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Home > Help Needed / General Tech Chat > Data logger why not

Mr Joshua

2296 Posts
Member #: 1954
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Luton Bedfordshire

I have been away from minis for near on four years as I have been running my son and his go kart which has taken all my time and money. If you think minis need deep pockets try cadet karting!

Now I make my point. For all the modification and customisation we do trying to maintain accurate speed data may become more comparative than approximate. With the various gearbox and wheel combos possible the dial does not always read true. To this end has anyone fitted a data logger with GPS to their car.

fitting a uni pro, Alfano or mychron would solve this issue added to that the ability to map tracks would give the boffins amongst you another mass of graphs and figures to digest. You can also modify the display to your preferred data. I'm going to piece together something for my next build and have it steering wheel mounted.

Own the day


wil_h

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9183 Posts
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Betwix Harrogate and York

I use a GPS logger on my hillclimber. I'm not overly impressed. I think a ground speed sensor would be best (that's what WRC cars use).

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

On 2nd Jan, 2013 fastcarl said:

the design shows a distinct lack of imagination,
talk about starting off with a clean sheet of paper, then not bothering to fucking draw on it,lol

On 20th Apr, 2012 Paul S said:
I'm mainly concerned about swirl in the runners caused by the tangential entry.


stevieturbo

3351 Posts
Member #: 655
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Northern Ireland



On 30th Jun, 2018 wil_h said:
I use a GPS logger on my hillclimber. I'm not overly impressed. I think a ground speed sensor would be best (that's what WRC cars use).


I'm sure WRC cars will use GPS and many many many other things.

And all loggers etc are not equal.

The only downside to a good GPS is ensuring you have a good signal, which if there is tree cover etc or tall buildings that can get more difficult, even with a good external antennae.

In which case it's easy enough to go down the route of undriven wheel speed for that aspect.

Edited by stevieturbo on 30th Jun, 2018.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will


Sprocket

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11018 Posts
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Preston On The Brook

https://en.wikipedia.org/wiki/Ground_speed_radar

On 26th Oct, 2004 TurboDave16v said:
Is it A-Series only? I think it should be...
So when some joey comes on here about how his 16v turbo vauxhall is great compared to ours, he can be given the 'bird'...


On 26th Oct, 2004 Tom Fenton said:
Yep I agree with TD........


jonny f

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Dorking

Im using a GPS speedo in my car. It seems fairly accurate but it does seem to struggle with signal occasionally. Not sure it would be ideal for a data logger.


wil_h

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Betwix Harrogate and York

The thing to say about the GPS is that when I look at the logs to compare runs the track route varies massively. It's just not accurate or consistent enough.

It's a useful tool to know roughly where you were and what speed you were doing, but like any measurement, you have to understand what you have measured and how, to make use of it.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

On 2nd Jan, 2013 fastcarl said:

the design shows a distinct lack of imagination,
talk about starting off with a clean sheet of paper, then not bothering to fucking draw on it,lol

On 20th Apr, 2012 Paul S said:
I'm mainly concerned about swirl in the runners caused by the tangential entry.


Rod S

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5814 Posts
Member #: 2024
Formally Retired

Rural Suffolk

Everything I've ever seen with GPS used for speed measurement tells me it is very accurate in a non-changing situation....
But otherwise, it lags at least a second, sometimes a lot more, behind real time.
I've seen it with ShadowDash (a Megasquirt / TunerStudio thing), every stick to the windscreen type GPS device that I've used, my Blackvue dashcam setup, and pretty much every dashcam video (with a GPS enabled one) that you can watch on YouTube.
Accurate, but delayed.

Schrödinger's cat - so which one am I ???


jbelanger

1229 Posts
Member #: 831
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Montreal, Canada

Most GPS units use time and position to compute speed so there will be a delay in getting the correct speed during changing situations. And some GPS are updating their position slowly (1Hz or less) so the delay is very obvious.

In theory the Doppler effect can be used for speed determination but I don't think this is used in the units commonly available.

http://www.jbperf.com/


Mr Joshua

2296 Posts
Member #: 1954
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Luton Bedfordshire

how many satellites do your respective units lock onto the one on my boys kart locks onto 9 not sure what the refresh rate is.

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Rod S

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5814 Posts
Member #: 2024
Formally Retired

Rural Suffolk

On 2nd Jul, 2018 Mr Joshua said:
how many satellites do your respective units lock onto the one on my boys kart locks onto 9 not sure what the refresh rate is.

Haven't a clue, 3 minimum obviously but they vary make from make (and what is available with tree/building blocking etc.)
Ask the manufacturers, but one simple point, more than 3 will make the position (hence the speed calculation) more accurate but processing more than three will slow the speed calculation down and if the "device" (whatever it is) has other things to do like data logging on a running engine, maybe even running an engine, or processing high resolution MP4 video like on a good dashcam, someone will have decided which is most important for the CPU.
My dashcam does 1080p 60fps video really well but the GPS speed superimposed on the video is at least one second (probably two) behind the video so it's obvious the video gets most of the CPU time.

Schrödinger's cat - so which one am I ???


Tom Fenton
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15146 Posts
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Fearless Tom Fenton, Avon Park 2007 & 2008 class D winner

&

TM legend.

Rotherham South Yorkshire

My mate runs a circuit car, he has a Race Technology dash/data logger and swears by it.


On 29th Nov, 2016 madmk1 said:


On 28th Nov, 2016 Rob Gavin said:
I refuse to pay for anything else


Like fuel 😂😂


Mr Joshua

2296 Posts
Member #: 1954
Post Whore

Luton Bedfordshire

I have had my sons data logger sat on the dash just registering the cars speed being the GPS sensor and it was on point for the entire journey the unit he uses is the unipro. Im trying to take the guess work out of my speed readings.

Own the day


stevieturbo

3351 Posts
Member #: 655
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Northern Ireland



On 1st Jul, 2018 Rod S said:
Everything I've ever seen with GPS used for speed measurement tells me it is very accurate in a non-changing situation....
But otherwise, it lags at least a second, sometimes a lot more, behind real time.
I've seen it with ShadowDash (a Megasquirt / TunerStudio thing), every stick to the windscreen type GPS device that I've used, my Blackvue dashcam setup, and pretty much every dashcam video (with a GPS enabled one) that you can watch on YouTube.
Accurate, but delayed.


You havent seen very many then

Even a basic 10Hz VBox is very very accurate, and still an industry standard for easy performance testing etc. Although more professional stuff would use their much more expensive gear.

Most GPS stuff you'd consider buying these days is in the 10-50Hz range, over that and it can get very expensive. But even 50Hz stuff is affordable these days.

Dashcam GPS is cheap shite, plain and simple so no sense even trying to compare it to something you'd use for a logger.

Edited by stevieturbo on 2nd Jul, 2018.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will


Mr Joshua

2296 Posts
Member #: 1954
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Luton Bedfordshire

Just checked and the unipro is up to 60hz

Own the day


Mr Joshua

2296 Posts
Member #: 1954
Post Whore

Luton Bedfordshire

Just checked and the unipro is up to 60hz

Own the day


Jimster
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9340 Posts
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455bhp per ton
12 sec 1/4 mile road legal mini

Sunny Bridgend, South Wales

I use and install quite a bit of loggers. I use personally the race technology range. I find the logging extremely accurate, often my times displayed on my dash are within 100's of a second compared to the official TSL timing taken at the circuit

Team www.sheepspeed.com Racing

On 15th May, 2009 TurboDave said:

I think the welsh one has it right!


1st to provide running proof
of turbo twinkie in a car and first to
run a 1/4 in one!!

Is your data backed up?? directbackup.net one extra month free for all Turbo minis members, PM me for detials

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