dmak_el

iTrader: (1)

Hi,

I just started tracking my car this summer. My car is pretty much stock with a k&n drop in, cat deleted pipe, ap pulley, a buddy club 1.3bar rad cap and a koyo rad.

I found that after about 10mins of lapping(between 70~90F), when i open my hood, there would be some coolant came out from the overflow tube and/or rad cap. The next day i check my coolant level, it will be low.

What caused that?? Is the car just running too hot? or i have a weak rad cap??

thx for any help.

Highway8

iTrader: (11)

Yes your car is getting hot but may not be overheating. The cap is doing its job and letting the coolant overflow. I also had some overflow on my last track day but it took until the outside temp was over 90 and I was almost 20 minutes into a run. My ECT reached about 230deg so I was about to shut it down or slow up. The stock guage showed in the middle but 230 is pretty hot for the 8. If you are going to track your car it wold be a good idea to get a real guage or a OBD2 display guage liek the MSD dashhawk or the scanguage 2. I dont know what the scanguage goes for but the MSD dashhawk is $300 but I can get it for $265 delivered. Also reads AFR and does data logging.

For info I have the stck radiator and stock cap. A lot of people are saying that the stock radiator is better then the koyo infact some people have gone back to stock from the koyo. The better radiator choice is the BHR or the mazmart although I have not heard the reviews on the mazmart yet.

swoope

iTrader: (5)

mine will spit a bit of coolant out. but that was in 90deg weather.

bad news . the koyo tends to be worse than stock..

so i agree with the highway8.

beers

dmak_el

iTrader: (1)

****...didn't know koyo is worse then stock

Highway8

iTrader: (11)

I believe the koyo has too many fins, so it restricts air flow and does not allow heat to be removed. I have also that an Antifreeze/water mix of 50/50 or 60/40 is best. The all with water wetter method does not seem to work for our cars. i dont have an experiance, just seen a few post about it.

dannobre

iTrader: (3)

I always have mine a little below the max mark otherwise it heats up and overflows a bit. If you are below low and still doing it you had better figure out where it's coming from....

TeamRX8

iTrader: (25)

the problem completely went away and never came back after switching to waterless Evans NPG-R coolant, but it's not for everybody ...

Highway8

iTrader: (11)

I have considered going to the Evans NPG-R what are the draw backs, if any, besides the high cost and what are the advantages for the RX8? How often should it be changed?

TeamRX8

iTrader: (25)

getting all the water out, just a cost factor more than anything else

if anyone adds water or standard glycol to the system inadvertantly (dealership etc) you have to start all over again

keeping extra around so that you don't have to put water/glycol in it for an emergency repair etc. and start all over again, adding water to it only eliminates the anti-boiling advantage and won't cause any other harm

change every 12 - 24 months depending on use, it's just a simple drain and fill procedure once you have it completely setup and water free

can freeze at -10 degF or lower

NPG-R

Highway8

iTrader: (11)

Have your tried pushing the envelope with detonation and been able to push it farther or do you just feel safer.

TeamRX8

iTrader: (25)

I pushed the NA envelope about as far as has been done to date

https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/all-turbo-talk-whats-highest-hp-na-rensis-153339/

Highway8

iTrader: (11)

Do you feel the NPG coolant allowed it to be pushed farther? or do you just feel more comfortable doing it because of the NPG?

I am considering going with the NPG+ for the added insurance.

dmak_el

iTrader: (1)

well, i have pretty cold winter up north...so i better keep the 50/50 mix.

so water wetter doesn't really work at all?? i was thinking trying it

Highway8

iTrader: (11)

I dont know the science behind it but several people have tested different mixes including all water and 2 bottles of Water Wetter. There test have shown increased cooling with a 70/30 or 60/40 mix (Water/antifreeze). Many people will still use water wetter even with the above mixes.

painoracing

Hi. Today was my second auto-cross event. I live in Puerto Rico. Temps were near the 98F. Different from my first event, today y used first gear in two corners. Better times almost 1.5 seconds. But, at first heat, had to enter after 4 laps because of big overheating and overflow. Second heat, still used first gear, but not for too long. Temps were better but got hi again and with overflow. My engine only have RB flash, catback and RB Revi. Nothing else. I used regular coolant. Nothing ot this happened in my first event.

Just thinking changing to regular water, with Waterweather (pink) and a radiator cap with more preassure. Any other sugestions?

Tks

dannobre

iTrader: (3)

Check that your fans are working properly

VashGS

Mazmart RE-Medy Hi-Flow Waterpump & REmedy thermostat installed?

Stock waterpump blowz at high rpm. This is like a 1979 part still till series 2 improved it.

olddragger

iTrader: (3)

read about evans coolant. True that is doesnt boil, but what are the temps the engine is experiencing using evans? The little info i can find seems to indicate that the overall temps, hot spots are not cooler but actually increase? If that is the case then what good is it other than allowing someone to finish a race without cooling getting totally out of control?
OD

painoracing

Yes. Fans were ok. They even are supposed to start sooner because of the RB flash. For the second heat we disconnected the a/c compresor so that the a/c fan would work all the time when turning the a/c on.

painoracing

After the event I drove my car back (it's my daily driver) and the temps were normal. Everything looked fine. I will considered your suggestions also. Tks.

Highway8

iTrader: (11)

True the overall engine temps can be higher because the NPG-r is not as good at removeing heat. However there wont be any localized boiling, which is what typicaly causes engine failure.

There are several threads about this and people are saying the renesis will warp or the seals will fail at XYZ temp. The stated XYZ temp may or may not be true with regular water or water based coolant that boils. I believe, (no hard evidence to support this) that without any localized boiling the XYZ engine failure temp will be much higher.

Without someone willing to push there engine temp to the extreme, we wont find out if this is true or not. For me, I will be aiming to keep my engine temps in the normal range and I have the npg-r as insurance. Maybe one day when I have money burning a hole in my pocket, I will plan to have a performance rebuild done and I will test it out and see how hot I can get it without failure. Thats a big MAYBE.

MagnusRacing

iTrader: (2)

Yes, a bit of coolant overflow/splater is very common when racing or tracking an RX-8.

Install a vented catch can (mine is a royal purple bottle with holes poked in it) and run your overflow to it. This at least will stop the coolant from getting all over the place.

painoracing

Tks to all for your suggestions.

I haved consulted with Goodwin Racing and Racing Beat, and followed your recommendations. I will do the following changes:

-Regular water and Watterweter (no coolant)
-1.3 radiator cap
-change the hoses for the RB silicone ones (for safety)
-Disconnect a/c compressor so fans will start at lower temp.
-Take engine covers off so air can circulate faster
-Develop some kind of lip under car to create low preassure and force air out
-Add some kind of catch can
-when using 1st gear, not hold it for too long

I hope this will help lower temps.

dannobre

iTrader: (3)

Also run your overflow down to the bottom of the rad..then it will run out onto the road...instead of all over your power steering connectors and the rad fans.....electrical bits, connectors and hot coolant don't mix

MagnusRacing

iTrader: (2)

Or please be considerate if you're running at the track and use a catch can