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  • FACT

    Votes: 19 59.4%
  • FICTION

    Votes: 13 40.6%

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Discussion Starter #1 (Edited)
FACT or FICTION. I've heard that running the heater with the AC and FAN turned OFF helps the engine run cooler, hence better operating performance. I also saw a WRC race a while back where one of the Evo's had trouble with the cooling system, so the driver compensated by driving with the heater on. Mind you, the dude (and co-driver) was wearing a full race suit so that couln't possibly be very comfortable.
 

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this is not enough to gain hp, turning the heater on will help your engine temperature if you have a problem but you won't gain perfomance
 

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False, no performance gain from running the heater.
 

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Focused Focus
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If there is any gain, you wouldnt feel or see it, but doin that does in fact help run slightly cooler.
 

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Discussion Starter #7 (Edited)
I wasn't refering to HP/FT-LB performance (sorry, not clear). I was refering to operating performance (runs cooler, better, etc.) I'll edit the post.

I am in Miami and it is starting to get really hot here. So I am in an all-out war to lower the underhood temperature (header cooling- wrap or jet-hot- coming soon). No over-heating problems, but I just want to lower engine bay temp as much as possible.
 

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If I read the Arturo's post right, two points have been covered.

1) Driving with the AC and Fans in the OFF position. -- This is only beneficial because the AC/Defroster saps (uses) up engine power driving the AC compressor. Thus there is less power to move the car forward. Most news sites say that if you want better gas milage try to use your AC less. That is another benefit of not using the AC, and general proof that the AC leeches power from the engine. I guess if you believe that using the AC makes the engine work harder, the engine then might be warmer, and thus hurt performance, but I think the fact that the engine has to work harder is worse than the small increase in operating temperature.

2) Driving with the heater on. -- This utilizes the heater core in the dashboard as another radiator to cool the engine. Under normal conditions this won't cool the engine enough to be significant but as with the WRC Evo, if something is not working correctly, this can help act as a band-aid for the problem until it can be fixed. So in dire circumstances turning the heater on could help get you to a safe place but during regular daily driving this isn't much help.

While that should clarify things, I couldn't vote because there are two (2) questions and they are both kind of right, but I guess the actual effects are minimal so not really effective enough for a Truth vote.
 

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the heater core acts like a 'mini-radiator' and drops the temps.

that being said, keep in mind, your car is DESIGNED to run at a certain temperature. there is such a thing as too cool... as long as you are staying near the halfway point, you are running fine.
 

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If you have a cooling problem in the middle of the freeway this might buy you some time to get off the road to a helpful stopping place, but other than that it is only usefull in the winter. (My 2 cents)I don't think that running the heater is going to get you anywhere near too cool.
 

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ive done it a long time ago to try to get my 280zx to stop overheating
 

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Titular Wit Here
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If you're in Miami, and it's starting to get really hot, why on Earth would you want to drive with the heater on if there is nothing wrong with the cooling system for the engine? Why lower underhood temperatures at the sacrifice of interior temperatures when there really isn't a reason to? Have you ever driven in traffic on a really hot day, with the heater on?? I have, because I had to (as others mentioned it works for overheating situations and this did happen to me once in another car) and I wouldn't do it again unless it was necessary. I must have lost 5 lbs. in sweat alone.
 

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Discussion Starter #14
Actually I used to do it in my GTI all the time. I just opened the windows and sunroof and pointed the vents out. Easy, no sweat. Of course, if I was sitting in the middle of traffic at 12 noon I wouldn't do it.

I have a SRI so I'm trying to keep the engine bay as cool as possible and I figure that every little bit counts.
 

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get a vented hood... the VIS invader has a nice vent right near the sri location
 

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I liked Scott_SVT 's comment "keep in mind, your car is DESIGNED to run at a certain temperature". Amen. You got gauges? Read 'em.

Don't tweak the not-worthy-of-tweaking.

The worst thing about his 2 Foci that Brett griped about, and I felt as passenger and now SVT driver, is how piss-poor they are about flow-thru ventilation (versus vehicles badged by makers on other continents), how heat comes into the cabin no matter what--along w/the AC even! So why be miserable for a micron of questionable 'improvement" in performance?

In 30+ yrs of Texas heat I've only driven w/heater on in hot times in emergencies--hose broke & temp gauge pegged. You are the human being. It's a car. A great one, yes, but you will not get a merit badge for sacrificing sweat glands for your car.

an old lady's thoughts.....
 

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You can't lower the temp below the designed operating temp. If you do, the T-stat will close and stop using the cooling system. Running the heater only helps you when the car is not 100%, as others have said.
 

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in that kind of heat.. use the damn ac...lol!!! seriously though.. the only time that "mehtod" should be used, is if your overheating.. and you need to buy time to get off the road safely... other than that.. dont sweat about it....lol
 

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There is no gain, however it does forcefully push hot air from under the hood to your face. My friend was driving with his dad once and the truck started to overheat. They pulled over for 5 min then continued to drive with the heat full blast and the car did not overheat all the way home. I doubt it would do anything for performance.
 
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