kevink0000

Blu,

Stop and try what I propose. It will cost you about $150.
Put the second radiator in front of the factory one, don't overthink it, spaced out about 2" if you can, or in a semi- laydown position, plumb in parallel or series depending on the size/flow of unit you get. You will get more benefit than any of the other changes you are considering in your post. In fact, you would probably have to do no more modifications for cooling at all after that. There is more air available there than people think.

TeamRX8

iTrader: (25)

I'm assuming you meant the FAL490, and would suggest this; install a remote switch that forces the fans on high speed, which means they won't be regulated on/off or turned off above a certain road speed and then report back to us. You would need to block off the 2nd radiator to verify it though.

If you need help understanding how to wire that in let me know, it's extremely simple. There are some other things I posted way back when which you don't have listed, and then just stopped telling people because they won't listen any way. Because a racer or two has reported not being able to get up to temperature on track even on a hot day. Which if you're as smart as you think you are means it's not the actual components that are at fault, but it's the final configuration of them that matters.



.

kevink0000

Team,

The fans are on high at all times in the summer. The ECU is not in control of them at all when I am running it this way. I had the stock fans running the same way previously. I installed the FAL490 (yes not the 480, you are right I had to check my orders, it was 2 years ago.) after installing the "first" 2nd radiator, and did not notice any large difference in running temp, or cooling capability after max thermostat temp was reached and surpassed. I exchanged the "first" second radiator for a 3 row second radiator of the same size, and got slightly better cooling, but ultimately felt in my case that a larger radiator than even this is warranted, which I will be installing on my other car. Again this is a setup for the extreme temps here in AZ, that I definitely feel can help racers at full power for long periods on hot tracks, whose posts about high temps are all over the place on the forum, with all the mods and venting, etc to try to mitigate, with little benefit that they report.

Additionally, my other RX8 exhibited a similar lack of cooling performance before the engine completely failed, it had the stock s1 system, and did not maintain thermostat temp going down the highway at 75-80 mph on 90 degree+ days. This was exactly similar to the operation of the 2004 rx8 I acquired from my son, which had a Koyo 2 row already installed.

I would like to hear you explain how the racer you mentioned was not able to get up to temp? What configuration was he running?

I would like to hear your explanation of what test you would like to see me perform on my car, and your theory and observations behind your request.

zli944

Installed the 54mm Koyo and it's been great so far, though ambient has been significantly lower since my Thill West day. Also put in fresh FL22.

Seems like the car doesn't break the 206F point anymore, as soon as the high speed fans kick on, it'll drop back to 190s to 200s. This was seen at Laguna and Sonoma, though ambient was at most, around 65F.
And for reference, I left the exhaust side foam off, while adding AC foam to the top, bottom and side (OEM config seemed to be missing the top). I also installed a BHR midpipe, but not sure if that has any significant effects on ECT.

Anecdotally, I've heard that dual radiator setups basically solve any cooling issues you may have.
If the summer temps end up being an issue, maybe i'll mirror something like this:

https://www.rx8performance.com/produ...adiator-system

TeamRX8

iTrader: (25)

hopefully without the catastrophic leaking core failures …

blu3dragon

iTrader: (1)

Sounds good. You really need to test it back at Thunderhill though. Dropping ambient from 100F to 65F will drop coolant temps almost as much.
For comparison, my last session at Sonoma coolant peaked ~189F on track in 66F ambient, but that same setup reached 220F at TH in 100F temps, and would have gone higher if I had not started backing off.

I'm actually trying to figure out a transmission cooler now.

slipshoddon

I installed the Koyorad and like you, not sure it helped a great deal. The fit was good, just a little tighter due to the larger size. I also live in Texas, and we are hitting 98/99 at this point so it's going to be a hot one. I have the low temp thermostat and flashed the primary fan trigger to 180 degrees, and the secondary fan trigger to 193. Also stuffed pipe insulation on the sides to prevent air from escaping around the radiator (similar to the OEM unit).

Even on a very hot day my coolant temp is generally below 200, and occasionally bumps up to 203/204, but drops back down below 200 when you have to come to a stop. Can't say it's a lot better but probably no worse than the OEM and it is all aluminum. I don't recall what I was running last summer that had milder summer temps.

TeamRX8

iTrader: (25)

if you have the OE fans then dump those for the FAL kit as discussed earlier. I would set Fan 2 lower as well, no more than 190 and as low as 185.

waiting until 193 is like waiting for the train to already be running away downhill before applying the brakes. Better to nip it in the bud early. If it takes both fans then let it have both. Because don’t forget that it has a thermostat to help out on the low end. All it really means is the fans cycle more and it might cost some minor gas mileage percentage. That’s what the fans are for though.
.

kevink0000

Fans are at best an incremental improvement if you plan on running any kind of power in those temps. Put in a second radiator. I have two 8s that behaved exactly the same temp-wise, and now the second one is getting the second radiator treatment. Above 90 degrees the stock system loses ground quickly. I waited until the temps rose here in AZ with my second car, and it proved to me again what the first car did. This chassis needs more radiator. Below 85 degrees or so, its actually acceptable in normal driving, so not everyone needs to do this. But, more power, slower speeds, higher ambient, and you find out what little margin was designed in.

If you are voluntarily shutting down due to heat, then more fan won't do the trick (assuming stock fans are not inop).

TeamRX8

iTrader: (25)

maybe consider the source.

this was an RX8-REW making 500+ whp with a factory RX8 waterpump, Mishimoto t-stat, Koyo S1 radiator, and FAL fans (zero foam stuffing btw and no undertray either) that the previous owner had cooling issues on with the exact same parts; 16 back-back 1:1 gear - 4.444 diff - 25.5” tires (137mph top speed) dyno runs and it never even came close to 180°F despite some crappy small fans blowing at the front of the car and the engine bay being heat soaked to near death.




.

kevink0000

Yes, consider the source.


Come to Arizona, homeboy.



The radiator on this car is too small, period. You can mitigate by gutting the engine bay, adding better fans etc. but, More Radiator Needed. Eventually one other guy will try it, and then another, then another, and it will become standard practice. The stock radiator size is too small, plus there are packaging issues in the engine bay.

TeamRX8

iTrader: (25)

Yes, Arizona is quite hot. That said; I’m in Texas the same as him, was previously in the Nevada desert with my RX8, have competed over most of the US48 in an RX8, and the previous owner of the example above was in central Florida. Never mind that the example engine is likely making 3x more whp than your Renesis. Yet you think it all comes down to AZ vs TX.

My position has never been that what you propose isn’t doing what you claim. My position is and has always been that you still fail to see to know and hear to perceive how to address it differently. I know you tried many things. I also know that you refused to see or hear me out from the very beginning and have concluded there was no way for somebody else to reach an understanding that possibly did, and still is, eluding you.

To the point that even the example above is discounted in entirety.
.

kevink0000

I didn't ignore it, its interesting, but only tangentially relevant. I don't see any elapsed time notation or ambient temp figure. I probably missed it again. Maybe you can enlighten me with those facts.

And this:

Did you have the AC on while doing those pulls? Does that car even have a condenser in place?

Was the a/c removing thousands of BTU/HRs of direct sunlight heat from the cabin during those pulls?

Were you in stop-and-go traffic for an hour in between those pulls?

While you were in stop-and-go traffic in between those pulls, was your car absorbing the radiator heat from the dump truck with the hydraulic fan in front of you?

Were you running the stock tune?

The hood was closed, right?

Of course you were on pump gas. No alcohol?

It's not an AZ/Texas thing, it gets hot elsewhere too.

I own a lot of cars down here, and maintain a few more for others. No other vehicle that I have driven in these conditions was engineered with less cooling margin than this one. This includes cars built in the 80s to current day. Its very obvious when you have seat time in multiple vehicles at high ambient temps.

You can spend $300 on FAL fans, and another $350-$700+ on a Koyo or dual pass radiator, take apart the engine bay, relocate the battery, and still not solve the problem.

Or, you can buy $150 or less, in parts, spend an afternoon fabricating, leave the engine bay and tune alone (if you want), and never have to shut down when making high power in the heat again. And also enjoy lower oil temps, because when the "keg" is hotter than it should be, the load on the oil coolers increases to where they then lose ground also.

The reason why that solution is cheap and more effective than others, is because it solves the root cause of the problem. Not enough radiator area as delivered by Mazda, for the airflow allowed by the stock setup.

How much do other "solutions" cost? How much did you spend?

Since you say I missed hearing you out, and my perception is flawed, etc, (recall that it was you who never answered my questions from last year) why don't you get specific and tell us all how you do?

TeamRX8

iTrader: (25)

you only speak the things you know of, being unable to speak of that which is still unknown to you.

I do understand what you’re saying, but as usual the relative magnitudes are being grossly misperceived.

A renesis engine under part throttle loading even with absolute maximum btuh AC loading is no where near the btuh loading of 500+ whp.

There are other things contributing to your situation that are still unrecognized on this forum. Knowing me as you do, would you believe me to intentionally lie or otherwise be untruthful? If so then your spiritual discernment tank is bone-dry empty.
.

kevink0000

Another word salad. I asked you for specifics, you declined. Keep it simple.

Moving on...

TeamRX8

iTrader: (25)

Your perception fails again. The opportunity to seek and to find, to ask and be given, was always before you. It was never in your heart about this any more than anything else though, but instead to engage me as a contemptuous man who only hears and knows the world. So of course it’s a word salad when there is neither an eye nor an ear, but only the belly. Just as the men of the world, you would rather saw me asunder the same as Cain, Ishmael, and Esau would do.

again I proclaim unto you … as bone-dry and as empty as Gehenna. In darkness you contend, and in darkness you remain. For he that does truth, he comes to the light. Therefore I shake the dust of your town from my feet and depart from it; anathema maranatha.
.

kevink0000

Like I said, moving on. You are too.
Too bad.

This is a car forum.

kevink0000

The 480 includes a fan controller, the 490 doesn't. If I remember correctly that is the only difference.

slipshoddon

I don't agree. You made this point earlier to me and I have the primary fans at 182 and secondary fans trigger at 193. With the Kororad S2 radiator and the OEM fans it is working perfectly. I'm in Texas and it is hitting 100 in the afternoon, but my coolant temp never gets above 195, but is typically between 185 and 190. So my conclusion is the Koyorad is a good product, especially since it is less that the OEM radiator and has no plastic. Alos, I looked at the FAL kit, they are nice but are 4 inches deep. I don't think they will fit with the Koyorad radiator and not necessary if you can set the temp triggers as I did..

TeamRX8

iTrader: (25)

unlike yourself I have no issue being wrong and admitting so when applicable

and the mystery of iniquity-based deception response aside, I’ll be more than fair and offer a first step in the process of getting the truth straight; consider the water pump inlet and whether it’s preferred to have only cooled coolant or hot coolant enter there.

but perhaps you may deceive yourself further relying on the testimony of both fleshy men and the world instead, yourself included.

again, the gall and the bitter root of wormwood you choose to accept in your fallen heart over a servant that does possess the testimony of *you should well know who, but the forum rules do prohibit me from clearly saying* does both deceive and consume you. Oh how you do err Kevin, and to your own demise. 😭
.

kevink0000

Ah, at last something tangible to discuss.

I am leaving out any refutation of your comments deliberately.

I am aware of the coolant bypass, (there is effectively more than 1 if I remember correctly).

I left it alone because I could not find a valid reason for its inclusion, and since I didn't understand the reasons the factory used it, ( quicker warmup for emissions was not enough for me) I decided not to change coolant routing, which I feel is a more invasive modification than adding a radiator, since it could affect local temps in the block in an unknown way.

In addition, I determined that in absolute terms, the radiator size was too small to cool the engine with the HP it makes as delivered. So, I went that route.

If you have more info then let it rip.

TeamRX8

iTrader: (25)

let me go ahead and make a plug for Mazdatrix with a picture, hopefully you’ll be healed from the blindness that was keeping you from seeing it


funny how you also overlooked the big condensor in front of the radiator on the example vehicle that was processing 500+ whp of over 380°F intake flow discharging from the turbo compressor and rejecting that heat onto it, again with just some crappy fans blowing through it as opposed to the 100+mph speeds if it had been out and about rather than strapped to a dyno …

trust me, there’s plenty more, not that you’re going to do anything but contend against the truth to the bitter end
.

kevink0000

last post missing bump

kevink0000

I never saw the example vehicle, I assumed there was an IC on it, but again I don't feel that was a good comparison.

I think we can both agree the stock radiator size will not support 500hp for an extended length of time in high ambient temps. The math isn't there.

I know what the coolant neck looks like. Do you know why the factory routed those bypasses?

kevink0000

Update:

On the second RX8 with an added radiator, I waited until temps were high here in AZ to see the stock system overloaded and heat soaking daily, in normal use (some hwy, some stop and go, grocery and food stops, etc, lots of time for heat soak.). The stock system starts to give ground in the high 80s, and then continues to rise with ambient temp in my experience with two cars. One with a Koyo, and one with an inexpensive plastic end tank Denso S2 radiator. Both showed very similar behavior. If you are asking for power, the temps rise very quickly and come down very slowly.

On this car with the Denso rad, I added an aluminum AW11 MR2 radiator in a semi-laydown position in front of the normal stack. I was able to try both series and parallel plumbing with this setup, and I found parallel to be possibly slightly more efficient with the parts I used. I can somewhat accurately judge the temp drop since I drive about the same loop everyday, and while still not perfect in my view, I am getting about a 14-16 degree reduction in temps at peak, sometimes more with extended highway running. Still not maintaining thermostat temp, but I hope to improve this with some better ducting I am going to try, which right now is non existent. Also, the A/C still works well. All the stock parts are in the stock positions in the engine bay, and the stock 195,000 miles fans are still in place.

As I have said more than a few times, this car needs more radiator. Not everyone lives in these temps, and YMMV, but if you are racing and are having to shut down still, even after spending $$$ on fans and the best replacement radiator available, you might want to look into more cooling capacity. If it helps me in the summer 105-118 for normal driving, it will also help you on a 92 degree racetrack under power.