Replacement radiator for88rx7 all aluminum reliable.replacements for stock auto

 

You're going to get a million recommendations for a Koyo and that's probably the safest bet.
I've had good luck with Godspeed but understand it's something of a crapshoot.

 

I too have had good luck with Godspeed but YMMV. Not sure how they or the Koyo N-flow work with the stock fan shroud though since the cores are thicker. I have an E-fan so for me no issues.

Also you said stock auto. Do you mean auto trans? If so that could be an issue as I don't think any of the aluminum aftermarket ones have provisions for the built in trans oil cooler of the stock one. In that case you'd have to run a separate cooler for the transmission or a stock replacement. Mazdatrix still sells stock radiators with the aluminum core and plastic tanks. I had one of the stock style brass replacements for a long time. Durable but as far as cooling goes it sucked compared to the Godspeed.

 

Are aluminum rads that much better than stockies ? Just wondering since mine works fine and i am planning on keeping her stock but if it helps cool that much better than i may upgrade.

 

I had the Koyo N-flow on my S5T2, and can verify that it will work with the stock fan shroud & mechanical fan. The shroud will need some trimming at a few points where it mates up with the radiator, but it can be made to work. Also, if you still have the stock air intake snorkel to the air filter box, you'll need to chuck the snorkel as it wont allow the hood to close with the thicker radiator.

 

I wouldn't recommend Godspeed. It doesn't work with the stock fan shroud. Also their customer service is terrible. I needed a replacement drain plug or to at least figure out what size plug it used. They had no idea what I was asking. They simply said try autozone we don't offer replacement drain plugs.

Koyo N Flow is the way to go. Work's with the fan shroud and you can always order drain plugs for it on amazon.

 

+1 for the Koyo radiators. I run a Mishimoto radiator in my RX-8 and it has been fantastic. Not sure if they make a replacement FC radiator or not. Something to look into.

 

Mazdatrix has a nice replacement which is what I would get. Actually I would go to my local radiator shop and they could find the same rad. for less.

 

have the koyo for an s4 and it fits perfectly and keeps engine coolant temps very reasonable. would recommend it for sure

 

I went with a 2 pass KOYO full aluminum on my s5. I re-used my existing brackets. I did however have to modify the intake snorkel slightly and also the fan shroud with a Dremel down low near the lower hose for fit. My 2 pass radiator did not come with an extended filler neck so the coolant cap was interfering with the intake snorkel, slight Dremeling of the plastic was required for everything to fit "OEM"

I highly recommend it.

 

Stock replacement from Rockauto is always an option.

https://www.rockauto.com/en/moreinfo...192362&jsn=355

 

I have the standard s4 koyo replacement. I believe the part number is hh060642. Works very well. Shroud fit with a tiny bit of patience to get it lined up properly.

Keep in mind the koyo rads will not have provisions for a trans cooler, so you'll have to get an external one.

The radiator you can buy through autozone or rock auto is junk.

 

I think about the only thing those have going for them is the internal trans cooler like the stock one. Even then I think an external one of the proper size will cool better. I would get one of the aluminum replacements off Ebay before I bought another one of those Autozone/ Rock auto ones.

 

I did buy an eBay radiator, a 2 core side flow $135 includes shipping. Shroud had to be modified to clear fan and and there was no hole for radiator switch, may glue this on latter, it only speeds up engine for cold start, did have to shorten bottom hose neck, it was too long. Also a few mods to to air snorkel to keep it looking oem Had to mount radiator as low as possible to clear air box snorkel. So far it works great.

 

So other than not being made properly and not fitting at all, it works great! Lol

I hope it holds...

 

I did not buy a replacement radiator so I did not expect it to be a drop in deal, have more time than money so it works for me.

 

It had been mentioned that the snorkel didn't work or needed to be modified for the Koyo N-flow. Only reason I bring it up is even the expensive one isn't a direct drop in(the N-flow not the stock style Koyo). Lower radiator hose has to be shortened due to the thicker core not a design flaw per se.
The jury is still out on long term reliability as it is cheap Chinese stuff.

 

I mean, the s5 is the only koyo available for the second gen as an N-FLO, and the 'jury' is still out as to whether or not that design is even worth it. I speak only for the S4 koyo radiator, which fit my car just fine using the stock fan and shroud. Granted I'm not using the stock airbox, but I doubt it would cause too much of an issue.

Additionally, the s4 koyo also has a bleeder screw and provisions for the heater circuit and the coolant level switch. I paid $224 shipped for mine. Works wonderfully and controls temps even when I'm beating on it on a hot day.

 

Now that you mention it I do recall some debate about the N-flow design. Had to search old threads to jog my memory. I remember thinking about staying with a single pass but went with the Godspeed at the time. Mostly due to price. So far so good.

 

The N-flo has a strong following, but from my research I couldn't seem to figure out why. I seem to remember that for it to be beneficial you'd have to get more airflow than stock through it because of how much it slows flow through the cooling system hitting the partitions and being diverted. My conclusion was that considering I'm running a stock bumper cover with stock ducting there simply was not a point to run more than a single pass. I was real worried about it at the time tho and felt the standard koyo would not be enough somehow. Trust me though, it is. We've had some 90+ degree days already and the temp sits at 178 all the time. If I start romping on it itll hit 180 and if I do it for quite some time it climbs to 182, but it's never gone higher than that, and it drops from 180 back down the second you come off the throttle.

All in all in my opinion the standard koyo is more than sufficient. On a track might be a different story but I feel confident the temps would not get out of hand.