Update

README.md

@@ -1,5 +1,10 @@
 # FluidSimCpp
 
+Solver performance measurements and reproducible SIMD/threading experiments are
+documented in [the optimization audit](verification/OPTIMIZATION.md). Current
+scenarios use serial pipe execution because per-substep threading costs more than
+it saves at their graph sizes. Portable compiler SIMD remains enabled by default.
+
 FluidSimCpp aims to reproduce sound from a physically accurate simulation of
 compressible flow in pipes and connected volumes, sampled at 44,100 Hz. Each
 audio sample advances physical time by 1/44100 second; adaptive internal
@@ -157,13 +162,19 @@ unboosted twin is unchanged unless `--turbo vz21` is selected.
 
 This is an estimated VZ21-size model, not a measured turbo map. Engine exhaust
 pulses are implemented; blade-passing whistle/wakes are still pending. The
-seven-second twin transient and all nine CTest suites passed. Sustained high-load
-performance is close to, or slower than, real time in the current benchmark;
-watch the underrun counter during testing. See
+seven-second twin transient and all nine CTest suites passed. The optimized
+7,000-RPM workload takes about 0.65 wall seconds per simulated second on the audit
+machine; actual playback headroom depends on the computer. See
 [turbo verification](verification/TURBO_VZ21.md) for assumptions and results.
 
 ## Saab B205 / 9-5 wagon baseline
 
+The Saab menu entry now includes an estimated GT17 turbo and ECU wastegate boost
+control (up to 0.45 bar gauge). Launch with `--scenario b205 --turbo gt17`, or use
+`--turbo none` for the naturally aspirated baseline. See [GT17 verification](verification/SAAB_GT17.md)
+for controller behavior, assumptions and tests. Charge heating and backpressure
+are simulated; an intercooler is not yet included.
+
 Select **Saab B205 / 9-5 wagon** from the desktop menu, or launch directly:
 
 ```sh
@@ -177,10 +188,10 @@ cylinder and 1-3-4-2 firing order. Four intake runners and four exhaust headers
 connect shared plenums and a tailpipe. The vehicle approximates a 9-5 wagon:
 1675 kg with driver, five-speed manual, FM55 B05 overall ratios
 13.70 / 7.12 / 4.77 / 3.62 / 2.67, and 4.05 final drive. No sixth gear is offered.
-Controls and dyno match the other scenarios. There is no turbo system yet;
-this is an atmospheric-breathing B205 geometry baseline. Pipe/cam dimensions,
+Controls and dyno match the other scenarios. The original atmospheric-breathing
+geometry baseline remains available with `--turbo none`. Pipe/cam dimensions,
 friction, idle/ignition maps, clutch, drag and loaded tire radius are estimates.
-It does not reproduce factory turbo power or turbo/exhaust acoustics.
+Turbo calibration and acoustics are approximate; factory power is not validated.
 See [B205 verification](verification/B205_BASELINE.md) for sources and checks.
 
 ## Current port status