FD Track Overheat
 

My mods include, Mazda Comp radiator (ducted) Crooked Willow Oil coolers (ducted), vented hood, underdrive pulleys, Evans NPG+ (0 pressure). I run 12psi with a TO4E cooled by a M2 medium IC augmented with an Aquamist 1s water injection system. The motor is stock and I run a high flow cat, so my power is in the 325-350rwhp range. To keep the car under 230f after 5-6 laps flat out is next to impossible. I know the Evans Coolant sytem runs hotter, however any additional insight would be helpful.

If it isn't the Evans, you've got something wrong with the car... i'd look at a T-stat that isn't opening, or fans not running... that car shouldn't even cap 200 degrees.

I have owned 3 FD's and have logged well over 125 track day's, ALL of them with the aforementioned mods have overheat issue's if you drive the car HARD. 200f in midsummer heat would be a act of God or a pack with the devil.

There are some great old threads, search for "cools like icewater" or something like that. I believe they post track temps as well.

That's crazy, I've run quite a few track days down here in the VA summer heat, and i've got a Fluidyne rad with 70/30 coolant (not even water wetter), CWR oilcoolers (not currently ducted w/ '99 front end, PFS intake... still have twin turbos and A/C installed, and run 10-12 psi, and drive very hard, and didn't see north of 100 C (212 F) all last summer in an entire 30 min. session... usually in the 90's (C).

The oil/water passages in my motor are ported, but still... with a single T you should be that high so quickly.... maybe it is the Evans.

Could the cat contribute to the heat somewhat? I would try no cats and regular coolant for a season to see if that helps. Maybe also a couple of holes in the thermostat.

What exhaust manifold are you using?

If you do some searching, you'll find that cars with Evans coolant tend to run hot. Some guys have seen 250F, without any engine damage. However, I think Evans likes more flow, I'm pretty sure they advise you to drill your thermostat.

Remember that overheating is usually a result of coolant boiling and not transferring heat from the metal engine parts. 240+ is just a temperature at which most coolant will boil, you might not necessarily be harming your rotor housings.


What heat range spark plugs are you using? Do they look like they've gotten too hot when you change them?



Good luck,
-s-

Thanks all for the feedback...

Hi Jack,

do you have your a/c removed? that made a huge difference for me. Also, think about the '99 spec bumper. the openings for the rad and oil coolers are much larger.

Hey Rich

Yes all the AC componets are out, maybe I could get Chris to sell me his 99 nose for short money..

An aftermarket front bumper well ducted is the best track cooling mod you can do (PERIOD)

Both Damian and I have Mazdaspeed GTC (big front openings) with well ducted radiators, no A/C and the OEM dual oil coolers and run zero pressure cooling systems with Evans.

Running 10 psi of boost on my 35R my highest temps of the season were 95C on a 85ish F degree ambient day. Damian's track car running 10-15 psi of boost does not get over 100C much either.

My point here is that it is possible to engineering the car with Evans and keep your temps in check. And as an added benefit you get to run zero pressure. :D

I'm thinking there has to be something wrong with the setup, something is failing (t-stat or plugged up rad or ?) or I guess you just might need more (still well ducted) air in the nose of the car.

Remember a lot of this depends on how hard you push it. From what I've heard Mr. Jack regularly puts the hurt down on the Ferrari and Porsche club guys that are running slicks at Lime Rock with street tires ;)

Thanks guys. I am looking at the GTC or 99 nose for more cooling, along with a large vent in the hood over the IC. Do you run stock fans?, my concern is the postioning of the IC impeads the flow of air out of the radiator. I was thinking about a large fan that flows more CFM.

My motor is completely stock other than exhaust. I run the stock radiator in the stock nose but added ducts and 90% water/10% coolant. I can't get my car to 230 any longer even if it's 100 degrees out.

I'd remove your thermostat and verify it's opening and fully open temps.

Ducting and water ratio alone make a hge difference in temps.

Radiator Info:
 

Spoke to Ron Davis who supplies the cores for AWR who make the Mazda Competition Radiator. Ron told me the core was good for 275rwhp in a "road race application" for street use or autocross you could push closer to 400rwhp. Given I am always pushing 300-350rwhp the answer was a bigger radiator. I have ordered the Koyo Race model R1443N which is the N-Flo radiator design. Most shops sell the R1443. Info below:

Here is a word from Matthew Souto from Koyo Cooling systems:

From the factory side, there are many tests done to make sure that the radiator has zero defects. Each radiator must pass the following tests: water, pressure, wind tunneling, heat cycling, corrosion, and vibration. Each of our radiators is produced to optimal dimensions, largest core size, which yields for increased cooling. Our radiators are hand-welded and polished to a finish. Our R cores are 2 1/16 inches while the V cores are 1 7/16 inches. We use Nocolok Brazing, (Nocolok is the type of furnace used to bond certain components together, like the fins to the tubes. The result is an extremely strong product. We use Heliarc Soldering, which is the highest in the industry for aluminum enforcement. In general, our radiator provide for a 30% increase in cooling efficiency over stock. There have been tests done by performance shops in the past. Cooling tests are not done very often because in the radiator industry a general understanding is that, larger core = more cooling. We also have started offering N-FLO radiators for some of the popular applications, currently only the RX-7. Basically what it makes the coolant go through the radiator multiple times before exiting, adding for even more cooling. We are developing a flyer for this and should also have the 240sx and Silvia models out in the future. I hope this is helpful information for you guys

All that "N-FLO" marketing mumbo jumbo is merely describing a multiple pass radiator. Very common.

Any aluminum radiator is easily converted. You slice through the tank with a bandsaw and TIG a baffle into it where ever needed and then move the inlet/outlet to suit.

https://www.rx7club.com/attachment.p...hmentid=142897

????? or you just buy it done for you for $50 more....

Don't know that a hi flow fan would do anything for you as the airflow from the moving car is greater. A vented hood would surely help- something like the original GT-40; maybe with a v mount? it is also easy enough to ditch the cat that you could take it out for track days.

Tom

Wow. Good info. Glad I have a Koyo :)

Certainly. My point is that this isn't some sort of new technology; multiple pass radiators have been around forever and they don't require going to a thicker core.

Specific to the 3rd Gen, as a production piece, this is.........

I have two related questions. 1) Is there an undertray make for the GTC bumper or do I have to fabricate one? 2) Is there good space for brake ducting with the GTC bumper? I presently have the rotary extreme dual oil coolers and have cut out part of my R1 lip for larger brake duct inlets.
Jack, I'm sorry for hijacking your thread

Mark

No. You can fab one up with a little effort. Search for a thread from Damian in the 3rd gen section about his super duper undertray/splitter. You can fab up something similar if you have the skills.

Same answer as above. Also check out a thread from John Magnuson (I always spell that wrong sorry John).