So after a few hot laps (no pun intended) how hot is too hot for the water temps? I have a power FC that reads in celcius.

 

I should also mention that I have a fluidyne radiator, fan bypass running, aftermarket stock mount intercooler, an aluminum AST...no cats either .

 

230 is too hot. If you start to approach that, you better get off the track.

 

So like 110c is OK I'm guessing? I've just never seen it get above 95 on the road so I was a bit worried. Sounds like I'm good then?

 

110 is NOT OK!!!!!! 110 is too hot.

Dont guess at your conversion, look it up:

Celsius Fahrenheit conversion

95 is low for out on the track. If you can keep it that low, you will be an FD hero!!

 

Where are you measuring this temp-- you may have contamination from nearby heat source (header perhaps).

The answer depends on where you are measuring, if the fluid is boiling, what radiator cap pressure, what is your oil temp

If your oil temp is under 275F, you are OK, but your coolant should not be boiling.

Make sure your rad fan is working. If you are consistently seeing these temps, you need more cooling: bigger rad and fan, oil cooler.

 

Oh, gotcha. When you stated 230 you didn't state F or C so I assumed we were talking the same language. Good to know.

Yeah the car seems to do fine as a normal driving car but on the track it heatsoaks like a bitch. I have the fans bypassed so I can keep them on constantly but being in boost almost 100% of the time makes it heat up like crazy.

I was measuring the water temp at the Power FC Commander.

 

My car also ran way hot on the track...even at 10psi i couldnt keep the temps in check. Wrapping my downpipe with DEI titanium wrap has kept my temps on the street as stable as i've ever seen them. NEVER gets hot, hit 185* today goofing off on side roads...If you're running an unwrapped DP it may be contributing to your issue.

I've kinda come to the conclusion that stock mount hardware with 100 more hp than stock with twins will not stay cool on the track on a hot day, ever. Need a full v-mount setup with vented hood to keep temps in check.

I saw 240 a few times before hitting the pits only 5-7 minutes into a 20 minute session on a near 100* ambient day. Car could not stay cool running only 10psi as mentioned before.

Jason

 

I can't imagine this is a good thing. Unless this is a common practice to have the fans on when your driving above 30mph (since the majority of fans on cars from the factory can only simulate 30mph movement), they're going to cause more harm than good. With the fans moving, you're actually creating resistance to the air moving through them. Above 30mph, the air trying to go through the fans is moving faster than the cubic feet/minute the fans can actually provide.

It may seem kind of confusing, but if you're going above 30mph, the fans should be off.

I can understand having a switch to activate the fans while you're going slow in the pits or when the car is stationary. But when you're at speed, they shouldn't be on.

 

I have had mine up to 114c at the track on occasion and its been fine in the five years I have owned the car. I would not recommend letting it go above 105, although in the moment I know its hard to let off. I find myself thinking "ok one more lap" in those situations.
Usually a cool down lap will bring it back to where it needs to be.

Fans, I have mine hooked to the AC and turn them on when I'm above 90c.

Whats interesting to me, here in Cali. The track that makes the most "heat" for me is Cali Speedway with the Roval. You would think Big Willow because it has an incline and is all high speed, but I am fine there.

Texas is pretty hot, are you running on one of the Speedways there?


Seems like with your setup you should not be running so hot, I am because I have FMIC and it blocks the radiator.

Do you have an undertray? I drilled a bunch of holes in my radiator thermostat and that helped but its not the proper fix.

 

My temp gauge on my stock car is also in degrees Celsius.

70-80C too cold, thermostat has only just finished opening (I have put my temp gauge in at one side of the thermostat so I can always see it open at around 60C. If I dont see it open, I can then deal with the issue before any harm comes to the engine)

80-95C not a bad place to be, if you can keep it there. I too have manual control of my fans by tying them to the AC switch (in addition to their normal mode also)
I will activate the fans at anything above 95C with the re-purposed AC button if they are not already activated. I will de-activate them when the temp has come back down to 80C. Rinse, repeat.

(The hottest I have seen is 110C after soaking in traffic and then a long slow uphill pull, on a hot day. That is too hot for my liking.)

96-110C You dont want to hang around in this area if you can help it. Too hot, too much heat soaked in, too hard to shed the heat, takes too long to get rid of it, and risk increases. I turn the fans on at 95C to avoid climbing into this area.

When I park, I open the hood to get the heat out and save the plastics.
Still daily driving the original 1992 engine, still with good oil pressure and good compression, does not overheat or consume any water

 

Once you see 100c it's time to start short shifting and taking it easy down the straights. In a mostly stock FD this will occur after 3 or 4 hard laps LOL so there are several things you should do to help with the temps.

Use 100% distilled water with 2 bottles of water wetter and be sure your radiator is in good shape.

Pull the bumper and remove the front grill so you can do the shark tooth mod (do a search).

Make sure your undertray is in good shape or sealing nicely at the bottom of the radiator and also add some extra duct pieces to either side of the oem duct to block those openings

Add a second oil cooler if you don't have one and make sure they are both well ducted.

At 10 psi the above should fix your water temp issues.

PS Just wanted to add that you should slow down at 100c because that's the point of no return or the temps will become uncontrollable or keep rising until you really slow down or have to back off considerably. It's been said that 117 or 245 and higher or so could damage your engine because at those temps the irons and aluminum cool at different rates and this could warp your aluminum housings causing a coolant leak this is also why it's important to let the engine cool slowly and not just come into the paddock at 110, shut the car down and hop in your students car.

 

From first hand experience, running stock will blow your water seals. It's only a matter of time

 

An older but still good thread:

https://www.rx7club.com/3rd-generati...ionale-136678/

 

Yep lots of info in that thread

Several things I'd now add at this time:

go vmount or go home for the serious track guy there is no reason to mess with anything else. It's truly the best way to control both charge and water temps.

As far as turbos go it would appear the borg warner with built in wastegate, bov etc.... is likely our best option there.

The PFC is still the a good choice for ECU on a basic track car making around 350 HP but I keep hearing more and more good things about the aem

Trans and diff both need coolers.

Once all the above is done the FD should be ready for some hard track work.

 

Good thoughts and I can see the logic. I've never really thought about it that way. I usually run the fans when I'm stuck in traffic or sitting idling as the temps start to rise when the car isn't moving.

Do you think with the fans OFF at the track I would have done better with it staying cooler?

My SS 3" DP is bare so wrapping it is likely a good idea. What's the best stuff to use? I've never dealt with header/DP wrap before so I have no idea what I'm doing. I'd imagine the stock turbos are a lost cause in terms of any wrap or turbo blanket stuff. When/if I go single that will be a consideration though.

And I'm running 11psi so just a little more boost than stock.

Thanks for the link.

And thanks for all the responses guys.

 

Also, I'm running the stock dual oil coolers. Is there something better?

 

On my track cars I keep the oil and water temps under 100c. If your oil is over 100c your water will follow it so dropping the oil temp will bring down the water temp

 

I think consensus here has been that 240 F. (115 C.) is about where the stock coolant seals start suffering. I don't think coolant seals care if you're on a track or driving past your house.
Consider a boost-activated water injection system. Carries a lot of heat out with the exhaust and reduces load on the cooling system. You also knock suppression and carbon control. All but eliminated temp spikes I used to see after periods of hard boost.

 

You might want to list what all has been done to the car currently...

 

I thought I had. The stock oil coolers, Fluidyne Radiator, SS 3" downpipe, stock twins, Rotary Performance midpipe with highflow cat, 3" catback, Aluminum AST, PF SMIC, 2200cc Injectors, Apexi PFC with Rotary Performance tune.

What is recommended for coolant and the ratio of coolant to distilled water? I wonder if I might benefit from a full flush.

 

The biggest problem with your setup (heat wise) is the stock twins. Frankly, they are just a full on nuclear reactor under the hood. Anything you do without switching to a single isn't going to make a huge difference over what you already have currently. Switching the twins out for a single will give you the biggest benefit. Pick a turbo that will give you the power you want at a lower boost setting. This will allow you to keep from working the turbo hard thus keeping temps down.

You might also look into a lower t-stat:

Thermostats

Upgraded water pump:
https://www.rx7club.com/3rd-generati...low-hp-735888/

If you don't have underdrive pulleys, I would recommend looking into them for the track since it will help with cavitation of the water pump.

A low as possible and still handle the conditions in your area.

 

Definitely a v-mount setup and ducting. I like Rotary Extreme's.
I'd also do a 180, 160 or remove the thermostat altogether if needed.

 

a valuable thread...

"running stock will blow your water seals. It's only a matter of time"

the aluminum rotor housing is in a difficult position... the top half sees only incoming air and fuel, which is fairly cool, while the lower half sees only significant combustion pressure and heat.

(slightly off topic but... the top half/bottom half heat situation is why the heat treat on the irons is different top to bottom)

aluminum is near the top of the list of materials as to heat receptivity.

if you run too hot the lower half of the housing width expands while the upper half does not.

the first item on my 6 page Spec Sheet is rotor housing width measured at the top and in 3 spots near the spark plug.

Mazda Spec is... if there is more than a .0024 width diff between top and lower the housing is not serviceable.

that's because under load it will not properly support the coolant seals.

i see around 10% of the incoming motors failing this spec. of course it isn't the 100+C coolant that warps the housing, rather it is the combustion chamber pressure (CCP) and combustion chamber heat (CCH), but the coolant temp is the indicator and needs to be respected.

since FDs make so much power from 1.3 L heat management is Job One.

Howard

 

Yep twins are hard on everything but can be used with proper prep

Peter hahn has run 99 twins for 10 years plus with no heat issues

Based on 8k shifts:

stock thermo is fine

stock water pump is fine

stock underdrive is fine

don't need the idler pulley if you keep the stock underdrive pulley just use a good belt and a good pulley and you are good to go. You know it's wearing when you start your car and get a squeak for 10 seconds until the belt heats up after slipping, so either pulley teeth are worn or belt or both

Things I've experienced recently: using oil only cooled turbo surprising lol will bring oil temps up quite a bit so go with combined coolant and oil turbo if possible. Can still be dealt with if you have big coolers and good ducting but you will still likely rob the engine of some power when it's hot like 90 plus degrees

Have yet to loose a good engine from heat, it's always apex seals warping which occurs at 5 to 7k and the engine still runs just low on compression/slow.

Howard, not sure what ccp and that other 3 letter acronym was but great info as always