Rad and intercooler set-up for 20B FD3

[colum]

your cooling system will only be as good as the the flow through the smallest part of the coolant passage, the sard thermo stat opens at a lower temp but more importantly, flows alot more than a stock fd when fully open. i did a comparison a long time ago on fduk and cant find the pictures anymore but the sard one opens 25% more than the stock fd one.

the koyo rads are great bits of kit, well worth the extra money spent over a chinese copy type affair

[Grant Monkhouse]

The N flow radiators slow the water passing through the radiator making it more efficient. However a cheap eBay rad can be modified quite easily to be like an N flow

[leeroy_25]

Hi Grant.. If I get the N-flow correctly the Mod would be to cut the upper and lower cappings off the core and weld in divisions. So the top has a division about 1/3 along then the bottom has 2 divisions at about 1/3 increments again. I guess you could just cut a section out of the rad and weld in the divider? Wish I had an ally tig welder too! Although not a huge amount of work I guess. You must need to make sure the division is welded accross the ends of the core between two water passages as well? To be sure you don\'t blank off a passage and that the water cannot creep between the sections of your N?
So Grant you would presumably buy a cheaper one and mod it to make it better?

Good shout with the thermostat colum. I need to make a note of that. Thermostat body and bits are in my mind the whole time but until i sort the rad and stuff I don\'t exactly know what I need. Might just buy a stat anyway.
do mazda not do a race stat at all? obviously I will google around anyway. Just surpised if there is only one choice.

Thanks
Lee

[Grant Monkhouse]

Yeh that\'s what I would I do, modding a cheap radiator. Saves cash. You only need to put 2 dividers in, 1 at the top 1/3rd across from the inlet then one in the bottom 2/3 a rooms from the inlet. You wouldn\'t need to weld them inside as the obstruction would cause most of the water flowing through the internal cores. This will stop the water just going from the end tank on top to the bottom end tank as fast as possible

[Grant Monkhouse]

Iv got an eBay rad, when I go home I will draw on it to show you what I mean

[leeroy_25]

Hi Grant,
Yeah.. That makes sense. pretty sure I get what you mean. Not sure why I added in the extra division!
So you just cut a slot in the upper and lower tank and get teh best fit you can on the divider..

Cheers
Lee

[Grant Monkhouse]

Yeh that\'s what I would do. Probably save you £200 on a radiator too

[Grant Monkhouse]

Can you see the red marks. That\'s where I would put the dividers
You don\'t need to use a Mazda specific one. You could even use an intercooler core with equal sized end tanks and insert the dividers

[leeroy_25]

Thanks Great.. Yep.. That\'s what I had in mind. I think if people run FD ones anyway they are quite a good size and the shape suits the packaging. so I can make a rad that is almost as good as proper N-flow for a fair bit less. Sounds like a plan to me.. If I need to get it cooler down the road I can always sell it on and invest in something bigger. but it should sure getting me running to begin with at least. I guess you are using that rad?!
IC wise I might be onto something too.. Now that we had the talk about CFM\'s I now roughly what I am looking for I think.
Oil cooler I will post pics later.. Someone mentioned the one I have might be older RX7. It came with the engine? It is not too dissimilar to this.. Possibly a bit taller though?
http://www.ebay.co.uk/itm/aluminum-oil-cooler-mazda-RX2-RX3-RX4-RX7-oilcooler-/170793291850?pt=AU_Motorcycle_Parts_Accessories&hash=item27c412d04a&_uhb=1
I know the FD runs 2 oil coolers as standard. all be it small ones. Sure one decent size cooler will do the trick and that is down to how they chose to package the various rads? The one I have may be too small but it did come with the engine? I put a good aftermarket oil cooler in my RB30 and I struggle to get the oil warm! Not huge either.
Thank you
Lee

[Grizzly]

Just dont for the love of God use a cheap ebay one, Possably the most important part of a decent set up? when i bought my Fd the rad was a cheap jobbie and the alloy end tanks where weaping at the point they had bent the alloy without warming it correctly.

Are you seriously looking to save £200 on a Rad of all things? sorry if i sound like i\'m having a pop but in my world Cooling is a no expence spared item you don\'t buy of Ebay Go to Rad tec or a rad maker if you want to make some thing custom.


N-flo slows nothing, they are triple pass rads, possably the only one you can buy for the fd that uses the whole area of the Core unlike normal rads that the coolant passes the easiest route so is less efficant. Dont use a stock BM or merc etc rad, they use Plastic end tanks which is also a bit of a no no.

[Grant Monkhouse]

I have used a couple of eBay ones, they worked great. I had temps drop 10-15C with them and no leaks. If it is good enough to get the car going and see  how things fit then they\'re worth it in my eyes. Cheap too. I asked a custom rad builder for one for my car, sent them dimensions and they quoted me 375 plus vat!!

[Grizzly]

Said before there are a few things you don\'t cut corners on and the no1 is water cooling sytem.

N-Flo or big PWR rad 100% all day. But thats my personal opinion if you want to cut corners its your motor at the end of the day.

[Grizzly]

I put a good aftermarket oil cooler in my RB30 and I struggle to get the oil warm! Not huge either.

Look into a Oil Thermostat, i have two 25 row Mocal\'s on my 450hp fd and it works really well, you would have to ask some one who knows a bit more about 20b\'s than me but quality Coolers (proberly 2x30row??) and a Thermostat would serve you well, i think they use two coolers to get good air flow through them (placed in good possitions)

[leeroy_25]

Thanks for the replies again chaps. I have noted your advice Grizzly and will explore some other options. I am in the meantime possibly picking up a cheap, probably ebay, rad to at least use for some rough sizing and I can always use as as guide to get a custom one done. There are a lot of \'branded\' rads you see out there that look very similar to the ebay ones by the way. My old FD had one and it worked fine for me? if you buy a core and start from scracth how do you know you are getting a decent core? I could get a custome one made easy enough as long as I can get a decent core and use the FD one for a size guide if not making it slightly thicker?

Might drop the rad guys you mention a line.

[Grizzly]

I have used a couple of eBay ones, they worked great. !

What Hp did you run with it on? Mine was ok until i started to wind the power up and the End tanks started to bulge / fracture at the end tank bends. I would never recomend one.