A dyno session is the only objective measure of what your build is actually making at the wheels — and the controlled environment that makes serious tuning possible. The dyno directory lists facilities you can rent for baseline pulls, tuning sessions, before-and-after numbers, and shootouts.
Some facilities also list Tuner as a service. Their profile shows both service chips, so you can tell at a glance whether tuning is available on site.
Dyno types, when each matters
- Dynojet — inertia-based, reads optimistic. Most published numbers in enthusiast spec sheets are Dynojet. Best for quick pulls and trend comparisons.
- Mustang / Mainline / Dyno Dynamics — load-cell or eddy-current. Reads more conservative. Best for tuning under sustained load and replicating real driving conditions.
- Dynapack — hub-mount, removes the wheel/tire from the equation. Great for very-high-power cars where wheel slip on a roller is a problem. Setup time is longer.
Comparing numbers across dyno types is a lossy operation. Two dynos of the same type at different facilities can read 5–10% apart. When sharing or interpreting numbers, always cite the dyno type and facility — "405 whp on a Mustang at Sheepey" is meaningfully different from "450 whp on a Dynojet at the local hot-rod shop."
What to bring to a dyno day
- A car that runs cleanly under part-throttle and has been warmed up. Don't bring a half-finished build.
- The fuel you actually run — if you tune on E85 and arrive with pump 91, you've wasted the session.
- A datalog tool if your tuner needs one for the platform.
- A plan for what each pull is for — baseline, post-mod verification, full tune session. The facility's rate goes a lot further when you arrive with a plan.
- Tape (real tape, not painter's) for any louver / bumper / vent that might separate at speed.