rx8dorifto

iTrader: (1)

wondering how good is our stock radiator. It looks pretty thick and made of aluninium. But not sure it has 1 or 2 core?

Anyone can share?

Easy_E1

iTrader: (2)

It sucks. Charles R. Hill has a better one.
The stock radiator does not have the cooling capacity it needs for the hot weather areas. As in Arizona. Coupled with the inferior water pump it fails above 110 degrees air temps. I speak from first hand experiance.

nycgps

iTrader: (1)

a Bigger Rad will NOT give you lower temp.

It just so that it have the extra capacity for *extra* heat.

If you're in hotter weather you should use heavier weight oil and more water than coolant. Say, a 70/30 mix. 70 distilled water, 30 coolant for anti-rust + lube the water pump.

Stock Rad is good enough for stock car.

To OP : stock rad should be single core, Koyo made should be 2 cores. Not sure about what CRH's will be. Fujita Engineering in Japan has 3 Layer Rad, and its Black.

Easy_E1

iTrader: (2)

^ You don't live here where 120+ and 10% humidity is not uncommon. And thats the problem ,, heat transfer. It reaches a point where it cannot displace the heat and continues to increase in temp. Believe me I have been through this with the Mazda Engineers. They spent three days with my car. They didn't speak much english either.
And four engines. New radiator and new water pump. Modifications to the air inlet section of the radiator. Computer logging,and whatever else they did.
And yes I'm useing 70% distilled water and 30% anti freeze. Right now the temps are not as extreme here. And the car is running cool. This coming summer will tell.

Phil's 8

iTrader: (3)

NYCGPS, listen to Easy_1 he speaks from first hand experience - he's had more new motors due to overheating than anyone I know. You live in a cool climate with lots of humidity and have no idea what we in the west with no humidity have for overheating problems. I've tried every water combination you can imagine and none did the job. The stock radiator has little heat transfer and seems to be designed for cool, high humidity areas. Actually 10% humitity that Easy talks about is high for most days over 115 as it yould be about 6% in Vegas. Thru past experience, I took several steps to avoid overheating when I was na (to no avail), but there was no way a stock radiator had the heat transfer area once I went FI, even with an aftercooler.

If your relying on your "gauge" to tell you when it's too hot, it may be too late.

chetrickerman

one thing i will say, is that you can use either tap, or distilled water. distilled water is only distilled until something contaminates it, like coolant. but if you are in hot temps 70/30 mix is better because coolant isnt as good at absorbing heat as water. some Red Line Water Wetter or Royal Purple Ice does good too

nycgps

iTrader: (1)

I know what he have been thru, I check this forum probably more than the owner and mods themself combine

Im saying that a bigger rad wont really help the problem, he can try the Fujita's 3 Layer Rad and its black, it should be able to help to get rid of the heat even better and faster, but wont really lower the temp (it probably will stay at certain level, but thats it)

Oh and if I dont rely on gauges to tell me its getting hot. what else should I rely on ? put my hands on the engine ?

Phil's 8

iTrader: (3)

I was talking about the stock "gauge". Some may not realize that it is useless. Notice I did not say a bigger radiator only one that transfers more of the heat. The Koyo model does nothing more than stock and I am not sure about Fujita as I am not interested in layering (cuz it suggests that heat transfer will be interfered with) just getting rid of the heat. Currently Ray's Black Halo Racing radiator is the only one that I am aware of that addresses my concerns.

Yea I was wondering if you were two or three people as I see your postings everywhere

nycgps

iTrader: (1)

Oh if you're talking about the stock gauge then yea its useless .... who saids Im relying on that, I mean really ?

I got myself a set of Defi quite a *while* ago

Koyo can hold more heat than stock I believe, they have a name in Radiators you know, just that this time is not as good. Mazda spent their time to do their homework in designing the Rx-8.

I want to try the Fujita's rad but its over a thousand bux ... and CRH is busy making our bracket support I believe ? so Im not sure when will his BHR's rad gonna be out.

Cant wait

P.S : Yes my posts are everywhere call me a loser. Oh hey, who is that in your avatar ....

Phil's 8

iTrader: (3)

You would be suppried at the 8 owners that think it's a real gauge. Is there any wonder as to why quite a few engines have been replaced? Of course that's not the only cause but a contributing factor.

My experience with Koyo and the 8 does not support your belief but then again I have an at and that may make a difference.

BHR will release the radiator shortly. He has one for the AT and the MT. Don't know much about the clutch bracket but it will be a little while yet. He has several irons in the fire may come together at the same time. I think that my avatar is why the clutch brackets have not been released yet, I think she has him cuffed.

El Kabong

So how does the humidity outside affect the cooling performance of my radiator?

It's obvious to me how the air temperature affects it. But humidity?

After all, if I'm in the desert, air temp 110 degrees, and I sit in front of a fan, I feel cooler (and my skin temperature IS cooler) than if I sit in front of the same fan in Houston at 110 degrees, 90pct humidity. That's because I perspire, and it takes energy to vaporize my sweat, and so the dry air cools me better.

Not as obvious to me how ambient humidity affects my engine, which does not sweat. I'm not saying it doesn't, just asking for clarification.

- Kabong

staticlag

humidity lowers performance of the engine because it displaces usable space in the air, but improves heat dissapation.

Which is why engines use water injection, or at disneyland they have those mist fans, etc.

staticlag

in response to the first question:

for the rx8 alternatives available right now: its okay. Can hold its own in mild to medium track environments, its totally fine for autox, start encountering major problems at 96+ degrees.

in comparison to other cars, this car sucks, can start overheating (212-215) at temps of 100 degrees F on the highway at about 80mph while on cruise control.

chetrickerman

you mean 100 degrees C?

staticlag

huh? no I mean ambient temps. Like turn on weather channel and it says its 100 outside.

Mazmart water pump is pretty essential upgrade.

The problem with the lower revs (like while in traffic and in cruise control) is that there isn't enough water going to the small stock radiator. It really can take a lot while its on the track in the higher revs when water is really pumping through it.

Like I have said in other threads, if you plan on running just the upgraded water pump on daily drive vehicles in hot climates, I wouldn't recommend an underdrive.

savedsol

Yes but who is it? Lindsey Dawn McKenzie? The Mazda Motorsports radiator is essentially a 3 row and costs $660. Mazda racing considers it the best. I'm interested in hearing the BHR specs.

Phish806

iTrader: (4)

My car woud tend to overheat on days 95+, on the interestate with the cruise set at about 75 or 80. After driving for a short time. Over the winter i added the mazsport cooling mod and added the AP pully which i later found out helps the cavitation at higher RPMs. I am still thinkin that i need to replace the radiator though just to be safe. Plus its just one of those feel good mods. Most likely goin with koyo or wait to see how things go with the BHR radiators before i actually decide and buy.

nycgps

iTrader: (1)

Human (or any living being) reacts differently to humidity.

Water can carry a lot of heat, and Engines does not sweat (it will be scary if it does ), when its 100% pure air with 0% humidity, Sure heat still moves out, but not fast enough.

Thats why when you spray water on some hot surface, the surface temperature will drop like crazy, cuz the water carry all the heat away into steam.

but why would you feel like **** on a hot humid day ? because there is a limit on how much water air can carry, if it reach 100% (or close enough), you have sweat all over you, The air simply cannot bring the water (which traps heat) away. So you will feel like ****. Thats why as soon as you wipe the sweat off your body, you'll feel 100% better.

For engines, which is mostly dry cuz its mad hot by nature, love moisture because they dont have water on them.

nycgps

iTrader: (1)

True true true ... the Mazda gauge is just ... Maybe I should email Mazda and suggest them to remove it, its useless anyway. (and the oil press gauge)

Aye Aye .... So many parts, so little money

nycgps

iTrader: (1)

Should I consider myself to be lucky ?

I had couple of 100f days last summer. Engine still works I had no gauges back then so I dunno what was it like on the water temp.

This coming summer Im gonna keep an close eye on it.

Socket7

So as one of those ignorant 8 owners who thinks the temp gauge means something, Why is it useless? I mean, i know it doesn't show an actual engine temperature, but it will continue to sweep upwards as temperature rises above normal right? Or is it that by the time the temp has risen enough to effect the gauge you're already screwed?

Sorry for the threadjack.

StealthTL

iTrader: (1)

Yes, it does work, but it has a huge 'dead band' in the middle, where it always shows the same reading.

But you are right, when clouds of steam are pouring out from under the hood, it will show 'Hot'.......been there, T-shirt aquired.

S

Phil's 8

iTrader: (3)

I don't think I called anyone ignorant, maybe missinformed but not ignorant . Stealth answered you question. Depends on where you live but at the lease an investment in a ScanGauge would be OK. Will not keep you from overheating but at least you'll know before the steam starts.

MyRXdrug

Man, you guys are talking about overheating, while my 8 can't keep enough heat in -23 degree weather to keep me warm!

Phil's 8

iTrader: (3)

Do they have roads at the North Pole?