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Cooling for the Road Course

Old 08-05-03, 10:27 PM
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Question Cooling for the Road Course

I've posted this question in two other places without what I'm looking for. My car is essentially stock (see sig - not obvious have a DP). I was at the track (road course) yesterday doing a lapping day. My stock temp gauge was ~90% and could only do short runs. Last time it was cooler out and I ran 6 hours out of an 8 hour day and the temps were 3/4. What should I be doing to keep it cooler?

A pully would help at the track, but what happends on long highway drives @3-4k boosting it a lot? A aluminum rad is expensive and would overcool it on the street.

Will there be a worthwhile difference removing the main cat?

I run the car in the winter so I'd prefer not to mess with the coolant mixture ratio, but I may not have much choice...

Suggestions?
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Old 08-06-03, 01:13 AM
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3/4 is dangerous. THat's about 220 on my guage. Not good for longevity. 90% is about 240 for me. That's very bad.

I don't know that an aluminum radiator will overcool the motor. Since I don't run a street RX-7, you probably know better. However, as it is on my NA RX-7 race car the aluminum radiator is almost not enough, I'm adding a fan to help things out and pull air in. That's probably a band aid until I can get a second oil cooler and ducting to them.

A pulley will help, mostly to reduce cavitation at high RPM. I seriously doubt that you would have any problems running a pulley on the street, even in the scenario you indicated.

I'll let the turbo guys comment on the cat, but as I understand it, that's going to give you more boost, not a good thing when you're already fighting temp problems.

So you asked for suggestions.

You need the radiator and pulley at a bare minimum, you may need a 2nd oil cooler as well if you plan on doing this a lot. Sorry, but stock isn't going to cut it.

You can add a splitter and ducting direct to the oil cooler and radiator, that will help, some ITS guys claim 10* cooler. But an IT splitter will definitely live a short life on a street car.

Good luck.

PaulC
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Old 08-06-03, 04:50 AM
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You will find that distilled water will drop temps between 5 and 10 degrees. So many people overlook the importance of this.

earl
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Old 08-06-03, 09:23 AM
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the stock turbo II cooling system is barely adequate for street driving when in perfect condition, and is not good enough for any longterm track duty let alone racing. at a minumum you need a larger radiator and an additional oil cooler. improving the radiator and oil cooler ducting would help. distilled water, water wetter, and these type of things will not significantly reduce the oil and water temps. I am assuming you don't have an oil temp gauge? I would bet the oil temp was in the 240*+ range. this will cause a catastrophic failure in no time and may have already done some serious damage.
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Old 08-06-03, 09:42 AM
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Tim

I am suprised the distilled water didn't help you. It dropped the temps in my 3 rotor and my cobra
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Old 08-06-03, 01:12 PM
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that small of a drop could be from alot of different things and it is more likely the outside conditions changed from one day to the other. I have used distilled water(don't bother anymore and have not seen any changes) and I use a water wetter product, but these will not overcome the deficiencies of the stock cooling system.
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Old 08-06-03, 07:23 PM
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I suppose that under stock conditions a Al rad would counteract the effects of the pully (if there is any). I really hope my temp gauge is wrong and I wasn't at 240!

No I don't have an oil gauge. I hope you're wrong about the oil temps, but you've scared me enough that I'm definately going to do something about it. I was running a full synthetic in part because I was told it would lower my temps substantially.

Thanks for the suggestions guys.
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Old 08-06-03, 09:56 PM
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I have a 2core brass radiator in my car it makes a huge differnce on the track. In addition I use a different thermostat and that makes the water temp 8-10deg cooler in all conditions.

It is the normal suggestion that if you use an aluminum radiator to have at least a 3 core or it is no better than stock. just something to think about if you are buying aluminum
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Old 08-07-03, 12:31 AM
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If you plan on tracking the car on a regular basis, I think a larger radiator would be a worthwhile upgrade. Run 80/20 or 70/30 water/coolant mix in the summer and I guess 50/50 for the winter(I live in California so I don't know). And make sure your radiator is well sealed. Check that the foam surround is still there. Make your own ducting to make sure air doesn't escape around the radiator.
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Old 08-07-03, 12:28 PM
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Welcome to the world of tracking a turbo RX-7...
Without a FMIC, we found that we could keep temps well under control with our Mazda motorsports radiator. We never saw more than 185 water and about 215 oil even in 100 degree heat. With a FMIC, things have changed. With the same heat exchanger setup we hit 220 water and 260 oil temps after 3 laps. By fabbing up some ducting from the underpan to the oil cooler we could keep temps down to 210 water and 230-240 oil. Still too hot and oil temps would start to climb after 6-7 hot laps. Right now we're setting up dual oil coolers in parallel hoping to drop our temps. If not, we may have to try another intercooler setup.
-Matt
www.bfimotorsports.com
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Old 08-07-03, 12:38 PM
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I will mention it since nobody else has... turn your heater on full blast while on the track. If you're not doing it already you will be surprised how much of a difference it will make.
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Old 08-07-03, 01:20 PM
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Originally posted by bros0000
If you're not doing it already you will be surprised how much of a difference it will make.
Per my Power FC display...the heater drops the water temps 1 to 2 degrees C...
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Old 08-07-03, 01:59 PM
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Originally posted by SleepR1
Per my Power FC display...the heater drops the water temps 1 to 2 degrees C...
On my car turning the heat on will typically move my linearized stock gauge a good quarter inch cooler. Enough to be noticable on a guage with no numbers. Depends on the car, the track and the ambient temperature though I'm sure.
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Old 08-07-03, 07:02 PM
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What sort of thermostat do you have that is lowing temps 8-10 degrees? I thought the thermostat would simply stay open if the temps warrented it?

What size/number of core rad do you guys recommend?

Also, do I need a oil pan baffle or will overfilling a little bit solve that problem?
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Old 08-07-03, 08:10 PM
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The thermostat I use is called the "Super Thermostat" I am not sure of the company who makes it. The design is different from a normal thermostat allowing for more flow of water. It does take a tad bit longer to warm the car up, especially in the winter but it works great.

If the track you race at will allow you can remove the front bumper cover when lapping, that will reduce the water temp by a grip. Around 15 deg. at least. If not then maybe you can get the type of bumper that has openings in the front of it.
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Old 08-07-03, 08:27 PM
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Mazda GTC nose and vented hood...
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