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I notice the other day when I had to change a headlight the engine bay is super hot. The headlight housing was almost too hot to touch. Has anyone else noticed this?
 

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Other jeeps remove hood insulation since they go under water often.

Your insulation keeps the hood paint from checkering.

Check the front fenders just near the headlight area. Super hod as that is about the only area for sitting heat to escape.

Hood vents may be nice idea.
 

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Underhood temps aren't an issue, especially with gas motors. They aren't even an issue with turbo diesels. You guys are getting worked up over nothing.
 

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Heat is a major issue when it comes to electronics, plastics and performance efficiency
Except the electronics were designed for the heat, the plastics these days take heat like a champ, and with the non-turbo engine, you aren't even pushing the heat that far, AND the heat only impacts performance if it affects the charge air temp. The only cars of recent manufacture that don't duct intake air form the cool air outside the engine bay are ones that have been modified by their owners.


77Cherokee is right, they aren't an issue, at least as long as they remain withing the range expected by the manufacturer. Which likely means operating the vehicle with ambient temps well above 100F.
 

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I notice the other day when I had to change a headlight the engine bay is super hot. The headlight housing was almost too hot to touch. Has anyone else noticed this?
I noticed my Renny pinged a little bit during 80+ hot/humid days with the A/C on using 87 octane gas. My hubby took the plastic engine cover off (heat-holder-inner) to let the engine breathe better and removed the rubber hood seal strip near the cowel to allow heated air to escape the engine compartment easier and I upgraded to 89 octane gas.

Easy reversible, no more pinging, (even on the 90+ hottest days) and it seems to run a little more peppy than ever before!


Cheers!
:x
 

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I noticed my Renny pinged a little bit during 80+ hot/humid days with the A/C on using 87 octane gas. My hubby took the plastic engine cover off (heat-holder-inner) to let the engine breathe better and removed the rubber hood seal strip near the cowel to allow heated air to escape the engine compartment easier and I upgraded to 89 octane gas.

Easy reversible, no more pinging, (even on the 90+ hottest days) and it seems to run a little more peppy than ever before!


Cheers!
:x
I have run when the temp was 99 degrees, running the AC, accelerating up a steep hill running 85 octane and had no pinging. I always have run 85 octane, never had pinging.

The ECU will adjust the engine operating parameters to compensate for temperature. I doubt your engine was actually pinging, so your hubby removed a bunch of stuff for nothing. Very smart people worked on this issue, what makes you think you can do it better?
 

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Heat is a major issue when it comes to electronics, plastics and performance efficiency
All underhood wiring, plastics, and electronics are rated to at least 125*C, so unless there is wiring running across the exhaust manifold, or there is fire, heat is not an issue.
 

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Oh brother....... :|The GREAT sour-puss, know-it-all, condescending internet forum moron has spoken...... <rolleyes>

As a Mechanical Engineering Technician employed in an engine test lab supplying engine durability testing services to the Big 3, Cummins and Catapillar (amoung others), a former employee of Lingenfelter Performance Engineering, a Corvette Performance business owner of 10 years, a professional calibrator in that business and 23 years in the professional automotive industry, I KNOW what detonation is jackazz and I know what it takes to control and/or suppress it-- either via calibration modification, an alteration of an engine's operational environment or the assembly components therein.

Of course the PCM in these vehicles has the adaptive capacity to re-actively curve/retard ignition timing to suppress det, but in the process, the det event had to occur first and as a result of the timing re-curve, power output is reduced in favor of engine component preservation until the det event either eases or subsides completely. In any case, the resultant action is RE-ACTIVE, not pro-active....

My observation of det in my wife's Renegade was in-fact audibly apparent at throttle tip-in and certainly felt in less power/acceleration when it occurred-- hence the desire to PRO-ACTIVELY curb the det event in the first place by providing the engine a means to shed the latent heat from its surfaces by removing the heavily insulated engine cover and to allow that heat to escape the engine compartment via a hood-wide, 11/16" air gap at the rear of the hood, where a low pressure area exists to evacuate that heat as vehicle speed increases. Add a bit more octane to stave-off whatever chance of det this thing could have over and above the alterations and you have a SUCCESSFUL, reversible, non-invasive, PRO-ACTIVE change that positively affected the performance of this Jeep.

Why don't you quit being such as dip-**** on this board by trying to help someone with helpful, ACCURATE information for once, instead of brow-beating them with your cynicism and sarcastic remarks and stay clear of the us that actually KNOW what we're talking about!

Now....I'm sure you'll jump right back in here and have the last word with your incoherent drivel like you always like to do, even though what usually comes out of head and makes it on this board makes everyone else who's read it dumber, so I digress-- have your way....it's what you do. I'm out and good luck. You certainly need it.......


Cheers!
Mr. Jeepmom ;)
 

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There is your problem. All your experience is engines in test cells. I could wrap an engine in insulation and as long as the cooling system is working, the engine won't knock. You should also know aluminum is a poor conductor of heat (better than brass, in case you go there). So a little more airflow through the engine compartment isn't going to do anything. Removing the hush panel and the hood seal will just let the engine be a little louder. Knock at throttle tip in is common and doesn't hurt anything as combustion pressures are low. You should also know that increased intake air temp will also cause the ECU to pull timing and fuel. Not to mention running the AC hogs power. Like I said, I am running 85 octane and have no knock issues.

And what is with the juvenile name calling? Are you 12? If you want to talk, talk like an adult.

You should also look into inboard boat engines. The do have venting systems, but for fumes, not heat.
 

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Oh brother....... :|The GREAT sour-puss, know-it-all, condescending internet forum moron has spoken...... <rolleyes>

As a Mechanical Engineering Technician employed in an engine test lab supplying engine durability testing services to the Big 3, Cummins and Catapillar (amoung others), a former employee of Lingenfelter Performance Engineering, a Corvette Performance business owner of 10 years, a professional calibrator in that business and 23 years in the professional automotive industry, I KNOW what detonation is jackazz and I know what it takes to control and/or suppress it-- either via calibration modification, an alteration of an engine's operational environment or the assembly components therein.

Of course the PCM in these vehicles has the adaptive capacity to re-actively curve/retard ignition timing to suppress det, but in the process, the det event had to occur first and as a result of the timing re-curve, power output is reduced in favor of engine component preservation until the det event either eases or subsides completely. In any case, the resultant action is RE-ACTIVE, not pro-active....

My observation of det in my wife's Renegade was in-fact audibly apparent at throttle tip-in and certainly felt in less power/acceleration when it occurred-- hence the desire to PRO-ACTIVELY curb the det event in the first place by providing the engine a means to shed the latent heat from its surfaces by removing the heavily insulated engine cover and to allow that heat to escape the engine compartment via a hood-wide, 11/16" air gap at the rear of the hood, where a low pressure area exists to evacuate that heat as vehicle speed increases. Add a bit more octane to stave-off whatever chance of det this thing could have over and above the alterations and you have a SUCCESSFUL, reversible, non-invasive, PRO-ACTIVE change that positively affected the performance of this Jeep.

Why don't you quit being such as dip-**** on this board by trying to help someone with helpful, ACCURATE information for once, instead of brow-beating them with your cynicism and sarcastic remarks and stay clear of the us that actually KNOW what we're talking about!

Now....I'm sure you'll jump right back in here and have the last word with your incoherent drivel like you always like to do, even though what usually comes out of head and makes it on this board makes everyone else who's read it dumber, so I digress-- have your way....it's what you do. I'm out and good luck. You certainly need it.......


Cheers!
Mr. Jeepmom ;)
*like*
 

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Oh brother....... :|The GREAT sour-puss, know-it-all, condescending internet forum moron has spoken...... <rolleyes>

As a Mechanical Engineering Technician employed in an engine test lab supplying engine durability testing services to the Big 3, Cummins and Catapillar (amoung others), a former employee of Lingenfelter Performance Engineering, a Corvette Performance business owner of 10 years, a professional calibrator in that business and 23 years in the professional automotive industry, I KNOW what detonation is jackazz and I know what it takes to control and/or suppress it-- either via calibration modification, an alteration of an engine's operational environment or the assembly components therein.

Of course the PCM in these vehicles has the adaptive capacity to re-actively curve/retard ignition timing to suppress det, but in the process, the det event had to occur first and as a result of the timing re-curve, power output is reduced in favor of engine component preservation until the det event either eases or subsides completely. In any case, the resultant action is RE-ACTIVE, not pro-active....

My observation of det in my wife's Renegade was in-fact audibly apparent at throttle tip-in and certainly felt in less power/acceleration when it occurred-- hence the desire to PRO-ACTIVELY curb the det event in the first place by providing the engine a means to shed the latent heat from its surfaces by removing the heavily insulated engine cover and to allow that heat to escape the engine compartment via a hood-wide, 11/16" air gap at the rear of the hood, where a low pressure area exists to evacuate that heat as vehicle speed increases. Add a bit more octane to stave-off whatever chance of det this thing could have over and above the alterations and you have a SUCCESSFUL, reversible, non-invasive, PRO-ACTIVE change that positively affected the performance of this Jeep.

Why don't you quit being such as dip-**** on this board by trying to help someone with helpful, ACCURATE information for once, instead of brow-beating them with your cynicism and sarcastic remarks and stay clear of the us that actually KNOW what we're talking about!

Now....I'm sure you'll jump right back in here and have the last word with your incoherent drivel like you always like to do, even though what usually comes out of head and makes it on this board makes everyone else who's read it dumber, so I digress-- have your way....it's what you do. I'm out and good luck. You certainly need it.......


Cheers!
Mr. Jeepmom ;)

OK, but
1) we have people who sawzalled a hole in the hood of the car and installed a vent of fit and finish not exactly congruent with OEM parts while removing the insulation under the hood. This will shorten the life of the paintjob and negatively affect the resale value of the car, especially in the short term. It absolutely should not be portrayed as an unalloyed good, and a counterargument should definitely be presented in regards to a "problem" without data to back it up.

2) The car reacts to "knock". The knock is simply vibration. There is no guarantee of it being detonation, and many things can set off knock detectors that are most definitely not detonation. You should know this. One of the things that can create additional chatter are the short piston skirts being used in newer cars in the chase of better fuel economy. This is what I assumed some of the chatter was on tip in, it turned out not to be so, but "it sounds like it's X" is pretty weak reasoning in this day and age where data logging is so easily available.

3) You can go get your car flashed. The above mentioned tip in growl/chatter/grumble at ~1500 rpm is gone after my last update. Way smoother and more quiet and behaving more like the engine does in other FCA offerings. That's also pro-active and doesn't involve vandalizing the vehicle. There's also the issue of putting a band aid on an underlying problem. If increasing airflow under hood does make it go away, have you fixed it, or just fixed it under a fraction of the circumstances the car will actually be exposed to?

4) From data logging, the pattern of pulling timing seemed to be pretty much about application of the throttle and not dependent on ambient temp or intake temp all that much. I'm still currently evaluating post flash behavior, free time is at a premium.

5) Alleviating under hood temps should be based on actually determining that they are indeed higher than intended by design. It's not like the engine block is a radiator and designed to dissipate heat. For more airflow to reduce heat, you'd need that airflow to be going over the radiator and/or intercooler, or at least reducing temps in tha vicinity enough to cause the radiator to be able to do more work.

Cherokee77's essentially advocating, to now rip out your insulation or cut holes in your vehicle because the plastic is hot, or because you find the temperatures to SEEM to be hot. His advice is correct.
 

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Ohh muh gosh..... Hahahaha! If you say so there sport.... LoL!

We'll leave some of you folks to your willful ignorance and stupidity, so as my hubby said....I'm out too!

Good luck!


Cheers!
:x
 

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wondering if there is a way to vent out some heat. I hear on other jeeps people remove the hood insulation.
I bought a pair of hood louvers. Getting ready to drill/cut the hood to install. I'm gonna cut the insulation for the holes but keep the remainder intact. Should help reduce the under hood temp...Gets a little "toasty" here in the desert.
 
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