s14 speedometer correction with z32 tranny the free way

[gsracer]

First off let me thank knate from freshalloy for his kph conversion thread because that pointed me in the right direction although this is a little different.

Now most of us run z32 trannys via the mazworx kit, on ka's sr's and vh's like me in our s14s and as you know the speedometer doesnt read right, actually very high ie 50mph is like 120, as a result i havent had a speedometer for over 2 years and it has realy irrated me.

Now you could probably spend the money and buy the dakota digital converter or you can do these few easy steps that are free and get the same result.

First step is to take the speedometer out of the cluster.



now you turn it around and look at the circuit board on the top you will see the letters ADJ with numbers, these are the adjustments.

Now unfortunatly i did not take pictures before i started, but the circled portions are what is soldered from the factory.





This is the tricky part, given what diff you are running and your tire size it can change the percentages of where it needs to be.

My setup is j30 (3.90) rear with 18s out back, most 18 tires are 25.2-25.6 inch diameter so this should cover all popular non stretch sizes

what you need to do is solder pin 9 together, bridge the gap so to say and desolder pin 7, open the gap. As shown in the rear picture.

This got me exact on my car tested up to 100mph.





Now thru the miracle of mathmagic, i was able to come with a combo that should get you close for a stock application 205/55/16 with a 4.08 rear diff, it should be plus or minus 2 % ( ie at 100mph you could either really be going 98 or 102)

You still need to solder switch 9 and 6 and still desolder switch 7





Im still working on the odometer, still reads twice as high but im sure theres a fix for that as well. Ill update it when i get it sorted.

[nyc240sx]

nice info iam going to do this i have a rb25det with a z32 trans and a skyline rear end 4.10 gears should i still follow that
"Solder switch 6 and 9 and desolder switch 7

[95KA-Turbo]

Hmmmm....I wonder if this can work with LS1 swaps.

[gsracer]

Originally Posted by 95KA-Turbo

Hmmmm....I wonder if this can work with LS1 swaps.

if the stock ls1 signal reads on the gauge cluster, just off id say theres a fairly good chance it should work.. iirc the ls1 uses a 4000ppm sender while the 240 is 2000 in which case it should in theory be adjustable down as it would be a 50 percent step down and there is enough range in the adjustment to get it down that far. Ideally i guess you would want to wire it up and then see at say 50mph how fast its reading on the cluster. Then adjust it down percentage wise from there. It will always be slightly off but you could get it down to within 2-4 percent without to much trouble i would think.

[nyc240sx]

Iam running on 225-45-17 in front and 255-40-17 rear which ones should i solder and desolder for this tire size any info greatly appreciate

[gsracer]

depending on what size your rear tires are, if they are stock then yes, if they are not stock id have to recalculate post up the size.

[Master Chief]

Cool.
How exactly are you calculating, wich pins to solder or desolder ?
Interesting if there is anything about the calibration in the FSM or somewhere.

Thanks.

[gsracer]

NEW AND IMPROVED METHOD


SUCCESS!!!!!!

In my trial and error aproach, i found the right circuit to put a resistor to fix the odometer. The only problem was apparently it reduces the signal BEFORE it goes to the speedometer so after that odometer would read right less than 4 percent off ie (travel 100 miles and odometer will show 103.6 miles) , and the speedometer was decreased by half. So all the adjustment i did up in the first post was cancelled out.


Here is the new and improved method.


Assuming of course you are starting off with a usdm speedometer that reads in mph. Desolder all switch joints EXCEPT number 7. This will take care of the speedometer.

Now here is the tricky part, you need to aquire either a resistor from another cluster ( the circled one in the picture) or aquire a new 6.8k ohm surface mount resistor ( should cost no more than .50 cents). And solder it where i show in the picture the j2 solder.

This will fix both speedometer and odometer. If you have another spare speedometer or circuit you can just swap it over, thats what i did.. best part it was free.

Heres the pic





also from knates thread on freshalloy the adjustment ranges

ADJ 9: -49.4%
ADJ 8: -24.7%
ADJ 7: -12.4%
ADJ 6: -6.2%
ADJ 5: -3.1%
ADJ 4: -1.5%
ADJ 3: -0.8%
ADJ 2: -0.4%
ADJ 1: -0.2%
ADJ 0: -0.1%



Not only that since i had it apart i readjusted the odometer and now have the lowest mileage s14 in the united states lol.

[95KA-Turbo]

Where can I read more about this? I don't understand it at all and would like to become more familiar with how the math works.

[nyc240sx]

your saying this is the new way to make your speedometer work correctly... I have my tachometer working using the j30 tach reads correctly. Speedometer is what my issue is can you explain this. I dont get it your saying take off the solder 1-9 and solder the 7 back together can you show the complete piece how you have it.

[gsracer]

Originally Posted by nyc240sx

your saying this is the new way to make your speedometer work correctly... I have my tachometer working using the j30 tach reads correctly. Speedometer is what my issue is can you explain this. I dont get it your saying take off the solder 1-9 and solder the 7 back together can you show the complete piece how you have it.

Ok stock comes soldered from the factory 3,4,5 and 7. Pay attention to what i circle and say in the pictures. NOt the actual picture its just for reference.

Heres a list i put together

This is what i got from my testing, the resistor on j2 needs to be placed no matter what. These are the switches that need to be open or closed.

18s with j30 rear gear
switch 7 soldered
all others open

18s with stock 4.08 rear
switch 7 , and 5 soldered
all others open

17s ie 245/255 35-40 sidewall with stock 4.08 rear
swtich 6, 7 soldered
all others open

stock 4.08 rear with stock wheels and tires 205/55/16
switch 6,7 soldered
all others open

These settings should be pretty spot on, at worst 1-2 mph off. You can fine tune it adding more or less percentage but that should pretty much get you where you need to be.

[ka-titties]

Originally Posted by gsracer

Ok stock comes soldered from the factory 3,4,5 and 7. Pay attention to what i circle and say in the pictures. NOt the actual picture its just for reference.

Heres a list i put together

This is what i got from my testing, the resistor on j2 needs to be placed no matter what. These are the switches that need to be open or closed.

18s with j30 rear gear
switch 7 soldered
all others open

18s with stock 4.08 rear
switch 7 , and 5 soldered
all others open

17s ie 245/255 35-40 sidewall with stock 4.08 rear
swtich 6, 7 soldered
all others open

stock 4.08 rear with stock wheels and tires 205/55/16
switch 6,7 soldered
all others open

These settings should be pretty spot on, at worst 1-2 mph off. You can fine tune it adding more or less percentage but that should pretty much get you where you need to be.

are these settings with or without a Z trans?

[nyc240sx]

it doesnt matter if its a z tranny, rb tranny, ka/sr tranny its going to work with anyone

[gsracer]

Originally Posted by nyc240sx

it doesnt matter if its a z tranny, rb tranny, ka/sr tranny its going to work with anyone

no this only works this way with the z trans....

[brndck]

oh jeezus this thread is awesome!!!
i don't even have a z trans but i still appreciate this kind of knowledge being available.

[bejota180sx]

great work!! it's always great to have this kind of info available!

[MongolPup]

I love it.

I'm sure the original Nissan engineers think we are ape-shit crazy but that's half the fun.

[nyc240sx]

went to my local radio shack couldnt find that 6.8k resistor i found one here online not sure if its the right one take a look
Amazon.com: KOA Speer 6.8K ohm Surface Mount Thick Film Resistor 0603 5% 1/10W RK73B1J (Continuous strip of 25): Industrial & Scientific

[fcdrifter20]

wow this is great. im gona have to try this on the s14 at the shop. Great info

[nyc240sx]

finished it on mine its working great +10 for you for figuring this stuff out and sharing it with us. Thank you

[breetime]

awsome thread!!!!!!!!!!!!

[irritatedmax]

wow, great info! thanks for sharing!

[hegamiz]

Saved... Thanks!

[knate]

Excellent work! I hadn't ever figured out the odometer part.. how did you determine the spot to put the resistor?

[bshotts]

Yes I too am wondering...trial and error or some basic math? I would like to know say for example if one wanted to convert the speedo and odo to read mph/miles rather than kmh/km from a 180 kmh JDM cluster mwahahahh.

[built kouki]

what if i have a jdm km/h cluster in a usdm s14... same deal as the usdm cluster in a usdm car? im running 255 40 17 's with a stock diff .... and z32 trans