Thread: Radiators: Mishimoto vs Koyo Review Questions & Questions?

Okays SO I know this has been discussed many time in the pass but I would like some which one betters and which one the community think (Updates from OLD post to new times)

This would be a Koyo R1977 (Now discontinued by Koyo) vs Mishimoto MMRAD-SEN-91SR (the current 2.0 version)

Here's some things I've researched and have questions about and REAL LIFE reviews/issues/actually own 1 or both before choosing (I'm suck in the middle haha)

1.)Warranties: Koyo has partially No warranty were Mishimoto has limited lifetime warranty. Any hidden info I may have missed during researching?

2.) Size Difference's: Koyo is a tad thicker (more fluid is a ++++) vs Mishimoto might have little better clearance with a turbo goodies/headers for na guys but by a very small amount (yes we all know that LITTTLE bit can go a LONG way lol). explain your intake on this opinion.

3.) Is there anyone who did/has Data showing that the size differences play is worth (especially since this is going on an nx2000)? Road Course temps? Daily Driving (if so what kind of weather/altitudes)?? long road temps? etc etc.

4.) Price: Obvious price is different by a good amount. Koyo $285+20 for cap (not included) while Mishimoto's $191 with cap included (both from authorized dealers)

5.)LONG TERM REVIEWS: I've seen when people first were getting the 1st gens. Mishimotos (then Mishimoto company decided to get with it and revised them correct-inlet/outle sizes & fitment). Anyone have issues after sooo many years running these? still holding up? temps etc.
KOYO's- been proven since they've been around but anyone have other reviews that maybe informative of any kinda issues?

6.)FITMENT: From pictures, it seems on the Mishimoto's passenger hose size of curve it gets pretty close to touching (from pictures) yet the Koyo has that weird HUMP (cap area) and it seems that was to help this issue aka has more clearance there. Any updates on that may been a issue for mishimoto over time with motor movement (yes yes I know solid motor mounts but this question was asked for those who man not want to go that route)?


I really appreciate any kind of real world straight up honest feedback. I've been battle with myself (haha) about these two in my head since Sept and still can't decided. I like the mishimoto due to the warranty is way better but were Koyo has the bigger core for cooler effect and has the longer term rep. (haven't really seen TO many on mishimoto)

My only input is that I've had both on my S13. First had a Koyo and ran 180 to 185 temp all the time (on the road, at the track, etc). Had to get another S13 running so I snagged it and sold the car with it. Replaced it with a Mishimoto because it was cheap. First thing I noticed was that the fin density wasn't as good, so it had less cooling fins per inch. It also didn't fit as well as the Koyo. It still fit fine, but not as "snug". Temps jumped to 190-195 all the time (btw, I have a full sweep temp gauge). Fast forward a few years and I replaced the radiator again with another Koyo (used even), and the temps dropped back to where they were originally with the first Koyo. Does the Mishimoto work fine? Yup. It's also a lot cheaper and the warranty is nice. However, if cooling performance is your number one concern (it is for me, especially now that I live in Arizona and track the car every month), then spend the extra cash and get the Koyo.

@2_Liter_Turbo Thanks for your review. I'm really leaning towards the Koyo Do to the history. Piece isn't the issue here...but I also do believe best bang for buck if the difference isn't a big diff. In your post, I consider it been a big difference.

Not a problem @gEE805 !

I ended up ordering a Koyo. Been the better performer I'd pay a little. Who said having an nx would be easy haha

You won't be disappointed!

Yeah. I was thinking that koyo was proven and you made me realize something I forgot since the last time I owned one (never installed though)....more cooling fins

I've been running a Mishimoto for awhile, specifically with Road Racing, and the temps are a few degrees higher yes, but I gotta vouch for Mishimoto's warranty process.

Soon as I bought my first one, I registered with them for the warranty. I've had 1 radiator crap out in about 4 years (I had a first gen), and all I did was call them and give them the serial, I had another radiator sent priority 3 day to me, didn't even want the old one back.

They seem to treat the racer/track community very well, and with how often I'm on track with temps going up and down like crazy, that lifetime warranty is a very nice thing to have.

That said, up until I got my Mishi, My Koyo never did me wrong.

Thanks for the review @cavern I appreciate it and I'm sure the person after me that researches for the same questions will appreciate it.

Koyo has been radiators a long time before any of these other radiator companies have been out.

Koyo is quality plain and simple. They use better cores, better welding process etc.

Not knocking on Mishimoto though as I also sell these and never had an issue with them. Mishimoto can offer a lifetime warranty when it probably only costs them 10-15 per radiator and selling for 200+.

Either way you probably cant go wrong with either or, Koyo might have a slight edge on the cooling features.