KidFrost

Ok, So this is simply for discussion purposes and my own curiosity so if you are gunna get all but hurt and start "flaming" just dont post... ok?

The question, just how important are IAT's on a forced induction application. Most people would answer obviously pretty important. So I am wondering, and I've searched, why more people don't do more to bring down IAT's. Yes, I know there are big *** air to air intercoolers/aftercoolers strapped to the front of just about every turbo Honda out there, but air to air cooling is not the most efficient way to cool charge air, however it is in fact more than good enough for most applications. I'm sure someone will chime in with a few others that I am unaware of but the two other ways I am referring to are Water to air "aftercoolers" and DEI's Co2 powered idea Cryo2.

Now my first question is, how cold CAN you get IAT's and what is the cut off in which colder is better? Is there some sort of linear graph that shows X number of Degrees = 1 Hp? I have searched, and have found mixed responses, however every where I go it seems "someone" chimes in with 10 Deg= 1% Hp increase. These anecdotal posts were all on non-forced induction applications, where cooling IAT's seems to be more of an issue. In the one forced induction application I saw someone claimed every 4-5 Deg = 1% hp increase.

Although I am sure there is variation from situation to situation there has to be some sort of collected consensus as far as going from say an eBay intercooler to a better one, ect...

If this is the case- 5-10 Deg= 1% increase in hp, Now I am obviously going to use my car as the example engine, if I could lower IAT's... say for the SAKE OF DISCUSSION.. 75 degrees over just my intercooler, that would be a 7.5%-15% increase in horsepower, on a motor that already makes 530 whp that would be 40-80 hp increase at the same boost level without increasing risk breaking something, untimely increasing longevity, safety, ect...

Now I assume at the same time one could most likely increase boost levels with IAT's that low and make even more power.

I quite honestly believe if all three forms of air cooling were used you could reduce IAT's more than 75 degrees, considering DEI claims a 50 degree drop in temp, with ONE intake bulb. I've yet to find what kind of temp drops you could expect from a PWR or frozen boost, water to air barrel. Never the less, I think this is a reasonable way to gain more power out of a setup with out spending too much money. If you could add both the DEI system and a water to air barrel to an already turbocharged system for around 1,000 dollars, you are talking about 1hp =$12.5-$25.

But for entertainment pouproses,

SHOOT A HOLE IN IT !



-KidFrost

tepid1

Lots of different variables to consider here....

Charge per and post IC temperatures, water flow thought the IC, charge volumetric flow, charge pressure, etc....

It's not as simple as you may think.

Also, depends on fuel being used. Some fuel responds well with cold charge temps. Others, like ethanol, responds well with warmer temps. Too cold isn't always the answer.

Westrock2000

IAT are important, because it is abstract way of saying how dense the air is. Anything that's colder means the molecules are not moving around as much. So if a gas a "cooler" it means more molecules of that has can occupy the same volume. And since fuel is injected proportiontly to the amount of air available, you can understand that cooler air means more fuel.

As to why people use air-to-air, there is 1 simple reason. They require zero maintaince. Everything else requires some type of periodic upkeep or refill of consumables. So air to air is more dependable for most people.

EDIT: Also, people have stated many times that's its more efficient to just directly inject nitrous into the intake tract instead of using nitrous or CO2 to indirectly cool the air by cooling some type of a heat exchanger. Because then you gain from both the cooling of the nitrous as well as the oxygen that gets released from the N2O.

Dark_Teg

Go buy yourself a Ford Lightning and you will be a pro on how hot IAT's can kill HP in no time. I just got my Lightning dyno tuned was seeing 170* IAT's which means we had to pull a lot of timing. The cooler the IAT's the more timing you can leave in which =HP.

We had to start pulling lots of timing after 4000 rpms and you can see the torque nosedive as a result.

xbigpitax

get a heat exchanger and make sure your intercooler pump is working. mine get to 130 max

Finest

Lower IAT's almost always leads to more hp, yes. I don't think there's a measurable chart or formula (or if there is, I'm not smart enough to proof it) to figure where it drops off due to all of the various different set ups around. Different turbos, different engines, altitude and climate, etc etc. Obviously you won't gain 500whp if you can get the charge air temp down to negative 50 degrees. Absolute whp is still determined by the cfm turned through the compressor wheels. Intercoolers are just heat exchangers, but remember they come later in the intake stream. So anything you try to do after the fact is just a quick fix and not a solution to the overall picture.

You also have to think further back down the stream to make sure everything else is working properly. Are you overspinning your compressor, which in turn heats up the charge air more than it should? Is your setup at the most efficiency possible? Or could you tweak a few more things to bring down that IAT before it even goes through the intercooler? Or even before it gets compressed?

SovXietday

All you will ever get out of this set up in the long term is ambient air temps, at the very best.

Reasons

1) A2A intercooler is always limited to air.

2) Your CO2 will do very little for cooling. The reason behind this is the comparative mass flow rates. You have massive mass flow rates of compressed air compared to relatively small amounts of non-compressed CO2, and CO2 has a relatively low cooling capability in the first place. Basically the CO2 is a fad. You'd be better off spraying a thick water mist, which has almost 4x the cooling capacity as well as a much higher mass flow rate.

3) Water to air will quickly be restricted to ambient air temperatures as well. Simple reasoning really, while you may have added ice to the system you're only source of cooling the water is the ambient air. Therefore, the system will quickly heat up and be restricted to the cooling medium, which is ambient.

Basically you have a lot of stuff that will not help you at all in the end.

KidFrost

I guess I forgot I even posted this.. I am just now reading the responses to the op. I am surprised, it didnt get shot down as much as I though it would.

tepid1- Well, you may have killed the whole thought process in the first reply. I am/was running e85 at the time of this post and you said ethanol likes "warmer" temps. Define "warmer temps" for me because, again there has to some sort of range that is good, better, best, so to speak. If your statement was linear, I could in theory remove my intercooler and make things plenty warms. Thanks for adding to the discussion non the less.

Westrock2000- So, in part you agree with my op, saying that IATs are as important as I think and there could be things done to reduce IATs and in theory create more HP out of the setup using some other forms of cooling. As for the No2 injection idea, I was talking about co2 for starters, but No2 causes alot of other risks and require other fuel modifications to keep up. Thanks for the input.

Dark_Teg- My point exacty! I wish I had a shop, dyno, and a bunch of money to research this on some sort of base turbo motor and create some real data.

xbigpitax- Thats what I was talking about doing....

Finest- So again, if I understand correctly you agree with my post as well. Why do you say anything after the intercooler to reduce IATs are a quick fix? if they reduce the temps to a given degree then they work, their effectiveness may not be optimal but they would still work. What I took from your post was maybe cooling the charge are BEFORE it goes into the compressor, however since the enemy here is heat, if you cool air before the heat source (turbo) I believe the air will collect even more heat during the charge process. therefore reducing the effectiveness of the cooling device you are using pre turbo. Also, this is all theory and discussing so lets assume the turbo system is effecient as its going to get before any more coolinf is going on. Thanks for your reply.

SovXietday- Given that your statement is correct, I bet most people would love to get their turboed IAT's to ambient air temp, idering most setups run at about 2x ambient. However I tend to disagree with your statement because I have heard of well intercooled/overintercooled systems getting IAT's within 15-25 degrees of ambient with just an air-air intercooler. So what you are saying is that no amount of cooling devices can produce temps lower than ambient? Have you ever sat in from of an air conditioner on a 100 degree day and felt the 50-60 degree air on your face? Its possible, trust me, Im just wondering if its plausible and or worth the hassle/$.



For ***** and giggles I attached a graph that illustrates a 22 degree temp decrease producing a 32 WHP increase, which = 1.45 WHP per 1 degree of temp reduction.

I will make a data graph to illustrate how sharp of an increase this is. Even if the graph starts to die off at some point i still feel that in the turbocharged 4/6 cylinder world there is room for improvement.

Thanks for the discussion fellas.

-KidFrost

F22Master

Good discussion topic. In for more real world testing

F22Master

Also:
http://m.youtube.com/watch?v=NmzLaaFQjiQ

bigG

iTrader: (6)

why not run through heater core and use a/c to cool water?

NotARaCist

iTrader: (1)

The equation for air density is actually very simple.



Lower temperature = higher density
Lower gas constant = higher density
Higher pressure = higher density

KidFrost

This isnt a bad idea for an air to water setup, I no longer have heat or air conditioning though..

Can you explain to me how this adds to the discussion?

Yes I understand air density is an important factor for HP output, but that dosent answer the question of: At what point are colder IAT's no longer beneficial to HP output.

There is no doubt that a concerted effort to get temps lower could make it possible i just dont think it has made its way into the Honda world yet.

Check this link out.

Dry Ice Intercoolers

NotARaCist

iTrader: (1)

A person or two said they didn't understand the "why" behind it. I was giving the short explanation. I studied aerospace engineering in college, which deals a lot with fluid dynamics - I have equations like that memorized. Also, if someone really feels like doing the math (namely, figuring out the temperature rise per pressure increase), you could solve for X and figure out exactly what the optimal pressure would be for a given amount of density. Use that with some more fancy math, and you could figure out, on paper, what the "perfect" setup for a certain motor would be. Remember all of that "x% power increase for y* temperature change" stuff you keep reading different numbers on? Yeah, use that math, and you could figure out exactly what that number really is.

If I wasn't running on 2 days without sleep, I'd try to do the math. As it sits, I might poke at it later, but I have other things on my plate, so if someone else who understands fluid dynamics wants to take a stab, there's your starting line.

wunfstgsr

Well i know certain water to air intercoolers can reduce the psi out put by 1-3 psi depending on what the setup it is so that can reduce hp because your going to have a bit less boost but it just might make just as much power with the cooler charge. Im looking to do a dyno on my ATI supercharged B series then ad a water to air intercooler right before the throttle along with the front mount intercooler and see if the added intercooler cooling the air charge ads HP or drops the hp, i know it will reduce the psi by 1-2 psi but ill just have to see what happens.

KidFrost

Well I dont see PSI being a problem, you can always turn the boost up to compensate for any loss in pressure drop accross the second intercooler. The tuner will be able to tell where the motor is at its limit for PSI and will automatically account for it. Additionally, Frozenboost W2A intercoolers claim a 0.2 PSI drop. So that make sit even less of a factor.

What worried me more what CFM rate at witch an air volume issue would come into play, however, the W2A IC's we rated to 1200 CFM, witch supersedes the CFM of my GT3582R.

SovXietday

Your bolded statement is due to the refrigerant and the 4 step process that is used to take heat from the space you are living in and then reject that heat outside.

Air conditions work by compressing refrigerant (refrigerant is a gas at room temperature) to 400+psi (R134a in your car is more like ~150psi) using a small piston compressor. It is then passed through a condenser where cool air is drawn across the refrigerant and cools it to a high pressure liquid. This process REMOVES heat from the system, at some efficiency. The fluid then travels to an expansion valve where it is converted from high to low pressure, and thus turned back into a gas form with very little gain in heat from friction. This low pressure gas is then sent through an evaporator, which is where the air conditioner is pulling the hot air in your house across the cold refrigerant and then passing it back out. Because the air is hotter than the refrigerant you will heat the refrigerant up, creating what's called superheat. This superheated gas is then passed back to the compressor and the cycle starts over.

As you can see, the air conditioner is capable of reaching lower than ambient temperatures because it is using an intermediate fluid designed to be a liquid at very cold temperatures and by basically transferring the heat from your house to the outside air. The process COULD work with water... if your IATs were 500+F.

Unless you are going to hook up your refrigeration system to your turbo system, which I do not at all recommend by the way (in car systems are way too undersized to deal with the amount of BTUs turbos move and you will undoubtedly superheat the refrigerant and blow the system to pieces), you have no hope of getting IATs lower than ambient for extended amounts of time.

You could roughly guess at HP per degree drop by generating the mass flow change of air going into the system(taking into account pressure and relative humidity), take into account engine efficiency (which is **** poor by the way), and you could pretty easily solve for the energy produced.

I am inclined to suggest that you're looking at something around 1hp/5F with a very efficient system. A difference in pressure of 1degree would make a considerably larger difference, especially because you have to consider the degree change on the Rankine temperature scale.

<-- mechanical engineer who specializes in fluids/thermo/heat transfer

There are better ways to make power. Buy a nice high efficient core, try to allow the turbo to bring in cool air to reduce the amount of heat the intercooler has to reject, and go have fun.