I'm looking at trying to keep my engine as strong as possible for as long as possible. I am in the process of upgrading the ignition system. I am not looking into doing power mods right now, but I do wonder if getting a better radiator and coolant hoses would be worth it or if it would be a waste of money. I have read several posts about some people having issues with high engine temps, but I am not sure if that is more of a SI thing than SII.

 

What year is your car? Mine is a 2011, and I have not had any cooling issues to speak of. A lot of what Mazda changed in the S2 cars centers around cooling and lubrication.

Even so, Koyo makes a nice replacement radiator that I have been eyeballing that is supposed to provide 20-30% better cooling. Changing the hoses will gain you absolutely nothing, and some "performance" hoses actually cause problems.

Koyo Performance Radiator | Black Halo Racing

 

If you have an S1, get a Sohn adapter, I think that's the best reliability upgrade you can install.
Coolant hoses aren't really an upgrade for performance, but if yours are really old, you may consider replacing them preventative. Maybe a scangauge or some other form of monitoring tool would help see if you're actually having heat issues? I don't imagine this is a big problem in Michigan.

 

I have 2010 GT. I knew the series 2 had the upgrades for the oil system, with the 3rd port added and the higher oil pressure. I wasn't sure if they did anything with the cooling system.
I saw the Koyo radiator too, and that was what I was looking at if I were to upgrade the cooling system.
I don't think I would have too much of an issue in MI. It generally only gets hot (90+) a couple weeks out of the year. But I am planning on taking some trips down to Alabama to visit my brother and extended family along the Gulf. My dad and I are talking about possibly making it a road trip and take a route through the Appalachians and having some spirited driving fun on some twisty mountain roads. Me in my 8 and him in his BMW 328xi.

 

I live in North Texas, where we have several weeks (or months) of 100+ degrees in the summer. My car is doing just fine for daily driving in those temperatures. You should be absolutely fine in an S2 car in Michigan. Maybe monitor your temps this summer and see where you are before spending any money on cooling?

I don't remember all of the cooling upgrades Mazda added for the S2 cars, but I know the radiator is different, the fans have higher current motors, fan speeds and turn-on temps are modified, air flow through the radiator is improved, etc.

The improvements to lubrication tend to also aid in cooling.

 

Well that puts my mind at ease a bit. Thanks.