limit max increased from .5 to 1. Waste gate open boost increased 2 pts. Peak torque and max torque redone as 1.2x stock tunes. Fast torque exit set to 50/25. Boost max limit added 1. Increased knock airmass. Further reduced main spark map, high octane to address KR. Transmission: increased TCC desired pressures, regulator gain, regulator offset, reset TCC desired slip to match Corvette, changed TCC adapt torque min. Disabled TCC in gears 2,3,4.

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Conditions: 81F, engine Baro 12.235 inHg 74% humidity; correction 1.037 SAE J1439.
Output: Measured max 466.7 hp at 5315 rpm, 467.4 Ft lbs torque at 5198 rpm so
Corrected 484.0 hp at 5315 rpm and 484.7 ft-lbs torque at 5206 rpm.

Goals: Eliminate KR. Reduce TCC slip rpm. Reduce throttle opening.

Results: KR was reduced at WOT pressures to under 0.5 (but not eliminated); good progress. TCC still showed slip even though TCC was not applied in gears 1-4. Unclear if that helped or not; reset to stock for next tune. Still throttle closing; going to try Sam’s driver demand map which further increases driver demand, and makes more linear. Keeping an eye on misfires; going to go a bit richer next tune, from 12.7 to 12.5 AFR (14.113/12.5 = 1.12904 PE value). Fuel pressure holding fine so far. Boost rose to 19.2 PSI then fell to 18.5 before the throttle opened around 5800 rpm; not sure why. Still seeing a flat HP curve from 5300 rpm to 6200 RPM instead of a steady increase; not sure why.

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