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  #13  
Old 09-26-2011, 09:40 AM
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Re: WK2 GC - Reducing Hemi Engine temp

The thermostat opening up sooner would not make much difference in his climate.
Extra cooling.
Engine oil cooler, with in-line oil canister add an extra quart or two to the system.
Custom radiator.
Its hard with these high ambient temps.
More bonnet mods with cold air ducted to the intake
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Old 09-26-2011, 09:41 AM
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Re: WK2 GC - Reducing Hemi Engine temp

You can try to change the thermostat, I think cannot be worst than the standard.
But You need consider phisic laws, means I think into hot weather, high output engine power and moderate speed, the water pump and the fan already runs at maximum with the standard thermostat.
So changing the thermostat You cannot have better performances.
The worst/hottest conditions You have as You run the car up-hill, and the speed is low.
If You run at high speed, the air flow is enough to cool down the engine, no matter You have 20C or 40C outside temperature.
I think Your HEMI has "NMCP" Heavy Duty Engine Cooling, right?
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Old 09-26-2011, 10:53 AM
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Re: WK2 GC - Reducing Hemi Engine temp

Some guys here would never take the risk, but Hasan's vents are a good step.

Chad at Black Ops needs to get the WK2 vented hood proto going.
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  #16  
Old 09-26-2011, 06:30 PM
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Re: WK2 GC - Reducing Hemi Engine temp

guys thanks allot for sharing your thoughts, the vents on the hood made some differences which I am very happy about it specially when I start moving forward after some stops , the issue that I don’t like beside the performance gets effected heavily between day & night time , the thing that I don’t like the most is the heat feeling coming in from the fire wall , gearbox side walls (beside my feet) & AC cooling goes down a bit just by sitting in traffic light for 10 or less minutes so I am checking all solutions
1- Hood Vent done
2- Thermostat - still checking
3- Oil coolers with auxiliary fans
4- Custom made radiators
5- More or bigger fans etc.

funny thing I am seeing this now , weather around 40C , I am not sure how much would that be in F , my worries when next summer - Aug to be exact & it hits 55C, so I am fixing what I think might bring the car down to 88-95C engine temp is possible
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  #17  
Old 09-26-2011, 08:02 PM
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Re: WK2 GC - Reducing Hemi Engine temp

I spoke to some SRT reps about lower temp thermostats when I was racing Vipers.

My goal was to have the cooling start earlier to get a jump on the temperature rise.

Their response was to not change it. The vehicles are designed to operate most efficiently at those temperatures. When the engine gets too hot, a light will come on, and the engine will reduce output to protect the engine. Up to this point, the engine will perform up to specs.

Running at the cooler temps will actually reduce mileage and performance and efficiency.

Best and most cost effective is to order the towing package which provides additional cooling to engine and transmission. Believe the off road package also does this.
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  #18  
Old 09-26-2011, 08:13 PM
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Re: WK2 GC - Reducing Hemi Engine temp

Unfortunately there's not really too much that can be done when ambient air is really truly hot.

Small incremental improvements CAN be made over the factory setup, but like I say, if the ambient is REALLY hot, well, no matter how efficient any intake or cooling system is, the engine's performance will be negatively affected.

Dry ice in the bottom of your air filter housing? You'd want to be super-committed though. LOL
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  #19  
Old 09-26-2011, 10:16 PM
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Re: WK2 GC - Reducing Hemi Engine temp

I applaud Hasan for his efforts, you have to be bold to not only "think outside the box", but to execute it.

Adding capacity to the oiling system etc will help, but radiant heat is a real problem on these (I saw it on my WJ) that is amplified by hot ambient air.

I have not seen the fuel system on these, but it is probably a returnless. If its anything like the 4.7, it probably has a U shape , with 2 banks of rails and a crossover connecting the two rails. These leads to boiling fuel.

By simply eliminating the crossover, and running a Y merge that break off into 2 separate lines from the feed (coming out of the firewall probably), directly into the rails, it will not only cool the fuel because of the insulation of the fuel line material, but because you have eliminated the crossover.

Cool fuel has been proven to make more power.
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  #20  
Old 09-26-2011, 10:42 PM
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Re: WK2 GC - Reducing Hemi Engine temp

For those wondering why, look at his location.

"ooooh, I get it"


It's a tough situation there. When sitting at a traffic light, you're above ultra-hot pavement which is radiating a ton of heat, and surrounded by other vehicles radiating more heat and trapping the air (mini heat island effect).

You don't want to lower the operating temperature of the engine, you just need the engine to be able to stay at it's proper temperature no matter what. If the foot wells are getting hot, but the engine temperature is not going past normal, then there's nothing wrong. If the engine temperature IS going above normal in these circumstances, then there could be a technical problem, or it just can't keep up with the intense ambient heat.

If the official weather actually is reaching 55C there, then you could easily find your Jeep sitting in pockets of 65-75C ambient temperature at times, or higher. Here in California just a few weeks ago, I took a picture of the Wrangler's rear view mirror thermometer reading 138F (59C) while sitting in a fast food drive through, surrounded by concrete and other cars. The official temp was 101F (38C).

This leaves very little room (just 15-25C) between the air temp and the desired engine temp. This means the cooling system itself is having to work very hard to keep the engine from overheating. There's no room to lower the temp of the engine any further. The only thing a different thermostat will do is let the coolant flow out into the radiator at a lower temperature. This does nothing if the temperature is already high enough for the thermostat to be always open - which it probably will be in your case.

The only things you can do to increase the engine's cooling capacity are:

1) More airflow over both the engine and radiator. This means more powerful fans when not moving, or more of them if possible.

2) More surface area for the the heat to dissipate. This means a larger radiator or more radiators.

3) Ensure the air flowing over the engine and radiator(s) is coming from outside the vehicle. This can be hard, and won't always help when sitting still, as the post-radiator air begins to fill the area around and under the engine bay. Also, sometimes making more vents can worsen airflow and increase temperatures.

If you don't have the factory cooling options for the engine and transmission (I suspect they're standard over there?), then have the dealer install them for you.

Is the engine ever actually overheating, or is the needle ever approaching the overheating range on the gage? If not, and the only symptom is the heat entering the footwell and the AC getting weaker, then you do not need to worry about the engine's temperature. These things are caused by the build up of warm air in the engine bay and under the car when sitting still. In fact, forcing the engine to a lower internal temperature with a thermostat would increase the amount of heat in the engine bay and thus worsen the footwell and AC "problems".

Have you had other vehicles there which did not exhibit any of these symptoms?

For the A/C, you could have an A/C specialist increase its capability. Yes, they can do this. I've heard stories of HVAC technicians tweaking their service trucks to blow air so cold that the dash vents get frost on them.
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  #21  
Old 09-26-2011, 10:55 PM
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Re: WK2 GC - Reducing Hemi Engine temp

It could also be as simple as hot air is less dense. Cooler air gives a better fill to the cylinders. This is why most engines try to draw their engine air from outside the hot engine compartment. Jeeps have a snorkle that is mounted high and goes to the front to draw in as cool air as possible.

Jeeps tend to be designed with more robust cooling than the average sedan due to its needs off road, towing and slogging through san dunes.

Your Jeep will be just fine. Installing a thermostat with lower opening temps will cause more problems than it solves.

Just stick your A/C on automatic and enjoy the ride.
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Old 09-27-2011, 01:25 AM
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Re: WK2 GC - Reducing Hemi Engine temp

You can alway put front misters pointing at your radiator...gets too hot hit the button and your radiator gets a fresh splash of water which will dramatically lower your temp as long as you are moving. With my track car thats what we use on the hot days here in Phoenix to avoid the heat soak.
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  #23  
Old 09-27-2011, 08:23 AM
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Wouldn't cold water on hot metal cause it to crack?

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  #24  
Old 09-27-2011, 08:43 AM
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Re: WK2 GC - Reducing Hemi Engine temp

Mist of water would be vapour before getting to anything that hot that could crack.
I would not worry about cracking anything with a misting system.

tried this on a grader out in the desert worked great for about 2 hours.
Until the radiator filled up with mud and hardened, could not be washed out.
Boss was not pleased!
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