What this table does
A pit lane limiter holds the car at a set speed while the driver keeps their foot down. The blunt way is to cut ignition or fuel once the car hits the limit. That works, but it builds heat in the exhaust and turbo, and it makes the pops and bangs everyone in the pit lane can hear.
DBW Throttle Max is a gentler first line of control. It caps how far the electronic throttle can open while the limiter is active, so the engine simply can't make enough power to go much past the limit. Cut then only has to trim the last bit. The driver can still keep the pedal pinned to the floor if they want.
This table only appears when drive-by-wire is enabled in the ECU's Engine Functions settings. On a cable throttle, the limiter relies entirely on fuel and ignition cut.
Reading the axis
By default the table's axis is the Pit Lane Speed Limiter Before Cut channel. That channel is the gap between actual speed and the limiter speed. At 0 the car is right on the limit. At 20, it's 20 km/h (about 12 mph) under the limit. So you're telling the ECU how much throttle to allow depending on how close the car is to the target.
How we tune it
| Distance from limit | Throttle allowance | Why |
|---|---|---|
| Well below the limit | Generous | Lets the car accelerate to pit speed briskly |
| Approaching the limit | Tapering down | Slows the approach so it doesn't overshoot |
| At the limit | Just enough to hold speed on the flat | Leaves the cut with very little to do |
- Start with a gentle taper and log speed, throttle and cut together.
- If speed overshoots and the cut is busy, reduce throttle closer to 0 on the axis.
- If the car struggles to reach pit speed, open up the far end of the table.
- Check it on the actual pit lane surface; an uphill pit entry needs more throttle than a flat one.
Related settings
This table works with the rest of the pit lane speed limiter. See the ignition correction and fuel correction tables for the cut side, and limiter wiring for the activation switch.
