FAQs

Question:

What are the reasons for Clutch & Launch switches?

Answer:

Clutch Switch is for sensing pressure on the Clutch pedal. This effectively allows the ECU to sense that the driver has rested his foot on the clutch and potentially disengaging the clutch mechanism. This allows the ECU to do two things, prevents the gearbox doing down shifts and damaging the engine, e.g. if the car was in top gear the driver rests his foot on the clutch, the engine is disengaged from the clutch and the rpm drops. The driver could effectively then downshift from top to 1st gear, let the clutch up and obviously destroy the engine.

The second use for this switch is that when the driver is in the car, the system senses that the clutch is being pressed and therefore allows the paddles to select a gear safely.

If at least one wheel speed sensor is fitted, a minimum speed can be programmed into the ECU so that the engine can go down the gearbox. This is normally programmed to the maximum rpm below the rev limiter in first gear e.g. if 1st gear was 60mph at 10,000rpm*, then unless the wheel speeds were below 60mph when the clutch was pressed, then no gear changes will happen until below that speed.

*Please note that this is designed to help save damage to your engine, but it cannot protect against rate of change damage e.g. if your engine is at tickover for example and the wheel speeds are at 60mph, when the clutch is released at tickover, the engine acceleration is likely to be too great and the valve train will lose control, this can cause valve to piston contact and damage.

If a clutch switch is not fitted, then the driver would need to press the neutral button to tell the ECU that he is ready to select a gear, he then pulls an up or down paddle whilst holding the neutral button. The ECU will then select a gear.

The Launch switch is used to control Launch and provided the Launch circuit is fitted and set up, this can be used in a similar way, but you must remember that Launch is designed to operate when the clutch is on the floor and therefore if the driver simply rests his foot on the clutch pedal then he can actually have the clutch disengaged but not have triggered the switch and therefore downshifts could still occur and damage the engine.

So my suggestion is normally Clutch switch is most important for safety and should always be considered the first option and the Launch switch is for Launch and only used as a back up.

Question:

Would I be correct in thinking that when traction control kicks in, I should not take my foot off the throttle at all (which is the immediate instinct) but continue to apply throttle and let the electronics do all the work?

Answer:

Everybody tries to use the traction control in a different way, some drivers assume (usually the slow drivers) that it will make them faster and instead of driving the car normally, drive the car with the pedal flat to the floor and let the traction control do all the work. The way I use the traction control and many of the quick drivers use it, is to drive the car normally but when the conditions are slightly suspect i.e. the driver is unsure of the amount of grip is available in certain areas, that the traction control will allow them to use slightly more throttle and be less cautious than they would have been. That way if a patch on the circuit is found to be less grippy than expected, the traction control will give you some extra protection.

One of the best example of this, is if you are drifting the back end of the car and suddenly hit a patch of oil, you would normally attempt to come out of the throttle to prevent the rear end of the car from producing an excess slide and putting you into a spin, because the traction control can detect this sudden change quicker than you can, it will back the power off and normally allow you to carry on at the same angle of drift without loss of control. If at the same time you back the throttle off, you will actually get slower and the angle of drift will reduce.

My suggestion is that the traction control should be used to help you to maintain grip in unforeseen circumstances rather than a crutch to rely on. Drive the car, do not change your driving style but experiment under controlled conditions so you get a feel for what the traction control can do for you. Traction control can not lose you grip, it can only help you to gain grip.

One last thing that is important with traction control, which many drivers feel including myself, is that when you have a normal start or lose grip is the sensation the driver feels of the car sliding and wheel spinning is quite intense. When the launch and traction control are working, the effect almost feels as if you are going too slowly, but the only way to tell is against the clock and in most cases the smoother feeling with the launch and traction control working, the car is faster but it just doesn’t feel like that for the driver.

Question:

The launch control is excellent although I have a question relating to the 7 launch sectors. I understand the sectors enable differing revs to be used for different track conditions. Should I be applying full throttle pedal prior to releasing the clutch with launch governing different revs depending on the sector selected? Until now I have only applied about 2/3 pedal prior to releasing the clutch.

Answer:

In theory you can use full throttle and the rpm during the launch phase will be taken care of by the ECU. If you use too little throttle, you stand a chance of the car bogging down and dropping below the target rpm. This is because the amount of power being produced by the engine is controlled by the amount of throttle opening, giving full throttle will give the maximum amount of power possible at the target rpm selected. This means you always get a known amount of torque at every sector you use. If you vary the amount of throttle, the torque will obviously vary and you will get inconsistent starts.

This is what Trevor Willis does and he commented that when he tries to drive the car during the launch phase modulating the throttle, that the starts are not as good. One important thing to remember is that quite often lower rpm will give a better start than higher rpm, even though from the drivers seat you may fill the start is quick, the clock is the best way to tell.

Question:

I have a question about the use of the launch control on dry tarmac in rally use. It feels incredibly hard on the car which, with two rear wheels each weighing about 20kg, leaves me sitting on the line just waiting for something to break. Whilst I can appreciate the time benefit on sprints & hillclimbs, I am not yet convinced of the benefit of launch control on my car on dry tarmac.

Answer:

We have customers who have very fragile transmissions. When using manual launches one particular customer was breaking CV joints, driveshafts and on a couple of occasions even split the transmission in half, once he started using launch and traction control, the transmission problems almost completely vanished. Another customer, who was breaking crown wheel and pinions also gained the same improvements in component life.

So it appears that a control launch creates less stress than a manual launch, which is controlled by the driver’s right foot and the amount of grip at each moment during the launch period, which could vary greatly. Don’t forget that on the sprint cars, the tyres are normally much wider and have far more grip, the number of starts that we have during each day easily goes into double figures, particularly when double driven and so far we have seen no increased wear.

Obviously, if your transmission is far too weak for the discipline/car/engine you are competing in or damaged already, it won’t save it!

Question:

What are the reasons for Clutch & Launch switches?

Answer:

Clutch Switch is for sensing pressure on the Clutch pedal. This effectively allows the ECU to sense that the driver has rested his foot on the clutch and potentially disengaging the clutch mechanism. This allows the ECU to do two things, prevents the gearbox doing down shifts and damaging the engine, e.g. if the car was in top gear the driver rests his foot on the clutch, the engine is disengaged from the clutch and the rpm drops. The driver could effectively then downshift from top to 1st gear, let the clutch up and obviously destroy the engine.

The second use for this switch is that when the driver is in the car, the system senses that the clutch is being pressed and therefore allows the paddles to select a gear safely.

If at least one wheel speed sensor is fitted, a minimum speed can be programmed into the ECU so that the engine can go down the gearbox. This is normally programmed to the maximum rpm below the rev limiter in first gear e.g. if 1st gear was 60mph at 10,000rpm*, then unless the wheel speeds were below 60mph when the clutch was pressed, then no gear changes will happen until below that speed.

*Please note that this is designed to help save damage to your engine, but it cannot protect against rate of change damage e.g. if your engine is at tickover for example and the wheel speeds are at 60mph, when the clutch is released at tickover, the engine acceleration is likely to be too great and the valve train will lose control, this can cause valve to piston contact and damage.

If a clutch switch is not fitted, then the driver would need to press the neutral button to tell the ECU that he is ready to select a gear, he then pulls an up or down paddle whilst holding the neutral button. The ECU will then select a gear.

The Launch switch is used to control Launch and provided the Launch circuit is fitted and set up, this can be used in a similar way, but you must remember that Launch is designed to operate when the clutch is on the floor and therefore if the driver simply rests his foot on the clutch pedal then he can actually have the clutch disengaged but not have triggered the switch and therefore downshifts could still occur and damage the engine.

So my suggestion is normally Clutch switch is most important for safety and should always be considered the first option and the Launch switch is for Launch and only used as a back up.