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I am planning to add a 12V DC blower (https://www.amazon.in/gp/product/B00LPUXVWS) to intake manifold of my Yamaha FZS FI 149CC engine. I thought it could work more like a supercharger, except it will be powered by battery instead of engine. Will this be feasible? What are the complications associated with it?

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    It wouldn't surprise me if this restricted the air rather than increase flow. – HandyHowie Jun 11 at 11:05
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    To make this work, you need a very high quality air compressor, in the range of at least a few hundred watts (one successful project I heard about is TQ250-24v, which translates 600W of power to 4.5PSI of boot for a 2L engine). Also, pressure matters. A blower generates a lot of flow but not much pressure. You need something that generates enough flow but a lot of pressure. – user3528438 Jun 11 at 20:27
  • The size and weight of the batteries needed to power an electric compressor to provide useful boost would probably negate the power gain. Better off harnessing the exhaust heat enthalpy with a turbosupercharger; useful energy which otherwise would be wasted. – SteveRacer Jun 12 at 1:44
  • There are electric superchargers manufactured (think it was Turbodyne that were making one to be used in parallel with a turbo, to produce up to about 5 seconds of boost while the turbo spooled up), but the power requirements are very large. And likely any significant boost would put the fueling outside the range of the ECUs ability to compensate for fueling, etc. – Kickstart Jun 12 at 7:58
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I thought it could work more like a supercharger, except it will be powered by battery instead of engine.

This isn't the first time someone has thought of "electric" supercharging.

There's nothing wrong with having electrical power source per se (the leaf-blower Monza comes to mind), but you're going to need way more than 10 W worth of power (which is what the product you linked is rated for).

SparkFun Blower from Amazon

I urge you to read through this article on the Twin-Turbo Zet for more details on why this idea won't work with the fan you posted.

In a nutshell, it highlights the fact that the engine requires a tremendous amount of air in comparison to what the fan can provide, so you're going to have to use orders of magnitude more fans, which will consume orders of magnitude more electrical power.

Oh, and all this is just to satisfy the engine's basic pre-boost requirement. To add boost, you're going to have to add even more air flow (and subsequently supply more power).

  • First of all, thanks Zaid for the knowledge. Considering I am trying to boost a relatively small single cylinder engine (150CC putting out 13.2 PS and 12 nm), won't it result in any improvement? 10w = 0.01 HP, will this addition be even noticable on daily drive? – Prasanna Sundar Jun 11 at 11:43
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    That depends on the numbers. You need to first of all meet the air requirement, then exceed the air requirement, then ensure that the extra air gets converted to boost, then ensure that the boost makes its way to the engine from the intake. – Zaid Jun 11 at 12:03
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    Don't forget you need an intercooler to cool the air after compression, or the heat from compressing it will decrease the air density. – GdD Jun 11 at 12:35
  • @GdD and increase temperature mechanics.stackexchange.com/a/17491/675 :) – Zaid Jun 11 at 14:03
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    @PrasannaSundar while not exactly the same, compare to car turbos that can spin up to 150,000rpm. There's a reason turbos and superchargers are powered by the engine (either via exhaust or direct mechanically): an electric motor needs to be big and heavy to push the quantities of air required. – mbrig Jun 11 at 20:43
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Using that kind of blowers as turbochargers is generally proved worthless. The main drawback is these devices are not capable of creating any significant pressure, especially considering internal combustion engine's air flow rate.

As @HandyHowie already mentioned one could even experience air flow restriction. Some quick maths: consider 1 cylinder 2 stroke engine with 150cc piston displacement at 3000 RPM. That results in roughly 150*3000*0.000001 = 0.45 m^3/min of air flow rate. Now the blower you've linked is capable of 16 CFM flow rate, which is about the same 0.45 m^3/min. So best case scenario: you don't get any extra power below 3000 RPM and lose power above that rev.

  • Thanks for the numbers, Max. That makes sense, I will try to get better air flow. If not, I gotta drop this idea. – Prasanna Sundar Jun 11 at 12:45
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This will not cause any increase in horsepower. Likely a decrease in horsepower due to restriction.

A unit like this simply does not flow enough air to make a difference. Think of it this way, your device needs to be able to flow more air (at higher than atmospheric pressure) than the intake stroke of the engine would flow typically.

If it cannot do this, you will not see an increase, and it may even restrict air flow causing a decrease.

Not only that, but if you do not modify the fuel injection map on your ECU, it will not inject any more fuel into the engine so power will not increase. Max power is based on how much fuel you can burn in the engine, if you aren't putting any more fuel in, no matter how much air in, there will be no increase.

For a small engine like this, you can probably find a very small turbocharger to use, get a skilled welder to create a manifold, then get a small ECU (MicroSquirt works well for bikes) and tune it for the increased manifold pressure, you may need larger injectors, or to increase fuel pressure also.

If were to do this, you likely would not need an intercooler, as you would likely not be compressing the air that much, if you were to go above ~5PSI you would want an intercooler.

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