Before you book
Preparing your car for a dyno session
Most sessions that end early were decided days before the car arrived. Half an hour of checks beforehand is the difference between a set of run sheets and a wasted drive.
A dyno session asks an engine to hold full load for longer than almost anything you do on the road. Anything marginal becomes obvious, which is useful diagnostically and expensive if it was avoidable.
The week before
- Spark plugs. Fresh, correctly gapped, and at the right heat range for what the engine is now rather than what it was from the factory.
- Fluids. Oil at level and not overdue. Coolant full, with a cap and a system that will hold pressure.
- Leaks. Anything weeping at rest will be worse under sustained load. Oil onto an exhaust is how a session ends.
- Belts and hoses. A belt that slips under load costs you the pull and sometimes the water pump.
- Tyres. Even wear, sound sidewalls, correct pressures. The driven tyres are what transmit everything to the roller.
Fuel
Arrive with at least half a tank of the fuel you actually intend to run. Not what is cheapest, and not a mixture of what happened to be in there. A calibration written on one fuel is not valid on another, and a car that is tuned on premium and then run on lower octane is a car with a problem waiting for a warm day.
If you are running ethanol blends, say so when you book. Content varies between pumps and seasons, and it changes the fuelling requirement significantly.
What to bring
- The parts list, including anything a previous shop fitted that you are no longer certain about.
- Any previous run sheets, so the session has something to compare against.
- The wheel lock key, if it has one.
- Any existing calibration file, if the car has been tuned before.
Faults that end a session
These are the ones that come up most often, and every one of them is cheaper to find at home.
- A misfire under load that is not apparent at idle or on light throttle.
- A boost leak, which shows up as a target the car cannot hold.
- Cooling that copes on the road but not under sustained load with no airflow of its own.
- A clutch that slips at full torque. Nothing can be measured through a slipping clutch.
- Fuel supply that runs out of capacity before the engine runs out of demand.
If any of those are already suspected, say so rather than hoping. We would far rather reschedule than spend your day chasing a fault a set of plugs would have fixed, and a diagnostic session is a better use of the money than a baseline the car cannot complete.
On the day
Turn up with the car warm if the drive allows it, expect the setup and strapping down to take a while, and plan on the car being here for the block rather than squeezed between other jobs. When you leave you will have the run sheets and a straight account of what the car did.
What this relates to
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