9

The only thing your car can sense is the number of turns of some part of the drive train. In the old days it was a gear right off the transmission, and today it's an electronic sensor in the transmission or somewhere in the drive train near the wheels. It's going to be a sensor that can determine how quickly the wheels are rotating. The way to calculate ...


6

Most speedos in the dash for modern electronic based cars, have a sensor in the output shaft of the transmission. It is a simple reluctor wheel and Hall effect sensor, or a gear driven motor which can then produce a signal for the PCM to interpret. Cars can also use the same method off of the anti-lock wheel sensor to get a "speed" indication. The more ticks ...


5

You cannot. You can't even do it that well with GPS. The only relevant OBD2 parameters are speed and RPMs. If the wheels are locked or traction is otherwise lost, neither of these can be used in the calculation. Brake pedal position is also not a standard PID so you won't always even have a reference point. I am assuming you want to log data from within ...


5

Manufacturers deliberately calibrate their speedos incorrectly. They make sure the speedo always reads higher than the actual road speed, and there is a very good legal reason for this. Speedometers must never read lower than the actual speed (European law (ECE-R39) says speedometers cannot show speeds less than the actual speed. Other countries have ...


3

The problem is with what they've said is, on a '97 Subaru Legacy, the wheel speed sensor is detached from the wheel bearing. You only need to remove the wheel to get to it (and could possibly do it without removing the wheel!). There is one bolt which holds it to the wheel hub assembly, then a couple more holding the bracketry onto the vehicle itself. Then ...


2

To calculate the actual speed you need: Transmission gear ratios Final drive ratio Tire diameter Engine RPM [tire diameter (in inches)] * [pi] * [1/(gear ratio * final drive ratio)] / [in/ft] / [ft/mi] * [RPM] * [min/hr] = MPH Constants: pi = 3.14159 in/ft = 12 ft/mi = 5280 min/hr = 60 I'm sure I could simplify this equation, but this is good for ...


2

Yes, the wheel speed sensors can detect if the vehicle (or at least the specific wheel the sensor is tied to) is moving. On most vehicles you should be able to tie directly into the wheel speed sensor and detect the signal, while not causing any issues with the vehicle itself while in normal operation. The sensor itself is a standard sine wave orientation. ...


2

Short answer is yes and no. Not sure what you mean by exaggerated, but it shouldn't be by that much. On the other hand, speed reported by the wheels hardly ever are correct on racetrack; if you are serious about telemetry you must use GPS data. All that said, mathematically speaking, you should be fine for comparing individual corners on different laps ...


2

The speedo will read incorrectly by the difference in the rolling radius. However, if you are that far over in a curve you would be well advised to be watching where you are going and for road imperfections than the, usually small, difference in speed of the speedo...


1

Many devices will capture signals, but you need to know what type of signal to send and also how many pulses per revolution. Otherwise it won’t work. Based on comnent: I fitted a rev counter from a petrol car into a car with a diesel engine by changing the instrument assembly. So rev counter was driven off the coil so needs 2 sparks per engine revolution ...


1

A problem in your quest for measuring the speed is where do you measure the speed. Is it the bottom of the wheel, the contact point, the centre of mass or the top of your head? All have the same angular speed around the centre of the turn, but different linear speed; because of the different radii. Comparing speeds in the corner isn't important, the time ...


1

I'm not entirely sure about the MINI Cooper S, but on most cars you don't replace the magnetic (or reluctor) ring when replacing the sensor. You don't need to unless there's been some kind of accident or something where it physically gets damaged. The ring is usually just a reluctor wheel which activates the ABS sensor (most of the time it's a Hall effect ...


1

The speed sensor should be located on the outside of the transmission housing on the passenger side. Looks like this. EDIT: Also found a diagram to repair the DPS6 transmission. This is where the speed sensors are located. Its a bit confusing as it assumes you have the transmission pulled out, but I hope it helps.


1

Keep one thing in mind: at a repair shop, 60-80% of the repair bill is for labour, not parts (on average). Wheel speed sensors are always on or near the wheel hub. Sometimes you can access them without taking the wheel hub off, sometimes you can't. I just helped a friend replace a wheel hub yesterday, and when they get rusted in (and my friend's was), you ...


1

On some cars, the input speed sensor to the transmission and the output speed sensor work in tandom. The computer can tell which gear the transmission is actually in and even adjust the harshness of the shift. If one sensor has actually failed, typically the car should go into a limp home mode. Are you sure these are current error codes or simply stored ...


1

It's not something you can calculate because there are so many factors which not one affect the calculation but will be different every time. These include; Tyre temperature Tyre pressure Tyre wear Tyre condition (i.e. flat spots, etc) Ambient air temperature Road surface temperature Road surface condition Road surface moisture level Residual temperature ...


1

Before replacing the sensor, disconnect it at its plug to the loom. Test for a resistence across its two terminals. The code is telling you of a short to ground. This can mean that the feed wire, the sensor assembly, or the signal wire is not conducting through the circuit. Check the cabling for breaks or damage, especially on its bends. No breaks, or no ...


1

It's not unusual for a second radiator to be present behind the main radiator, often to cool the transmission fluid. If these fluids are mixing (water and transmission fluid), then both radiators have been damaged and are leaking their fluids together. Both radiators will need to be removed and repaired. Sometimes coolant will appear in engine oil because ...


1

I take it from the wording, English is not your first language. To answer you outright, there is no reason to mix coolant and oil, under no situation where a vehicle is concerned. If you are actually asking why oil would be fed through something containing coolant (radiator or such), the reason would be simple in that it is cooling the oil. By cooling the ...


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