mx5cartalk.com

I'm trying to put together some information on the MX5 (NA/NB) OEM Brakes.

Master cylinder diameter
1900-00 22.22mm
2001-05 24.0mm

Brake Booster
1990-00 4.74:1
2001-05 9.7:1 (ABS)
2001-05 6.4:1 (NO ABS)

Pedal Ratio
1900-00 4:1


Caliper Piston Dia
NA (F) 51.1mm (R) 31.75mm
NB (F) 51.1mm (R) 31.75mm
NB8B (F) 54mm (R) 34.9mm

Proportioning valve
NA Knee Point 427 PSI, 60% of front pressure (597 PSI at 995 PSI)
NB
NB8B

Pedal Travel
NA 133mm
NB

The proportioning valve story is a little more complicated than that.



NA6 and NA8 are both seriously underbraked at the rear - this shows why you should fit an NB one.

manga_blue yes the proportioning valve story is a little more complicated than what I have put on the forum, but it should suffice for the moment.

I already have NB8B fitted, however it is running on a NA6 master and booster but the NB8B proportioning valve.

I'm trying to do some calcs hence trying to collect some more information. I know from my data logging that front lockup happens at about 780 PSI, however I do not know how much KG on the pedal it takes to generate the 780 PSI.