fungus mungus

Using a Yellow Box speedometer calibrator to convert from KPH-MPH

There's been a little talk here and there about using a speedo calibrator to convert the JDM cluster KPH to MPH, but no real write-ups on it. I found some info on other forums on the net, but info was conflicting on how well these work. I had read there were issues with VTEC engaging properly when running one of these. More on this later.

I know of one H-T member (rickkane) that installed this with success, so emboldened by his success, I decided to order a Yellow Box from Yellr (an Australian company). These are commonly used on motorcycles, but can be used on cars as well.

Basically, it's a little yellow box about the size of a Zippo lighter with 4 wires and a set of 8 DIP switches. The DIP switches are used to set the correction factor for your speedo.

Installation


No pics of the installation, but this is a very straight-forward process. The instructions are very clear and easy to follow...just 4 wires to splice.

I would like to begin by saying that YELLR assumes you're going to install this between your VSS and your ECU, but for us folks with VTEC, this is less than ideal. The reason is that the correction factor for going KPH-MPH is 61%, so the ECU would only be getting 61% of the original signal from the VSS, which would affect the engagement of VTEC, particularly in 1st gear. You'd probably be OK in 2nd-5th because your speed will be fast enough that the ECU will allow VTEC to engage.

That said, I decided to put the Yellow Box between my ECU and my speedo, taking the VSS out of the equation. VTEC engages properly and the correction works fine.

There are 4 wires:

RED - power
Black - ground
WHITE - VSS signal in
Gray - VSS signal out

All you need to do is find the pin on the ECU for speedo signal (I believe it's B10 on an OBD1 ECU) and splice in the Yellow Box with the white wire going to the ECU and the gray wring going to the speedo. Splice red into a 12v power wire and ground the black wire.

This method also means you don't have to route wiring through the firewall, simplifying things.

CALIBRATION

The manual comes with a calibration table with correction factors listed in 1% intervals. The standard correction for going from KPH-MPH is 61% (that is, 61% of the signal is sent to the speedo, causing it to read a lower speed). I set it to 61% at first by moving the DIP switches to 0110 1111 (0=down, 1=up). This caused my speedo to be about 5 MPH fast at 60 MPH (60 on speedo=55 actual), which is pretty much par for the course for the stock speedo in EG Civics. I decided to tweak the calibration more and settled on a 72% correction factor. Checking it with my iPhone running a speedo app, I was able to verify that it's DEAD ON accurate:


Once calibration was set, I just tucked the Yellow Box behind my optional audio console and enjoyed my 180 MPH speedo.

Obviously, the Yellow Box would be useful to any of us with EGs, regardless of whether you're running a JDM cluster or not. We all know stock speedos are inaccurate, so this is an effective way to fix that issue. The correction factor would probably be around 111% for a USDM/UKDM cluster if my calculations are correct. Of course, your mileage may vary.

fm

latino911

WOW. GREAT INFO.

Former User

Nice thread. Link added to FAQs sticky.

fungus mungus

Ron, I'm honored...thanks!

fm

BlueIntegraBoy

iTrader: (5)

It's about time someone in the States did a write-up. They've been doing this in the UK for decades.

fungus mungus

Yeah, when I researched this, all I found were forum posts from people in the UK. I suspect they import a lot more JDM cars into the UK than we do in the US, thus the need for such a device.

fm

usafdad120108

wow awesome write-up may be getting one of these and a cluster swap soon

BigMike0147

Great! Thanks for the info! I think I'm going to try to do this with my JDM cluster. Is there a way you think you can do this without splicing into the harness?? I need to look more into it.

fungus mungus

No way that I know of. There are pnp kits for other setups (mostly bikes), but they don't make a pnp kit for Hondas.

fm

Chef Andre

iTrader: (1)

THANK YOU!!!! I will be making this modification.

tlarimer

iTrader: (3)

Nicely done, I looked into this kit, but decided to and went with a EDM VTi cluster in MPH.

fungus mungus

Thanks tlarimer,
Remember that the yellow box will correct inaccurate speedos too...I'm not sure about EDM speedos, but every cluster I've had in my EG has been 4-5mph over actual speed. This device will fix that. Though it may be more $$ than you'd want to spend to fix that minor problem.

fm

tlarimer

iTrader: (3)

Yeah, the EDM ones, at least the 2 that I've had in my EH3 have been off the typical honda 4-5mph. Eventually I may pull the trigger and correct it, but I'm trying to complete my EDM rear headrests and Gathers audio system with integrated Sirius/iPod hookups first.

Keep up the good work, I enjoy reading what you have figured out or done to your EG.

Tim

lzylst

iTrader: (1)

Thanks for the write up. Quick question though. How does splicing the white wire between the VSS and ECU take the VSS signal out of the equation? Am I not understanding something or am I reading into it too much?

How are you wiring the box between the ecu and speedo when you are tapped into the VSS signal coming into the ecu? That still technically makes it so you are between the VSS and ECU. Like I said earlier I may be missing something here.

mikesanto70

Awesome post, 2 questions,
1. I have a droid, is that speedo app avail and how much?
2. I'm pissed I bought an SI 145mph cluster for my EK when I could have had a 180 CTR, will this yellow box work the same on an EK? OBDII ?

Thanks,
MS

fungus mungus

I think you're over-thinking this. This box is normally installed between the VSS and the ECU. Instead, it's being installed between the speedo and the ECU. There's the signal out that goes to the speedo...that is the wire that you interrupt by splicing into. That is, one side of the yellowbox goes to the ECU and the other goes to the speedo.

fm

fungus mungus

While I don't know if this particular speedometer app is available for the Android, I know there are several speedo apps for android phones.
Yes, it should work the same way. Just find the correct wire the goes from the ECU to the speedo, interrupt it as described above, and you should be good to go.

fm

fungus mungus

The connector on an OBDII Civic is C18 and should be BLU/WHT. Here's a diagram.

fm

lzylst

iTrader: (1)

Thanks for the clarification. The word "splice" was throwing me off track. I was thinking "splice into" as in addition to not interrupt the signal. Makes sense now. Thanks again for your time and effort put into this thread.

fungus mungus

Yeah, I didn't think about how the word splice could be confusing. I should have said something more like "cut the wire between the ECU and the speedo and wire the white to the ECU side and the grey wire to the wire going to the speedo".

fm