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sin0822
Date registered: Dec 1899
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| Air intake fans?
So ive been doing some reading and thinking, and it seems that this has already been done and its called like an electric supercharger, i was thinking about installing 4X120mm 100+ CFM fans next to each other in a grid on the inside of the filter pushing air into the intake. Do you think this woudl do anything? |
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Marcelc
Date registered: Dec 1899
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| RE: Air intake fans?
sin0822 - 5/29/2008 5:49 AM
So ive been doing some reading and thinking, and it seems that this has already been done and its called like an electric supercharger, i was thinking about installing 4X120mm 100+ CFM fans next to each other in a grid on the inside of the filter pushing air into the intake. Do you think this woudl do anything?
An 8 cylinder 4.3 litre motor takes in about 1 litre of air per revolution (2 cylinders firing per revolution) at wide open throttle which equals 6,000 litres of air at 6,000rpm. This seems a massive amount of air to be delivered by electric fans - how much could your fans produce?
Even if your fans can provide enough air - are you able to increase the fuel injection to make use of it? And will the MAF and engine computer cope with this redesign?
Personally, I doubt if it is a practical proposition.
Incidentally, if my maths is incorrect, please advise me!
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Marcelc
Date registered: Dec 1899
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| RE: Air intake fans?
Marcelc - 5/29/2008 6:25 PM
sin0822 - 5/29/2008 5:49 AM
So ive been doing some reading and thinking, and it seems that this has already been done and its called like an electric supercharger, i was thinking about installing 4X120mm 100+ CFM fans next to each other in a grid on the inside of the filter pushing air into the intake. Do you think this woudl do anything?
An 8 cylinder 4.3 litre motor takes in about 1 litre of air per revolution (2 cylinders firing per revolution ) at wide open throttle which equals 6,000 litres of air at 6,000rpm. This seems a massive amount of air to be delivered by electric fans - how much could your fans produce?
Even if your fans can provide enough air - are you able to increase the fuel injection to make use of it? And will the MAF and engine computer cope with this redesign?
Personally, I doubt if it is a practical proposition.
Incidentally, if my maths is incorrect, please advise me!
I should have said that is 6,000 litres of air per minute - not to mention the question of pressure
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sin0822
Date registered: Dec 1899
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| Re: Air intake fans?
6000 liters = 6 cubic meters per minute = 212 cubic feet per minute these fans all together would push in around 400+ cfm. |
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sin0822
Date registered: Dec 1899
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| Re: Air intake fans?
also like this doesnt cost me anything to build... lol i have too many computer fans lieing around i have a remote switch that i can trigger from inside the car and activate these fans remotly whenever id want too. I acutally think my engine is putting in too much gasoline....
Edited by sin0822 5/30/2008 12:41 AM
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Marcelc
Date registered: Dec 1899
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| Re: Air intake fans?
Another approach is to construct a ram air input.
I will be very interested to hear how it turns out, please let us know after you've tried it.
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sin0822
Date registered: Dec 1899
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| Re: Air intake fans?
i will deffinatly let you know how it goes. |
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turbine
Date registered: Dec 1899
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| RE: Air intake fans?
Hi Guys,
Don't waste your time with so called electric superchargers. There have only been about 2 documented attempts at this and both ended up requiring a 4 KW electric motor, with a rather complex array of moving and fixed vanes, suplemented by many 12V batteries in parallel to sustain the power requirements.
Why small electric fans will not work comes down to simple maths. A 5 litre V8 engine, assuming 100% VE [volumetric efficiency] will at wide open throttle suck in about 15,000 litres of air per min, or 530 CFM. Thats 250 litres of air a second. So if anyone can get an electric fan that flows 530 CFM under the engine bay well done!
Not that it would be of any use, as 530 CFM is not forcing additional flow, in other words no pressure is being produced at this flow rate to force additional air into the engine. To get even a tiny boost of 1 psi, about 1000 CFM will be required.
So you want perhaps 8 psi? See the problem?
But hold on it gets worse. Whilst a bladed fan can produce air flow, it cannot produce significant pressure as fans rely on unrestriced air flow as the blade cuts through the air. If the airflow is restricted [eg. to build up pressure] the blades simply begin to cavitate and pressure drops off dramatically.
Only a centifugal impeller [or srew type supercharger] can produce both high flow and pressure at the same time.
Ebay has a couple of sites with these so called electric supercharges. They are installed just before the entry point to the air filter box. All have been tested and where a totally useless except for one which produced 2 psi on a 1000cc engine at idle speed!
But it was a good idea anyway.
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sin0822
Date registered: Dec 1899
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| Re: Air intake fans?
yeah i guess that made sence i figured i needed some pressure and not just air flow. But yeah i can get the fans to produce 530 cfm thats not hard a decent computer 80mm 12v fan can produce 100cfm but they are loud. I wonder if i could get my hands on like 9 of them that might do somthing, but its not worth my effort i guess. IDk ima try it anyways i really dont care what i do with this car nowadays. |
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turbine
Date registered: Dec 1899
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| RE: Air intake fans?
Air flow is only part of the issue, generating pressure is the real problem which as I already indicated previously cannot be attained using simple bladed fans. You would have to use a centifugal impeller, similar to that used on the compressor side of a turbocharger to get pressure. So if you can find an electric motor that has the power to spin this up to 80-100,000 rpm the its a go!
Having said this, I have recently got involved with large RC model electric helicopters, and noticed that there are currently available 22V brushless motors with powers upwards of 2500W, which equates to over 3HP. If you have access to a machine shop [lathe, mill etc] perhaps you can get hold of a used turbocharger, throw away the 'HOT' part [meaning the heavy cast iron turbine part] and then adapt one of these high power brushless electric motors onto the compressor shaft. This would make a very neat small package.
Dunno though, I haven't done any serious calculations or checked as to what speed these brushless motors can get up to. If they cannot spin up to the required RPM, then perhaps a simple gearbox could achieve this.
Now you have me thinking....................
No harm in experimenting and all fun and games + lots of spare time.
See ya!
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Marcelc
Date registered: Dec 1899
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| RE: Air intake fans?
Would an air scoop in the bonnet be more successful than fans?
Even if fans provide enough air with sufficient pressure, there is still the issue of how to increase the fuel injection to account for the extra air, or will the MAF do this automatically?
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Tarydesign
Date registered: Dec 1899
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| RE: Air intake fans?
But your 430 ALREADY has a secondary electric air intake ( Electric Turbo )!!! -Check the fuse box descriptions to believe!
Open the bonnet, look directly in front of the engine in the middle is the motor and compressor, two pipes go back towards the engine and across to each side, where the air has to pass through a one-way valve and solenoid, and down into the inlet manifold!!
Clean up those valves and solenoids as they get blocked- and you might be amazed at the difference!! 
PS Brushless motors for the planes/Heli's only go up to 20 000 rpm MAX (good ones) but you can get any power you want -for a price and you'll need a speed controller=$$$$ ... Sorry  |
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turbine
Date registered: Dec 1899
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| Re: Air intake fans?
Very good, I like the humour re the Electric turbo!
And yes, I know brushless motors only go up to about 20,000 rpm, but a simple 5:1 gear drive will get the impeller up to the required 100,000 rpm so problem solved. The question is wether a 3HP motor has enough power to do this.. I suspect not otherwise it would have already been done.
Ah well so much for the easy way out right?
On the question regarding air scoops, forget it. Calculations have shown that for a normal sized bonnet air scoop to provide the amount of airflow and pressure necessary to produce even a minscule amount of boost requires that the vehicle needs to be travelling in excess of 350 kmh, ie a drag car perhaps. They have a small airscoop mounted on top of the supercharger to aid in capturing air when travelling at those insane speeds.
The alternative is to increase the dimensions of the air scoop to 1 m x 1 m [mounted perhaps on the roof] to get similar performance at slower speeds. Will look impressive anyway.
If it could work, then it would be done already.
On the subject regarding if the engine management will cope when the intake air pressure is increased. A certain amount of tollerance can be accomodated by the injector pulse width and flow, as required to cope with the varying engine operating conditions. But I suspect there is a limit to this and once we begin to force additional air into the engine, the standard computer will not be able to handle this. Normally when converting a normally aspirated engine to forced induction, fuel injectors must be changed to high flow units, fuel pressure regulators changed and the fule injection computer calibration [chip] modified to cope. Not to mention exhaust systems etc etc.
Now your entering into an expensive world where $10,000 for such modifications will disapear before your eyes. And lets not forget the horrendous increase in fuel consumption with a turbo or supercharged V8 pulling 2300 kg.
Oh the fun of owning and modifying cars.
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Marcelc
Date registered: Dec 1899
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| Re: Air intake fans?
Thanks Turbine for these precise answers, the ram air input had always dwellt on my mind; I notice that my ML 270 does have gaps to the sides of the radiators blocked to aid in moving air into the front inlet.
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