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Old 07-03-2002, 05:28 AM   #1
Icon25rs
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Question Hoootttt Air

How harmful is hot air to a suby engine? Cause it has been really hot on the east coast and my baby grl has less pick up than it did before when it is really hot. Plus for all you ppl that own a MY02 I took that damn piece off that is in the front left side of the car where the air pipe is. All it does is block air from getting in there. I am waiting for a Larry Ganz pipe, I hope to get it soon. But I took that piece off back in January and got a tad bit more horse power. But then again it was cold outside. Do you think I should put it back on still I get the pipe?
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Old 07-03-2002, 08:24 AM   #2
Legacy777
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Hot air is BAD.......mmmmmkkkkkkaaay....

There was a graph floating around at how much hp you lost with the increase in intake air temp charge.....don't know where it is now......

But it essentially was pointing at that any benefits from an open style filter which sucks air from the intake bay is negated from the higher temp.

I had been running an open style filter on my legacy for about 5 years or so. I recently put the stock box back on. I like the results of putting the box back on. Idle is a lot smoother, mid-range torque is better. Only thing I lost was the quickness in how it revved in the higher rpms. I'm goin to be custom doing some extra tubing to plumb to the bottom of the air box to give it more air. So hopefully I'll get that quicker revs back.

Josh
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Old 07-03-2002, 07:08 PM   #3
Mapplex
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Default hot hot hot!

I'm melting!!! melting!!! Here in VT it's currently 93 F and with the heat index it feels like 104 F according to the weather channel.
I could literally see the waves of hot air escaping from my Subi when I opened the door. Anyone want dashboard fried eggs? some toast? or does anyone need to incinerate some incriminating evidence? My Subi's a car by night, oven by day.
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Old 07-03-2002, 07:10 PM   #4
Legacy777
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welcome to what it nearly feels like in Houston.......hahaha....might not be quite that bad right now.....but it gets bad during august......
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Old 07-03-2002, 07:33 PM   #5
Kevin Thomas
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Default Hrrmmmm

Here's a question for you........which of these scenarious makes more hp:

1) 50F + 87 octane gasoline,

2) 100F + 92 octane gasoline?

In both cases timing isn't retarded because there's no detonation or pinging.

Pop Quiz!

Hot air is BAD if it causes detonation and/or pinging. Otherwise, it's not harmful at all.
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Old 07-03-2002, 08:10 PM   #6
Legacy777
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octane isn't really goin to make more hp....especially if your ecu is designed to run on 87......you're just wastin money unless you got a chip and such.......

In either case....it isn't detonation.....it's volume of air.....cold air is more dense.....hot air is less dense.....you can fit more air inside a 1 cubic foot container at 50 degrees then you can at 100 degrees.

Principle is the same with an engine.....it becomes more pronounced because you are compressing the air......pre-ignition and detonation really don't come into the picture.....neither does octane......
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Old 07-03-2002, 08:11 PM   #7
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Definatly number 1 if in fact there is not retardation. Higher density of oxygen in the comustion chamber

edit: I posted this reply before legacy777 response showed so I agree'd with him without knowing it prior.
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Old 07-03-2002, 08:23 PM   #8
Patrick Olsen
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Default Re: Hoootttt Air

Quote:
Originally posted by Icon25rs
How harmful is hot air to a suby engine?
How harmful is it? You're joking, right?

Seriously, the power output of Subaru engines is rated as SAE brake horsepower. The SAE part means the engines are tested/corrected to specific conditions, specifically STP - standard temperature and pressure. The standard temperature (correct if I'm wrong, guys) is 77degF. It is safe to say that if the temperature is above 77degF you risk doing catastrophic damage to the engine internals. That's why there are no cars in the Middle East, the desert Southwest, northern Africa, etc. It's just too damn harmful to the engines to run in that kind of weather. You might as well just pour a bag of sand into the engine, it'll have about the same effect.

Pat Olsen
'97 Legacy 2.5GT sedan
Walkin' to work cuz it's too hot for my car...
























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Old 07-03-2002, 08:43 PM   #9
skid00skid00
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Default I remove hood gasket at base of windshield

I remove the hood gasket at base of the windshield.

This helps rid the engine bay of hot air AFTER you stop.

Note that when you're driving, there's high pressure at
the base of the windshield, so you'll be pushing air
under the hood from there, reducing the low pressure
area under the hood, reducing the amount of air
flowing thru the radiators...
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Old 07-03-2002, 08:58 PM   #10
djinn1973
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Default

The kind of temp that you are talking about is not really going to "Damage" you engine at all... The loss in power that you feel is from the hotter air being less "dense" I would dare say that any thing up to about 115-120 is o.k. to drive in, but why would you want to?

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Old 07-03-2002, 09:10 PM   #11
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Don't listen to Patrick Olsen. He's wrong! I swear I've seen cars in Egypt.

I've even rode in one - it's like a 4 hours trip in a mid-70's Peugeot 504 from Aswan to the temple of Abu Simbel. That car has some aftermarket A/C, but it was still pretty hot inside once the sun came out, in the middle of July. The worst thing about that trip was that the top speed was like 60MPH, and we were passed by modern Euro-spec tour buses.

Finally, during the midway break, I found out why that car was so slow. It actually has a 1.3 or 1.5 liter Toyota engine in it. Poor thing has to pull a mid-size sedan with 4 persons and A/C...

Oh, my post has nothing to do with any discussion in this thread. So, please disregard.

-Ray
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Old 07-03-2002, 11:09 PM   #12
Kevin Thomas
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Question Time to be annoying.....

Quote:
Originally posted by legacy777
In either case....it isn't detonation.....it's volume of air.....cold air is more dense.....hot air is less dense.....you can fit more air inside a 1 cubic foot container at 50 degrees then you can at 100 degrees.

Principle is the same with an engine.....it becomes more pronounced because you are compressing the air......pre-ignition and detonation really don't come into the picture.....neither does octane......
Ok! So lets say you have a stock 2.5RS on a really really cold day (10F) vs a turbocharged non-intercooled 2.5RS (just on the verge of detonation) on a 100F day @2psi. Here...there's a 90F difference in temps but the turbocharged RS should be making around 20hp more than stock. Problem is power is lost at approximately 1% for every 10F + so there's a 9% power loss for

One car has way more denser air but one has more volume.

Pop Quiz!
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Old 07-05-2002, 03:52 PM   #13
Legacy777
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Default Re: Time to be annoying.....

Quote:
Originally posted by Kevin Thomas


Ok! So lets say you have a stock 2.5RS on a really really cold day (10F) vs a turbocharged non-intercooled 2.5RS (just on the verge of detonation) on a 100F day @2psi. Here...there's a 90F difference in temps but the turbocharged RS should be making around 20hp more than stock. Problem is power is lost at approximately 1% for every 10F + so there's a 9% power loss for

One car has way more denser air but one has more volume.

Pop Quiz!
Kevin......your example.....is sorta like comparing apples and oranges......you really can't compare a turbo charged setup to a N/A setup......

What I said will hold true when comparing a N/A to N/A or TC to TC.
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Old 07-05-2002, 04:08 PM   #14
aek
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Default

I just had a trip to New England for 4 days and it's damn HOT !
However, I didn't notice a lot of HP loss.

I don't know why but I think the K&N may help a lot. I cruise on the highway @ 80 ~90 mph with AC on "2".

I was wondering if a hood scoop on MY02 RS help extract hot air in the engine bay
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Old 07-05-2002, 05:34 PM   #15
Jayson_K
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Nahhhhh the hot air provides less wind resistance and lets you go faster man
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Old 07-05-2002, 08:08 PM   #16
RaceCarRiot
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Talking because there aren't any funny posts in n/a anymore...

no no no, you guys have it all wrong. it's better to have your engine bay full of HOT air, since hot air is less dense, and therefore weighs less, reducing the load on the engine, suspension, brakes, tires, etc. in fact, if you talk enough while in or around the vehicle, you may be able to generate more air, and lower your ET by a few tenths. if someone made a hot helium intake, it'd be even faster, since helium is much less dense.
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Old 07-07-2002, 08:18 PM   #17
Icon25rs
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Default

Why don't I just carry the car on my back. That way I save, gas, engine life, load, and everything else you guys put on here. And I have been to the desert and it is way hotter and wetter there than here. There was still cars out that, they looked like crap but they ran. I didn't think I would get such wild answers. It just proves Suby owners are nuts. Who else would WANT to drive sideways all the time.
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Old 07-07-2002, 09:20 PM   #18
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[....looks around, and cautiously starts backing away....]

....weirdo's....
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Old 07-08-2002, 01:33 PM   #19
Kevin Thomas
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Talking Re: Re: Time to be annoying.....

Quote:
Originally posted by legacy777


Kevin......your example.....is sorta like comparing apples and oranges......you really can't compare a turbo charged setup to a N/A setup......
People are always talking about comparing apples to oranges. They are both FRUITS. Anything can be compared if they are not exactly the same.
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Old 07-09-2002, 10:26 AM   #20
Jack
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Default Ray, you're full of Kwan!

Pat is right. There are no surviving cars in the deserts of the middle east and central Asia. That's why they started extracting so much oil from the ground. They run a car for about 2 weeks. Then they need to buy a new one.

And you need to be very careful about openning up the hood scoop. When running very fast, the incoming air builds up pressure under the hood and pretty soon the front end of the car picks up and.....well, you've seen dragsters flip, right? That happened to me at Lime Rock with my 2.5RS. Front end picked right up and flipped me over. I slid into the runoff area at Big Bend on my roof. Fortunately, the Easter Bunny was watching and came to help me flip it back upright. I still ended up with a 1:12 lap time.

Really, I wouldn't lie

jack
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Old 07-09-2002, 12:20 PM   #21
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Wait just one minute here....what is this? Comedy? Jokes? Jokes in the NA forum? WHAT IS WRONG WITH YOU PEOPLE!

NC
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Old 07-09-2002, 02:31 PM   #22
pope
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Default concept

why dont we just tape ice cubes around the intake manifold then? DUH
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Old 07-09-2002, 02:34 PM   #23
ciper
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Because the tape wouldnt stick?

Just fill the bottom of the air filter box with ice!!!
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Old 07-09-2002, 04:28 PM   #24
phucvtec
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I have to believe that if is was energetically efficient to cool the intake air by having the engine do work, oh, such as bolting an inner cooler on the CAI, running the air conditioning compressor, and blowing cold air tangentally through the inner cooler, this setup would exist in all NA vehicles. It may sound neat, but there is no benefit of innercooling the air in a NA engine, since you can only reduce the temperature to that of the outside air, which is what is being drawn into the engine! I guess exploring the "ice cube" option is not such a bad idea
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Old 07-09-2002, 05:54 PM   #25
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When doing runs, some people cheat by placing a bag of ice on their intake manifold or around the intake tubing. There was an issue of Car and Driver that tested two modded Vettes against each other. At the end of the article, the noted that the results may be skewed because one of the other teams where icing down their intakes between runs.
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