Intake temp and HP relationship
 

I remember this being mentioned before but couldn't find it. Does anyone remember the relationship between hp increase and temp drop?? (x hp for y deg drop)

I have heard that for every 10 degrees F that intake temperature drops, HP will increase 1%.

That's what I've read (on this forum) too, but that just can't be right! These turbo cars run like mad when it's cold out and feel like a dog in the heat of summer. I wouldn't think 50 degrees =~15hp judging by the seat of my pants...but who knows. Anybody happen to have dynoed a car in the winter and then done the same car in the summer by any chance? Looking at the uncorrected numbers could answer this once and for all!

I was the one who quoted the 10 degree drop in temp increases HP by 1 - 1.5%, but I read another source today, that said it closer to 1% every 4-5 degrees based on their dyno results.

more power to the IC-AC!!!

K

edit

Here is a thought. In the quest for more hp, ideas and gadgets have been flying around. Things such as liquid injection, IC spray, using air to liquid ic with ice water etc. But it seem that all the ideas so far are designed for a short operating period (very short). So I'd like to add my little light bulb to the ever growing list.
Air conditioning is simple process where by the freon is allowed to expand into a device called the evaporator (pretty much just a radiator). The sudden expasion is endothermic and effectively turns the evaporator into a block of ice, the air that travles through the evaporator is than significantly cooled. A device that acts like an evaporator/heat exchanger and tapped into the existing ac system can be made to attach to the ic. And it serves two purposes. One, it will significantly cool the external air passing through the ic, sort of like driving in the winter time. Two, due to the metal to metal contact and thermal conductivity, the ic it self would be cooled significantly thereby cooling the internal air flow more. This would effectively resolve the standing heat soak problem completely. When sitting in traffic the ic would turn ice cold.
A counterpart idea to this is, screw the ic period. replace the ic with a tubular evaporator (the diameter needs to be calculated to minimize pressure drop). And effectively you'll be blowing freezing air into you manifold. We are talking 30 deg F intake air temp(that's below 0 deg C)! This would even work for NAs. It gives the term cold air intake a new meaning. And this would not be a one shot deal, like the ic spray or water injection and requiring refills. Just imagine the hp increase.
Ideas, comments???

You can't get something for nothing. Do you really want to be running your AC when driving aggressively? AC zaps quite a bit of HP.

Also, I think that the amount of cold air the evaporator could generate would never be enough to cool the IC effectively when running hard. The BTU removal would be too much for the small AC system in our cars. Hell, think of all the ambient air forced into the IC during an 80mph sprint vs. the piddly air that comes out of your AC. All this forced ambient air isn't even enough to cool the IC down to ambient temperatures.

Well, you can turn it off when you're gettin' on the gas. I was thinking the same thing. Thermodynamics says you'll create more heat than you create cold, but it would be a good idea to have it run say, when the brake pedal is pressed.
~Tom

Me and a friend also thought about the a/c idea but the down side I saw was running the a/c when it was cold outside. Even when its cold outside you still heat soak real bad in traffic so the cooling would still be necessary but who want to run the a/c when its 40-60 degrees outside???

Is there a way it would be rigged up to work without blowing air into the car? It would need to be easily converted so that you could blow air into the car for summer.

It would prob be a good idea for guys up north that dont need a/c to blow in the car during the summer. They can just rig the a/c to work with the IC and that it. A lot of guys up north pull the a/c anyway, down here believe me you want ac read bad. 105 temps with 100% humidity sucks big time.

STEPHEN

I think you guys are missing the point... The AC would never have enough BTU removal to have much effect on the IC temperature. Think of it this way, your AC would have to be blowing on the IC with the same air flow or more as what is going through the IC into the engine. Does your AC blow with the same flow as the 2 turbos???

whitet777: i see their point. they are saying that dont run the ac when your sprinting, but run it when the brake pedal is depressed. i do agree with you that the AC doesnt have enough power to overwhelm the heat production of the 2 turbos BUT, it certainly has the power to cool it downwards. so, if your stuck in traffic, instead of your intake temperatures going up, you see them going down. this idea wont keep your car very cool at all times, but it will effectively cool it down when stopped (even if the process is slow).

I will agree that for the short time you are stopped, it will cool the IC. But, Trexthe3rd said, "But it seem that all the ideas so far are designed for a short operating period (very short). "

I am just saying that for the amount of modifications that would be necessary to use the AC to cool the IC, that the returns would be very little. This solution would not give the long-term cooler IC temperatures that Trexthe3rd wanted in the first place.

Get one of these

http://www.coolflow.com/prod1.htm

The liquid cooler idea is getting there. I think you guys misunderstood my discription. I am not blowing ac air onto the ic, the air is still comming from the normal airflow created by the traveling speed of the vehicle, it is just passed through the 'evaporator' and then the ic. The amount of airflow is the same but colder. At the same time, due to the thermal conductivity of metals, the evaporator will cause the ic to be around the same temperature (near or below 0 deg C). AC is an enclosed system, the only difference would be the enclosed volume change due to the addition of an extra evaporator. The technical difficulty lies within the efficiency of the compressor, it's designed for a small car and therefor have a relatively low ouptut.
Basic calculations show that the hp gains from the temp drop far out weighs attempts such as removing the ac system for increasing hp.
The coolflow is definitely a step in the right direction though. It's basically an air to liquid intercooler that uses part of the ac to cool the liquid instead of a typical radiator. It's got potential