Probably a stupid question re JDM

bonester · Postby **bonester** » Wed Feb 28, 2018 12:20 am

Are Eunos Roadsters (NA) speed limited? My speedo only goes up to 180km/h. Aussie ones go up to 220km/h. If it is limited, how? Jap bikes aften have a limiter built into the speedo, which is easily bypassed.

This got me thinking:

https://www.carthrottle.com/post/this-i ... rburgring/

Postby **NitroDann** » Wed Feb 28, 2018 12:25 am

Yeah a screw in the cluster.

Dann

bonester · Postby **bonester** » Wed Feb 28, 2018 12:59 am

Thanks for that. Found this after you gave me advice:

https://www.youtube.com/watch?v=XGrb0w2cjak

I assume the speedo just winds past the 180km/h on the speedo.

StillIC · Postby **StillIC** » Fri Mar 02, 2018 8:41 pm

Well, I have a 180 speedo but no limiter. The speedo gets to somewhere around where 190 might be and then just sort of stops even though the car is still accelerating.

bonester · Postby **bonester** » Fri Mar 02, 2018 8:46 pm

Cool.

hks_kansei · Postby **hks_kansei** » Sat Mar 03, 2018 12:14 am

As above, mine has a 180k Speedo and has cracked the 200 mark, Speedo needle just kind of goes a bit past 180 and stops in no man's land

(Worth noting, mines an NB, so electronic Speedo rather than mechanical)

Mr Morlock · Postby **Mr Morlock** » Sat Mar 03, 2018 8:56 am

It's not a speed limiter-the speed is limited by the capability of the engine and conditions. Speedos always have an end point on the calibration.

Postby **NitroDann** » Sat Mar 03, 2018 9:37 am

Jap ones can have a 180 screw as far as i am aware.

Dann

hks_kansei · Postby **hks_kansei** » Sat Mar 03, 2018 5:46 pm

Mr Morlock wrote:It's not a speed limiter-the speed is limited by the capability of the engine and conditions. Speedos always have an end point on the calibration.

As the Speedo (well, gauge cluster as a whole) is wired into the body loom of the car some models do actually have a speed limiter as part of the gauge cluster

Some Nissans (and by the sounds of it NA MX5s had similar) simply have a screw installed in the back of the cluster to enable the speed limiter. The screw simply completes a circuit that enables the limiter, without the screw the circuit is incomplete and the limiter is disabled.

Japan has some oddly specific rules, one being that cars must be electronically limited to 180kph (not sure if the Speedo stopping at 180 is a rule, or just they figured why add marks if it can't reach them)
The screw method is a very simple and cheap way for them to implement it

ianoz · Postby **ianoz** » Sat Mar 03, 2018 7:48 pm

not just cars - my grey import bike had the 180 cutoff too. That used an opto-coupler in the speedo with a vane that broke the beam at the right point.

StillIC · Postby **StillIC** » Sat Mar 03, 2018 8:35 pm

Mr Morlock wrote:It's not a speed limiter-the speed is limited by the capability of the engine and conditions. Speedos always have an end point on the calibration.

All JDM vehicles are limited to a maximum speed of 180 km/h by law. And as HKS says, why put a >180 speedo on a car that will never see such speeds (unless fiddled with).

Wolfgang · Postby **Wolfgang** » Sat Mar 03, 2018 8:37 pm

hks_kansei wrote:
Mr Morlock wrote:It's not a speed limiter-the speed is limited by the capability of the engine and conditions. Speedos always have an end point on the calibration.

Japan has some oddly specific rules, one being that cars must be electronically limited to 180kph (not sure if the Speedo stopping at 180 is a rule, or just they figured why add marks if it can't reach them)
The screw method is a very simple and cheap way for them to implement it

I believe there was a "gentlemens agreement" between the manufacturers and the government to limit cars to 180kmh and 206kw for safety reasons.