Anyone running bonnet cooling louvers?

[glend]

After my recent heat management problems towing in central Qld I have been thinking and researching heat mitigation for the KJ. I just wanted to find out if anyone has installed bonnet cooling louvers on a KJ here in Australia? It seems some people in the hotter areas of the US have done this with success.

Story appears here:

http://www.lostjeeps.com/forum/phpBB...hp?f=6&t=48910

The Rocky Road kit:

http://www.rocky-road.com/kjlouver.html

Raceace look like the original source of the Rocky Road offering:

http://www.raceace.com/products.html

Install instructions:

http://www.raceace.com/installation.pdf


Then there is the el cheapo Whitworths option:

https://www.whitworths.com.au/main_i...AbsolutePage=1

Think I prefer the Raceace as it has a reputation in the Jeep community and the look suits the KJ bonnet.

[KJ_andy]

There's a few threads around on this and not a bad idea as good airflow works even at slow speed.
Options available such as these
http://www.tellico4x4.com/product_in...ducts_id/31362

[barryh]

I have no experience with louvres for a KJ, but I have used on a track car that I had in the past. In my research of a few years ago it stood out that the position of the vents was really important. They had to be positioned as far forward in the bonnet as possible, preferably just behind the radiator. There have been many cars that had vents placed right at the back of the bonnet where they looked nice i.e. Datsun 260Z, but this position is in fact a high pressure area caused by the air flow against the windscreen. As a consequence there is little flow to aid cooling. Have a look at the positioning of vents on Mitsi Evo and Lotus sports cars as these cars are of recent design.
Also as I remember there was detailed testing of this theory on the "Autospeed " website that should still be available. barryh

[cmohr]

I know my old KJ had a heap of heat under the bonnet until I added the thermo fan onto the Transcooler, then the entire under bonnent engine area was vastly cooler than before, with no change to the actual engine running temp. I must say that I never had any kind of actual engine temp issues at all, always ran just on halfway, just had the transmission temp issues.

One thing I was going to do before the thermofan was put in a air scoop and pipe that would bring fresh air into the engine bay area to help blow out all the hot air. I bought a 120mm alloy flex pipe from Bunnings (from the kitchen dept - apprently used for stove exhaust vents, and was going to have it pickup air from down under the bullbar and bring it up into the engine bay area. Of course something would have to be done to block it if and when doing water crossings.

[glend]

Thanks for the suggestions guys. I suppose that there are a couple of recent changes to my KJ that might affect airflow into the engine bay: I put the TJM bull bar on; I mounted my Narva lights on the bullbar in front of the radiator, and I added an infill panel between the bullbar steel carrier and the KJ engine bash plate (to protect the lower radiator hose and tranny cooler lines, and smooth out the airflow under the KJ).

Now the lights used to be mounted on my nudge bar, and the infill panel is the same one I used between the stock bumper and the bash plate - no heat problems with that configuration (I did tow down to Jambo and back but the air temperatures were not too bad then).

The problem with scoops is that they do scoop up crap like mud, and are a great way to spray the engine with water during a water crossing.

I recall hitting puddles on the Birdsville track that had water going over the top of the KJ, and I can just imagine what a scoop would do in that situation - I'll pass on the scoop.

I have heard a suggestion that removing the rubber lip at the top of the firewall would allow airflow out the back of the bonnet and improve cooling.