Go Back   EcoModder Forum > EcoModding > Off-Topic Tech
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 04-16-2017, 09:30 AM   #1 (permalink)
aero guerrilla
 
Piwoslaw's Avatar
 
Join Date: Oct 2008
Location: Warsaw, Poland
Posts: 3,538

Svietlana II - '13 Peugeot 308SW e-HDI 6sp
90 day: 58.1 mpg (US)
Thanks: 1,056
Thanked 635 Times in 399 Posts
Rescaling the speedometer

I remember a time when car speedometers ended at 180 km/h, our P307's speedo goes to 210 km/h. I've only gone to 150 once, when we bought the car, since then I try to keep my speed below 100-110 km/h.

We are looking at getting a new car, and almost all of the models I've looked at go to 230 km/h, even though I searched for "eco" models.

Why do I need a speedo that goes almost twice as fast as I'll ever need to? Except for the Autobahn, most highways in Europe are limited to 120 km/h (140 in Poland and Bulgaria). Why not re-scale it to 0-150 to get better resolution?

Question is: How would I go about doing that? It's not enough to print a new background, I need to reset/recalibrate the step motor (or whatever it is) that controls the position of the speedo indicator needle. How?

Then there is question of how legal the new setup would be...

__________________
e·co·mod·ding: the art of turning vehicles into what they should be

What matters is where you're going, not how fast.

"... we humans tend to screw up everything that's good enough as it is...or everything that we're attracted to, we love to go and defile it." - Chris Cornell

Piwoslaw's Peugeot 307sw modding thread

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 04-16-2017, 04:14 PM   #2 (permalink)
Master EcoModder
 
nemo's Avatar
 
Join Date: Nov 2010
Location: US
Posts: 994

Chief - '06 Pontiac Grand Prix
90 day: 19.41 mpg (US)

SF1 - '12 Ford Fiesta S
90 day: 20.31 mpg (US)
Thanks: 192
Thanked 235 Times in 182 Posts
I would think the first thing you would need to know is how the speed of your vehicle is determined.
__________________

  Reply With Quote
Old 04-16-2017, 04:31 PM   #3 (permalink)
aero guerrilla
 
Piwoslaw's Avatar
 
Join Date: Oct 2008
Location: Warsaw, Poland
Posts: 3,538

Svietlana II - '13 Peugeot 308SW e-HDI 6sp
90 day: 58.1 mpg (US)
Thanks: 1,056
Thanked 635 Times in 399 Posts
When comparing to a GPS, the stock speedometer shows 2-4% higher than the actual speed. When I use an OBD tool (ScanGauge) to read the speed, it is spot on with the GPS, not with the speedometer(strange...).
Quote:
Originally Posted by nemo View Post
I would think the first thing you would need to know is how the speed of your vehicle is determined.
Most likely a sensor on the transaxle (when I floor it and the wheels spin, then the speedo goes up).

Which gives me an idea: add a second magnet to the transaxle, so the speedo shows twice the speed, then re-scale the speedo's background. Unfortunately, this would double what the odometer logs
__________________
e·co·mod·ding: the art of turning vehicles into what they should be

What matters is where you're going, not how fast.

"... we humans tend to screw up everything that's good enough as it is...or everything that we're attracted to, we love to go and defile it." - Chris Cornell

Piwoslaw's Peugeot 307sw modding thread

  Reply With Quote
Old 04-16-2017, 05:17 PM   #4 (permalink)
Master EcoModder
 
nemo's Avatar
 
Join Date: Nov 2010
Location: US
Posts: 994

Chief - '06 Pontiac Grand Prix
90 day: 19.41 mpg (US)

SF1 - '12 Ford Fiesta S
90 day: 20.31 mpg (US)
Thanks: 192
Thanked 235 Times in 182 Posts
Quote:
Originally Posted by Piwoslaw View Post

Most likely a sensor on the transaxle (when I floor it and the wheels spin, then the speedo goes up).

Which gives me an idea: add a second magnet to the transaxle, so the speedo shows twice the speed, then re-scale the speedo's background. Unfortunately, this would double what the odometer logs
That would be a major downside. Maybe there is some way double the signal going to just the speedo.
__________________

  Reply With Quote
Old 04-17-2017, 02:35 AM   #5 (permalink)
aero guerrilla
 
Piwoslaw's Avatar
 
Join Date: Oct 2008
Location: Warsaw, Poland
Posts: 3,538

Svietlana II - '13 Peugeot 308SW e-HDI 6sp
90 day: 58.1 mpg (US)
Thanks: 1,056
Thanked 635 Times in 399 Posts
I think that the signal from the speed sensor is collected by the ECU and translated to PWM for the speedometer. This means either I would have to catch that signal between the ECU and speedo and change it to something different, or somehow change something in the speedo itself.
__________________
e·co·mod·ding: the art of turning vehicles into what they should be

What matters is where you're going, not how fast.

"... we humans tend to screw up everything that's good enough as it is...or everything that we're attracted to, we love to go and defile it." - Chris Cornell

Piwoslaw's Peugeot 307sw modding thread

  Reply With Quote
Old 04-17-2017, 08:05 AM   #6 (permalink)
Master EcoModder
 
oldtamiyaphile's Avatar
 
Join Date: May 2009
Location: Australia
Posts: 1,510

UFI - '12 Fiat 500 Twinair
Team Turbocharged!
90 day: 40.3 mpg (US)

Jeep - '05 Jeep Wrangler Renegade
90 day: 18.09 mpg (US)

R32 - '89 Nissan Skyline

STiG - '16 Renault Trafic 140dCi Energy
90 day: 30.12 mpg (US)

Prius - '05 Toyota Prius
Team Toyota
90 day: 50.25 mpg (US)

Premodded - '49 Ford Freighter
90 day: 13.48 mpg (US)

F-117 - '10 Proton Arena GLSi
Pickups
Mitsubishi
90 day: 37.82 mpg (US)

Ralica - '85 Toyota Celica ST
90 day: 25.23 mpg (US)

Sx4 - '07 Suzuki Sx4
90 day: 32.21 mpg (US)

F-117 (2) - '03 Citroen Xsara VTS
90 day: 30.06 mpg (US)
Thanks: 325
Thanked 445 Times in 314 Posts
Gut the speedo and fit a nice modern GPS speedo back there.

Universal GPS Car Speedometer HUD MPH KM/h Plug Speedometer Overspeed Warning#IR | eBay

You can get nicer ones if you want to spend more.
__________________






  Reply With Quote
Old 04-17-2017, 10:22 AM   #7 (permalink)
Eco-ventor
 
jakobnev's Avatar
 
Join Date: Oct 2010
Location: sweden
Posts: 1,574

Princess - '92 Mazda MX-3 GS
House of Tudor
Team Mazda
90 day: 53.54 mpg (US)

Shirubāarō (*´ω`*) - '05 Toyota Prius Executive
Team Toyota
90 day: 54.88 mpg (US)

Blue Thunder - '20 Hyundai IONIQ Trend PHEV
Team Hyundai
Plug-in Hybrids
Thanks: 68
Thanked 651 Times in 412 Posts
Send a message via MSN to jakobnev
Black elctric tape on all the numbers and lines after 150.
__________________




2016: 128.75L for 1875.00km => 6.87L/100km (34.3MPG US)
2017: 209.14L for 4244.00km => 4.93L/100km (47.7MPG US)
  Reply With Quote
Old 04-17-2017, 03:07 PM   #8 (permalink)
Permanent Lurker
 
seifrob's Avatar
 
Join Date: May 2011
Location: Czechoslovakia (sort of), Europe
Posts: 336

Dáčenka - '10 Dacia / Renault Logan MCV 1.5 dCi (X90 k9k)
90 day: 47.08 mpg (US)
Thanks: 128
Thanked 185 Times in 84 Posts
If its just a whim, its imho not worth the effort. You could tap the speedo PWM signal, process it in some microcontroller (arduino, picaxe...) and send forth, but...
Why not to utilize big-screen MPGuino, Torque Pro app or something similar, if all you need is more precise speed info?
  Reply With Quote
Old 04-18-2017, 12:38 AM   #9 (permalink)
aero guerrilla
 
Piwoslaw's Avatar
 
Join Date: Oct 2008
Location: Warsaw, Poland
Posts: 3,538

Svietlana II - '13 Peugeot 308SW e-HDI 6sp
90 day: 58.1 mpg (US)
Thanks: 1,056
Thanked 635 Times in 399 Posts
It is just a whim, just a thought-experiment on how it could be done. I really have no intention on playing with PWM...

But thanks everyone for the feedback
__________________
e·co·mod·ding: the art of turning vehicles into what they should be

What matters is where you're going, not how fast.

"... we humans tend to screw up everything that's good enough as it is...or everything that we're attracted to, we love to go and defile it." - Chris Cornell

Piwoslaw's Peugeot 307sw modding thread

  Reply With Quote
Old 04-18-2017, 02:19 AM   #10 (permalink)
Permanent Lurker
 
seifrob's Avatar
 
Join Date: May 2011
Location: Czechoslovakia (sort of), Europe
Posts: 336

Dáčenka - '10 Dacia / Renault Logan MCV 1.5 dCi (X90 k9k)
90 day: 47.08 mpg (US)
Thanks: 128
Thanked 185 Times in 84 Posts
If a car dashboard were one big LCD screen and not dozen of individual light bulbs, LEDs, dials and other goodies, it could be a mere constant adjusting.

  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com