Shinobi-X

By my understanding, the use of an air box is easier for filtration and emissions, along with keeping intake noise under control, in combination with the reason you've provided. I'm looking for something more conclusive than that though, which could apply to those of us with modified vehicles. I don't believe my setup is the most efficient, but I'd like to know by what degree.

True, but I'm just asking for information based on what DamonB and some others made a few comments* about earlier. In actual application, I figure anything before the throttle body is rather important with regard to air temps...so I'm hoping someone could clear things up. Granted there will be a difference in temps between a filter and before the turbo, but if this temp has no or little bearing on actual power, then I'd like to know, preferably with numbers.

*"I don't think anyone argues that there IS a difference in intake temps, but the hot air guys often insist that these differences don't matter because they happen to have a "big" intercooler. Rubbish."

^^ I agree, now I'd just like to know why that specifically is the case.

Kento

Think about that for a minute...if getting air outside the engine bay isn't that important, then why spend the money and R&D time to route the intake to the outside? Manufacturers could save tons of money/time by just grabbing air from the engine bay, and it will be a lot easier to quell intake noise under the hood than from outside it.
Take the IC out of the equation then. If it wasn't an issue, you wouldn't see so many normally-aspirated racing machines drawing outside air. The only "numbers" that would have any real credibility would be someone conducting a clinical test to weed out all the variables, but that's a lot easier said than done. Does it make a 20-hp difference? In some cases, probably not, but it can under many circumstances that aren't out of the realm of possibility for a street-driven car. In any case, who cares? It's easy power to obtain that's supported by plain physics, and there are plenty of physics problems out there that don't have documented clinical proof, yet have tons of supporting evidence to confirm the basic theories.
Compressing air increases its temperature; if you start off with a lower temperature, you end up with a lower temperature after compression...simple fact. If you have a big IC, great...you can end up with even lower intake temps.

What I'm seeing is a lot of people don't care about an extra 5 or 10 horsepower. They demand big number increases. If they don't care about gaining any power through a relatively easy method, then they probably shouldn't worry about it, the debate is irrelevant.

dubulup

This should have been closed after the first post.
True Story. How is there now 4 pages...I doubt anything said here hasn't been said before.

renkenkyo

iTrader: (6)

Part of the each horsepower gain during cold nights is due to the fact that the IC also becomes more efficient at dissipating heat. Looking at all standard turbine applications, getting colder intake temperatures, from jets to anything else has always been better because it increases the efficiency of the compressor and the heat dissipating component.

jayk

Agreed... Where are the 'search' pundits now?

DaveW

AND, everything's been said 3 times here, alone...

adam c

iTrader: (2)

You can say that again

rynberg

Read Posts #44 and #46. If you don't understand them, get a Thermodynamics book from the library and start reading. And renkenkyo, the second part of your post negates the first part and actually supports Posts #44 and #46.

It's simple guys....you start with a cooler intake charge, you end with a cooler intake charge. It doesn't matter if you use a computer case fan or a 10-foot long IC after the turbos. It doesn't matter if the ambient temps are 10 deg or 120 deg.

Donovan

A little off topic but still about air intake temps. I have a CWR carbon fiber intake box ( I think) It's the one with the blue top?
I'm wondering if I cover the outside with reflective tape if it would have any effect on the box heat soaking and even reflecting the heat at higher speeds? The side of the box is just black carbon fiber now.

Kento

By "reflective tape", I take it you mean the "heat resistant insulation" tape. It will help a bit, but actually carbon fiber is a pretty good insulator by itself. The only reason it heat soaks after a while is because carbon airboxes are usually built thin for weight considerations.

Shinobi-X

I stated, that my interest was in the degree of how much power was lost/gained. Obviously cold air is more attractive for any intake, but for some people thats not always an option after certain mods. Hence why I raised the question of if it would be more important to focus on other portions of the system. If the difference is more than negligible, based on numbers, then I plan to alter my setup.

The OEM Mazdaspeed Miata for example pulls air from within the engine bay, as seen below, so I figured that it may not be as critical as some were making it...with knowledge of thermodynamics, but no actual numbers, I can only ask...

Kento

That is not completely true. The second-gen Miata has a sizeable opening just behind the driver's side headlamp through which fresh air channeled from in front of the wheel well is directed at the airbox intake. There are numerous aftermarket "cold air airboxes" that basically close off the area from the intake to the opening.

ReadyKW

Is this suggesting that a large IC does not remove more heat from the intake charge than a small IC?

If vehicle A has a hot air intake and say a monster v-mount, and vehicle B has the stock air box (which according to your link, is the superior air box) and stock IC (or even no IC), that vehicle B will have cooler final intake temps due only to the fact that it initially drew in the colder air?

If all things are equal cold air wins, but one of the advantages to having a hot air intake would be to run a truely massive IC such as the RE monster v-mount or HKS v-mount.

In any case, when I see intakes such as the HKS RS, I wonder if anyone has tried to fab an enclosure around them that seals to the hood and put a NACA duct in the hood over the enclosure.

Kento

Where does it "suggest" that?
You're reading way too far into Damon's statement "The hot air guys seem to think that as long as you have a decent intercooler it doesn't matter." Read the last part of the post.
Look at it this way: Which is the cheaper and easier way to get cooler intake temps? Run a decent airbox with an aftermarket IC, or spend $$$$$$ for a "monster" V-mount?

rynberg

How are you getting your first question from my post???? Of course I'm not suggesting that! If you read my posts and the other response in question, it should be very obvious what I was stating.

What's the point of running the monster v-mount when the standard one works as well as you need it to and allows cold-air box. In any case, the v-mount configuration most likely reduces the temps that a "hot-air" intake would see anyway, because of the radiator mounting.

BLitzed33

Yes, on my car, Ray Wilson made this intake setup, its 4" piping running from my turbo down through the frame to the cool air duct with a velocity horn and air filter. Its a one off custom setup, but it works VERY well, but only with one oil cooler..I run a upgraded 28 row mocal.

dubulup

Did you read any of the important information in this thread
Vehicle A is not making the power it should be:PERIOD:

poss

iTrader: (5)

Why are people still debating this?

It's simple, everything being equal, the colder the air going into the turbo, the more power the car will make. PERIOD. The only thing in question are the quantitative results.

Donovan

I actually was talking about silver reflective tape. Like high temp foil tape. Think of the survival blankets used by backpackers, or the foil windshield sun blocker. The blanket keeps heat in when it's cold and keeps the heat of the sun reflected when it is turned outward. I wonder if putting some reflectice material on the outside of teh box would lower temps a bit.

carbon man

In designing an air intake you should try to get
As cold an air supply as possible
As still an air supply as possible
As high an air pressure as possible
then the construction of the air box to insulate from heat soak.
Alloy is NOT a good material to make the air box from because it conducts
the under bonnet tempreture. Carbon Fibre is one of the better materials
to make an air box from.
Any change of air direction should be made as smooth as practical
(turbulant air is a restriction)
The position for the air intake has an effect on how much air you get.
examples,

if you take an intake from under the front guard which is in a vacuum you get less air pressure,

if you take an intake from the radiator duct you can reduce the cooling effect of the radiator (it starves for air),

If you take the air intake from close to the ground you will usually get a higher tempreture as the road temp is usually higher than ambian temp,

If you take the air intake from under the bonnet you will get a higher pressure but you will also get a higher tempreture,

On an FD, I believe the front numberplate area would be the best place to get air to an airbox.

If an air induction system is working properly there should be no air induction noise (induction noise is turbulant air.)

The photo is from the RX7-SP air box

Kento

It certainly wouldn't hurt. Not sure how effective it would be, however.

renkenkyo

iTrader: (6)

Well I wasn't really argueing one way or the other. I was stating that on cold days, the improvement in horsepower not only comes from the intake getting colder air, but the IC as well. Thermodynamically speaking cold air makes the system more efficient since the temperature difference is greater allowing a greater rate of heat exchange.

That being said, more air also helps because it allows more combustion in the engine. How these balance out, I'm not sure since that's specific to the car. I think most people here can agree that a cold air intake helps. It just comes down to whether or not the additional air is worth the additional heat coming into your engine for the open element.

There's no real arguement here, I just think some people want to justify that their specific setup. The cost benefit of each still stays the same. I'm more interested in numbers. Do people have dyno numbers for cold air and open air intakes with the same setup? Lastly, does a dyno reflect the real life benefits of a cold air box. Then again I'm no expert.

Sorry for the long post,
Josh

adam c

iTrader: (2)

I don't think a dyno would be a good comparison. It doesn't take into effect the air pressure created by the movement of the car. A better test would be a 3rd gear run from 40-90 mph. I doubt that anyone would go thru the effort of changing intakes to do this test.

It's easier (and more fun) to just argue about it

ReadyKW

Well, to me it reads that the IC is irrelevent, colder inlet will trump any size IC. I was just pointing out that a large enough IC can compensate for the hotter intake, compared to a cold intake and smaller IC. Every setup and application for these cars seems to involve a compromise, people will differ on what is the priority.

Actually, he used the term "big"

Well, they may not matter compared to a smaller IC and cold air. Cold air is great, just not always practicle. Individuals will set their own priorities. Discussions such as this can help sound out ideas and theories. No need to go into attack mode if someone asks questions our offers a different mindset.

Yes I did, and I can read quite well thank you.

rynberg

Some people on this thread have posted that if you have a big IC it doesn't matter. That is simply wrong and I was pointing it out. You can have a 10-foot IC and the intake temps will still be hotter with a hot air intake than a cold air intake. I'm not saying that a cold air intake with a small IC will be better than a hot air intake with a bic IC. You are misreading my point.