OEM Brake Pads - F1Y2-33-28Z vs F1Y4-33-28Z - What's the difference?
 

So it seems there are 2 types of front brake pads for my car (2004):

F1Y2-33-28Z (regular)
F1Y4-33-28Z (sport)

What is the difference? I got the regulars as I was told that is what I should get for my car but just wondering if the "sport" would also fit and what the difference is?

Also in some places the designation sport/regular for those part numbers is listed the other way around.

autos have standard suspension and brakes

m/t have sport suspension and brakes

what trans is in your car?

It is a manual. I got the regular pads - the F1Y2 as that's what my local dealer said I need according to the system. The pads fit in the calipers and all.

The pad material though was tapered, so right now the area that touches the rotor is smaller than the overall pad shape and as they wear out the area will keep increasing.

Not sure if the other model is that way too. Don't understand why the pads don't use the entire area either ...

the autos (standard suspension and brakes) have smaller front rotors than the m/t cars (sport suspension and brakes)

The usage of "Standard" is somewhat of an inaccurate label for the smaller brake pads.

Basically, there are 2 sizes of brakes for the RX-8. The "standard" is the normal size from a factory perspective, with the Sport being the larger size that comes with the Sport package.

However, the Sport package was added automatically to every RX-8 with a manual transmission, every automatic transmission that was a Touring or Grand Touring, and was also added to some automatics in the "base" trim. So probably 90%+ of the RX-8s in the world have the Sport brakes as a result. The "standard" is actually quite rare, as you had to have an automatic with literally nothing added to it at all.

As a side note, the Standard brakes can fit under a 16" rim, but the Sport brakes can only go down to a 17" So seeing 16's on an RX-8 automatically means it has the Standard suspension.

Thanks RIWWP. I understand that but I was wondering what the difference is between the 2 part numbers. The "regular" ones that I received, do fit my calipers perfectly, so they will work.

However, i was wondering if the other part # has a more agressive compound or larger initial surface area or ... any idea?

According to every reference I have ever seen, they are physically different sizes, and not interchangeable.

I would be more inclined to believe an error was made somewhere, even if not by you.