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Incorrect Speedo Speed. Need Advice On Calibration!

advan

By advan,
in General Automotive Discussion

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GTRsean Grand Master

GTRsean

Posted
Posted

Either change tyre diameter or take the speedo out and change the calibration resistor in the back of the speedo.

HPI magazine had an article on it a couple of issues ago on their R33 GTS 4 door with RB26DETT project.

hanyou Grand Master

hanyou

Posted
Posted

haha umine is the same deal as you but everytime i hit boost the 'hundred thousand' number move... hahah so basically i go thru about 200,000kms a week :)

really do need to get that replaced lol..

its good in a way having it 10km/h up from wat it really is.. cause i find myself not speednig at all cause it already loooks like i am haha

dangerous_daveo Grand Master

dangerous_daveo

Posted
Posted
not true having a uncalibrated spedo is a fine aswell!

dont kno if u loose demrit ppoints tho.. doubt it

Yes but if you are 10kmh under the speedlimit. Good luck getting pulled over!

Abo Bob Grand Master

Abo Bob

Posted
Posted
haha umine is the same deal as you but everytime i hit boost the 'hundred thousand' number move... hahah so basically i go thru about 200,000kms a week :D

really do need to get that replaced lol..

its good in a way having it 10km/h up from wat it really is.. cause i find myself not speednig at all cause it already loooks like i am haha

hahaha

baron25 Proficient

baron25

Posted
Posted
i am pretty sure that jaycar makes an inline circuit kit to recalibrate your speedo. that's all the details i have though.

Yeah, they do - catch is you've gotta be handy with a soldering iron, it's a DIY thing.

  • 2 months later...
Munkyb0y Grand Master

Munkyb0y

Posted
Posted

old thread, i know, but rather than risk a "use the search button" warning, i'll just add on here.

I had a GPS and a friend in my car (borrowed both, i have no friends).

He was watching the GPS screen for speed readout. Apparently, this unit updates 5 times per second, so i assume it's accurate.

At 60kph on speedo, the GPS stated 65kph.

At 110kph on speedo, the GPS stated 112kph.

This sounds backwards, does it not?

I have 18's on my car. And i assumed my speedo would be out a little.

But it looks to me as if the speedo/needle isnt really accurate, or the error/difference would have increased at higher speeds.

How have you guys found your R33 speedos to be?

Konrad Grand Master

Konrad

Posted
Posted

I have 3 spedos in my car - stock gtr cluster (in a s1 gts), blitz r-vit (consult connector style display unit) and gps. They all fluctuate... i assume the consult readout is the most accurate but the gps in particular can read anywhere from 90 - 110kph when the cluster reads 97 and the consult readout is 100kph..

Konrad Grand Master

Konrad

Posted
Posted

i think it depends on how good the signal is at the time... if i'm crusing at a constant speed (well constant according to my other 2 spedos lol) it still fluctuates maybe 5kph?? I have a navman icn-320 if that helps (basic model one)

nsanity Rising Star

nsanity

Posted
Posted
hmmmm, so it may be the GPS that is out?

I thought those things were very accurate.

the most accurate way to measure your speedo differential is to actually do the math.

RPM through gears into the diff with the Tyre/Wheel radius.

the ADR's allow for a 10% error in the Speedometer accuracy - ADR18

although the police do not seem to recognise this - specifically in victoria (3km/h over can and will get you a ticket..)

Victory Mentor

Victory

Posted
Posted

I have a "Road Angle" which is a form of GPS unit that stores the location of all fixed speed cameras, red light cameras etc etc and it also provides accurate speed readouts.

I would suggest that the accuracy of your speedo all comes down to your tyre size. I run a R33 GTR V-Spec and a R33 GTS-T Series II and the speedo readings are the same in each car for the same tyre size.

Exact Speedo reading = overall diameter of 651 mm

Typical Sizes :

275/30ZR19

275/35ZR18

245/40ZR18

245/45ZR17

5% over registration = speedo 105 and actual 100 = overall diameter 643

Typical Sizes :

265/30ZR19

265/35ZR18

235/40ZR18

235/45ZR17

11% over registration = speedo 111 and actual 100 = overall diameter 633

Typical Sizes :

225/50ZR16

Munkyb0y Grand Master

Munkyb0y

Posted
Posted

well this is mine

5% over registration = speedo 105 and actual 100 = overall diameter 643

Typical Sizes :

265/30ZR19

265/35ZR18

235/40ZR18

235/45ZR17

but the gps was stating 112 at speedo-110, 65 at speedo-60.

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