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  #49  
Old 12-13-2011, 01:49 AM
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Re: WK2 GC - Reducing Hemi Engine temp

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Originally Posted by FlyinRyan View Post
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.
however correct me if i'm wrong since I'm not privy to OE timing maps, but my experience with programming/tuning standalones is that there is no engine temp compensation to ignition timing. Only based on knock sensor values do we retard timing - ignition retard is a reactive and not a preventative event.

Items that lead to fuel precombustion are IAT, Fuel Temp, and Plug temp. No parts of the combustion chamber should be getting hot enough to glow and predetonate the a/f mixture (if so, you've got a bomb on your hands and your thermostat has nothing to do with that 180F or 200F). So if performance is your game you would want to keep these to a minimum so as to keep predetonation to a minimum, the other way to keep it to a minimum is to just run a higher octane fuel.

Our OE timing map is retarded (literally) because it's programmed that way and not because our motors are pinging. These motors were basically designed to run on 85 octane fuel, in 120 degree heat, and short 2 quarts of fuel (exaggeration fwiw). As most of us have found out for whatever reason our motors are happier with 87 octane versus 89 or 91 even though general tuning knowlege tells us the motor should be running leaner and therefore more powerful using less fuel with higher octane fuels.

in short, a 20 degree water temp is barely anything worthwhile when you're trying to cool down a motor with operating explosions upwards of 1400F

(found some interesting info on the LX forums)
ust a quote from Mopar Muscle Magazine.

"Trying to launch the more powerful SRT8 was not an easy task. The 6.1 actually delivered its best e.t. during its third hot-lap. The Daytona did its best on its second hot-lap. These new Hemi's are the only motors we've ever tested that run stronger on a hot-lap. Remember, a cooler-than-stock thermostat (160- or 180-degree) is not recommended for any bone stock third-gen Hemi. Dyno and strip testing proves it."

http://www.moparmusclemagazine.com/t...t_results.html

http://www.mgcarz.com/thermostats.html

Even the SRT engineers say the Hemi runs best at a hot temperature.

Lastly, operating temp for oil is 210F. meaning that lower temps will net less viscose oil meaning you aren't getting the proper lubrication for your motor. Also a motor running at full operating temp is fully expanded and running with its proper clearances.

Again, the all important question we should all be asking is, what is the proper operating temp for a motor, and yes you can get too hot AND too cold. My impressions from basic research are 200-225F are just fine for our motors. If your car is going to overheat and see 260, you can surely bet something else is to blame and not your tstat. at 260F both the 180 and the 200 tstat are fully open with the fan at full blast.
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  #50  
Old 12-18-2011, 07:42 AM
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Re: WK2 GC - Reducing Hemi Engine temp

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 ! :-)
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  #51  
Old 12-18-2011, 03:07 PM
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Re: WK2 GC - Reducing Hemi Engine temp

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.
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  #52  
Old 12-21-2011, 10:33 PM
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Post Re: WK2 GC - Reducing Hemi Engine temp

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!
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  #53  
Old 12-22-2011, 08:30 PM
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Re: WK2 GC - Reducing Hemi Engine temp

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

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Originally Posted by ron13 View Post
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!
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Old 12-22-2011, 11:36 PM
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Cool 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.
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Old 12-23-2011, 03:36 AM
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Re: More BS and more cheese.

Quote:
Originally Posted by ron13 View Post
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.
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Old 12-23-2011, 07:19 AM
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Re: WK2 GC - Reducing Hemi Engine temp

Well, I see that this is going well.
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Old 12-23-2011, 11:58 AM
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Talking 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.
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Old 12-23-2011, 01:27 PM
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Re: WK2 GC - Reducing Hemi Engine temp

it's funny people get all butt-hurt on a jeep forum...damn
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Old 12-23-2011, 03:25 PM
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Smile 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!
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Old 12-24-2011, 10:40 AM
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Re: WK2 GC - Reducing Hemi Engine temp

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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