I was changing the hoses and my stock radiator that is 17 years old broke, no surprise that the plastic is brittle after all these years. What upgrade options are there these days? I'm going to change out the water pump and change the hoses to silicone hoses while I'm at it.

 

CSF 3164 is a great upgrade, drops right in and will set you back about $300.

 

The Koyo HH is also a fantastic choice

 

Any links?

 

Sure
https://lmgtfy.app/?q=csf+3164

 

~$350 shipped and 1.89” thick

compared to ~$309 shipped and 1.63” thick for the CSF

works put to about the same price per inch thickness, but slightly more capacity in the Koyo for a slightly higher price

ps: the search link above isn’t working on my iPwn
.

 

I ended up going with a stock OE Replacement Radiator off Rockauto. It has worked sufficiently for heavily spirited driving, and light duty track use... However I will note: all my under-plastics are intact which on the RX-8 will make the difference between staying cool on track, and overheating after 2-3 laps even with quality, aftermarket, large capacity radiators... (I also have no AC Condenser)

 

that’s what I have on my NA Renesis RX8 except the slightly thicker S2 version, lighter than the aluminum aftermarket radiators
.