DaleClark's guide to Calibrating your Speedometer
09-18-12, 07:42 PM
#26
RX-7 Bad Ass
Thread Starter
iTrader: (55)
Well, first pass at calibrating a KPH speedo was a mixed success.
We had, previously, pulled off the KPH face and put the MPH face on the gauge. I THINK it was due to the KPH face having already been removed, it was a spare JDM cluster I had.
The calibrating got it to line up perfectly with the US face, but having swapped the needles the needle was rubbing slightly so it would take a long time for the speedo to come up and slow down. But, it DID calibrate.
Long term I think we'll be getting Jon another JDM cluster to use for parts, swap that speedo into his car, and see what we have.
The odometer will still read KPH from what I can tell, and it is lit up "KPH" on the odo. In theory there's some "switch" somewhere to switch that over to MPH, but that may be beyond my ability.
Anyhow, this is an EASY mod to do, it takes like 15 minutes to get to the cluster and drill the hole for adjustment. Then, another 10 minutes to drive around and calibrate, then 15 to put it all back together. Get out there, try it, post up your results!
Dale
We had, previously, pulled off the KPH face and put the MPH face on the gauge. I THINK it was due to the KPH face having already been removed, it was a spare JDM cluster I had.
The calibrating got it to line up perfectly with the US face, but having swapped the needles the needle was rubbing slightly so it would take a long time for the speedo to come up and slow down. But, it DID calibrate.
Long term I think we'll be getting Jon another JDM cluster to use for parts, swap that speedo into his car, and see what we have.
The odometer will still read KPH from what I can tell, and it is lit up "KPH" on the odo. In theory there's some "switch" somewhere to switch that over to MPH, but that may be beyond my ability.
Anyhow, this is an EASY mod to do, it takes like 15 minutes to get to the cluster and drill the hole for adjustment. Then, another 10 minutes to drive around and calibrate, then 15 to put it all back together. Get out there, try it, post up your results!
Dale
09-18-12, 08:57 PM
#28
Awesome to hear, well it looks like this thread alone has single handedly saved me some cash. My cluster has been acting straight funky lately all do to the speedo acting up. I don't think its sending proper info or power or whatever to the tach and the power fc (speed was reading sporadic on the power FC and the tach just wasn't working on the guage). I was about to start slowly piece together a speedhut kit one guage at a time and have a complete custom cluster. But now I'll just buy a JDM cluster I've been eyeing for way cheaper and do the calibration then switch the MPH face over. Also a random thing I noticed, the odometer may still read kph but I think it'll start calculating miles traveled due to the recalibration. The reason I say this is because when my speedo started acting up and reading way faster speeds than I was traveling, the mileage on trip meter and odometer would go up faster and vice versa when it was registering a slower speed than I was traveling.
09-21-12, 11:54 PM
#31
Jesus christ all mighty, iv been hateing my speedo it is like 5-7mph off and finally a fix for it!!!
but i am a little confused at this part.
Are you saying you had it within 3 mph of 30, why would go to 40-50 and adjust it from there? if you got it 100% or 99% at a lower mph is it going to make a difference down or higher? (even though you said its going to be accurate up higher)
but i am a little confused at this part.
I eventually got it to within 3 mph at 30mph. Getting close. Now, tiny adjustments are key - like BARELY bumping the screwdriver into a turn. Once it seemed pretty close at 30, I went to 40, got that close, then to 50 and got it dead-on. At that point you should be within a good margin, if it's accurate at 50, you're going to be accurate up higher, but you could keep tweaking if you so desire.
09-23-12, 09:57 AM
#33
This is another Awesome Dale Clark thread. Ever think of writing all of this up into a manual/book?
I had crossed off the list all of the KPH speedos as I wanted MPH readings and this allows us to now use any speedos. Great, great thing!
As an aside and regarding the odometer, I am assuming this doesn't impact the ODO and its readings? In other words, if you get a KPH speedo and adjust it for MPH, the odometer doesn't also then adjust for MPH too does it? That would be a big plus if it worked that way. I had a guy that could adjust the speedo for MPH but the ODO still would have been in kilometers.
I had crossed off the list all of the KPH speedos as I wanted MPH readings and this allows us to now use any speedos. Great, great thing!
As an aside and regarding the odometer, I am assuming this doesn't impact the ODO and its readings? In other words, if you get a KPH speedo and adjust it for MPH, the odometer doesn't also then adjust for MPH too does it? That would be a big plus if it worked that way. I had a guy that could adjust the speedo for MPH but the ODO still would have been in kilometers.
10-03-12, 09:37 PM
#35
3mph error at 30mph will NOT be 3mph error at 90mph.
faster you go, greater the error.
90% of 30 mph = 27mph
90% of 90 mph = 81mph
the speedometer is not accurate enough to determine 100% accuracy at low speeds.
- easier to dial in accuracy with high speed (better resolution) and the lower speeds will apper more accurate.
i think Dale's reasoning for not adjusting above 50mph is because the speedo will be accurate enough for legal speed limits (70mph tops).
- relatively easier to argue getting clocked at 75mph in a 70, than 80+ in a 70.
- if you are intentionally speeding you're not relying on the accuracy of the speedo.
but "if you so desire" to adjust to 99% accuracy at top speed, youre error at lower speeds will be uncanny.
Last edited by nismosilvia270r; 10-03-12 at 09:47 PM.
10-07-12, 12:47 AM
#37
This thread is definitely one of the best!!! It has saved me a lot of money. I finally installed and calibrated my jdm cluster and it reads accurate to my gps speed. I also got the added bonus of getting a cluster that lights up green at night (refreshing to see something different). I'll update later on tomorrow with the whole tripometer still reading kilometers or miles now, but I'm pretty sure it still records kilometers (contrary to my previous belief). Also would like to add that you can calibrate the cluster while the car is on instead of having to turn the car off then back on.
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Demonsniper1 (12-23-19)
10-08-12, 09:53 AM
#40
RX-7 Bad Ass
Thread Starter
iTrader: (55)
Sweet, glad you added that! I'd love to figure out how to get the "miles" light instead of the "km" light to come on in the odometer.
Dale
Dale
10-13-12, 01:42 AM
#41
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Glad to see there are secrets about these cars still being discovered!
Gotta dig around Dale's other threads to find out what else I've been missing out on lol.
Thanks Dale!
Gotta dig around Dale's other threads to find out what else I've been missing out on lol.
Thanks Dale!
04-16-13, 04:15 PM
#42
Rotor or no motor
iTrader: (24)
Great thread. Thanks dale
As for the reference speed.. power fc reads different from the speedo.. I guess thats also a good reference speed that it can be used. Im sure the gps is more ideal but maybe with the power fc is easier
As for the reference speed.. power fc reads different from the speedo.. I guess thats also a good reference speed that it can be used. Im sure the gps is more ideal but maybe with the power fc is easier
04-16-13, 04:33 PM
#43
RX-7 Bad Ass
Thread Starter
iTrader: (55)
The PowerFC is also using the same speedometer sensor. The error from changing the gearing will be the same error. GPS is an outside reference that's accurate.
Dale
Dale
05-28-13, 05:57 PM
#45
Thanks for this writeup!!!...I have the white faced 2000+ gauge and the potentiometer screw in mine is white instead of blue but it is in the exact same location...I just did the 4.44 ring and pinion swap and found this just in time....thanks Dale!
05-28-13, 07:00 PM
#46
Racing Mechanic
For the rx-8 diff 4.444 with 255/40 r17 at 3000 rpms is 112.5km/h or 69.9 mph
10-20-13, 08:06 PM
#49
Racing Rotary Since 1983
iTrader: (6)
Dale, nice find and thanks for sharing.
i do have a question re my speedometer. i have a T56 in my 2 rotor and have a Dakota Digital module that corrects to the proper speed into my ViPEC V88 ECU. the speed is accurate to a GPS. i have an additional wire tied in to the FD harness.
my speedo is accurate to 60 mph and then drops to zero. eventually it will hunt around and generally settle back to zero.
would you have any idea as to what direction i might head to fix it? prior to the trans swap it was working well.
thanks.
howard
i do have a question re my speedometer. i have a T56 in my 2 rotor and have a Dakota Digital module that corrects to the proper speed into my ViPEC V88 ECU. the speed is accurate to a GPS. i have an additional wire tied in to the FD harness.
my speedo is accurate to 60 mph and then drops to zero. eventually it will hunt around and generally settle back to zero.
would you have any idea as to what direction i might head to fix it? prior to the trans swap it was working well.
thanks.
howard
10-21-13, 06:08 AM
#50
Senior Member
180 Km/h JDM speedometer with 300 km/h faceplate ?
I am playing with the thought of buying just 300 km/H face plates for my speedo and see if i can recalibrate it to that . But as i understood playing with the adjustment affects also the odmeter ? Meaning , even if i get the speed of the needle correct , it will ruin my od meter reading and make it inaccurate ?
Am i correct in my understanding there ?
Am i correct in my understanding there ?