What is the ‘best’ radiator? Are Koyo any good?

[Erdin]

Hi Clive, ya i do think you may be right it probebly is the under drive pullys so im gona upgrade to a ellectric water pump in the near future and see how it goes, the pullys dont seam to be helping when your at high revs for anylong time.

thnks
Erdin

Hi Erdin,

Real puzzled that you feel your water pump can\'t keep up, I ran a HUGE rad that was twice as thick and also dimensionally bigger than a KOYO on my car and the only problem I ever had was getting the car warm enough to open the thermostat !!!

I did however deliberately ran a standard size water pump pulley because as I have often said, under drive kits are to stop cavitation at high revs on race cars and not FD\'s sitting in traffic ticking over on a hot summers day when they need all the water flow they can get !

BTW, my company has sold quite a few Koyo Rads with never a problem or any kind of complaint and also as one of our here members knows from when I fitted a PWR rad for him, I was absolutely appalled that the thing did not want to fit in any shape or form without lots of modifications, i.e. butchering the thing in, indeed if he hadn\'t have needed to drive away I would have sent it back and fitted a Koyo.  

Hopefully this was just one of a bad batch and the guy was just pain unlucky as I must admit I have never heard any other complaints about PWR.

[Christopher]

I have an ARC one and its huge. Dont know if there is different types but Ive never had problems with temps, even with the intercooler blocking it.

[20B_boy]

The problems you had with the PWR rad might have been because there are 2 types, stock replacement and race. The first one is 39mm thick and I think the race one is 57mm. The stock one is a straight swap and holds about a litre or so more than the mazda OEM rad.  I changed mine with no issues in my garage.

Thanks for clearing that up Frankie. If you had trouble fitting it clive it mustve been the race job which is the 57mm core. The stock replacement (which holds over a litre more than the stock rad) is just that - a straight replacement!

We used to sell the koyo\'s which we paid less for and made more on - now we sell PWR....

All PWR stuff is hand built in aus to a very high standard - abel ran PWR chargecoolers on what it still (I tihnk!) the fastest RX7 in the world - the products are without question first class.

At the end of the day a stock rad in perfect nick in the stock position should work fine...

R.

[rx7veilside]

clive is it poss to run standard sized pulleys after removing airpump..i have the greddy blue pulleys on mine but want to return to standard size to keep water temps down..i have pwr rad but big fmic on cruise i see 88-89 but rises rapidly in traffic and rises up to 95 when my fans kick in..are the standard pulleys larger or smaller than the underdrive ones and is a special belt needed to run standard pulleys with no airpump

[clive]

clive is it poss to run standard sized pulleys after removing airpump..i have the greddy blue pulleys on mine but want to return to standard size to keep water temps down..i have pwr rad but big fmic on cruise i see 88-89 but rises rapidly in traffic and rises up to 95 when my fans kick in..are the standard pulleys larger or smaller than the underdrive ones and is a special belt needed to run standard pulleys with no airpump

Stock pulley is smaller and this means it runs faster and yes there is a shorter belt avalible but these are special order as they are not a conventional belt length.

[rx7veilside]

i have 2 pulleys the alternator and water pump do i need to replace both and how much is a replacement belt to run it all..thks

[clive]

All you need is a standard pair of pulleys, I am sure if you post in the wanted section you will get a pair from one of the guys who have changed their pulleys for an underdrive kit.

[rx7veilside]

clive how much is a belt is it a mazda item or a multi fit tks

[Iwan]

I\'m running FMIC and Koyo rad. With low-temp thermostat, water- temp never go past 80°C even running high speed 260-280km/h  on autobahn.

I highly recommend the Koyo alu rad.

REgards
Iwan

[Freddy]

I have a FMIC intercooler and Koyo Aluminium rad on my other FD;

http://www.mazdarotaryclub.com/forums/showthread.php?t=20028&highlight=immaculate

During spring and summer when I had the Koyo Rad fitted; IIRC I never saw temps go above 90 degrees on a hot day in traffic. On the motorway, around 83 degrees. The rad seems to play very well with hard acceleration, fast driving.

Have not driven it lately so I cannot comment on winter driving.

HTH

 

[rx7veilside]

freddy did u have a underdrive pulley kit on yours i think i see higher temps because pump is running slower

[M@r]{]

since ive spoken to Pip, he says the Koyo rads are excellent - he can supply them too  

[Freddy]

freddy did u have a underdrive pulley kit on yours i think i see higher temps because pump is running slower

Not on this one. I do on my two tone FD on which I see higher temps with a similar sized ali rad and fmic.

HTH

[rx7veilside]

must be the pump running slower due the pulleys then..dont think i need the pulleys as it only a road car not track or 1/4 miler..was running 496fwbhp till 2 tips said bye bye

[gmogle]

{\']since ive spoken to Pip, he says the Koyo rads are excellent - he can supply them too  

Did he say how much ?

Gareth