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WK2 GC - Reducing Hemi Engine temp

26K views 78 replies 33 participants last post by  AlexIVK 
#1 ·
#35 · (Edited)
I also took the engine cover off and now it hangs on the den wall. It CAN'T help ambient air circulation inside the engine compartment whatever that may be.
My temp gauge shows movement under harsh conditions which I do not like, and I have the tow package with heavy duty cooling. I have been following this thread with interest. Thanks Scottina for ur intervention.
The thermostat determines at what temp coolant starts to flow into the engine. So the higher the thermostat value, the hotter the engine will always run. Thermostats started getting hotter to help with emissions. Heat is the enemy of ALL machinery, simple friction and thermal expansion. There is an "ideal" (stoichiometric) air/fuel ratio for engines and I am sure there is also an ideal temp at which an engine will produce best POWER. Note that today the emphasis is not on power, but EMISSIONS. Personally I like a 180 thermostat with a fan that comes on EARLY enough to keep it there. Hypertech offered this exact option with all its programmers, for GM cars anyway, so I'm not just blowing this through my kazoo.
 
#36 ·
ron 13 ,
I am a big believer of what you’re saying specially if you live in hot environment like mine I petty all engines that work in such weather , i am going for thermostat but didn’t decide which one as I am still looking plus I am ordering the oil coolers with auxiliary fans beside the hood vents I made , I will see what happens & update you guys
 
#37 ·
Yes Mr. Hasan, I believe it is the most cost effective path. The ULTIMATE solution is what we're talking about PLUS a larger capacity radiator. The fact that the temp needle starts to rise with harder use indicates that radiator capacity might be a bit on the marginal side. When I'm in stop and go traffic on a 100 degree day with the air blasting and towing a 23 ft boat, I don't want to see that damn needle doing ANYTHING but staying nice and low on the scale.
 
#39 ·
to be honest Gents, this would be the 1st time to go through 55C+ in American car , I used to do that allot in Japanese cars , seeing from inside my car too many cars on the roads from different makes hoods up & radiator green water all over the asphalt is not a pleasant site & people sweating like ....... so to save myself the agony I am going ultra cool from now & will update you , man at that time you can even touch the cars doors from the out side or any chrome or chrome plated buttons coz it will burn your fingers so lets see I cant wait :rolleyes:
 
#41 ·
Hi all,

I have installed the JET 180 thermostat yesterday with positive results.


Before:
Engine radiator temp. 94C – 112C
Engine Oil temp. 92C – 108C
Gear temp. 74C – 89C

After:
Engine radiator temp. 81C – 97C
Engine Oil temp. 78C – 95C
Gear temp. 65C – 81C



One more good news Hasan. No need to order it there is a local shop that sells it :thumbsup:
 
#42 ·
I'm curious about this. Are you saying that the transmission cooler is part of the radiator? I thought it was separate?

Honestly, having a lower temp thermostat will do nothing for you if the actual cooling aspects of the car are not upgraded. Namely radiator, fans, oil cooler, trans cooler.

Hasan, if you really want to help prevent an overheated motor, your best bet would be to start with a large engine oil cooler. Oil retains heat a lot better than water and if you can cool your oil you will reduce your radiator load by a lot.

Also what ratio are you running for coolant to water? Simply put the best cooling agent is water, the reason we use coolant/antifreeze mixtures is to keep water in its liquid state and corrosion resistance. I'm assuming you don't have freezing issues, so lets get to boiling issues. Keep a higher water ratio to aid in cooling your vehicle. To keep water from boiling and vaporizing, you would need to swap to a slightly higher rated radiator cap. Considering our vehicles are new and in a maintained shape the increased system pressure should be ok.

If you are not towing, then I really wouldn't worry about trans temps
 
#43 ·
I too would like to lower the engine temp. Mine constiantly wanders between 195 and 225. Not so much on the freeway but mostly in the city. Apparently this isn't due to the thermostat but the electric cooling fan. The fan won't even begin to turn on until the temps reach 220. This is not confidence building. I would like to see the temp hit 195 and lock in solid after that. I don't see how putting a lower rated thermostat is going to help when the electric fan is going to let it heat up to 220 anyway. Now if I can figure out how to fool the sensor voltage by putting a resistor in parallel and have the fan turn on sooner. I have noticed that the fan will come on sooner when running the AC. So there must be something in the programming also.
 
#44 ·
so here's a question to you folks that are going with the "cooler is better" thinking, what temp range would you want the motor to run at and why? I think the Chrysler engineers did a fine job at asking this question and implementing solutions for these problems. 99% of climates in the US would work fine under OE conditions. I've driven through the Mojave dessert up a mountain range in 115F (46C) heat with A/C and 5 passengers/gear and the car didn't skip a beat

We have an internal combustion motor in our cars, creating hundreds of explosions every second. There will be heat - you just need to understand, how much is too much? Exhaust temps are about 1000F max 1400F, so water at a measly 225F is quite a feat no? chew on that.
 
#46 ·
The idea in this case is to lower coolant temp to reduce the PCM's likelyhood/urge to retard timing due to knock. The engine is designed to run presumably on 89, you'd be surprised how much timing the PCM pulls even running on 89 octane.

Efficiency goes up with heat, but the threshold to detonation goes down. In this case, whatever allows the PCM to run with the least amount of KR possible.
 
#47 ·
The late, great Smokey Yunick:

"It is easy to see how overheating can be a problem, but I think some racers overlook the fact that it is possible to 'overcool' the engine. Some guys go to great lengths to keep the engine temperature down to 180 degrees. And, though the engine doesn't overheat, they don't realize that they're putting energy (heat) into the cooling system that could be used to produce power at the crankshaft. Running the engine at 180 degrees will drop the overall horsepower by 2%-3%. For max power the cooling temp should be at least 200 degrees...."
 
#48 · (Edited)
The late, great Smokey Yunick:

"It is easy to see how overheating can be a problem, but I think some racers overlook the fact that it is possible to 'overcool' the engine. Some guys go to great lengths to keep the engine temperature down to 180 degrees. And, though the engine doesn't overheat, they don't realize that they're putting energy (heat) into the cooling system that could be used to produce power at the crankshaft. Running the engine at 180 degrees will drop the overall horsepower by 2%-3%. For max power the cooling temp should be at least 200 degrees...."
Mr. Yunick was and still is considered a genius, but he was racing and building in a time that didnt have fancy-pants technology like knock sensors. at least outside of a engine dyno lab. He also had complete control of the fuel/spark curve. Apples to Oranges comparison.

Given the excessively sensitive nature of the PCM to retard timing (example: if it senses .5-1 degree's worth of knock, it will pull 3-5 degrees as a precaution), the above paragraph, while still valid, is made *somewhat* irrelavent because of the nature of the sensors to pull timing due to either suspected detonation, pre-ignition, or excessive IATs. And the fact that as of right now, there is no way to remove or reduce these power-robbing functions.

Engines all follow the same principles/laws , unfortunately PCM control does not.
 
#50 ·
Some fundamentals are in order here. Colder intake simply means Colder air is more dense and with the right fuel load can provide a better "charge" for the engine to work with = more HP potentially.
However the original thread was about operating engine temps.
Engine temps are designed with many things in mind, like Emmissions, Engine timing, fuel injection mapping -duration of spray, droplet size, etc, etc, and even things like oil weight play an important part in an optimally tuned engine, not to mention the environment that the vehicle is being used in, (Hot, or cold) the range of variables is greater than we can modify with "add ons' thus the ECU's of today's modern vehicles taking these variables into their mappings, along with the Mfgr desire to gain fuel economy low HC emmisions, etc.
Any MSE – Automotive Systems guy will tell you (Me included) that making broad statements on this or that "add-on" being better than a well engineered solution, is like saying turning on the fans will help, while driving down the highway.
Fans are for low speed driving to keep the engine coolant at an optimal range, turning the fans on while at speed is counter fundamental to the airflow. Take the fans off completely at high speed = a better performing cooling system. They actually slow down air flow through the radiator at speed ! I've got lot's of dyno runs and track data to prove it !
Mod carefully my friends - let the cursing begin ! :)
 
#51 ·
This is why I'm glad I listened to my buddy who used to work in Toledo at Modine Radiators (Radiator supplier for Jeep at the time...prolly still are). He told me: "Always get the tow package on your Jeep. It comes with a bigger radiator, bigger fan, and just keeps the engine a little cooler all the time."

Hence, the tow pkg on my JGC OS and her always running cool no matter how much I've pushed, sat in traffic on 95 degree days, or whatever.
 
#52 · (Edited)
Sorry guys. BS and BS and more BS.

I have never heard ANY engineer say that machinery runs better at higher temps. Basic physics and metallurgy-At the molecular level increased heat ALWAYS means increased (UNCONTROLLABLE) thermal expansion. This is why ALL things can MELT. At the macroscopic level this ALWAYS means greater variation in tolerances. As tolerances decrease in value, the degree of thermal expansion becomes more critical to the function of the device. That is why it becomes such an issue in devices like high precision/sniper rifle barrels. Ask any military sniper about the accuracy differential between a cold and hot barrel.

In machinery exposed to repeated heating/cooling cycles, there is undoubtedly an ideal operating temp range and tolerance range. But that range is always lower, not higher for the above stated reasons. Engines run hotter to deal with emissions, not because it is good for them or causes them to make more power.

Maybe the 6 with the trailer package stays cool, but my hemi with the same package shows far too much movement of the "temperature gauge" for my comfort under the conditions you describe. And that thing is no precision instrument to begin with. It is merely a "relativity meter." I want as much reserve between me and the side of the highway as possible on a 100+ day.

Stay COOL!
 
#53 ·
swiss cheese has fewer holes than your arguments. honestly, what background do you have that can fight against PhD's and engineers that spend their living engineering OE quality parts that are meant sustain through 200k miles of harsh driving including towing? There is a set operating temperature for EVERYTHING and going outside of that isn't recommended. See what happens when you lower your body's operating temp to below 85 degrees F, will you perform better? How about race pads below 100F? will you run into a wall? If engineers knew that motors would run at 215F they would build the motor for those tolerances and expansion ranges. Hell, oil is designed for that temp range. Again, if your car is going to overheat at 260, an open thermostat wouldn't have saved it, something else was the culprit
 
#54 ·
More BS and more cheese.

My advice would be to spend some time with a high school physics book. I didn't learn anything in college or grad school that contradicted what I learned from that.

By the way, induced hypothermia is a therapeutic intervention used in open heart surgery and other clinical situations.

You need to read or get out more. Cheers.
 
#55 ·
Re: More BS and more cheese.

My advice would be to spend some time with a high school physics book. I didn't learn anything in college or grad school that contradicted what I learned from that.

By the way, induced hypothermia is a therapeutic intervention used in open heart surgery and other clinical situations.

You need to read or get out more. Cheers.
not to start a pissing contest but I broke the curve in AP Physics in High School all year long. i still don't get what basis you have to think you know more than what engineers created the engine for. multiple mopar/srt talks from the engineers have confirmed that the temperature of the motor was designed that way. just because you have a 'feeling' that the car is running hot doesnt mean that it is, who are you the 'car whisperer'?

I've been working on cars over the past 15 years and every functional modification comes from cooling intake charge or helping the motor maintain its operating temp via oil and trans coolers amongst other things turbo, tuning, etc. I've got my track car tuned to a nice 400RWHP out of 2.5L and a pretty linear torque curve.... with the stock thermostat. spending time arguing about a f*cking thermostat is ridiculous. at this point, if you want your car to have less strain, pull the spare out of the rear trunk and some fat out of your head.
 
#57 · (Edited)
Panties in a wad fried rice?

HO! HO! HO!

I have posted on this particular thread before and have agreed with what most of my fellow members are saying and have also disagreed with a few, most notably now the eminent fried rice.

Hypertech thinks the "f___king" thermostat is important enough to offer a lower temp thermostat together with a provision on their programmers for lowering the temp at which the fans come on. In my book this trumps any clown's delusions of grandeur on the subject. Most of you guys seem to get this.

Again, dispensing with emotion and depending on actual facts and science, what fried rice seems to be saying (and definitely Smokey Yunick) is that an IC engine is MORE thermodynamically efficient at the temperatures we are discussing, 220 vs. 180. That is, at 220 an IC engine is able to extract both more thermal and mechanical energy from a molecule of gas than at 180. I can find no scientific support for that premise and certainly no mathematic formula to describe it. IT COULD therefore be true. But the TOTAL effect on the incoming ambient air temp, together with frictional losses secondary to increased thermal expansion, etc. might easily eradicate that increased efficiency.

I have never helped someone on the side of the road because their engine was running too cold. At a minimum, I want as much reserve between functional operation and overheating as possible. That alone means 180 is better than 220.

I don't worship at the altar of OE engineering the way fried rice does. Their objectives and priorities could be different than mine. We all seek to modify our vehicles to OUR purpose and priorities and that is why I think the premise originally put forth by Hasan on this thread is valid.

Take your meds and calm down fried rice. If you want to get all emotional and self righteous find a Tea Party forum. Otherwise educate me with facts and science. THAT is the only thing that impresses me.
 
#59 ·
Sorry, briefly off topic.

Hey armored saint, do you work for Larue? If so I have another butt hurt problem. I am looking for a scope mount to use with my Leupold and Knight's SR 25 that provides both correct eye relief and cheek weld with the standard stock. I was looking at the LT 135. Having trouble getting scope high enough. Any thoughts or experience on this would be appreciated. Thanks!
 
#60 ·
Comparing my wg/wj crd and the WK2 HEMI.
The wg radiator is twice as thick more courses then the WK2.
They look about the same size.
The WG CRD has the same radiator part number as the V8 version.
The WG fan looks more robust with more pitch on the fan blades, but is also hydraulic run.
The WK2 has a combined transmission cooler and condenser.
The WK2 radiator end tanks appear to be less then half the size of the WG's.
Both are aluminium core with plastic tanks, remote header tank.
 
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#66 ·
I'll say it again, makes no difference. You're wasting both time and money installing a low temp thermostat. I've towed 6k in 115F ambient temp up the sierras and never saw my water temp rise above the normal temp range. Oil temp and trans temp rose, but all within tolerances. The motor was designed to run at these temperatures and to tow with OE equipment. (i have a 4x4 v8 which comes standard with upgraded cooling parts) Unless you're doing something more extreme than this, then save the headache of doing all this.
 
#68 ·
Well in my daily driving the average speed is 100m/h and once a week I do some offroading on the sand dunes so it gets really hot today for example after racing someone in a new Nissan maxima I did 220k/h so after I slowed down the oil temperature was 235F . so isn't this extreme enough to get a stat ?
 
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