sammytcl

iTrader: (1)

skyse3p and i have the same oem front but my whole front grill has been drilled out. mazdaexe has the autoexe front

the blitz unit actually can show the intake air temp and outside air temp, but for some reason, with the interceptor-x, it doesn't work. it will work on stock ecu though.

if scott see this post, please let us know if the wiring of the interceptor-x has anything to do with the intake air temp and the outside air temp readings not being shown correctly from the obdII port, and if there is a way to fix it. thanks in advance.

sammytcl

iTrader: (1)

i am running idemitsu 20w50 with premix.
skyse3p is running idemitsu 10w30 with premix.
i am not sure what mazdaexe is running.

TeamRX8

iTrader: (25)

don't waste your money on that so-called water-based racing coolant, it's just bling-bling marketing in a jug

MazdaManiac

iTrader: (3)

I thought you were an advocate of the Evans stuff?

TeamRX8

iTrader: (25)

that's not the same thing, he bought some water-mix glycol from Japan



edited my previous reply to say "water-based"


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AMG-RX7

That is an issue that I battled with on my FD for a while. Once you go to a thicker rad, you DO need to worry about the ability of air to make it through the rad. Battery relocation and eliminating other stuff behind the rad that can choke air flow helps a lot.



Another thing that helps a lot is proper ducting. I don't hear any of you guys talking about that but it is very important. I don't know how extensive you guys have tried to duct and seal your radiators but do try it. I tend to use cheap sheet metal bought from Home Depot to fab the ducting that I have done on my FD. Air takes the path of least resistance. Give it an easy way to get around your rad and it will do it - rather than go through it.

Vented hoods can also help depending on where the vents are. Shortly after the radiator is good to have. Too far back and it sucks in air rather than expels air. This is the last step after doing all the other things you can do to improve cooling.


On my turbo FD, I battled with heat issues for a couple of years. After some trial and error, a custom V-mount radiator and intercooler setup is what finally fixed it for me with the addition of the Re-medy water pump and some ducting. I was at Buttonwillow 4/26-27/08 with NASA. We had 90 F ambient temps and my car stayed cooler than it ever has at 96C on Sunday's second and third sessions. I have some minor ducting for the IC and rad in the more critical locations but still need to finish up the rest of the ducting that I want to do. I'm a HPDE3 level driver fwiw. Looks like some of you might be more talented than I.

The engine bay, and as a result the cockpit, also stays a lot cooler with this setup.

Here is some input I posted recently.
https://www.rx8club.com/showpost.php...&postcount=567

olddragger

iTrader: (3)

good points---ducting is very important and blockage also. I have been speaking of the blockage in the 8 for a long time.
Simple things also---remove the front rotor symbol (i call it the bucktooth) you will be surprised at the increased airflow without it.
FOr years i have been interested in an electric water pump and a better thermostat(we need a barrel type).
And pay attention to the temps in that second rotor!
olddragger

mazdaexe

Update / Correction on my info.

I actually have a koyo radiator. And I actually went up to 240F on the 4th (not 7th) lap in the 3rd session!. Sky was actually right behind me all the time (Im guessing I should have blocked some of his airway), but he only went up to 230F.

Im not on stock coolant, but some other brand. I forgot.. will update when I remember.

Going to try put the stock radiator back on and check the temps again.
Just doesnt sound right that Im running hotter than Sammys Turbo'd 8...

LionZoo

I don't have real gauges, but at Buttonwillow a month earlier in 100 degree ambient conditions, several guys had cooling issues while my car ran fine and had no boilover. My car has the Mazsport mod, the Mazmart pump, 80% water mixture with water wetter, and a 1.1 bar Mazda Millenia coolant cap. All day, the pressure in my cooling system wasn't even high enough to cause the coolant cap to vent.

MazdaManiac

iTrader: (3)

I will bet $5 and a six of Franziskaner that its the Koyo making it hot.

olddragger

iTrader: (3)

i have ran road atlanta --20 min session on a 106F day with over 50% humidity, temp on the tarmac was over 140F-- alternator got so hot the belt edge actually frayed. Coolant temp never went over 215F---oil never over 225(this was before I was fi'ed). the surface of the alternator was as hot as the coolant!
one secret is to keep rpms down. that 8-9.2 range generates a lot of heat.
olddragger

MazdaManiac

iTrader: (3)

That is interesting.
I shoot the inside of my engine compartment with my laser thermometer all the time and the alternator is consistently the hottest thing in there, often by a huge margin.
I've seen the body of the alternator get up to 280°F while the rotor housings were only 210°F.

sammytcl

iTrader: (1)

thanks for the correction steven. first post updated.

sammytcl

iTrader: (1)

after reviewing the video clips, i just realized that, for some reason i shifted mostly between 7500-8000 rpm that day, so my water temp should get higher earlier and a lot more back fire if i would have shifted between 8500-9000 rpm!

AMG-RX7

One other thing about my setup. When I went V-mount rad/IC, I had my Koyo reworked to be a dual pass rad. A dual or multi pass rad might help the FI guys a bit. If they don't already make a dual pass rad for the 8, let me know and I'll look into getting one made.

sammytcl

iTrader: (1)

koyo doesn't have it in the US market.

olddragger

iTrader: (3)

nope.
About the alternator--I wonder if a fan could be added to it and if so how much help would it be. Sounds like anything may help!
OD

Red Devil

^^^
vented hood and belts with stronger, more durable backing (don't know off the top of my head the specs of Mazda's belts)

TrochoidMagic

ok, so correct me if i may sound like i'm bringing out the basics which maybe everyone may already know.

-water boils at 212deg., and is affected by altitude. so 212 at sea-level, correct?
-coolant. its function... not ANTI-FREEZE, effectively raises the boiling point.

what i'm trying to get at is...coolant's function is to raise boiling point. so why are so many swear by running "waterwetter" to pure water or a ridiculously high water-coolant ratio? if it in fact is just a slightly more effective coolant, one bottle is still not enough.

water bubbles, and boils so quick...why run more of the stuff? 80/20, 90/10, whatever... its too low for coolant to effectively do its job, no?

if people think i'm smoking crack and choose to stick with the cleanest water like it makes a difference in cooling better... than i got a gallon of evians i can exchange for the motul brake fluid you got there... =)

those who are racing and out of warranty... why not try some 100% propylene glycol from evans?

BlueRenesis82

Well, the problem is that people like me that live in the Midwest would have to be draining their coolant twice a year, which may seem like no big deal, but coolant is expensive, and it does make a HUGE mess if you don't get it setup right. So you could go all water, but the seals on the pumps and everything else need some additional lubrication that just water does not provide.

Detrich

AMG-RX7

Its a bit more complicated than that.

The cooling system is pressurized. When you put water under pressure, this raises its boiling point. The presence of coolant / anti-freeze, water wetter etc also raises the boiling point. Water dissipates heat much faster in its unmixed form than when mixed with other fluids or chemicals.

I used Evans for a while and it does the job in extreme heat environments. Oddly enough my car ran 1-2 C cooler in highway cruise situations running Evans. Its still a pita and doesn't smell that great and its a bit pricey and hard to replace so I went back to water/coolant mix.

Check out this cooling thread: http://www.rx7club.com/showthread.php?t=571088

LionZoo

That's why I recommend going to a higher pressure cap if you go to a higher water mixture; the higher pressure prevents the water from boiling as soon. I run a 1.1 bar cap instead of a 0.9 bar cap to effectively raise the boiling point a bit. Of course, you have to pay attention to the condition of your hoses; running more pressure might expose your cooling system to more pressure than it's designed for, but for now everything looks fine on my car. I think heat is a bigger factor than pressure in the demise of stock rubber hoses anyway. Nonetheless, if you have the means I'd recommend uprating your hoses when you go to a higher pressure cap.

MazdaManiac

iTrader: (3)

It is interesting to note that Mazda went to a 1.1 BAR cap on the previous rotaries to cure overheating issues and puts a 1.1 BAR on just about everything in the product line.
The RX-8 has a .9 BAR for reasons of which I am not aware.
Probably had a bunch in a bin somewhere and was cutting costs.

Jedi54

iTrader: (7)

MM: what do you recommend for upgrading hoses?