An intercooler fan powered by turbo boost?
Some months ago in Fan-Forcing Your Intercooler, Part 1 we covered the fitting of an intercooler fan – a device that forces air through the intercooler either when it is getting over-heated or when the car is moving slowly and so there is little outside air being pushed through it. It’s an especially effective approach for underbonnet intercoolers.
Making that particular design even better was the use of a very powerful centrifugal blower. The blower – salvaged from the tip – was a VW/Audi cabin ventilation fan from a Kombi. And it sure moved a helluva lot of air!
Unfortunately, despite my disassembling the motor and greasing the (plain) bearings before it was put into service, after a few months of hard work the blower failed. Delving inside it (again!) showed that the top bearing was completely stuffed – not only was the bearing surface badly worn, but the shaft was also pitted and scarred. Given the rubbish tip origin of the blower, perhaps it was already well on the way out – although I don’t remember there being much of a problem the first time I looked inside it.
Anyway, this particular unit needed to be retired. Or the electric motor part of it did, anyway. That thought prompted another – could I retain the compact centrifugal blower and its associated housing, but use a new electric motor? I tried a few different ones but none had the power of the original – not surprising, when that bugger drew no less than 15.5 amps!
But did the motive force even have to come from an electric motor? What about instead using another fan on the other end of a common shaft, and driving this second fan with a nozzle connected to a turbo boost source? Kind of like a mini turbo but using a bleed of boost off the plenum and spinning a fan that pulled air through the intercooler? Such a system would need no maintenance or control, and would increase in speed as boost also went up. The downside would be that it wouldn’t operate when the car was off-boost (say stopped at the traffic lights), but that was possibly not too great a downer, particularly if when on the boost the thing worked like a Trojan.
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