Accelerometer?

i posted somethin about this concept earlier but got inconclusive responses. If acceleration is a function of speed over time and we have speedometers couldnt we just have another program in a datalogger or something and add to the plot graph of vehicle statistics acceleration per time?

also if many people had this couldnt we theoretically see exactly whose car is faster from our graphs instead of guessing from weight, pk hp, area under the curve, gearing, and a slew of random comparable parts listed?

it seems as if it would be the most accurate benchmark piece of information one would use when talking about their car or sizing up another. "hey i accelerate at ___ m/s"

just some food for thought. it seems like it would be usefull for street tuning and track days as well. why dont we have accelerometers? (aside from those random ones you can that require you to mount somethin on your windshield)

 

Evoscan and Mitsulogger both log MPH and time. So you could log and see how fast you accelerate to a certain speed.

 

i was thinkin more along acceleration at given rpm that you could display as another line in the graph of a dyno or somethin like that as well

 

I think the Innovate LMA-3 has this function built in, would be great with the LC-1 cable bundle

The 5 internal sensors are intended for capturing Manifold Air Pressure (MAP or Boost), Cylinder Head Temperature (CHT) or Exhaust Gas Temperature (EGT), RPM conversion (from a tach signal or inductive clamp), Acceleration, and Injector Duty Cycle (or Dwell). The internal MAP sensor is a 3-bar absolute pressure sensor, providing accurate data up to 44.1 PSIA. The temperature measurement circuit features a K-type thermocouple. The internal accelerometer features 2 axis measurements for a variety of mounting options.

 

The problem with accelerometers is drag and drift. Even two Evo's with the exact same amount of HP and TQ can still accelerate at different speeds due to driver input, tire pressure, tire size, road conditions, vehicle bodywork, and many other variables.
And accelerometers require accurate calibration.

 

+1, excatly what i was going to say

 

still, to see if a mod has had any impact on your own car,-
you should be able to witness before and after.

 

All you will get by measuring speed over time will be an average acceleration. Remember, as you are accelerating, it won't be a linear x m/s/s. You need to take into consideration traction, gear selection, and power output at different engine speeds, as well as other things.

 

What would be a good indication of how well the engine responded to a mod is integrating the function of the acceleration vs. time curve. By looking at the curve you should also be able to tell where you have gained torque or hp as well. However, for each run before and after the mod, all other variables (traction, gear, throttle, drag, vehicle weight, incline, temperature, pressure...) would have to be constant; which is difficult enact.

Of course, you could always just overlay the modded dyno curve over the pre-modded curve and simply look at to gain instant insight haha