Who has the wrong and the right speed

[Vaders R33]

I am doing my rb swap into a s14 this weekend and Ive seen several people say they have speedometer discrepencys. I am looking to find out who has this problem and who doesn't and what is the difference.

Thanks

[RB20DETodd]

I used the KA speed sensor, seems like 2nd and 3rd gear are off speed wise and my odometer reads 1 mile for every .8 mile i go, i was in 5th driving through Wyoming going 80mph exactly when a hi po decided to pull me over, out of everyione else going 80 cause i was the ricer, and he said i caught you going 80 in a 75 lol mi scuzi didnt work for me

[T_love]

I just stuck with the RB speedo. That way i know the readings are right. Takes a bit of time to get the conversions/estimations down but after a while you almost forget that its in KM/H

[Joe]

I am doing my rb swap into a s14 this weekend and Ive seen several people say they have speedometer discrepencys. I am looking to find out who has this problem and who doesn't and what is the difference.

Thanks

pretty much what it boils down to is this

RB20 = KA or RB20 sensor

RB25 = rb25 only or it will read off.

[gawdzilla]

I just stuck with the RB speedo. That way i know the readings are right. Takes a bit of time to get the conversions/estimations down but after a while you almost forget that its in KM/H

the speedometer accuracy has nothing to do with which speedometer you're using. if you use the correct speed sensor for the transmission, you will get the right speed reading on your speedo. assuming you dont change your rear end or tire size too drastically.

[Vaders R33]

good points. I do plan on stying with the factory cluster but didnt know if I should use the KA or RB sensor The diff should be fine its out of a J30 and has worked well with the KA.

[Darius]

Did you mean factory R33 cluster or KA cluster?

[300Plus]

the speedometer accuracy has nothing to do with which speedometer you're using. if you use the correct speed sensor for the transmission, you will get the right speed reading on your speedo. assuming you dont change your rear end or tire size too drastically.

Thats not true, if you use the rb25 speed sensor on a speedometer that wasn't ment to read the same voltage it will be off. R33 cluster is the way to go but i hear there are resistors you can buy to correct the stock cluster

[Darius]

I'm using the stock KA cluster and bought this to adjust the signal. Another nice thing about this is that I can adjust the signal further to compensate for my J30 differential being 4% taller and creating a 3 mph error at 75 mph. I should finally have an accurate speedo after all is said and done.

http://www.dakotadigital.com/i...6.htm

Also bought one for the tach signal from the ECU to the cluster.http://www.dakotadigital.com/i...7.htm

[Kansei240sx]

Actually, the RB25DET transmission speed sensors can also use the 91-94 300ZX turbo speed sensor with a red gear on the end.

Ls automotive also makes kits for the s13 cluster for the inline 6 configuration

[gawdzilla]

Thats not true, if you use the rb25 speed sensor on a speedometer that wasn't ment to read the same voltage it will be off. R33 cluster is the way to go but i hear there are resistors you can buy to correct the stock cluster

ok, to narrow it down some more.. The rb25 speed sensor with the stock s14 speedo in the cluster will work and give you the correct speed. i cannot verify this to be true on the 13s cuz ppl seem to be having problems with them reading half.

[David_NISMO]

I'm getting half speed on my s13. I don't know why it would work in the S14. I'm assuming that the s13/14 have the same transmission, therefore both s13 and s14 clusters would be setup for the same number of pulses per minute.

[Vaders R33]

darius that doesn't look half bad. do i need to be a engineer to wire it up right? otherwise i like where this is going.

[gawdzilla]

I'm getting half speed on my s13. I don't know why it would work in the S14. I'm assuming that the s13/14 have the same transmission, therefore both s13 and s14 clusters would be setup for the same number of pulses per minute.

thats the same reasoning i used to assume it would work on the s13 mine works perfectly fine on the s14. r34 rb25 trans w/ rb26 motor in s14. maybe the difference is b/w the 25 and 26 motors. 26 ecu takes speed sensor input directly, whereas 25 ecu takes it from the speedometer.

[David_NISMO]

thats the same reasoning i used to assume it would work on the s13 mine works perfectly fine on the s14. r34 rb25 trans w/ rb26 motor in s14. maybe the difference is b/w the 25 and 26 motors. 26 ecu takes speed sensor input directly, whereas 25 ecu takes it from the speedometer.

Man, there's got to be an easy fix. If I ever get around to it, I'll show my Dad the wiring diagrams. He's a Senior Electronics Instrument Control Technitian at a nuclear plant here. They're in an outage for the next 6 weeks and he's working 72hrs a week, so, unavailable. It just sounds WAY TOO coincidental to be exactly half off. Maybe there's something there to be had.