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.
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.
Thoughts: reduction in spark to reduce KR at high pressures may be limiting hp at high rpm. Consider a richer PE and attempting to restore spark and still avoid KR or misfire.
The above chart is based on a layout file for HP Tuners to help with analysis.
The red line is HP, the light blue line is Torque, across two gears, 2 & 3, from 17 to 78 mph.
The dark blue line is throttle (versus pedal input), or how much the PCM commanded the throttle. The white line is RPM.
The yellow line is boost. There is a strong correlation between the boost curve and the Torque or HP curves before/after 5252 RPM where they cross by definition. Boost holds at 17.49 psi in second, and rises to 19.47 psi in 3rd gear.
At the highlighted snapshot moment, driver demand is at 109%. After this, driver deman falls off; I am not sure why. Later in the run at 5696 rpm in 3rd gear the commanded throttle opens due to boost pressure limits being exceeded, and boost falls off after that point, crushing the HP curve from there. Those boost limits will need further attention in the next tune.
The gold line is TCC Slip RPM. I note that here in my tune E TCC slip is actually well controlled in 3rd gear, and falls across 2nd gear rev range. I plan to increase the TCC pressures across 2nd gear parameters.
Overall this layout was helpful in analyzing individual tests, and comparing across scan files for these parameters.
Purpose: Keep the throttle closed again after boost ramp up. Eliminate TCC slip. Study KR vs PE by going richer, so closer to tune c2.
Plan: Raise PE to 12.7 to try to address KR; no change to spark map for this run. Address TUTD shift RPM to try to enable automatic shift up in 1/2/3/4 not 5/6/7/8 so can hold those if needed for dyno. Adjust Turbo Knock Mass to raise desired boost level to try to close throttle. Study scanner with car to understand missing channels. Modify TCC pressure apply ramp to reduce TCC slip. Rescan.
Data: 2nd gear 456.8 hp @ 5838 rpm / 458 torque @ 5126 RPM with 17.4 psi boost at peak hp 3rd gear 464.8 hp at 5320 rpm / 469.5 torque @ 4660 RPM; with 19.4 psi boost at peak hp Corrected 3 gear: 467.2 hp / 471.9 lb-ft torque
Result: Still getting KR at WOT at 12.7:1 PE and current spark map. Throttle opened at 5718 RPM in at 71 mph on one test, stayed closed in another. Desired boost just before 34.5, actual boost 34.4 psi. Then desired boost falls off and throttle opens. 2.3 degrees KR showing at that point. MAT 133F. Boost 19.1 psi. Cyl airmass 1.34. fine on boost max limit but pinched on knock airmass. So further knock airmass adjust?
Comparative results from last 3 scans on TCC slip error; still needs attention. For the gallery images, right-click then select view in new tab to see full page versions.
Missing parameters: Connected to vehicle, then repolled vehicle for parameters. Now everything is showing again. I think this happened after I changed from stable release to beta release, but beta release is seeing all the parameters after repolling.