clokker

iTrader: (2)

That intake actually shares the same fault as the efan.
In both cases it's easier to pull air from the engine bay than from the desired area.

In the air filter's case, why should it strain to suck air through a tube when it has unlimited access to an ocean of free air in the bay.
Same for the fan...much easier to pull it's intake air from the unshrouded side (again, the bay) than to pull it through the rad core.

Devices like these are inherently lazy- they won't do hard work unless you force them to, basically by cutting off all access to air except from where you deem optimal.

In this example, the fan is mostly just churning the air already in the bay around and the filter is sucking that same air in.
Pretty much the worst case scenario.

Dak

I believe you are wrong about the fan. You can feel it pulling a good deal of air through the nose of the car. This is with the hood closed. It may pull some air in around the sides due to being unshrouded but the majority of the air is being pulled through the radiator. The fan wasn't meant to be shrouded. The design intent of the manf. was that being unshrouded it didn't block off part of the radiator and restrict the flow of air at speed when the fan isn't used for cooling the air flowing through the radiator is.

As for the ducts. I never had any misconception that it is pulling air through them. When sitting still I'd agree no air is pulled through them. No air is ever pulled though them by the intake. The goal was due to their placement in the nose air would be forced through them at speed which would cool the the air around the filter. As I said before the filter is cold after driving and does get warm after sitting and idling for a bit is why I think it works. As for the duct size. I'd like larger ones but they are the largest I could fit without cutting anything.

rotarygod

iTrader: (1)

I knew that would be the first response to pop up. This is true with ANY intake system as the intake manifold on all cars heat up pretty badly. In the summer with an S5 intake manifold I have gotten intake temps over 160* while sitting still for a while. This is with a cold air intake too. With the filter in the engine bay it doesn't go up by very much. I have no doubt that he can improve his setup but I guarantee the amount of power he is losing from under hood heat still doesn't bring him down to the power levels of most other people. All it takes is some heat shielding. The location isn't an issue. The engine bay isn't that hot (relatively speaking) as long as you are moving. Heat gets rejected fairly well. In the real world he probably only loses a few horsepower to underhood heat as opposed to cold air until he sits still. This is when it really hurts most.

I do agree that he probably did dyno the car with the hood up which probably affected power numbers from the real world somewhat. Then again I also believe that everyone that dyno's with a form of fuel that they don't run on the street or tries other things to increase their power numbers (how many times do we see this bs here?!) is cheating the results far worse than this. Then again I also understand that dynos are good for nothing more than before/after comparisons on the same engine and is a tool for tuning and shouldn't be used to accurately judge the true power of an engine so of course any numbers should be taken with a grain of salt.

NZConvertible

Every fan should be shrouded. There's no such thing as a fan that works better without one than with one. Even if it's just a ring shroud that seals the fan to the surface of the radiator without covering any more of it's area, this would considerably improve the fan's efficiency. As it is, quite a bit of the air the fan's moving is being drawn in from the sides instead of through the radiator. 10% would not be unrealistic.

That simply doesn't happen. A radiator is very restrictive to airflow, and air can be fed into and out of it through a much smaller area without restricting flow any more than the core already does. The stock fan cowl has a discharge area about half the size of the radiator core, and this is more than enough.

The local cooling you're hoping for is very unrealistic. The engine can suck a lot more air than those ducts can provide, so while some of the air entering the intake may be from them, most will have come from the engine bay, and most of that air has come in through the radiator. Putting your hand on the filter isn't a very good indicator of intake temp. I know from my own experience in measuring air temps at the filter how hot it gets in there.

That's exactly why I didn't bother with any ducts on my car. I cut two large holes in the sheetmetal near the filter to provide a path for air from outside the engine bay, then made a shield that mostly prevents engine bay air from reaching the filter. That way outside air is sucked in all the time, not just at speed.

That's the thing, one the street you aren't moving all the time. Depending on where you are it can be stop-start even in light traffic. With an exposed intake I found that if you stayed at speed the temps wouldn't be too bad, but once they got up they took a long time to come back down.

Dak

I didn't mean that it worked better at drawing air through the radiator without one. Only that when not in use it provided less restriction to the air coming through the radiator. I'll admit I got this from the literature on the fan manufactuer's website. I guess I fell prey to their marketing by not researching alittle more. It works fine so I don't feel took. This fan talk is hijacking the thead.

I'm not going to argue about the ducts as I don't have any hard facts to back up their usefulness or if they make any difference. I was just presenting a possible way of getting cool air to the filter area. I've known for a long time I need to build a box and seal the pod from the hot engine bay.I just haven't done it.

NZConvertible

It might seem that way when you look at it, but in reality is doesn't.

When you do, you'll need much bigger intake ducts. If you seal the box really well, air will be forced to come through the ducts causing a restriction. If you don't seal it well, air will simply be drawn in from the engine bay. Like I said, it needs to be much harder for engine bay air to enter the intake than it is for ambient air. That's the trick to making it work effectively.

Evil Aviator

In the case of most fixed-pitch fans, a powered fan will restrict the airflow when the vehicle is at speed.

Hypertek

iTrader: (3)

You NA guys can take all the time you want calculating the non-potential gains of this mod.. maybe if your modding from stock airbox.. but thats it.

Twins80s

iTrader: (3)

Just an idea has anyone thought about swaping to the TII intake mani? Then you could actually move the filter to the other side of the engine so it is further away from the exhaust, and still have a shorter path for the air.

Dak

Do you mean a fan that is on and running after the vehicle is at speed or just the fan sitting behind the radiator? I have mine wired with a temperature switch. It typically doesn't seem to run when I'm moving. Seems most of the time when I'm on the highway or country roads when I get where I'm going it is not on. I can usually hear it kick on if I'm sitting still.

Evil Aviator

When the car is at speed, the fan is a small restriction when it is stopped, and a huge restriction when it is running. Yours is hooked up correctly.

sleeepyhead

The hp gain is very little if any, but as people have said, the stock intake is more than enough to make good power for an NA. I do think it pulls harder at high rpms than before but it might just be a placebo effect. One thing that did change was the throttle response which was much better. I did a hand out the window test and i can feel cool air curling around the hole and into the box. The box is riveted aluminum with heat tape all over it. Its hella ghetto rigged with zip ties and all but setup like this, I have a steadier idle and everything seems more reliable. Also I haven't failed tech at autox or a track day yet . I would have gone with a duct or a scoop but rain was a consideration. The whole project took me only a weekend to do, cardboard template, making the box, and slicing up the hood too. I plan to get an s afc or some kind of fuel controller and unghettoing the intake when i have a little more time

NZConvertible

It's just a proof of concept right?

ezraaspland

sleeepyhead You cut your bonnet for air flow to your filter? Does it look silly when the bonnet is down? Do you have pics?

clokker

iTrader: (2)

Well Sleepyhead, you certainly answered the OPs question...yes, it has been done and here are pics to prove it.

I wonder if instead of cutting the hood you could remove the wiper motor and pull air from the same cavity that the cabin intake does.

*The wiper motor hole might be too small but it's just a test, like.*

It'd be sweet if it worked as you'd have a totally stealth install.

NZConvertible

Do you think there might be a downside to this plan? Clue: He was worried about rain ingress...

And yes the hole would be too small. Drilling another bigger hole would be a much better idea.