I came across this the other day for Eunos roadsters. Is there any truth in it?
To get rid of this limiter, you have to remove a screw from the printed circuit board behind the speedometer… Looking at the printed circuit board , there are two big multi-connectors ,each with 12 connections. They are labeled ‘a’ to ‘l’ and ‘A’ to ‘L’. The ‘G’ connection is marked 180kp/h sw and, if you follow it up the board, it leads to a screw. Removing this screw disables the speed limiter.
iddy
Yes, on a Mk1
On the 1.6, the screw completes a circuit to a contact on the speedo set to where the needle moves to at an indicated 180kph. Removal of the screw disables the speedlimiter on the 1.6. On the 1.8, its never been confirmed if Mazda used redundant cruise control circuitry in the ECU, as a speed limiter.
Hi - Would I be right in thinking that this acts as a “Rev” limiter?
Rod
The effect is the same; whether its achieved through common circuitry is another matter. When the speedlimiter is hit (e.g. on a track), the car stutters, as it does when the revlimiter is reached.
Only in top gear - it is definitely speed related and not rev related.
Not a particularly difficult job to do - jus sometimes disconnecting the speedo can be tricky if you haven’t done it before, but follow the FAQ on the job and it works fine.
Having done that to my K reg 1.6L S-Spec I can assure you it will exceed 100 mph, but try as I might (in Germany, downhill and hood up) it will not go over 200kph (120mph) - and that was just about hitting 7000rpm in top.
You will exceed 100mph without doing the mod, (180kph/1.6 =115mph), On a test run I did get mine to that speed and did get the judder so would like to try the mod myself. Is there any danger of engine damage if the mod is carried out?
It’s not any more distructive than redlining the car in any other gear - the enigne doesn’t know it’s in fifth. The limiter is just there as a JDM speed limiter - UK cars don’t have it.
I’d be more worried about driving licence damage [:D]
I’d be more worried about driving licence damage 
Only if you try it on the UK roads, I did think about a blast down the runway at RAF Fairford whilst we were there for a show last night but the site of a copper with a machine gun made me think agian.