Skyline Speedo Correction (r33 Example, Nismo Cluster) - Minor Adjustments Without Extra Parts...

[some_cs_student]

This tutorial is partially based off the information from Propper speedometer to MP/h conversion by andy42uk-2 on SkylineOwners.com (registration required).

Problem

The speedo reads incorrectly, in my case I was under by 7km/h at 100km/h, for some owners this is perfectly fine, for me I found this quite annoying as I always see people passing me in 60, 70 and 100km/h zones because I am under the speed limit, but I don't know by how much because I don't have a GPS in the car.

Solutions

Besides the obvious, accept that your speedo is inaccurate and guess, you may wish to install an electronic device that will allow you to tweak your speedo reading, as per Blk33's Speedo Corrector, Speedo Corrector Installed on a R33 GTR

One alternative I found, as mentioned at the very top of this tutorial, is that the European skyline owners commonly modify there speedo's from km/h to mp/h without any electronic converters, and this works great for them.

The cluster I was working with

In theory, its the same for R32, R33, and I believe even R34, but I have only tried this on a Nismo 320km/h speedo, as pictured in the attached images.

Removing the cluster

Removing the dash is quite straight forward its described in detail in the stereo howto's, once you have that off the R33 has 2 screws at the top of the cover for the cluster, and two at the bottom.

Once you remove the front cover, there are a further 3 screws holding in the cluster.

When you remove the cluster, there are 3 large connectors on the back, each connection requires you to press the top and bottom at the same time to remove any of the 3 large plugs.

There is also a little hook that holds the cables in, you simply remove the cables from its path...

I was unable to remove the power connector from the side of the cluster, I worked with the cluster in the car which was annoying.

Removing the big black plastic thing from the cluster

There are small black plastic things that hold the cluster together, they are very strong and I didn't find a simple way to push the pins down to release it, once you get a few of them down the cluster will come apart.

Once done, you need to remove the unscrew the 4 small screws on the back of the speedo itself.

Once done you will have the speedo out by itself...

The adjustment solder pads

On the speedo (pictured) there are small pads numbered 0 to 9, right next to the "ADJ" (adjustment).

Some of them will have a piece of solder on them joining the two sides together, others will have nothing.

According to the tutorial I referenced, removing a link increases the speed of the speedometer, I found the opposite.

Testing

If you have the correct equipment you could test the speedo on a bench, I had no such equipment so all testing was done manually, this was quite frustrating as it involved connecting things back up again each time to drive the car with a GPS in it and test it, but I think its worth it .

My results

These results are for an R33 GTR with a Nismo 320km/h cluster, here's what I found, the picture is *before* any modifications were made, there are always some of the "ADJ' already joined when you start.

At first there were:

2,3,5,6,7 all joined together by neat little solders, I was roughly 7km/h under at 100km/h when last tested but I didn't test this time (in retrospect it would have made a good baseline)

Removed the connection (the solder) for no 2, ~6km/h under around 60 km/h, 70km/h showed a similar difference.

Then, decided it needed more, so we removed: no.3 and no.5, consistently 10km/h under (worse!), so 60km/h was 50km/h, 70km/h was closer to 60km/h.

I decided at this point that maybe its backwards and I need to "add" new ones, so 6 and 4 were soldered in 3km/h under at 60km/h, 5km/h under at 80km/h.

To summarise, 4,5,6,7,8 are now joined, so joined no 9. Appeared to make little difference, 3km/h under at 70km/h, not 100% sure that the join worked there.

Decided to keep tweaking, added 3 and 1, now about 2km/h under at 80km/h (roughly) and 99km/h or 100km/h at 100km/h compared with the GPS, I also did further testing with a PowerFC, and its close to 58km/h at 60km/h, which is great.

The only thing I remembered afterward is I'm running 235/45/17 and I should be running 245/45/17 which will make it really damn close to perfect.

The other important note is the speedo itself is not perfect, the bottom of the 60km/h mark is 57km/h, but the top is 60km/h or 61km/h.

Should you do it?

It worked for me, I'm not guaranteeing it will work for you, its not that hard but its time consuming, I recommend you try it on a weekend where you have spare time if you are going to attempt this.

According to the UK forums no. 9 is the largest movement and no.1 is the smallest I am not sure if this applies to km/h, as the UK forums also mentioned something above adding links to reduce speedo reading, I found the opposite...

If you try it PLEASE post your results in this thread, I'm sure it varies for everyone...

[some_cs_student]

The image's got de-attached during the attempts to upload the tutorial, the super closeup image is from Tom_R33GTST on the skylinesowners forum, I couldn't get a photo that good.

Also, quoting from the GTR UK forums topic on Blk33's tutorial:

As far as I can tell the same PCB is used for all speedos on the R33 regardless of Nismo 320kph, standard 180kph, UK mph speedo, GTR or GTS. So that same signal to the drive motor which operates at each of these various speed ranges has to be generated by the PCB. If you're running 320kph clocks you will likely lose some resolution and any non-linearities in the speedo range will be magnified when compared with a 180kph display. I don't remember the jumper settings that i ended up using when I modified my 320kph speedo to read in mph but because my speedo has a possible max of 320mph, any issues would magnified even further.

Best of luck if you try this! Please try to post results only below, it may help other people with there adjustments, probably post your car type, speedo type and your initial and final adjustments...(and if you've modified any diff ratios et cetera).

For example, in my case:

R33 GTR

Initially 2,3,5,6,7 joined, off by 7km/h at 100km/h, approx 5-6km/h at 60km/h

Finished with 1,3,4,5,6,7,9 (roughly I know I had 2 or 3 unsoldered at the end) off by 2km/h at 80km/h

Compared with a GPS

Standard diff ratios

Oh, I don't think this will work for R32's, not sure about R34's, sorry, the 10page skyline owners thread linked in my initial post, it may have more information about this but I didn't see it here, and I cannot edit the initial tutorial post...

[JD_R33]

Good work dude

I had been wondering how/if I could recalibrate the Impul 300k speedo in mine, but the speed variation doesn't seem to be linear. It's out by about 2kmh at 80kmh, and around 5kmh by 110 when compared to turbo timer/gps. The variation seems to grow with the speed.

I guess that adding another 2kmh adjustment across the board would be better than nothing.

Do you happen to know what kind of signal the speedo gets sent from the speed sensor/ecu? Is it something that can be reproduced on the bench?

[some_cs_student]

I guess that adding another 2kmh adjustment across the board would be better than nothing.

Do you happen to know what kind of signal the speedo gets sent from the speed sensor/ecu? Is it something that can be reproduced on the bench?

Be careful how accurate you make it, changing the tyres will also change things...

But, yes it can be done on a bench, see the very first link at the top of my original post for the tutorial, you'll have to register but the 10page discussion of "Propper speedometer to MP/h conversion" has the information you need, not sure if anyone did it with an Impul Speedo, but they tested with stock and Nismo versions I believe...

[datsfreak]

thanks for the info on this.

Ive got a r33 that was a auto and now a manual SO it has a 4.4 diff which makes my speedo read(with the wheel size change) about 7% high.

ie It needs to be reading 107kph for the car to do doing a real 100.

My standard r33 180km speedo had only the 4 and 5 factory joined.

After abit of trail and error I came to 1 - 3 - 4 -5 being joined and it seems close,that judging by the tacho- I dont have a gps but I will borrow one and check.

will edit this if it out and needs to change - take note those who do Auto-manual convos.

[R34 4dr]

im in the process of manual conversion on my R34.

[datsfreak]

BTW is the nismo 320km cluster just the front covers for the standard gauges, just with the j2 jumper bridged to reduce the speedo sweep? If it is where do I buy them?

Edited June 14, 2009 by datsfreak

[daineisdabomb]

so wat r the numbers 1-9 for? and how do u no which numbers change wat?? eg if u had them all soldered would it add 9km/h to the speed??

[Boostman]

Hey,

I have converted speedo to MPH, I really want to have it back KPH :)

I have S2 R33 manual turbo, what ADJ pads are soldered in factory ?

mine MPH conversion has J2 soldered and ADJ 6,8,9 + pesl not touched. I attached photo of mine MPH converted speedo

[KiwiRS4T]

On 6/14/2009 at 8:48 PM, datsfreak said:

thanks for the info on this.

Ive got a r33 that was a auto and now a manual SO it has a 4.4 diff which makes my speedo read(with the wheel size change) about 7% high.

ie It needs to be reading 107kph for the car to do doing a real 100.

My standard r33 180km speedo had only the 4 and 5 factory joined.

After abit of trail and error I came to 1 - 3 - 4 -5 being joined and it seems close,that judging by the tacho- I dont have a gps but I will borrow one and check.

will edit this if it out and needs to change - take note those who do Auto-manual convos.

How does a manual conversion make a difference unless the gearbox is out of something different - in which case doesn't putting the auto speedo drive in the manual box fix it (unless you have an R32 box I guess)?