Mazda MX-5 Miata banner
1 - 19 of 19 Posts

·
Registered
Joined
·
63 Posts
Discussion Starter · #1 ·
I have recently come back from playing on the good old autobahn and found that i hit just over 120pmh (friend behind me confirmed).

I thought that the 1.8 imports were restricted to 110mph and was controlled by the ecu?

Any ideas how I managed to get above the 'limiter' with a standard ECU?

Done some Googling but not couldn't really find anything.

Cheers
 

·
Registered
Joined
·
5,115 Posts
On a Mk1 the limiter can be overcome by removing screw from the rear of the instrument cluster - from memory, look for a screw labelled '180kph'.

Maximum speed is often limited by air resistance though.
 

·
Registered
Joined
·
5,115 Posts
Ah, must have changed for the 1.8, thanks for the clarification.
 

·
Registered
Joined
·
410 Posts
I had my S/C 1.8 import up to a true 135 ( GPS ) on the autobahn with the OEM Ecu and EMB piggy back.

I assumed the limiter was on the speedo and had been removed.
 

·
Dr. Eunos
Joined
·
5,466 Posts
Not on a mk1 1.8 import ... Ecu controlled
Not true! My J2-Ltd (same as the one in your avatar) still had it`s 180kph screw fitted when I bought it.
 

·
Registered
Joined
·
271 Posts
just removed my cloocks to check .... and no screw in place !!!

But on a "private " road , down hill foot to the floor the needle went round

to about 115mph and stoped at about 5k in top ..... so confused now ?

Picture091.jpg
 

·
Dr. Eunos
Joined
·
5,466 Posts
Mark of Penarth MX5 informs me that 1.8`s do indeed have a speed limiter in the ECU but I still cant see how as the ECU has no way of knowing what gear you are in.

My J2 has done a downhill 127mph sat-nav speed and there was more to come, my passenger was a bit of a train spotter and very excited to have gone faster than a Mallard?? That is when I slowed down and just stared at him a bit puzzled.

Just to add, I can see how a Mk2 ECU with it`s electronic speedo drive knows the vehicle speed but not the Mk1
 

·
MARK AT TOTAL MX5 REPAIRS
Joined
·
5,726 Posts
I am led to believe that in the mk1 1.8 speedo is a reed valve type electric switch which acts as a vss and when the car hits its limited speed it sends a signal to the ecu to cut the power.

here is a pic of the rear of the speedo and the reed valve

1210538_orig.jpg


i have never investigated or tried to delimit a mk1 1.8 but i am sure it has been done..

you may need to do the same thing as on a mk2 which is....

Remove the white and black wire from the wiring connector that plugs into the back of the dials. This is located on the wiring connector that plugs in on the back right hand side of the clocks and is on the 5th terminal from the right. you can just cut the wire instead and tape up the ends.

(pic below is not mine but does show the speed sensor wire from the clocks to the ecu)

128969_orig.jpg
 

·
Registered
Joined
·
3 Posts
I am led to believe that in the mk1 1.8 speedo is a reed valve type electric switch which acts as a vss and when the car hits its limited speed it sends a signal to the ecu to cut the power.

here is a pic of the rear of the speedo and the reed valve

1210538_orig.jpg


i have never investigated or tried to delimit a mk1 1.8 but i am sure it has been done..

you may need to do the same thing as on a mk2 which is....

Remove the white and black wire from the wiring connector that plugs into the back of the dials. This is located on the wiring connector that plugs in on the back right hand side of the clocks and is on the 5th terminal from the right. you can just cut the wire instead and tape up the ends.

(pic below is not mine but does show the speed sensor wire from the clocks to the ecu)

128969_orig.jpg
Apologies for resurrecting this thread but, on the NA 1.8, where the reed valve would be? Which part needs removing?

Many thanks
 

·
layabout
Joined
·
2,350 Posts
here is a pic of the rear of the speedo and the reed valve

1210538_orig.jpg
that is the vss sensor as used for cruise control, suppose it could supply a pulse / signal for a speed limiter BUT it would need a lot of computer power (unheard of in the 90's 😲 ) as opposed to the earthing of the ignition circuit on earlier cars....

where the reed valve would be? Which part needs removing?

^^ the above is connected to the 'RSW' screw on the rear of the mk1 cluster (wire position 'F':unsure: green / red?)



Rich.
 

·
Registered
Joined
·
3 Posts
that is the vss sensor as used for cruise control, suppose it could supply a pulse / signal for a speed limiter BUT it would need a lot of computer power (unheard of in the 90's 😲 ) as opposed to the earthing of the ignition circuit on earlier cars....




^^ the above is connected to the 'RSW' screw on the rear of the mk1 cluster (wire position 'F':unsure: green / red?)



Rich.

Hi Rich!

Thank you for getting back to me.
Would, in your opinion, removing any of these screws do the trick?

There was another thread:

Please check post #13/#14
Unfortunately the user is no longer active, but he claimed that cutting out this "reed valve" behind the speedo removed the limiter.
However he didn't mention any of those screws?
The pictures are no longer available either

Thanks again,
Enzo
 

·
layabout
Joined
·
2,350 Posts
Would, in your opinion, removing any of these screws do the trick?
removing a screw to test is non-destructive & reversable (y)

also Easy:p

claimed that cutting out this "reed valve" behind the speedo removed the limiter.
imho that is a little drastic - especially if you don't know for sure:rolleyes:

However he didn't mention any of those screws?
interesting that theres 2 very obvious screw-holes in that imageo_O

your choice, personally I'd look for something reversable in case of fuckup:ROFLMAO::ROFLMAO::ROFLMAO:

Rich.
 

·
Registered
Joined
·
2,417 Posts
On the rx7 fd you literally cut an input wire to the ecu from the dash.. suspect the same on a import 5... my eunos only reads 114mph but aftermarket ecu so no limiter..
Mellens.net for drawings.

Sent from my SM-N950F using Tapatalk
 

·
Registered
Joined
·
1,725 Posts
Mk2 imports are exactly the same. I made a thread about doing it on my old mk2 RS years ago

Edit: Thread here Mk2 1.8 Import Speed Limiter Removal

Was the Speedo output wire to the ECU that I removed to disable the limiter
 
1 - 19 of 19 Posts
Top