Radiator Upgrade, Questions
 

My rad has a crack and is leaking coolant, so i am taking the opportunity to do the coolant system correct. I do have an Automatic transmission so keep that in mind when answering. I need some input on what all should be changed out/upgraded.
So far the shopping list is
BHR Radiator
RX8 RE-medy Hi Flow Water Pump (04-08)
RX8 RE-medy Thermostat (04-11)
Looking for some ideas on any good hose kits for an automatic
also anything else i should do while I'm in there. Anything you would have done differently in your build or anything i should add to the list. Trying to keep it under $1500 But if i need to go over then i need to go over, just want it done right.

What are your goals?
What modifications have you made?
Are you a weekend track hound?
What is the climate like where the car is driven?

If you're NA with little or no mods, buying an aftermarket radiator doesn't really make sense to me. The OEM radiator is really pretty good.

If you're not tracking the car and it's being used in a moderate climate I wouldn't worry about the RX8 RE-medy stuff either.

No mods yet, and that's a big yet, I would like to play around with stuff later. I would rather get a good foundation for modding later. The only other things I have on the checklist of things to do after getting this all done is the BHR Ignition and Dual Resonator/catback. Which i will honestly probably just buy everything for that when i buy the rad stuff. I live in Central FL so Temps can get pretty high in the summer. If I'm going in the wrong direction here then feel free to point my the right way and i will definitely look into it

I beg to differ WCS. The stock radiator is a piece of junk. It does not have the cooling capacity for hot climates. I should know. The BHR radiator is an upgrade for the cooling system. Better cooling means less chance of over heating. Keeping the coolant temps down will also add longevity to the engine.

Keeping this engine at the proper temp is the most important goal you should have.

Lucky you, since you have an auto. I track my 2007 6speed auto, and drive in west Texas on hot days. After the first trans went out, I put a derail 18,500 btu tube type rad on the trans and got the temp down there lower 14 degs.

It keeps dragging the water temp down also, and last time on track during 85-90 deg weather the highest temp I could get on trans or water was 210 deg.

I hooked a scan gauge up and found the trans temp code off of a Miata site.

My whole install, and details are laid out under REDRX3RX8 auto trans cooling mod.

The cooler was about $48 from amazon.

Easy, would you mind commenting on what the differences are between the BHR rad and the Ron Davis rads? I hear talk about how the RD rads are one of the best (albeit coming at a cost), but I am unsure as to what exactly makes it different.

best one is the one from Mazda Competition, which is really the same as knight sports with a 53mm core (THICK) and it's a bitoch to install (don't ask me how I know)

for any rad to work, people really gotta transfer the foam properly (or just use whatever they can find to seal it up) ...


one thing to note (everyone) is that a "better" rad will not make ur car run any cooler, the lowest temp is always handled by the thermostat, NOT the radiator. what a radiator does is that (when it's working properly) will keep the water temp as close to the lowest temp set by the thermostat as possible. So yes, a "better" rad is better for your car. but for a street car (Which probably 90% of the rx-8s are) stock rad is mostly fine. change the coolant every year or 2 (and use higher H2O rate) might be a better idea.

The mazda competition radiator is a Ron Davis rad

if you are a DIYer, it might be a BETTER idea for you to get a good MT Radiator and fab your own AT oil cooler and mount it somewhere.

last I checked it was made by Koyo with different spec

but the price ... not so sure if it's worth it. meh. depends on how one look at things. it's 700 bux now :(

I paid much more than that for Knight Sports so ... :)

https://www.rx8club.com/rx-8-parts-s...-davis-227526/ :dunno:

I know about that one, years ago it was koyo tho, and the ones they sell in Japan are made by Koyo also

and I had Ron Davids rad before in my 8 ... and I swapped it out for Knight Sports, cuz knight sports has Z flow and cools better.

oooo ... i was always under the impression that the koyo was no-bueno. Gunna have to do more reading.

koyo is just an OEM, they make rads for other OE and will do custom rads for their customers.

Honestly I see no problem with using Koyo rad (yep I had it and it's still in my garage collecting dust lol) and I had no issues with it, people probably didn't seal the rad sides up couple years ago, overheated (for obvious reasons), and blame Koyo for everything. later they found it's really the sealing issue but never bother to correct the mistakes they made.

hmm.. you learn something new every day. I was looking at a koyo rad but disuaded by the people who said it was garbage.

You know what they say about opinions. There are plenty of guys in Texas that track during the summer on stock cooling components. It's the condition of those components that matters.

That said I have the Mizu multi row aluminum radiator (see Mizu thread), a dual FAL fan shroud setup, a secondary Derale cooler with a 6.5" fan unit (see build thread), the Mazmart thermostat and water pump, and this is with the added heat to the coolant that the turbo adds.

9krpmrx8 put in my cheap auto trans cooler, and the cooling is outstanding.

I measure a 14 deg f drop from inlet to outlet on it, and when I cruise on the hwy at anything under ambient 60 deg f. The engine will be 175-180, and the trans will be as low as 140 deg f.

It works great for me since I only drive in warm weather on the way to a track.

If you used as a daily driver, you'd have to install auto trans fluid thermostat or tape cardboard every winter.

*the more you know*

And 40w8 tracks more than any of us in his 6 port, 6 speed auto RX-8 GT and he is on a stock radiator, water pump, etc. His only mods are the BHR kit and the secondary trans cooler.

Ron Davis makes more than one radiator for the RX-8

The Motorsports rad is the same as the AWR rad ...it is very similar to the Griffin Rad that BHR makes

Ron Davis makes a dual pass quad core rad....that is huge ( I have one in my car)...but it is very pricey....over $800

For most scenarios...the one I have is overkill.....but it works well for my use ;)

^ aha, thanks for the clarification

the big one is code-named "mothers special"

Ordering
 

Thanks for all the info on the rad, I looked into everything and im still sticking withe the bhr griffon rad, I am ordering the parts tomorrow, Im ordering the bhr radiator, remedy pump and stat. Still looking for a good hose kit that has all the hoses (all the ones i can find only have two)BHR used to have a set, but i see its no longer there :( another question, BHR pipe + borla vs TurboXS kit and cold air intake, What would be the better choice out of the two, Both will cost about the same but I dont want it to sound horrible. Let me know, all orders are going in tomorrow.

So I have pretty much narrowed it down to the bhr midpipe either way, Any input between the borla and the turboxs exhaust? Pretty big price difference there, but that doesnt mean the sound is bad. Ive read on here that the turboxs is an awesome setup, But if the borla sounds better I will go with that. Im not looking for crazy loud, nice lows when idle and sounds nice on revs is the target