Oh look, someone has reinvented the Surbo

I thought we did this before, or was it another group? The scamsters selling these things appear to be taking electric bilge-blower pumps from boats and selling them as "superchargers". The correct term for them in this application would be "restrictors", since they can't possibly shift enough air to do any good.

MeatballTurbo raved thus:

::

:: Electric Supercharger my arse. Any gains would be lost towing the :: powerstation needed to make enough amps to operate an electric :: compressor surely.

Ooh, they claim 5% more horsepower. You'd be better off farting into the induction, surely.

I did a quick calculation the other day for my modified ax. If i did full throttle at 1000rpm, it would gulp in

700 litres of air a minute. 1000rpm being a good rev range for a supercharger to work. More than 10 litres a second??? To get 11 in its got to be pressurized. Hows a little electric motor going to do that??? More like a wacking great turbine running at 5000rpm pulling 30amps. ....... Which would stall my modified ax.

'ang on, is this another "s*1t in the carburettor@ joke?

"Up to 15 more horsepower* GUARANTEED for $299.00"

So why has anyone bought one ?

You can get a 15bhp boost by farting during a drive (almost).

That seems like an overstatement, although I have to admit I know a few lager and curry houses where... but anyway...

15 bhp for 150 quid isn't shoddy. I've seen people paying a lot more than a tenner per bhp. Heck, I bet we'd all be reasonably happy to pay 4000 extra for a brand new Sierra carrying an extra 400 bhp, no?

As for the idea itself, seems that tests on the particular *product* aren't enormously impressive (unless they are claims by the maker) but the principle seems to be feasible. I'm still gathering data on this, there are "pumps" that can deliver 20% more air at the sort of cfm I require (which would include most cars under 4 litres, ruling out turbos and supercharged cars, but not a lot else AFAICS.) The main issue seems to be overheating of the axial compressor and thus dramatically shortened longevity. Which means it can be done, to some extent, if nothing else. And would be a good money spinner if you need a new one when you show off a bit.

I'm normally sceptical on this sort of thing and the website makes me more so, but there may be some merits. I'm still undecided on the idea as things currently stand. Won't be buying the kit from USA for 300 bucks, though.

!

does exhaust pressure equal inlet suction? I was musing to myself on whether or not a simple turbine arrangement on the exhaust with a shaft connected to another turbine on the inlet side would have any benefits whatsoever?

This is a joke, right? I mean, that'd never catch on.

Why go the bother of turbines? A simple shaft with a few dozen flat plate vanes, rotating slowly (compared to a turbo) in a cylinder will do. 4 ports on ends plates, inlet at one end, exhaust other. Put inlet suction port slightly after exhaust outlet to down pipe, inlet delivery slightly after exhaust feed from manifold. Passage of exhaust gas down exhaust pipe causes suction, inlet opens suction pulls fresh air in, rotation closes the exhaust outlet and then uncovers the exhaust feed which when inlet suction closes compresses the inlet air, when the inlet delivery is opened it blows the inlet air out, then the exhaust outlet opens and the exhaust gas expands away down the exhaust pipe pulling fresh inlet air in.

It's called a pressure wave supercharger - one makers trade name is Comprex. The trick is running the shaft at just the right speed to get the gas transfers without much mixing of inlet and exhaust in the vane passages or spill from ends.

Has been used by Opel and Mazda on oil burners.

A catalytic comprex from CAT.

-- Peter Hill Spamtrap reply domain as per NNTP-Posting-Host in header Can of worms - what every fisherman wants. Can of worms - what every PC owner gets!

when I say turbine, all I mean is spinning vane.

Just thought I would say that the motors on that look EXACTLY like the ones I have from a model plane. From the video they even sound the same. I tried these for a joke on my mates deisel and it did nothing lol. If I can be arsed I may try one on my mates car and see if it can even make positive boost pressure which would be seen on his gauge lol!!!

Actually, the theory is sound. One major automotive supplier - Visteon, I think - has a very similar concept intended to "fill in" the low-down torque on a turbo engine before the point where boost comes in.

Practically, I think the power of the thing is much too low. A rough calculation says a 2 litre engine at 6000 rpm boosting by 0.1 bar (1.5 psi) needs 1 kW of "air power". Given the inefficiencies, you'd need the fan motor to be at least 2 kW (as opposed to the 0.8 kW it actually is) to deliver this.

I'd expect a significant gain in low-end torque from one of these things, especially on an off-boost turbo engine, but probably very little at the top end on any sort of engine. On a non-turbo engine you might risk upsetting the ECU due to the pressure change, so I personally wouldn't use one. On a modern turbo engine, the ECU will just open the wastegate more and drop the boost at higher speed to compensate, so again you won't get much benefit.

Nice idea but...

Tony

(replace "nospam" with "fuel" to reply)

Sure, but then you just put two on, in parallel.

Worth testing, if someone can get hold of a few bits of kit and a rolling road.