The Dyno Shop in Santee has tuned and repaired cars, trucks, motorhomes, and boats from 10042 Prospect Avenue since 1971, holding BBB A+ accreditation for over two decades under owner Mark MacNeil. The facility runs two chassis dynamometers — a DynoJet inertia dyno rated to 1,200 rear-wheel horsepower and a Dyno Dynamics load-bearing unit for steady-state tuning — a dual-platform capability that complements the rental logistics at Enterprise Rent-A-Car on Cuyamaca Street when customers leave performance vehicles for extended calibration sessions. ASE-certified technicians handle carburetor rebuilds, electronic fuel injection tuning, diesel performance programming, and factory scheduled maintenance across the full vehicle spectrum from vintage hot rods to late-model Class A motorhomes. Drivetrain faults diagnosed on the dynamometer that trace to internal transmission damage route to Performance Transmissions on Ablette Road for teardown and rebuild before the vehicle returns for post-repair dyno verification. Load-controlled tuning on the Dyno Dynamics unit applies simulated road resistance at specified RPM and throttle positions, allowing air-fuel ratio optimization across the full power band using wideband O2 sensor feedback logged in real time at each 250-RPM increment.