Summer's coming, open your \"eyes\" (NA models)

[Steampunk]

This was actually the very first tip I got, from Uncle Arthur, years ago, and I thought I would bring it up again.
Last track day and picnic (Queensland events) I was asked why I had my lights up all the time.

I had a very slight radiator leak, and apparently having the lights up can reduce engine bay temps by 10% or more.

I confirm this is very true cause when I touch components such as my strut brace, and metal intake after driving witht the lights UP, they are very-warm to touch but not searing.

If I try it with the lights down, pretty much anything metal in the engine bay is too hot to touch.

(I have no heatshield over my headers by the way)

Just a quick tip for those that may have overheating issues.

[ZenArcher]

Big difference in intake temps too.

I did some data logging the other day.

Cold rainy day - initial temp readings were at 60kph around town running. Then I went out to the 80kph zones.

With my headlights down - but also keeping in mind I have a headlight cover that has a air intake slot in it. Air temps slowly went down and settled at around 34 degrees.

With the headlights up, air temps dropped incredibly fast and were at least 10 degrees cooler.

Without the headlight lid air intake slot, air intake temps were shockingly high - eve n though it was cold and raining.

[Steampunk]

Zen's findings confims that it can reduce temps by up to 30% !!

[corners]

I have a headlight cover that has a air intake slot in it.

Where did you get this?

I have been looking for ages!!!

[StanTheMan]

what was the thing in America? 1 extra HP for every 7 deg of farenheit?

can anyone convert that?

[Steampunk]

1 horsepower = 0.746 kilowatts
1 degree fahrenheit = -17.22 degree celcius

[adamjp]

1kw=1.34hp
1hp=0.746 (3/4)kw

C=5/9(F-32)

68F = 20c
86F = 30c
100F = 38c

[Fatty]

this is an interesting topic for discussion. for some time i have been toying with the idea of putting a NACA duct on my headlight cover.
here is an explanation of the benefits of the naca duct
http://en.wikipedia.org/wiki/NACA_duct

you can buy a premade mx5 headlight cover with naca duct already fitted (very expensive tho) or you can buy a duct from a racing supplies store, and cut up your headlight cover and fit it yourself. some time ago i posted a wanted ad , but i have yet to get a spare headlight cover (i don't really want to hack my original one up).

anyway, i got this idea from one of the guys on the miataturbo forum , he reported significant improvements in engine bay temps after doing this mod.

i am still unsure if it's a good idea tho....

see, your radiator cools your coolant because there is a pressure difference between the air on either side of the radiator. this pressure difference helps to suck (or push, not sure which ) the air through the radiator. by fitting a duct, or raising your headlights, i think you are actually reducing this pressure difference. SO , whilst your engine bay temps may improve, it is possible that your coolant temps may actually rise.

now, when you add an intercooler in front of your radiator, i'm guessing that the pressure difference would become even more important, as you now have blocked some of the airflow... this is why i'm hesitant to try this idea out.

this is all just random thoughts in my head (maybe i think about this sort of stuff WAAAAAY too much ), but it would be very interesting to see some data on this, i guess it may be a trade off.

[ZenArcher]

jcs86

I bought the vented headlight lid a few years back from a place in Sydney, but they are no longer around now. Well, their website is no longer working and the phone number doesn't work.

The other place I have seen them at is MX5 Mart in NZ.

This is the one I have - raised vented
http://www.mx5mart.co.nz/db.cgi?db=mart ... records2=1

They also make the NACA one as well
http://www.mx5mart.co.nz/db.cgi?db=mart ... records2=1

Do I hear a group buy coming on??

They make some other nice stuff too. I like their white face dials and at $75 NZD, I am getting more and more tempted to buy them.

I know I have read a lot of posts about radiator temps going up with the headlights up or by using these headlight vents because of so called reverse flow - load of bunk IMHO.

Again, with all the data logging I have done to get my computer to work the way it should for daily driving - ie factory like tune, there has been no difference in radiator temps at all, headlights up/down, vented or not vented headlight lid. The only difference in temps are the intake air temps being higher or lower.

[Fatty]

Again, with all the data logging I have done to get my computer to work the way it should for daily driving - ie factory like tune, there has been no difference in radiator temps at all, headlights up/down, vented or not vented headlight lid. The only difference in temps are the intake air temps being higher or lower.

that's good to know. maybe i am worried about nothing then ? altho as i said, with an intercooler blocking much of my radiator, i'm very hesitant to place further burdens on my cooling system.

the intake air temps is a good benefit with this mod too, a very good benefit. i already have a cold air intake tho. i wonder if this would help the cold air intake even more, or have no effect?

[Fatty]

PS - the prices for the NACA duct headlight cover on that website are a LOT more reasonable than the ones i was looking at from the USA!!

[ZenArcher]

the prices are pretty good on everything really. Convert them back to Aussie and even postage is reasonable too.

I have yet to buy anything from them, but have spoken to the owner over the phone and he is a very reasonable guy, good to talk to. Other people I know have bought stuff and no worries. I really want those white face instrument dials, at $75NZ, it is heaps cheaper than anywhere in Aus.

Before I changed jobs I was in the middle of negotiating with Archery New Zealand for me to go over and spend some time conducting coaching clinics for archers and coaches for a week or so. If it all went ahead I was going to also be bringing home a large suitcase load of MX5 bits too. But I ended up changing jobs and have retired from coaching for a while so I can spend time with my family instead.

But do plan a trip to NZ one day for the family. So will definately calling into MX5 Mart while I am there.

[Steampunk]

Fatty; your concerns about pressure differential and it's effects on cooling efficiency is well founded, although inconclusive. I think opinions are pretty much divided evenly regarding this.

That, amongst other reasons, is why I haven't modded my car by putting naca ducts, indicator intakes, raised bonnet kits etc.
The way I figure it, is if Mazda found that driving with headlights up is detrimental, then they wouldn't have made the car with pop up lights.

I am stating the obvious here, but when you take a look at the car when the lights are up, it still produces a decent seal, hence the engine bay doesn't get dirty with debris and rain spatter. Therefore, even the smallest entry points that air gets through is enough to make a difference.

[corners]

Yeah it does seem good.

I had this made:
http://www.revlimiter.net/mods/duct.html
but have never gotten a headlight duct.

Obviously they make heaps of difference so I shall get a K&N filter and the Duct

[MXkal]

i just spent the $6 and made a sleepy eye switch. Works nicely