smart51
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| posted on 26/3/08 at 11:18 AM |
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SVA demister
Are the 200W electric demisters any good or are they a waste of time?
I need a demister for SVA and a heater probably wouldn't be a bad idea but my project only has a 250cc scooter engine so I'm guessing that
it won't make a lot of waste heat. Any that it does make would be lost in the pipes from the back of the car.
Whay would make a good SVA proof demister?
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Paul TigerB6
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| posted on 26/3/08 at 11:25 AM |
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quote:
Originally posted by smart51
I need a demister for SVA
Only if you fit the windscreen. Leave it off would be my advice for SVA
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Mr Whippy
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| posted on 26/3/08 at 11:27 AM |
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can you get away with no screen at all for the SVA test? Could you just put a bare bones 'thing' through and finish it off properly after?
200w, what is the rating for the generator, add lights to that and is it going to charge the battery? From what I've noticed small bikes aren’t
overly generous with their output.
when are you going to post a picture of this contraption?
[Edited on 26/3/08 by Mr Whippy]
Fame is when your old car is plastered all over the internet
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smart51
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| posted on 26/3/08 at 11:38 AM |
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The 12V socket on the donor loom has a 180W rating, so I'm going to guess that a 200W heater isn't asking too much for occasional use. In
any case, a demister would be useful so I plan to fit one anyway.
The chassis isn't far off now and I'll be posing pics soon.
I was just wondering if anyone had used one of the ceramic ones and could say how good / how bad they were. I was also inviting other suggestions
about how to do it.
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Mr Whippy
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| posted on 26/3/08 at 11:42 AM |
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does it have a water radiator? I was thinking you could put it up front somewhere and direct the air through it and into the cabin?
can't wait to see it 
Fame is when your old car is plastered all over the internet
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BenB
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| posted on 26/3/08 at 12:00 PM |
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I'd use heat from the engine. Or not fit the screen until after SVA (though misting at speed (been there, got the brown pants t-shirt) might be
a problem if you fit it post SVA without a demister)
Okay, so a 250cc engine isn't going to be chucking out tons of heat but the alternator isn't going to be chucking out the amps either.
It's not going to be impressed if you wack on a 2000w demist system (and the 200w ones are puny).
The internal combustion engine is not an efficient device. They give off most of their energy in heat and noise!! You'll be better off using the
waste heat than adding in yet more inefficient stages (ie producing electricity from kinetic energy, producing heat from electricty, and of course
producing kinetic energy derived from electricity derived from kinetic energy to drive the blower fan)....
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smart51
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| posted on 26/3/08 at 12:32 PM |
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Rather than tapping off some of the hot water from the engine (there won't be much) I could put the heater in series so that all the hot water
goes through it. Is there such a thing as a bypass valve so that in warm weather I can turn it off? The only valves I've seen are simple taps.
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Bluemoon
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| posted on 26/3/08 at 01:15 PM |
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You can get bypass valves search ebay for transit heater valves..
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Mr Whippy
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| posted on 26/3/08 at 01:24 PM |
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Why use a separate heater? The radiators a pretty good one and all the heat from the engine would be going into the cab. Don't know the layout
of this thing but a bike radiator is usually quite a small affair and easy to fit at the front. A simple flap could be used in the summer for
redirecting the warm air elsewhere operated by a lever. I like cars and bikes which are fiddly and need constant footering to keep them going. Who
wants to sit back and do nothing but steer? Yawn….. Give me loads off knobs, levers and switches, preferably in unfeasibly awkward locations 
Fame is when your old car is plastered all over the internet
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BenB
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| posted on 26/3/08 at 01:54 PM |
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Range rovers have a nice heater control by-pass valve. I think I might have one in the garage if you're prepared to wait a few years whilst I
find it!!! For some reason it's vaccum actuated (though converting it to cable would be the job of seconds)....
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Chippy
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| posted on 26/3/08 at 05:33 PM |
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Couple of 12v hairdryers, tucked up behind the dash, should work fine, and they are fairly cheep. HTH Ray
To make a car go faster, just add lightness. Colin Chapman - OR - fit a bigger engine. Chippy
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