Tree DR

Had to try it. Got a 9inch cooling fan and stuffed it right under my stock filter and wired it to my auxiliary silinoid. No more lag time to get air to the motor.
Now you say you can't get enough air to the motor under full throttle. Ok? What's the largest filters air flow rateing? 1400cfm is what this fan is rated for.
Only went to get milk so far about 5mi. definitly no lag on the bottom end, I'm not raceing though. I'm more interested in mpg than power anyway.

Raspy

Sounds like fun but I don't see how a little more air pressure in the air filter will improve mileage. And turbo lag is not caused by the lack of air supply it's the time required for the turbo to spin up and the fuel system to recognize the change and respond.
Let us know how it goes.

Wetspirit

Tree DR

If the motor doesn't have to suck air through the filter to get the turbo to spool up it should be much faster spooling. It deffinitly is much quicker off the line. I'm not raceing, just seems to have a lot more torque off/at idle.
If the motor doesn't have to suck air in should reduce the load and maybe I'll see some mpg improvements. Probably more gains at lower rpm so town driving might be better for this mod. Then again if your not geting enough air through your filter fast enough for the racers, this might be a possibility.
Don't the racers disconect from the filter when racing?

qzilla

First thing you need to do is pull the top of your airbox off to do a simple test. Let the truck idle while you do this. Being very, very careful slide your hand over the hole in the airbox where it draws air from. DO NOT STICK YOUR HAND IN THE TUBE. Just make a flat hand and start sliding it over the hole. Once you get a decent amount of your hand over the hole you will understand why at idle adding a fan will make no difference on the bottom end. BE CAREFUL THE TURBO AT IDLE IS ENOUGH TO DANG NEAR SUCK YOUR FINGERS OFF!!!!!

The reason people run without airfilters or with larger airfilters is for more available air at boosted levels. At idle or right off the bottom the only thing you can do is add fuel to spool the turbo more quickly.

Tree DR

If the motor at idle has 0 boost and it takes some fuel to get the air sucked through the filter to start produceing boost how much hp or load is put on the motor befor boost will start?
I've felt the suction created by the turbo. Have you left your intake off or loose, try it and see if you can feel any differance in low end torque.
What I'm getting at is the amount of time and energy the motor uses to get the air to the motor.
I see the statements about this airfilter only gets me 30lbs or boost and this one gets me 34lbs. Because of restriction of air flow. If you had no restriction maybe you'd get 34lbs at 2600rpms instead of 3200rpms. More efficient because of less restriction at the air filter? It would probably be more like 3000rpms instead of 34000rpms but you get the difference. More power sooner because of less restriction.
Actuall at idle with the fan on it makes the motor work harder than with out it on. To much air? At least thats what the edge monitor tells me.

abc4yew

DR, Your set up is acting like a low pressure supercharger for startup spooling. I can't see how it wouldn't be a little help for building boost sooner and getting the turbo spooling before heavy fueling. People always think that turbochargers are a free source of air pressure to the intake but the resistance caused by the force of driving the compressor wheel is part of the load on the engine. If you used a gasoline powered supercharger instead of a turbo...your motor would have zero spool up time and no drain on the motor to supply intake air....it would show more RWHP for sure. If it was able to push 1400 cfm it would be good enough for wide open throttle. If the Fan wasn't able to keep up you have a 9 inch hole very little blockage to slow air flow down to supply the turbo. Basically the battery is supplying the power to supercharge the turbo.....but the batteries are being fed by the Alternator which will have a higher load on the motor. I think it would add hp and torque earlier on the curve. Easy to test....just dyno with and without. You may have a cheap turbocharger booster that improves the power and economy of the motor. Where did you source your fan. Did you block off the stock air inlet to the box? ks

Raspy

When you feel the suction in the intake at idle you're not feeling the effect of the turbo. It's the engine lowering the pressure in the intake manifold as the valves open on the intake stroke. The turbo doesn't start boosting till the engine is working and the exhaust velocity goes up. The engine is working harder when the fan is blowing into the intake 'cause it's generating the current to run the motor on the fan. It probably has a little higher cylinder pressure too, but not much.

If you could get more overall power out of the engine by running an electric fan you may have invented perpetual motion. Why not throw away the turbo and just run a fan? You could and it would be called an electric supercharger. Unfortunately it might take fifty horse motor. Your fan, and I don't know what it looks like, but lets say its a squirl cage high volume design, is probably only capable of about 1/2 PSI or so. By the time you are putting out about 300 horsepower it is more likely to look like a restriction than a boost.

It has made an improvement at low speed. Hmmm, give us more info. Pix?

I'm not trying to be difficult, just thinking out loud.

Wetspirit

Tree DR

The fan is not going to make boost. I found it on www.partzfinder.com it's a 12v 9inch cooling fan for a transmission cooler probably, $35 approximatly delivered. I had cut some of my stock air box out to make it fit under the filter. The fan is pushing air through the air filter not sucking it. The fan is only supposed to use 3.5amps so I doubt that will put a load on the motor. I'm useing the stock box and filter. With the filter installed over the fan there is a good flow of air comming through the filter. I do have the bottom of my air box swiss cheesed and the front cut out.
I'm thinking about sealing off the botom and front just to see if it will lower the intake air temp that my www.scangauge.com $130 is showing me. Before I installed the fan my intake air temp was usually about 20deg above outside air temp. I haven't done much driving since installing the fan, all in town, but 10 to 12deg is what I'm seeing above out side temp. For someone trying to get cool air from some other location and has to much restriction getting the air to the filter this might work.

omaharam

Just so everyone understands how the system works, here is the process.
You start your truck.
The engine is now idling. During the idling process, the pistons are moving up and down and creating a vacuum on the downstroke while the intake valve is open. This pulls air into the engine. Upon INITIAL start up, there is only one source of air, and that is the air that is already present and just resting. Once the engine begins to spin, under force from the starter, it immediately begins the process of air intake and air exhaust. The cycle has been started and now the starter can dis-engage and let the engine turn itself. As soon as the first piston starts its first exhaust stroke and the exhaust valve opens, you have exhaust. Exhaust is what spins the turbo. Therefore, at idle, the turbo is spinning. It does not show boost, because at that point it is not producing any more air than the engine could suck in on its own. It has nothing to do with intake air initially. If you ad a fan that turns on with the ignition, you are generating a little air before the engine starts to spin. Once the engine is running, it doesn't need that air at idle. If it did, you would see boost from the turbo at idle. So if anything, the fan might allow the engine to start ever so slightly easier due to the available air at initial startup. Once the engine is running, the more air the engine takes in, the more exhaust it must exhail. The more exhaust it exhails, the more force on the turbo wheel. At this point, the turbo is at full effeciency. Meaning that how ever fast the exhaust wheel is spinning, it is driving the compressor wheel at the same speed. Once max boost is reached, the turbo is at its full volume. The only way to get the turbo to do more, is by increasing the the exhaust force. The only way to increase the exhaust force, is to increase the intake air. The only way to do that, is use a larger compressor wheel - translated - drop some $ on a new turbo.
My thoughts are this...The turbo will pull as much air through the system as it can. If the intake is unrestricted, it will pull all the air it can handle, it does not need the help of additional forced air.
In my opinion, you are actually CREATING a lag problem and potential bearing problem for the turbo. Follow me here. The turbo is creating pressure entering the engine. You lift your foot off the throttle and now there is no where for the air to go. It reverses direction and runs back into the compressor wheel, causing the compressor wheel to slow down instead of simply deccelerate to a stop. This causes stress on the bearing. Also, now when you get back into the throttle, it takes longer to spool the turbo back to max speed because you have slowed it down with the reversing air. The fan that has now been added to the intake side is still forcing air at the compressor side of the turbo. Now there is pressure being applied to both wheels in opposite directions, causing even more stress on that bearing and slowing down the wheels faster and furthur. When you get back into the throttle, it now takes even longer to spin the turbo back up to speed.
This is all on the presumption that the fan moves enough air to even matter - which I'm not sure it does.

My final opinion - TAKE THE FAN OFF RIGHT AWAY! I don't think it helps, and I think it could hurt.

abc4yew

Omaharam, 3.5 amp fan motor causing more harm than say barking the turbo or letting off the throttle quickly. . All the fan is doing is overcoming the pressure drop across the filter caused by the restriction of the media. The air box isn't sealed.... the fan is just blowing air across the filter directing the air flow straight through the filter. The air that is not needed escapes out the stock inlet. An airbox supply at atmospheric pressure versus one at atmospheric + 1psi is an improvement. TREE DR put a pressure gauge on that thing and keep things rolling.
The perpetual motion argument would only apply if the fan caused the engine to be over 100 percent energy efficient. Right now it's probably 50% percent efficient. Without a turbo the motor is say 40% efficient. If the motor is able to draw additional power from the intake fan using the stored power in the battery at low rpms that would be great. The battery can get recharged when the truck is running stable at speed. If the fan shut off when the boost got over a level where the powered fan would be a restriction versus a help, or by rpm would be better. I like innovative ideas....might not be awesome but sometimes, like tone ring mod, bhaf, lockup switch,...have a benefit for some and cost little. ks

Rolngthun

"The engine is now idling. During the idling process, the pistons are moving up and down and creating a vacuum on the downstroke while the intake valve is open. This pulls air into the engine. Upon INITIAL start up, there is only one source of air, and that is the air that is already present and just resting"

Your looking at that wrong. The piston going down does not create a vacuum, it creates a low pressure eviroment. Air is not pulled into the cylinder, it is pushed in my atmopheric pressure. So the air is not "just resting" it is being compressed by the atmosphere. This all of course excludes forced induction.

Tree DR

The air all around us is at 14.6psi give or take a little. The (MAP) manifold air presure gauge on my scan gauge shows me that. With the fan on it doesn't increase the MAP readout at all. All the fan does is make the filter restriction none existant. It is pushing air through the filter not just at it. I have a vacume gage laying around I could hook up to the intake to see if at higher rpms there is still negative intake pressure. You guys looking for more hp need more air right. You can get more air with the stock air box than you'll ever need probably. If after I hook up the vacume gage to the intake it shows some vacume, I'll get a better filter.
Q: Why does my Scan gauge show atmospheric pressure and added boost but my Edge monitor only boost? Where are the two different sources for boost? Also my Scan gauge Load and Edge Load don't show the same numbers.

omaharam

I never mentioned the amperage draw of the fan, or that it in and of itself would cause more harm than "barking" the turbo. What I said was that the fan could potentialy be causing the problem of the turbo "bark" to be worse, as it is trying to spin the compressor wheel one direction, while the return air from the throttle body is trying to spin the exhaust wheel the opposite direction. And by the way, letting off the throttle quickly is what causes the turbo bark, they are not two unrelated actions. Also, the way he described his set up, the only way for the air flow generated by the fan to escape out of the airbox is through leaks or back through the fan before it could go out the factory opening.

omaharam

You got me. I was using the wrong terminology. It does not create an actual vaccum, just as you stated, but rather a space for air to enter. However, this does not change my thinking regarding the use of the fan. As soon as the engine begins to produce exhaust, the compressor wheel of the turbo is spinning and is producing air flow that is greater than atmospheric pressure. As soon as any load is placed on the engine and the turbo begins to produce "boost pressure" that is measurable, the electric fan is useless - IMO. Again, I believe that the compressor is getting all the air volume it can move. A 50gal drum only holds 50 gallons, no matter how much more liquid you try to inject - the only exception would be to change the density, and that's not what we're talking about here.
I would love to be proven wrong on this - really. If I could make a simple mod like this to produce a favorable outcome, I'd do it. I like the suggestion to take it to the dyno and run it both ways. I still, however, hold to the fact that upon throttle plate closure, you could be increasing the negative results of an already existant problem.

Rolngthun

Don't take me wrong Omaharam. I agree the fan is totally usless. Certianly since it was mentioned the air box is vented. Unless the air box is pressurized before the filter, nothing is gained.