Where it runs
Organised quarter-mile racing in Jamaica centres on Vernamfield in Clarendon, an old wartime airfield with a concrete launch pad, a wide shutdown area and proper timing equipment. Events also run at Jamwest Motorsports Centre at Little London in Westmoreland, on the west end of the island.
Event days are the only place to find out what your car actually runs. A road is not a track: there is no timing system, no marshals, no medical cover and no shutdown area, and the number you think you ran is a guess. Every serious ET on this site was set at a sanctioned meet.
Dates move around, so check the race day schedule before planning a weekend.
Your first pass, step by step
Your car gets checked before it runs. Expect them to look at the battery tie-down, seat belts, the absence of leaks, tyre condition, and that nothing loose is in the cabin or boot. Empty the car, including the boot and door pockets.
You queue in lanes. This is the time to check tyre pressures and drop the windows. Watch a few pairs go up before your turn so the routine is not new to you.
Water box first, for cars on slicks or drag radials. A street car on regular tyres usually skips the wet box or does a short dry burnout to clean the tread. If you are not sure, ask the starter rather than guessing.
Roll forward slowly. The top bulb is pre-stage, the second is stage. Once both cars are staged the tree can drop at any moment, so get your feet and revs set before you light the second bulb, not after.
React to the last amber, not the green. On a street car, do not dump the clutch at high rpm: a slipping, controlled release usually gives a better 60 ft than a violent one, and it will not break anything expensive.
Shift cleanly, stay in your lane, and look for the finish-line lights. Brake progressively after the stripe and take the first exit road. Then collect your ticket at the timing booth.
Reading the ticket
A timing ticket is not just an ET. Each mark tells you about a different part of the run, and comparing them is how you find where the time went.
| On the slip | What it measures | What to do with it |
|---|---|---|
| RT (reaction time) | How long after green before you left | Does not affect your ET. It only decides who wins a close race. |
| 60 ft | The launch | The most useful single number. Fix this before chasing power. |
| 330 ft | Launch carrying into first shift | A bad 330 with a good 60 ft usually means the first shift. |
| 1/8 ET and MPH | Half the race | Shows whether the car is still pulling or already flat. |
| 1,000 ft | Top-end acceleration | Where gearing and power delivery show up. |
| 1/4 ET | The whole pass | The headline number, and the least diagnostic one on its own. |
| 1/4 MPH | Trap speed | Reflects power to weight. Trap speed barely moves with a better launch. |
Two cars can run the same ET for completely different reasons. A car with a poor 60 ft and a high trap speed has power and no traction. A car with a strong 60 ft and a low trap speed launches well and runs out of engine. The fix is different in each case.
Glossary
- ET
- Elapsed time. How long the car takes from the moment it leaves the starting beam to the moment it crosses the finish line.
- 60 ft
- Time to cover the first 60 feet. The launch measurement. On most street cars, a tenth found here is a tenth and a half off the ET.
- Trap speed
- Speed recorded at the finish line, averaged over the last short section. Closely tied to power-to-weight ratio.
- Reaction time
- The gap between the green light and your car leaving the stage beam. A perfect light on a full tree is .000, and anything before it is a red light and a disqualification.
- Pre-stage and stage
- The two top bulbs on the tree. Pre-stage means you are close; stage means you have broken the starting beam and the car is ready to run.
- Deep staging
- Rolling slightly further in, past the normal stage point. It improves reaction time but gives away a little ET, and it is easy to roll through the beam and red-light.
- Full tree and pro tree
- A full tree drops three ambers in sequence with a half-second gap. A pro tree drops all three at once, then green four tenths later.
- Dial-in
- In bracket racing, the time you predict your car will run. Run quicker than your dial-in and you break out and lose, which makes consistency worth more than speed.
- Density altitude (DA)
- Air temperature, humidity and pressure combined into a single altitude-equivalent number. Higher DA means thinner air, less power and slower times. Naturally aspirated engines feel it most. Live DA for both Jamaican tracks.
- Grains of water
- How much water is in the air, per pound of dry air. Humid air displaces oxygen, so high grains costs power even when the temperature looks fine.
- Slicks and drag radials
- Slicks are soft, treadless race tyres that need heat from a burnout to work. Drag radials are a street-legal compromise with far more grip than a normal tyre.
- Limited slip differential (LSD)
- Sends torque to both driven wheels instead of letting one spin. On a powerful front-wheel-drive car it is one of the biggest launch improvements available.
- Launch control
- An ECU function that holds a set rpm with the throttle flat, so you can release the clutch at the same rpm every single time. Consistency, not power.
- All-motor
- Naturally aspirated. No turbo, no supercharger, no nitrous.
- WHP
- Wheel horsepower, measured on a chassis dyno after drivetrain losses. Usually 12 to 18 percent below the engine figure on a manual front-wheel-drive car.
- Shutdown area
- The distance past the finish line for slowing down safely. It is the main reason a track is not the same as a road.
Getting quicker without spending
- Take weight out. Spare wheel, tools, boot contents, half a tank instead of full. Free, and it works on every single pass.
- Set tyre pressure deliberately. Write down what you ran and what the 60 ft was. Two or three passes of this teaches you more than a forum thread.
- Run cool. Heat-soaked intake air costs real power. Let the car cool between runs instead of queueing with the engine idling.
- Change one thing at a time. Two changes on one pass means you learn nothing from the result.
- Log the air. A pass on a 900 ft DA morning and a pass on a 2,300 ft DA afternoon are not comparable, and people chase imaginary problems for weeks because of it.
- Practise the tree. Reaction time is the only part of a drag race that costs nothing and needs no parts.