Intake fan.. possible mod?

[farmerpatrick]

Hello all,
I have bought a non-egr intake manifold for my 6.2 "c" Blazer and I want to start fabricating an airbox and intake setup to get the max amount of air. Something like what the Dr. did. I was thinking about those vacuum operated ram air motors they used in early mustangs. But, then I thought, why couldn't you put a 4" electric fan in the intake hose to pull more air from the front towards the engine. The fan would be cheap and easy to do.. Is it a stupid idea? I've never seen anything like it except maybe the old 280 Datsun's. But their fans were controlled by the computer and switched on and off.
How fast/big of a fan could I use? Where would I find a high output 12volt electric fan, say the size of a PC fan?
Any suggestions?
Patrick
currently getting 19.7 mpg mixed city/highway.. Think this would help/hurt?

[britannic]

To do it properly, you use the compressor from a turbo with the shaft spun by a powerful electric motor. By the time you've got that far, you might as well bolt on a turbo and really have some fun :D .

If the fan cannot provide enough CFM, it'll become a restriction and your EGTs will go up.

[Stage1]

I would think that cool air may be more effecient then natural ram air? The cooler air is providing more oxygen; therefor more fuel can be burned.
FYI, J C Whitney has a air intake kit, not sure if it will fit our diesels?


Les

[NH2112]

I don't think you'll be able to find a 4" fan that can move even a minute fraction of the air volume that gets rammed through the intake, and the heat from the motor will actually result in (slightly) higher intake air temps than you'd see in the same system without the fan. I'd concentrate on increasing airflow by increasing the size of as many intake components as possible (lose the silencer, make a bigger air cleaner a la Dr. Lee, use 4" or 6" hose from the grille), and perhaps insulating them against engine compartment heat. Getting the hood louvered is a great way to reduce engine compartment temps, too.

[farmerpatrick]

Well, what about a marine blower vent fan, like the ones that go in the bilge compartment of many larger inboard boats. I know that there are several different diameters and such. I found one on eBay for 11.99 that moves 135 cfm of air. Would that not be enough? Does the intake suck more than that on it's own? That one is only 3" diameter, but they go right inline , and if you had dual tubes, one on each of them...
Any other ideas

[NH2112]

Well I'm sure someone here can figure out the exact volume of air a 6.2L diesel moves at idle, but my guess is 6.2Lx650RPM/2 (since it's a 4-stroke.) That works out to 2015 liters per minute, and there are roughly 27 cubic liters per cubic foot, so you get approximately 74.6 CFM at idle. Double the RPM to 1300 and you've exceeded the flow rating of that bilge vent fan. Obviously the engine doesn't run at 100% volumetric efficiency so you won't fill each cylinder with 0.875l of air, but it should be in the ballpark.

[BC Clark]

Here's a quickie! Remember carburetors? A standard match on a small block was 500 to 650 CFM. Guys pushing it went 750 and above or multiple carbs. Now the fact is that you are trying to compress the air with a blower, or attempt to push it faster than you can suck it so the manifold pressure becomes positive instead of a vacuum, increasing density. Ventilation blowers are not rated with any pressure difference (some are rated in inches of water on the pulling side not the exhaust side). More than likely to do any good, an electric fan would have to be able to move around 900 CFM minimum. Turbos also able to compress the air after pulling through the air cleaner, hard to say what the effect of the air filter will be blowing into it.

There was a guy selling "electric turbos" on e-bay but I think he got shut down.

[britannic]

Whatever you use would need to generate positive boost pressure at all rpms. At a minimum 2psi or more would be of some use.

Another option is a belt driven turbo compressor (poor mans supercharger), I've seen some kits that use these and provide about 5psi or so.

[farmerpatrick]

Well, I'm definitely glad I asked.. You guys definitely have some valid points. I'm not trying to build gobs of power.. Believe it or not, I'm pretty happy with the power it has stock. I'm definetely not trying to turbo the old beast. Too afraid I'd end up like so many others, melting pistons and such. If I wanted a turbo, I'd have bought a 6.5LTD equipped truck/suv. I just wanted to boost it's efficiency a good degree, economically. Maybe, I'll just stick to a big ole air cleaner, and a big homemade "ram-air" intake.
One day when I have a chance, I'll drop the mufflers and see if it makes any difference. No cats on it now... but it does have EGR. I'll ditch the EGR as soon as I get this manifold and intake setup.
I work at Advance Auto Parts as a part-time job.. And I priced a computer for a "J" engine.. 90 bucks. Unfortunately the computer is the same, it's the PROM that's different, so now I'll have to find a PROM from a "j" engine.
Any other suggestions?

[britannic]

I haven't heard of anyone melting a piston because of fitting a turbo, headgasket failures are much more likely because of too much boost.

Overfueling, overadvanced timing, faulty injectors and cooling failure, are some of the reasons why a piston would melt.

[britannic]

Click here: Electric Turbo (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2469648911)

[JeepSJ]

Interesting - full boost at any RPM. I wonder how many RPM's that little electric motor is spinning. It probably can't match the shaft speed of a true turbo.

[britannic]

It doesn't have to match the conventional turbo rpm if the compressor is matched to the electric motor.

[arveetek]

One word:


Leafblower!!!


:D


Casey

[britannic]

Preferably a leafblower that runs on diesel and has it's own turbo :D :D !


Originally posted by arveetek:
One word:


Leafblower!!!


:D


Casey

[ 03-25-2004, 06:50 PM: Message edited by: britannic ]

[farmerpatrick]

For what the price of that thing's going to go for on eBay, I could do a few other mods on the engine. Dual idler timing gears.. Homemade intake.. And still have a few bucks for an oil change and McD's. Or I could probably get a junkyard 6.5 turbo with some miles on it for that.
Looks really interesting though, thanks for pointing it out. And I do appreciate your advice.