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Hi,

I have a 1989 NA turbo, its used mainly for track work but some road driving, the temp gauge usually sits just under half way. On Friday I spent a couple of hours down the track in 38 degree temps and after doing 3 laps, 3-4 kms, the temp went up to 3/4 and rising. It soon came down when I left the track. Im just wondering what the best "bang for my buck" purchase would be to help keep the temps down?

I currently have an upgraded radiator (70ml) and the aircon fan is wired up to come on when I dont have the aircon on with the flick of a switch, therefore two fans are running.

I was wondering how much difference;

An oil cooler would make?

An Mania cold air intake would make? ( where you put a hole in the firewall)

Any other suggestions?

I dont mind spending the money if its going to make a significant difference.

Someone told me the gap between the radiator and the black plastic fan cover should be blocked with rubber to make the fan more efficient (see pic) and that it doesnt help having the intercooler in front of the radiator but I really dont want to move it and cant imagine where it would be moved too.

Ive just had and new Adaptronic 440 ECU installed and had it tuned, increasing the horsepower from 150 to 190.

The air flow metre can now be removed as its no longer required with the new ECU (my tuner tells me)

Would appreciate and suggestions,

Thanks Nicky

Turbo + trackwork = coolant re-route. It's pretty much a must do item for you. You could pick up a high flow thermostat at the same time. MX5Mania sell them.

An oil cooler will help a bit, but not as much as the re-route. A CAI will get more air into the engine so you can make more power by burning more fuel and therefore make more heat. Fans are there to keep the air flow going while you're stopped or crawling in traffic. Switching fans on while you're travelling at any sort of speed won't make any difference.

Thanks Manga, can you explain the coolant re route? I havent got a clue

Search through this forum. There are heaps of posts abut it, plus a group buy that might still be active. Basically the coolant flow route through the engine is compromised by the way Mazda adapted an east/west engine to north/south so that flow towards the rear of the head is poor. With the stock MX5 arrangement temps fluctuate a lot during hard work and there is always a risk of overheating around numbers 3 and 4 cylinders. The re-route restores the main outlet to its proper place, at the back of the head. The engine temps are much more stable when the re-route is done.

The coolant re-route should be done.

However as you are track only (and some road) consider going to a thinner radiator as the only times the fans will be needed is when you are waiting to go, plus you can always turn the heater on to take away some of the heat from the engine.

As the your intercooler is blocking air flow then a thinner radiator may assist with greater cooling. It would be worth doing differential air pressures to see what pressure loss you are getting in front and behind the radiator.

Also have a look at this article http://www.circletrack.com/preview/ctrp_0006_radiator_cooling_system_basics/

Do you have the factory undertray?

Dann

NitroDann wrote:Do you have the factory undertray?

Dann

Dann good call!

NitroDann wrote:Do you have the factory undertray?

Dann

Yes, but its not on the car.

Put it back on, this will probably solve the problem.

A reroute is highly suggested but the tray should fix it.

Dann

Great! Will try that first then, thanks guys

Undertray back on and have a look where air can get round the radiator. Air will take the path of least resistance. If you have gaps between the rad support and radiator, fill these with sponge to direct air through the radiator.

The undertray will help draw air through the radiator and away.

70 mm is really thick. Shouldn't have needed anywhere near that thick.


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70mm is a massive radiator but its there now so lets work with it.

Coolant re-route is a must on the NA. Later cars had a different head gasket design so do not need it.

Imagine air flowing through the hole in the front of the car. Now imagine air to be like water...it will always take the easiest path to drain away so if you have nothing to force that air to go through the radiator it will just go around it.

Put the undertray back but see how closely it fits to the radiator. The one on my car was all saggy and had a few inches gap under the radiator so I turfed it and made a new one of my own. I have also blocked all the gaps in the panel over the top of the radiator and stuffed foam around the fans. If you seal the fans to the radiator they will draw air through the radiator and not just in the gaps.

I also have an oil cooler on my car, I need to re-jig how air is getting to it though.

Ill put down 100 bucks that it's not a 70mm core just 70mm tank width, which is pretty normal for a 42 or 52mm.

Just put the tray on and seal it up around the radiator. It doesn't NEED a reroute it has a tuneable ecu, a reroute would definitely be ideal however.

Dann

The radiator was in when I bought the car, the guy used to do a bit of rallying in it. It is a PWR and measures 70ml thick at the top, dont know whats inside it. I will do the tray and fill the gaps. See how it goes and keep the re route in mind. Ive been looking into the re route and its quite interesting, seeing these engines were originally made for the 323 rally cars and the coolant was run the better way. Its a shame they changed it for the MX5.