Radiator for NB SE, looking at CSF and Koyo

[Luke]

I don't know how, but my original SE radiator with 87000kms and 14 years of use, 9 of those being on track is still going strong. It has just gone from black to a really dark shade of green. So it may be on its way out this year...Replacement time.

SE's have a really tight engine bay compared to other MX-5's so this has limited the options I can use.
ie no 52mm ebay specials.
The main clearance issue is because aftermarket TBI pipes stick out further than stock. Mine is a BEGI and clearance with the radiator hose is limited as it is.

I'm very fussy with fitment, ie no stuffing around cutting and bending things so I have ruled out:
Flyin Miata's Cross Flow. They cost to much and have some poor reviews when it comes to fitment and life of the radiator. Supposed to be better now but I don't want to pay what they are asking regardless.
Mishimoto 37mm. Same reason as above for fitment and way to expensive for what it is.
And all ebay specials, including cooling pro. Plus SE stock radiator is generally better at cooling than these to begin with.

I've pretty much narrowed it down to the CSF dual core 41mm unit or Koyo Hypercore 36mm unit.
They both seem to get decent reviews in the US for fitment and specs, no reviews here for the CSF though only one for the Koyo.
The CSF supposedly cools a little better than the Koyo Hypercore, but I have not seen real proper hard data.
The Koyo has the advantage of using factory style radiator cap and drain cap.

I'm leaning towards the CSF, mainly due to price being less for much the same performance as the Koyo.
There also seems to be more sellers.

This car is used for track work most of the time. It is road registered to drive to the track.

Anyone want to share their experience with a CSF or Koyo Hypercore here in AUS if they have one.
Where you got if from and how much you paid would be good info as well.

[Nevyn72]

I have the pre-hypercore Koyo 37mm and am very pleased with it.

Fitment was perfect using all factory points for locating and radiator fans.

Only real issue is for the top radiator hose. With the slightly thicker radiator plus the slightly larger intake elbow I had to trim the hose quite a bit and it still 'leans' on one of the fan support frames......

Purchased direct from a US eBay supplier as even with shipping it was still cheaper than local suppliers.

[Nevyn72]

Admittedly the interference with the fan support probably has more to do with the sandwich plate spacer on the thermostat housing though....

Here's a picture of what it looks like.

[greenMachine]

I just put the Mania alloy one in. No problems, nothing need trimming, everything fits.

However, I wanted to install a swaybar brace, but that proved a step too far, it needed the bottom fan supports trimmed, which I was not prepared to do without more thought/consultation/research.

[93_Clubman]

I don't know how, but my original SE radiator with 87000kms and 14 years of use, 9 of those being on track is still going strong. It has just gone from black to a really dark shade of green. So it may be on its way out this year...Replacement time.

For info, when they eventually go light brown they're closer to becoming a problem, ie cracks forming - my 1993 still runs its original rad which is now dark to mid brown.

[Luke]

I don't know how, but my original SE radiator with 87000kms and 14 years of use, 9 of those being on track is still going strong. It has just gone from black to a really dark shade of green. So it may be on its way out this year...Replacement time.

For info, when they eventually go light brown they're closer to becoming a problem, ie cracks forming - my 1993 still runs its original rad which is now dark to mid brown.

There is another reason for changing it other than the colour starting to change.
Plus track dríven cars seem to blow them when they are dark brown from what I have seen.
I have been running the car for 9 years very hot. Lets just say I have seen well North of 100C. I have seen over 110C through OBD data!!!
So the stock ECU keeps changing timing, fuel etc to try and keep the car cool which kills the power.
I only have been using the car on track between April and October for this reason.
When I do March and November days the car just has no go after about 2 laps. Forget the summer months.
So extra cooling will be much appreciated.
I won't be dumping the original radiator, that will be a spare floating around.

[Luke]

Admittedly the interference with the fan support probably has more to do with the sandwich plate spacer on the thermostat housing though....

Here's a picture of what it looks like.

That looks very nice.
That pic alone is swaying me over to Koyo.
It looks more factory style.
The CSF is polished making it look bling. Same reason I went for BEGI TBI instead of FM's.

[Roadrunner]

I've got the Koyo as well. Fitment was perfect but it is tight. You have to drop the fans into the engine bay first and then slide the rad in, and then bolt the fans to the radiator. I learnt the hard way by bolting it all together first and then put a hole in it trying to get the combo into the gap. I also had to trim a few mm off the fan shroud arm near the top radiator hose so that it didn't rub. But like Nevyn72 this is mostly because I also use a temp sensor spacer on the thermostat housing pushing the hose forward.

[Luke]

Anyone bought through Amazon US before???
I can get a Koyo Shipped to my door from FR Sport on Amazon for $442 AUD. Yes they ship to AUS, checked that.
Just a bit weary as I have never used Amazon before.
Plus FR Sport website directly gives you a ridiculous shipping quote of $460 on top of the $300 purchase price. Not sure how there calculator works but it is way off.

[bruce]

Perhaps email them asking the difference in shipping quotes (and ask them to match it).

[Lokiel]

Amazon are THE premier online shopping site, they pioneered it so you can trust them (I've bought a lot of stuff from them).

Who are they using for shipping though?

If it's their own shipping you should be OK because they won't want to tarnish their reputation if it gets lost (ie. they'll guarantee delivery).

FedEx or UPS are very reliable and are worth paying extra for.

If it's USPS then I recommend an alternate shipper if they have other options.

I've lost 2 expensive (> US$300) packages with USPS and USPS basically told me to "bugger off" because it was delivered outside of the US so was out of their hands (one of the items was last tracked as being received at their Chicago depot but nothing after that so it hadn't even left the US before it was lost).

These days I only use USPS for items under US$100.

[theo]

I have the CSF 41mm on my NA (CSF2862). It does what it's supposed to. Don't have any data to say if its better or not.

Can say it was very well packaged, is well made, and was easy to install. Didn't have to modify anything.

Bought it from ebay last year for $325.60 including shipping from the US.

[Luke]

Just two things I would like to know for those that have a Koyo and can measure or look at it.

Is there a gap between the radiator and fan shroud or do they fit nice and snug?
Gaps are bad as fans don't work effectively. Aluminum tape can fix this, but a nice fit is better than tape.

How deep are the actual tanks in mm?
Koyos website has every dimension except for the tank depth.

CSF tanks are 2and3/8 inches. That is 60mm! I have seen some fitment pics of one in a MSM in the US and it looked very tight. Especially after he fitted a BEGI TBI. Mine is as bad now with my original radiator as his pics show with the CSF!!! I think some it is because my TBI is slightly turned to the passenger side forcing the intercooler hose more forward.
https://forum.miata.net/vb/showthread.php?t=584043

[greenMachine]

Is there a gap between the radiator and fan shroud or do they fit nice and snug?

The Mania one doesn't, there is a gap of 10mm or so. That is another item on my list, with the sealing of the radiator ducting. However, I am not really worried, as we don't do traffic up here in beautiful downtown Canberra ...

I now recall a post on MTnet which involved drilling out the plastic mount to allow the mount to slide over the post, and then be secured with a collar of some sort. I wish I had remembered it when installing the radiator.

Can't answer on the thickness.

[Roadrunner]

Hey Luke, There is a 10-15mm gap between the Koyo and the factory fan shroud when fitted. From memory the fan blades sit pretty flush with the mounting points so having a bit of a gap is probably a good idea as you wouldn't want a flexing blade hit the radiator core.
Nothing some adhesive foam strips wont fix.
This goes the same (and probably more importantly) for the 10mm gap between the front of the radiator and the cross member.

This stuff works perfectly: https://www.bunnings.com.au/moroday-gre ... l_p4061873

The other thing to consider is the huge gap under the radiator. The factory unit has foam moulded to it to force the air through the rad.
I tried using foam and it disappeared after the first track day, so there is a lot of wind force at the bottom of the radiator. I ended up bending some sheet metal to block off this gap and noticed cooling improvements immediately at the next track day.