Poor man's forced induction!?

AliK

AliK

Vehicle Dating Officer
Staff member
Club Member
Guys,

I was looking for an air hose and came across this! Has anyone entertained the idea of a fan in their induction path for an NA engine?

A part of me is convinced but I also can't help thinking at high revs it must become a restriction if not fanning open filters.

On a serious note though, I've often wondered why we haven't cracked electric turbo chargers yet.


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http://pages.ebay.com/link/?nav=item.view&alt=web&id=261126100147
 
Re the nice shiny red electric fan
Dont confuse flow with pressure

I've often wondered why we haven't cracked electric turbo chargers yet
Click to expand...
Due to it being impractical I guess.

To generate enough flow (typical boost figures are over 1 bar) a turbo impeller has to rotate many tens of thousands of times a second and will sap power from the engine , as always its a trade off against losses, an electric "supercharger" is feasible but impractical due to the fact that you require a motor specifically to drive the "pump" which has a significant weight penalty alongside a large power drain (electrical) for instance a supercharger requires several 10's of hp to drive it effectively, an electric motor driving a pump with that capacity would be fairly large and draw many 100's of amps from a 12 volt system (remember low voltage systems have higher curent draws) where as any commercial supercharger or turbo uses the exisiting engine to drive it, not "free" energy but exisiting energy.
 
Skiddel has all the points that I was going to. Although I would also make the point that an electric motor powerful enough to replace a tradition turbo would take up a fair bit of room too.
 
A good way to think about it is for a 2.6 litres engine at 6000 RPM you are (roughly of course) sucking in ((2.6*6000)/2) litres per second = 7800 litres of air.

Just doing a quick google to find a medium sized air compressor I found this:

http://www.screwfix.com/p/scheppach-hc53dc-50ltr-twin-cylinder-air-compressor-240v/76494

Thats 412Ltr/min costing 2.2kW of power to get 6% extra litres of air.

How does this compare to a turbo? Take a CT26 stock turbo for a 7MGTE, that pushes out 35 lb/min. 35 lb is 15875 grams of air, 1.2 grams of air per litre so ~13000 litres per min.

Now of course this constricts flow in the exhaust which robs power, but you get the idea.

I think the above is correct, had a long day so happy to be corrected.
 
That kind of compressor isn't what you would use for air needed in volume and at speed. If you wanted to investigate that, you'd be looking at a twin helical compressor. Problem with them is that they consume a fair bit of oil usually.
 
post some litres per watt figures for that type of compressor, let's work out how efficient you could make it
 
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