R34 350z lsd conversion (speedo)

[Daquavuis]

Anyone know anything about a r34 350z lsd diff conversion?.  I have 350z lsd conversion layin around and thought about chucking it in my r34 I got all the offset adapters but am having trouble figuring out on how to get a speedo reading. Any help would be appreciated thanks

 

(I have both speedo sensors from r34 and 350z)

 

[GTSBoy]

R34 vehicle speed sensor is in the gearbag.

[Daquavuis]

3 minutes ago, GTSBoy said:

R34 vehicle speed sensor is in the gearbag.

hey man nah I’m sure they get it from the diff like the s15 my speedo went out in the past and I just replaced the sensor in the diff and everything was working again

(idk if this helps but I got a HR34 sedan)

[GTSBoy]

auto?

[Daquavuis]

Yea I plan on chucking in a 20det box soon so should I even worry about it? If it ain’t too difficult would I be able to get a reading out of that?

[Daquavuis]

4 hours ago, GTSBoy said:

auto?

Yea I plan on chucking in a 20det box soon so should I even worry about it? If it ain’t too difficult would I be able to get a reading out of that?

[GTSBoy]

OK, that explains it. The auto NAs are not something that even enter my thinking 99.9% of the time.

If you put a small turbo box into it then you could use an appropriate speedo sender in that and connect to the dash. The caveat there is that I have no idea if the calibration of the dash would be even close to correct. It might not even work. I do not know how the diff mounted speed sender works, and there is every possibility that it is different to the signal generated from the gearbox mounted sensors.

I would suggest hooking an oscilloscope up to your speed signal from sender to dash and recording the waveform at some known speeds.

[Daquavuis]

1 minute ago, GTSBoy said:

OK, that explains it. The auto NAs are not something that even enter my thinking 99.9% of the time.

If you put a small turbo box into it then you could use an appropriate speedo sender in that and connect to the dash. The caveat there is that I have no idea if the calibration of the dash would be even close to correct. It might not even work. I do not know how the diff mounted speed sender works, and there is every possibility that it is different to the signal generated from the gearbox mounted sensors.

I would suggest hooking an oscilloscope up to your speed signal from sender to dash and recording the waveform at some known speeds.

 

 

yea that might be an issue the sensor in the diff is for both abs and speedo same with the 350z diff except the 350z diff has 4pin connected while the r34 one is 2 pin. 

[Kinkstaah]

One thing you may be able to leverage is the fact that the R34 N/A has the same setup as a S15.

The S15 also is a car that gets 350Z diff swapped, so they will also likely have this problem.

The caveat of course is it's possible the dash is different between the R34 NA and the S15, but the subframe/sensors/axles/diff setup are the same.

I can't remember now as it's been too long, but I don't generally think people need to swap dashes between the N/A dash and the turbo dash when they do things like change the gearbox out, turbo their car, manual swap it, it's just not something I've seen mentioned so this could be compatible.

[Komdotkom]

Having seen a 350z diff swap I wouldn't do it, they don't really fit because the diff mounting ears are higher up the case and the diff sits very low in the sub frame.

I looked at it but am getting 3.5 gears from Neat instead.

Edited July 21, 2024 by Komdotkom

[Daquavuis]

Just now, Komdotkom said:

Having seen a 350z diff swap I wouldn't do it, they don't really fit because the diff mounting ears are higher up the case and the diff sits very low in the sub frame.

I looked at it but am getting 3.5 gears from Neat instead.

Put it in about 2weekz ago I haven’t heard anyone do it before but all the parts just fit right in the diff sits quite low and the diff ratio is pretty f**ked I thought I bought a 3.6 but I ended up with a 3.3 I believe😭

looking into finding something closer to the original ratio to the r34 diff (4.1) 

also having trouble trying to get somewhere to get a speed reading as the r34 sedan gets the speedo reading and abs from the diff 

[Daquavuis]

update i did some test and think the diff has a 3.3 ratio i also took it out and readjusted the offset bushing on the subframe which made the diff sit higher about the same as the stock r200 r34 diff.  (P.S : you'll need an 18mm spacer fabricated from your driveshaft to diff flange as there is a gap i think it might be unnecessary for some skylines  

I have a HR34 which is also a 4speed automatic which is now slower with the smaller ratio as the OG ratio is 3.9. ill see whether or not ill change the ratio after i do my manual swap. I am putting in a RB20det gearbox in it honestly hoping the gearing will be better if not ill probably steal a crown and pinion from a g37 or some with the 3.9 ratio

[Daquavuis]

On 14/06/2024 at 1:55 AM, GTSBoy said:

OK, that explains it. The auto NAs are not something that even enter my thinking 99.9% of the time.

If you put a small turbo box into it then you could use an appropriate speedo sender in that and connect to the dash. The caveat there is that I have no idea if the calibration of the dash would be even close to correct. It might not even work. I do not know how the diff mounted speed sender works, and there is every possibility that it is different to the signal generated from the gearbox mounted sensors.

I would suggest hooking an oscilloscope up to your speed signal from sender to dash and recording the waveform at some known speeds.

After some inspection it seems that the diff has a metal gear near the diff flange with the sensor slotting in a hole that hovers above it. I believe it is some sorta Hall effect sensor which reads the amount of rotations of the pinion to calculate the cars speed. 

the 350z also uses this mechanism on the diff except it has it on either one of the diff flangers and 2 seperate speed sensors. I soldered the wires and i still have no reading. 

might just go with the gps speedo at this stage haha

[GTSBoy]

7 hours ago, Daquavuis said:

the 350z also uses this mechanism on the diff except it has it on either one of the diff flangers and 2 seperate speed sensors. I soldered the wires and i still have no reading. 

Yes, well, that wouldn't work even if the sensor was compatible, as the pulse rate would be all wrong.