Datalogging

[thorburn 121]

I'm just interested in finding out

1. Who's using it?

2. By what means are you using it?(standalone datalogger, ecu, cameras, etc)

3. What are you logging? e.g what sensors are you using

4. What are you trying to achieve by datalogging? looking for the smaller picture, not just quicker lap times

Reason for all this is I picked up a racepak G2X pro and I'm looking to get more use from it. It's a fairly advance piece of kit(although the rest of the market seems to be catching up in leaps and bounds atm) that I still haven't been making the most of.

I'd like to buy a few more vnet sensors and cables. But there is such a large choice that I'm not sure where to start

any-who dump your load on me and share whatever info you can

[Paragon 14]

The effectiveness of any data logging is all down to how good the software is ( or not ). Most punters get taken in by the shiny hardware because they can understand that and touch it, feel it.

Start off simple and build up. For example the single most useful channel is speed, you can learn a lot from overlaying just speed from different laps. Once you have that sorted add throttle, then maybe G, see if all corners have about the same peak G, see that left and right are the same peak, if not look around, why aren't they the same ? turning in too aggressively ? Later to improve lap times add brake pressure.

But it is all down to the software.

Cameras can be useful if you are still trying to find the correct line. However good data loggers with gps have this covered because they can be quite accurate for a single day.

[hybrid 1044]

I got a little bored so made my own.

http://bimmersport.co.nz/topic/43901-prototype-dslive-data-acquistion

[thorburn 121]

Andrew- I've currently had some attempts at logging. I'm fairly familiar with logging engine parameters due to tuning a couple of engines and a little bit of practice on a dyno.

I've got a few friends with drag cars and bikes that we will be attaching the logger to. Currently I've just used the basic built in sensors (gps, gforce, and battery voltage). I've also got 2 shock travel sensors(which can be recorded at 1000hz)and an rpm sensor that i've yet to try.

If I find some time i'll install it and take some basic logs to show what I'm up to.

Josh- It really is a beautiful piece of kit. I'd hate to think the amount of hard work has gone into it.

[hybrid 1044]

Cheers James, yeah a fair bit but well worth the reward of learning experience that went with it. I love the 1khz sampling rate of yours, really makes tuning for fuel and suspension possible for very detailed analisys and tuning.

For me I have all of the following:

Engine Speed, Engine Temperature, Engine Oil Temp, Ignition Angle, Intake Air Temp, Adapted Throttle Position, Road Speed ​, Air mass, Injection time Bank 1, Injection time Bank 2, Exhaust VANOS Angle Actual, Intake VANOS Angle Actual, Lambda Bank 1, Lambda Bank 2, Idle Control , Fuel Cut Cylinder Fade, Knock 1, Knock 2, Knock 3, Knock 4, Knock 5, Knock 6, Battery Voltage, Exhaust VANOS DME Target, Intake VANOS DME Target, Engine Load, Clutch swtich, Gear Position, Oil Pressure.

Planning brake pressure, suspension travel on all 4, slip angle amoung quite a few other things.

[thorburn 121]

Are you doing gear position via calculation or do you run a some sort of hall effect arrangement at the shifter?

I didn't realize the injectors in the s50's were batch fired. Or have you grouped them together for a simpler display?

Out of interest do you find any one cylinder is more likely to knock on your engine?

The only slight let down about racepak is you get stuck with the vnet system. The only cheap way(i know) of adding a lot of sensors is to attach it to a supported aftermarket ecu.

[polley 916]

Stand alone

Engine RPM

Coolant temperature

Coolant pressure

Air temperature

Boost pressure

AFR

Target AFR

Oil Pressure

Ignition angle

Wheel speed x 4

Vehicle speed

Wheel slip

Battery Voltage

Injection mS

Injection angle

Throttle position

Current gear

Traction control cut %

Calculated litres of fuel / hr

Boost control valve PWM %

Usually logging at 10 hz for day to day, but will bump it up to 100hz if im trying to sort out issues.

Edited April 8, 2014 by polley

[hybrid 1044]

Are you doing gear position via calculation or do you run a some sort of hall effect arrangement at the shifter?

I didn't realize the injectors in the s50's were batch fired. Or have you grouped them together for a simpler display?

Out of interest do you find any one cylinder is more likely to knock on your engine?

The only slight let down about racepak is you get stuck with the vnet system. The only cheap way(i know) of adding a lot of sensors is to attach it to a supported aftermarket ecu.

Calculated, The ZF 5speed I have doesn't support gear a gear position sensor. Hence the clutch switch. It has the added bonus of the ability to measure how fast your shifting gears around the track. You can literally add up and deduct the clutch in time and work out where you're loosing time in gear changes.

The injector output from the ECU is grouped, the ECU function is individual.

The way the knock works is its three sensors that work on listening to each cylinder on alternate cycles to pick up on each cylinder. Its pretty even and only detected it when I was forced to put 95 in out of town.

You could always try to reverse engineer it and build your own sensor array / communications system.

[thorburn 121]

Troy- I didn't realize you could change the logging frequency on the DTA. Does it record to a SD Card? Which wideband are you using? and how do you find it

Josh- 3 knock sensors is a few. BMW went a bit overkill with the s50 engines.

I've got a lot of learning to do before reverse engineering the racepak gear(I don't plan on doing it). Even a basic can bus seems like wizardry to me. You wouldn't have any links to books or sites that'll teach me a bit about the subject?

[hybrid 1044]

Josh- 3 knock sensors is a few. BMW went a bit overkill with the s50 engines.

I've got a lot of learning to do before reverse engineering the racepak gear(I don't plan on doing it). Even a basic can bus seems like wizardry to me. You wouldn't have any links to books or sites that'll teach me a bit about the subject?

They did and didn't. Maybe for every day use yes I agree. However the same ECU was used for Group-N and Group-A so was one of the first BMW road ECUs to have high speed engine telemetry which is awesome for 1996 technology, it has some great features that were only present in higher end aftermarket ECUs such as Pectel or Motec. This was an evolution from the race bread ECUs found in true BMW motorsport race cars EG ECU4a in the DTM cars etc

Yea don't we all, The hardest part with CAN is building a transceiver and software library for it. Or using an existing one. The sensor input part is dead easy.

Also if they load any of the CAN messages with a coded protocol. Then you have to reverse engineer it. (I would expect so)

PM me for my email address and I can respond more about it.

[polley 916]

Can choose from 1,10 and 100hz. Logging can be enabled from a switch or wheel speed or all the time. It only logs to internal memory so is limited. And can be quite slow to download which is a pain in the ass. I'm using a innovate mtxl, its alright, I suppose it could be faster. But it all seems to work quite well in closed loop

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