Cold air = bad???

I was reading the reviews on 2gnt and then i read this one... http://www.2gnt.com/nuke/modules.php?name=Reviews&rop=showcontent&id=85

It was saying that cold air is actually bad for your engine, you need some warm air, the cold air will dry the gas before it gets burned. Is this really true???

from what i know cold air is always better for your combustion...
1

Cold air intakes can easily suck up water which is bad for the engine.

it doesnt suck it up that easily, more likly to when there is a really bad rain storm or you are driving through puddles, a lake, or a river :evillol: but other than that it isnt bad at all, i know when i use to have it i just wouldnt drive crazy in the rain, and i never had a problem!

I am not talking about the water!!!

well duckydsp was and thats who i was replying to!!! OBVIOUSLY

and now i will reply to you, colder air is better for the engine! why would companys make intercoolers? and cold air intakes if it wasnt? its been proven a hundred times that your cars performance is better with cooler air, its not like the air is 5 degrees... it is somewhat warm, you engine is gunna perform differnt in the winter anyway so i am talking about summer weather! the temperature of the air on average in the summer depending on where you live will most likly be in the 60-80 degrees, now tell me that that temp is cold!!!

colder air is more dense and pack in more oxygen making your car burn your fuel more efficiantly, in turn leading to higher hp and overall performance. Now, cold air can be a problem if the air is very cold and your not giving your engin enough fuel. That can cause your car to run too lean, and cause engine failur. only if you have a larger turbo with stock injectors and a large intercooler would you really have to worry about getting too cold of air which very rarley happens. I personaly havnt herd of anybody blowing up motors because of too cold of air but i have read about it a few times.

on a side note, i had a shop instructor in high school that said the optimum air intake teperature is 47.8 deg Farenheit. anyone know any more about this???

I've never heard of that, and it seems way to accurate (to one decimal place) to be true. But, on the other hand, the stock 2g ECU (and perhaps 1g, never looked into it) WILL pull 1 degree of timing out below 35 degrees, just like it will over 84 degrees. Coincidence? I never really stopped to question why they do that, I'll have to look into it.

I've never heard of that, and it seems way to accurate (to one decimal place) to be true.

well to my understanding that was what temp was found in a lab in which the fuel and air could make the most power. and again that was just what i was told. the instructer knew his shit though. he use to run in a mini tractor pull series. and had been a mechanic all his life. so i trust him in the information he gave. but i guess it will be something to research. :thumbsup:

From what I know intake air can be too cold. Air too cold prevents fuel from properly vaporizing. This is more of a problem for engines using a Carb. Fuel injection I would assume is only effected mildly. Overall the cooler and dryer the better I would say, simply because the turbo is going to heat it all up again. I ran a few weeks ago with my hood off and noticed a slight increase in power. The temp was like 35 degrees something like 30% humidity. Head stayed nice and cool along with the turbo.

the only theory i heard about cold air...is with the turbo...that cold air with a turbo messes up air : fuel ratio or something like that...that's what i heard is tru about the new Evo...but i dunno if that is tru about the older DSM's is it and is it even tru with the EVO?

Only if the ECU is shyte. There is an intake temp sensor in all cars (except those with hot-wire air flowsensors, the sensor itself takes air temp into account by the process by which is measures air) that will compensate so AFR stays correct. No dSM or EVO will have problems with this.

I dont know if you can get TOO cold, but on a turbo car im sure you want as cool as possible because the pressure increase is going to heat it quite a bit, so I doubt you could get too cold air into the engine.

I dont know if you can get TOO cold, but on a turbo car im sure you want as cool as possible because the pressure increase is going to heat it quite a bit, so I doubt you could get too cold air into the engine.

id have to agree with that it does not matter how cold it is that turbo will heat it up nice and warm.

Its also important to remember that after the turbo heats the air, the intercooler brings it back down ;) Even on the shyte inefficient sidemount, it will cool it a god bit. On a FMIC that is ~80% efficient, it can cool it down more than you would think on a cold day. But, it will always be somewhat warmer than it would be on a NT car. Additionaly, the turbo is only heating the air under boost. So in effect you are NT until you floor it. So the atomization and condensation issues could still be present at cruise. But WOT is all we care about anyway :)

Its also important to remember that after the turbo heats the air, the intercooler brings it back down ;) Even on the shyte inefficient sidemount, it will cool it a god bit. On a FMIC that is ~80% efficient, it can cool it down more than you would think on a cold day. But, it will always be somewhat warmer than it would be on a NT car. Additionaly, the turbo is only heating the air under boost. So in effect you are NT until you floor it. So the atomization and condensation issues could still be present at cruise. But WOT is all we care about anyway :)

an FMIC will cool the air quite a bit but it won't get it anywhere close to the original outside air temp. Also even at cruise your heating up the air. The exahust housing on a turbo can be reeeal hot. (you guys know that.) there is a deffinate increse in air temp. Any way uour ECU should compensate for colder air. That is why you get worse gas mileage when it is cold.

cold air=good

an FMIC will cool the air quite a bit but it won't get it anywhere close to the original outside air temp. Also even at cruise your heating up the air. The exahust housing on a turbo can be reeeal hot. (you guys know that.) there is a deffinate increse in air temp. Any way uour ECU should compensate for colder air. That is why you get worse gas mileage when it is cold.

The intake air doesnt pass through the turbine housing. The little bit of heat that tranfers to the compressor housig isnt going to heat it up much, since the temp is low and the air doesnt spend much time in there. The vast majority of heat imparted on the intake air is heat that is normal added by the process of adiabatic compression. The rest of the heat is from the lack of eficiency inherent in every compressor wheel (no such thing as 100% efficient wheel). At cruise there is no compression, and therefor no adiabatic compression, or efficiency problem. Have you measured this temp increase, or are you asuming it increases at cruise? ;) It will be very small. I have friends with dSMs that are running temp sensors in every concievable location. I can get an exact number if anyone is interested.

Let us say that:

Intake temp is ambient temp. Both are 0 degrees.
Turbo is 75% efficient
FMIC is 85% efficient (they work well in cold air)
we are at sea level
boost is 15 psi
IC pressure drop is 1 psi

Turbo outlet temp will be 137 degrees, but IC outlet temp will be 21 degrees. I'd say the IC does a pretty good job of getting it back near intake temp. This is almost a bes case example though to be perfectly fair. But 21 degrees is still damn cold. I hav never had any trouble either way with my car at 25 psi in this type of weather. Just to run the numbers again to see hte difference, Same scenario but 25 psi gives me 201 turbo outlet temps, and 30 degree IC outlet temps. Not much of a change...

Now I'mnot trying to argue! Just presenting some numbers. I think to say that it "wont get it even close to the original outside air temp" is a bit misguided. Now this is at full throttle and full boost, imagine how small that temp increase will be at cruise. This is my point.

PS. Just for shits and grins I ran the numbers with boost at 0 psi. Sure enough, turbo outlet temp also is 0, and IC outlet is also 0. So the only heat imparted on the intake will indeed be from the heat in the compressor housing, which is minimal. Even when my manifold is glowing, I can touch the compressor housing without getting burned. The only way it may be adding any appreciable heat at cruise might be directly after boosting, and the same couldbe said of a heat soaked IC.

the FMIC efficiency is varibale. It depends on how much air accually flowes through them. We just got done doing test at Caterpillar proving grounds with air to air intercoolers. We ran a c-19 with 34 PSI. We first ran the intercooler in 55 degree air with no flow. The efficiency was horrible. like 24%. As we increased air flow the efficiency increased. Yopu need to have air flowing across the fins. I'm not trying to prive your math wrong...it was quite accurate, I just wanted to state that fact. Make sure that your getting enough air flow to your intercooler. I know that the air does not pass through the turbine housing. On my turbo though you don't even want to touch the compressor housing afer you have been driving. Must be differences in location of the turbo. Just out of crouisty, what kind of EGT's do your turbo 2.0 guys experence?? As far as the cold weather thing... I don't think it matters. My uncle has a 1989 Turbo Trans Am. He has a TE-63 turbo that puts out 27 PSI and an ATR liquid intercooler that he run 12 gallons of icewater through ( the capiacty of the resivors and the accual intercooler.) We have Air temp. sensors before the turbo after the turbo and after the intercooler. Sorry I can't give you the exact numbers i have them written down at his house and can't rembember them. Ill call him up tommrow and getthem. Anyway that temp of the charge air was lower than the temp of the outside air. As far as the heat transferd over from the turbine side to the compressor side. I'm just telling you what I know about the turbo charged buick v-6. I like what you said about how an intercooler works well in the cold. efficiency greatly depends on outside temp. I know we are talking about cold weather but it's something that should be said. You intercooler efficency is decreased as the aoutside temp goes up.

air can be to cold..fuel wont vaporize...know from happening in cold wisconsin was ..a winter..when air temp was thirty below...

I've never heard of cold air being bad either , specially not on a turbo thats why people get intercoolers for more cold air, as a matter of fact my car is performing faster than usual and all i got is turbo and intake....so I doubt it.