Since it seems that '91 N/A's were equipped with all kinds of different trim levels it's always been kind of difficult buying replacement parts for the braking system especially when you buy parts at your local parts store rather than the dealer. So anyway, I go to the auto parts store (Auto Zone) and ask for a brake master cylinder. They ask the questions, year, make, model, turbo or non-turbo. 91, Mazda, RX-7, Non-turbo. I get the BMC install it and return my old one for the core charge. Brakes work fine and it installed with no problems. Several months later I go to buy some brake rotors. Same questions, same answers. However, when I get the rotors they are solid and look different I order the Turbo’s brake rotors and they match; 4 piston fronts and vented rears. So now I’m wondering did I get the right BMC are my brakes working as good as they should be? Is there a big difference between the N/A BMC and the Turbo? The auto parts store shows 2 different part numbers. Are my brakes not working to their full potential?

When I buy parts from the dealer they ask for my VIN # and it tells them exactly what’s on my car from the factory.

 

The MBC is the same between the small brake and the big brake. Only difference is the GXL ones that has the extra sensor

Buy a Mazda OEM part next time..

 

So I guess I'm ok then...What sensor on GXL's are you talking about?