I think I've replaced my radiator about 5 times over the past 12 years or so. It's in a Vmount configuration so I've changed the mounting solution a few times because I figured it was due to how I had it mounted, but nothing has worked. I don't remember if every single failure was the same, but at least the last two or three have been the same. I'll see coolant dripping from the front (bottom) right corner and it's usually coming from the fins in that corner, but once it was coming from the fins in the rear (upper) right corner and running down. I always thought it was just me, but I talked to my buddy tonight and he said he had the same issue with the last Koyorad he used too. Has anyone else had these issues? I'm getting really tired of changing radiators more than I change the engine. It's just not right! lol

My buddy said he's been using a cheapo eBay radiator for years now with no issues. Since I'll be getting it modified for Vmount anyway, does anyone have a line on cores I could get and just have one built locally?

 

The eBay/cxracing/rotary works v mount radiator works great in all respects. Theres no real reason to modify a radiator to be v mount when you can just get one that was designed to be one.

I can't speak on the performance of the radiator in an actual extended high performance environment but for everything else it works very well. I would imagine it would perform just as well.

 

Rotary Performance in Garland recommends the Mishimoto over the Koyo.

The Mishimoto requires NO trimming and is a more OEM fitment. Mishimoto quality is somewhat variable, but I believe quality issues were limited to their earlier radiators.

 

Not sure if there are multiple fd mishimoto radiators but the last one i saw was an oem replacement. It was as thin if not thinner than a stock plastic radiator so that would explain why it fits "better". The koyo is a larger unit so reasonably yes, it would require modification

 

PWR sells into the US - cheaper than we can buy them here. If they carry the full line, cores should be available? In a V mount and custom made, tanks at the sides, rather than top and bottom is a far better way to go IMO.

If the rad is rubber mounted and no torsional stress, might be worth checking for any stray current, koyo here must be over 15 years old and watertight.

 

Banzai Racing has a how-to on installing the Koyo. It's a bolt in -

https://www.rx7club.com/3rd-generati...-tips-1107155/

I have a feeling there are quite a few fakes out there. If you got it on Ebay it's quite possible it's a fake.

I've had one in my car for ~10 years with zero problems, many friends running them with zero problems.

I also don't know if something with how it's mounted could cause a problem. They are supposed to be on rubber isolated mounts. If it was hard mounted that could cause problems.

Dale

 

No experience with the regular Koyo, but I had an N-FLO for 4 years, it did about 10k miles and was in excellent shape when I pull it.

This is back in 2011-2015, I wonder if their quality have drop since?

 

Also have a Koyo N-FLO from ~2011, modified for v-mount. Swap it out and back every few years for emissions testing and it is still solid.

 

From what I've been told, the mounts have to be modified to fit properly. That wouldn't be a huge issue for me but I'm also planning to change the mounting altogether this time and make some mounts that will use the two pins on the bottom with the rubber isolators. I also plan on having mount points on those brackets for the RX-8 condenser I've been using, and I have a plan for the inlet and outlet that I haven't seen on any available radiators. Currently the way I have the radiator set up, I have to do so much modification to fit the condenser, side mounts, changing the end tanks, etc. I'm trying to make it more modular so it won't cost so much if I have to go through this again.

Regarding the performance of the CX Racing radiators, they seem to be doing well, so I wouldn't be worried about that too much.

I was looking at Mishimoto a little bit ago and I only found that thin one too, so I guess that's out.

I'll look into that. My buddy looked them up last night and they were pretty pricy, but I'll see if they have just the cores. I'd rather keep the tanks at the top and bottom for reasons I mentioned above.

My current setup is using rubber isolators. The last one was too but I added more this time thinking maybe that's what it needed. I think the first few were hard mounted though, which is why I assumed it needed isolators. I'm not sure what you mean by stray current.

I don't think I've gotten any of them on eBay yet. The first one I bought used back in 08 and that one took several years to go. I think I bought the next one from RX7store and I believe that one died after a few years and I got another one from there and it was bad from the start so they sent me a replacement. I don't remember where I got the last one but I just bought one on Amazon that I'll be sending back. I'm not sure how convincing the fakes are but the boxes and all documentation looks legit. These last couple have been on rubber isolators and it hasn't made a difference. My buddy has his custom V mount radiator hard mounted and he hasn't had any issues yet for the several years he's had it like that. Surprising to me, I always plan on using isolators.

I've had at least a couple N-Flos and I had the same issues with those. I thought I had read that being an N-Flo modified for V mount was the cause of the issue but maybe I'm mistaken. The reasoning was that the coolant is flowing back to the bottom with the outlet at the top, and something about increased pressure. I bought a regular U flow this time but after hearing my buddy's experience I'm planning on sending it back.

I never tried to get a warranty from Koyo since they were all modified but he tried and they told him to kick rocks, and that one was stock mounted I think.

 

mounting of the rx8 condensor on the radiator is not as complex as people make it out to be. same with mounting the radiator in the car. it simply doesnt have to be a complicated manner. in my own car ive had 2 L brackets holding my radiator up since 2015 and no issues. for other peoples cars i use all 4 mount points just because. on the bottom of the frame rails there are quite a few threaded holes to choose from. all you need is an L bracket on either side with one point on the rad and another on the car. if you want to go above and beyond then you can mount the upper points too but i promise its not necessary at all. the 2 side mount points, the radiator hoses and the weight of the coolant and fans keeps the radiator more than secure and locked at whatever angle you set it at.

 

I've had a Vmount since 2008 and have had it mounted a couple different ways. The first one had some janky mounting all along the bottom and attached to the tie downs on both sides, and the last 3 or 4 have been mounted similar to yours. The first with angle brackets was mounted without isolators, but I started using some after that. I've always had the rear corners mounted too, also using isolators, although I know the rear mounts weren't really needed.

I was thinking about mounting the condenser like you did because it would make it easier to swap the condenser too if I ever needed to, but that's one more thing I'd have to get modified on a new radiator and I'm trying to minimize that. Maybe I'll just have those condenser mounts welded on too, get the end tanks exactly how I need them, and just cut the end tanks off to swap over onto a new core if I ever need to again.

 

Ive been running N-Flos for the last 10k miles or more without a single issue.

 

https://shop.pwr.com.au/faq/pwr-radi...-affect-my-ca/

A mate's datsun/nissan workshop had an extreme example of this several years ago. 240Z left on a hoist over a weekend with a huge puddle under it by first thing Monday - massive pitting in all aluminium components.

 

I've run N-Flo at least a few times now and they failed too. Not sure what's going on.

Holy ****, I've never heard of that. Thanks!