Perf Radiator ?: Koyo/Fluidyne/Mazda Motorsports....
 

I'm building my car to be streetable but mainly focusing on tearing up the road race tracks here in Northern California.

I've tackled the following: suspension/wheels/brakes/driveline (425rwhp/400rwtq)

I now am looking to upgrade the cooling system.

SR Motorsports makes a 2" thick replacement radiator.... anyone running this?

Is the Koyo or the Fluidyne supposed to be better?

Lastly what about about the Mazda Motorsports unit?

Are the stock fans sufficient or do those need to be upgraded also?

Thanks in advance,

-Mark

Radiator
 

I run a gt3 car in Texas and Oklahoma, it gets hot here and I had to duct off my radiator and oil coller because they were not getting warm enough on a 100 plus day, what did I use? a ADDCO racing radiator from a circle track shop, daul pass and fit great, at about 1/3rd the cost of the Mazda unit.

The SR Motorsports Radiator is a relabled Koyo Radiator. Don't pay extra for the label.

Koyo's not big enough IMHO

Look at having a Griffin custom setup for you, then fab brackets to mount it

PaulC

Use the new AWR. (that is a period at the end of that sentence)... ;)

AWR supplies many of the Mazdacomp radiators. That or a griffin would be my choice.

Anyone care to bring some tech to this besides just saying that model X is better than Y in practical experience? Explanations or data as to why? Avg cooling temperature differences between brands?

I'm looking for a good radiator to cool a track FD3S (no longer going to be a stock car, so it needs an aftermarket radiator).

Why would one 2" core radiator be better than another? The Fluidyne, IIRC, is not a 2", so compared to the Koyo, the Koyo would have better cooling capacity if all other variables were the same (provided the extra 0.5" didn't choke airflow or something like that)?

Parameters that I have found:
Size of core (well, can't do much about that if you want it to fit in a stock application)
Fin density (fins per inch, I guess if it looks "packed" then it is about as good as you can get)
Number of tube rows (most aftermarket upgrades are 2 row and thus thicker core)

What makes these other radiators better?

I'm looking at non-name-brand radiator with a 2-row 2 1/16" core. Why would a Koyo be better or worse than this?

Silkworm: approximate cost on the custom Griffin setup? Specs on the core?

GT3_racer: looked at double-pass, it won't be as easy to implement because of the plumbing location change...

Hey gnx7, are we talking about your FC or FD?
There are vastly different answers depending on which year?


-Ted

The key to proper cooling is ducting. I've piddled with this for years on track FDs and my current setup (Koyo, moved my PS line to a power steering cooler, removed AC condensor and completely fabricated NO LEAK ducting) works very well in Texas heat. I run 11-12psi boost and the water temps stay at 190-195 with oil temps around 200. Call 1-800-radiator, get a Koyo and do the ductwork.

I was running a 26x19 IIRC, it was too wide, and too deep to fit with the swaybar and battery. If the battery isn't an issue, 26x16 will work nicely, otherwise 24x16

You'll want to have them put 1.5" inlet/outlets on the passenger side, and a 5/8" heater bung on the lower side (unless you've blocked off your heater line)

Make sure to specify the sizes on inlet/outlet, as the standard comes with a 1.75" outlet on the bottom

Shouldn't cost that much, I think I heard something around 250.

The hassle will be mounting it, since it won't come with mounting brackets.

PaulC

Thanks for the replies guys... I think this can be a good topic for many of us.

RETed- My FC is in RX-7 heaven. I'm building the FD all out now.

Paul (Silkworm)- If you cut the radiator supports I was able to fit a 27.5x19" Griffen $189 radiator in my FC. Not pretty... but functional. Allows a beefy 18" fan that will pull crazy cfm.

I would like to know the physics behind this one myself... I do plan to do some ducting to let no air past the heat exchanger and direct it fully thru it as nearly every dedicated race car I've seen has this setup. Small opening sealed duct up front that opens up to the nearly the full size of the radiator and seats. Basically a box in front of the radiator. This is on a Southwest tour car (NASCAR 600hp 358ci Ford) and on an SCCA full tube chassis Stang (Greg Picket's car).

GT3 Racer- Could you PM... I'd like to talk to you further about your setup. What fan (s) are you running?

TX guys should have some good input as they certainly aren't living in the North Pole during the summer! ;)

-GNX7

I'm with Silkworm. Have it fabricated and save a couple bills. I had a Howe core custom fabbed for my ITS car and it came in around $250. Mine was pretty much a bolt in with custom hoses. Just take your time and measure it accurately and fitment shouldn't be a problem.

As far as performance, the core is a 2-row with 1" tubes. It's setup for double pass which is more efficient than a single pass. Pretty sure all the aftermarket rads are double pass anyway. Water temps are always right in the 210 area (with the exception of some high temps last weekend...guessing we had a bunch of air in the system). At any rate, DO NOT underestimate the cooling needs of a track car. Having said what I run, I would strongly recommend a 3-row core on anything, especially a boosted motor. A 3-row will not give an extra 33% of cooling but every bit helps.

As has been mentioned, ducting is all important. Seal the flow to the rad and get eveything else out of the way. Some form of extaction behind the radiator or at the back of the hood helps as well.

Fans won't make the system. If you're not getting cool air on the rad without a fan, the fan will not be able to pull cool air through it.

Koyo is nice, but without proper ducting it's not doing its job.

Sorry about the thread ressurection, but has anyone seen the new Dual pass koyos? They look pretty promising, but I haven't seen anyone give their thoughts on it.
I have a Griffin Dual-row that I was going to get some custom brackets put on, but am not sure yet..
http://store.summitracing.com/partde...5&autoview=sku
Would the new Koyo be better? I know I can use the stock shroud with it which would be a plus..I have a Black magic fan that I was going to put on the Griffin as well. I use my car for daily driving and auto cross and Thunder Hill track events...It might become less of a daily driver once I buy another car.

Koyo seen here:
http://mazdatrix.com/b8.htm

Do a search on aluminum radiators and a bunch of stock car shops can build a custom unit for about half the AWR or KOYO. I had mine built by Childress Racecars in North Carolina. Faxed them a hand drawing with dimensions and in a week I had my radiator. with shipping about $300. double pass and I have never had any overheating problems. AWR and Koyo are better if all the OEM systems are to be kept. AWR uses Ron Davis cores which are one of the best(maybe the best) but are not cheap.

If you need something to bolt right in go ahead and pay the top dollar. I'm suggesting the same thing a few other members already have. I found a used Addco radiator from a Chevy powered stockcar for $75. I cut one hose nipple off and moved it to the passenger side with the other one(it was a cross flow). Half way between the hose nipples I cut a slot in the end tank, shoved a plate into the slot and welded it all up. So now I have a deluxe double pass 4 core radiator for under $100.
Oil cooling should be your bigger concern.
Hit the swap meets and save some dough.

I got a new custom made one that will cool with out any problems fro sale. ;)

https://www.rx7club.com/20b-forum-95/pettit-banzai-20b-radiator-sale-523477/

Koyo with an efan is the way to go.

is all of this based on aftermarket cores with thesame sieze core as standard or are we talking bigger? I'm going to have a custom one built as well but still debating about stock size core and thickness...

I built mine with a core that was the size of the opening, which is about an inch wider. If you use a double pass(so both hose connections are on the same side) you wont have any cooling problems with the same size as stock. they custom guys will weld on the brackets and all you need to di is mount it to the stock location. a couple minutes of measuring and a couple phone calls is all it takes.

Anyone who happens to know or has the AWR unit for a FC know the demensions? I want to know if a flex-a-lite fan measuring H-17.5 and W- 21.5 will fit the face, and not conflict with the upper hose connection

I know one of you guys has one. lets go with the info

the AWR unit is exact an replica of the OEM unit only with a slightly thicker core, so if it fits the stock radiator it will fit the AWR unit.

I use a koyo. Compared to stock it is huge. My temps have never went over 200 on the hottest of days on the street with the AC on. I haven't tracked my car, just auto xed. But it's worked well for me. I just had to shim up the Intercooler shroud a little so it didin't contact the fans.

Huge in the sence of thickness or is the core larger regarding lenght and width?

double thickness. Twice that of OEM. That's why you have to flip the brackest when installing it that come off the old radiator.

On my 1st gen I use a Howe aluminum radiator, available from summitracing.com for $250 at the time. 22" x 19" , 1.5" thickI think. Stant 25psi cap.

The bridgeport water was running too cool, I had to put duct tape over the rad to warm it back up.

the radiator is the same length and width so that it will mount to the OEM location. core is thicker for better cooling. it was designed to bolt in as the OEM with all threaded fittings for all OEM systems. don't know about installation procedures but size is the same as OEM.

i dont have access to my car, since Im in the middleeast, but what are the dimensions of the stock radiator (FC) I know RX-Heaven had a vintage air fan and shroud, and had to modify the shroud to fit alittle. Just checking everything before I purchased anything

That was a set-up CAR& came up with, search his posts, my Radiator is alot larger, so no use to you, on the fans which are twin FALs with a frame, and flaps. GL, Carl

proper ducting is the one of the keys to good cooling, You MUST decrease the under bonnet pressure, (more bonnet vents are good) seal around the lights and oil cooler to stop unsued air from entering the under bonnet area, increase the louvers in the undertay to suck more air out (becarefull not to let too much air under the car or you will have less grip)
Don't use the radiator or intercooler ducting to feed air to the airbox, (it will lower the air pressure in front of the radiator)
Make sure the ducting to the radiator and intercooler is sealing properly as the air will take the easiest path.

one of the other keys to good cooling is bleeding ALL the air out of the system and not having air locks.

another key is to have efficent water flow. If you have restrictions in the cooling system like tight bends and ill fitting hose work the waterpump can build pressure on the pumped side but will be sucking on the inlet side and this lowers the boiling point of the water at the pump. If the water boils at the pump the pump will cavitate and the problem is amplefied.

If using a front mount intercooler try to put as big a gap as practical between the cores (do not mount directly to each other) and make sure the ducting seals between the cores. With a gap between the cores the air has a bit of time to redirect the air before entering the second core.

If you can use seperate ducting for the intercooler and the radiator.

Intresting thing for the IC to radiator gap. I try to mimic what I see from RE Amemiyas street/track cars. One thing I have noticed about there white FC and FD, is that the IC is very close to the raidator. I have placed my IC only a couple inches from my radiator,moved my oil cooler up behind my front bumper, and cut the front bumper to match. I will be ducting from the front bumper back.

the other thing that I have found that helps is to have the coolers laying all most flat and have the air enter from the under side and of the coolers. Mazda is one of the few car builders that has done that in production cars. Heat rises so if the cold air enters under the cooler then when it heats up it rises and pulls more cold air in to replace what has risen. This works when the car is stationary without the need for fans, once the car starts to move the increased air pressure in the front of the radiator forces the air through. On cars where the radiator is standing verticaly when the car is stationary the hot air rises from both sides and fills the radiator duct with hot air and as soon as you increase the air pressure on the front of the radiator it has to push that hot air back through the radiator before it can get some cool air. This condition is tipical in stop start traffic and on a standing start to a race.