Jumpy Guy
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| posted on 2/6/03 at 11:02 AM |
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Demisting - to do or not to do?
Spent yesterday at Knockhill watching Caterspam racing, and noticed something.
On a couple of road cars, they dont have any vents for demisting on the dash.
SVA says its needed though.....
Why none on cats, even with full screens?
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StuartA
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| posted on 2/6/03 at 11:11 AM |
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I suspect they went through SVA without a windscreen and then put the screen on afterwards. This gets round the demist and wipers problem. We are
planning on aeroscreen for SVA and then see what it is like on the road before deciding if we need a 'proper' screen.
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Jumpy Guy
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| posted on 2/6/03 at 11:24 AM |
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hmmm- thought that at first but...
there were five different cars, none of which had any demist....
Does anyone have pictures showing how they've done demist on their car?
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Findlay234
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| posted on 2/6/03 at 11:46 AM |
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Remember that cateringham is made up of very expensive pork. The windscreens may well be electrically heated screens, so no need for vents.
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StuartA
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| posted on 2/6/03 at 11:58 AM |
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Hmmm hadn't considered the pork option! 
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macspeedy
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| posted on 2/6/03 at 01:17 PM |
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fan heater
I used the heater matrix and fan from my donor sierra, pic in my archive, there is now a box around the fan so fresh air is pulled from vents through
the bonnet, also there are two holes at the other side that line up with two holes in the bulkhead, after that it will into a dividing box, air will
always beable to go up to the windscreen through mini demister vents, around you knees one either side i will use sierra vents from either side of the
dash having these open or shut and controling the fan speed adds enough flexibility i think. Folding aluminium is relatively easy and very
rewarding.
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Jumpy Guy
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| posted on 2/6/03 at 02:55 PM |
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anyone know where to get narrow demist vents?
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macspeedy
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| posted on 2/6/03 at 04:21 PM |
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Europa, but they a'int cheap
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macspeedy
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| posted on 2/6/03 at 04:22 PM |
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is that the top bit or the under neath bit?
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Danozeman
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| posted on 2/6/03 at 06:31 PM |
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Mini demister vents are small and thin and are available from scrappies or mini spares places very cheap.. Ideal for kit cars.. Thats what i will
use in mine if i dont put and aero screen on for sva then change to proper screen..
[Edited on 2/6/03 by Danozeman]
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chrisg
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| posted on 2/6/03 at 07:34 PM |
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Yep,
I used the complete Mini heater.
Had to build the bulkhead out for it tho....
Cheers
Chris
Note to all: I really don't know when to leave well alone. I tried to get clever with the mods, then when they gave me a lifeline to see the
error of my ways, I tried to incite more trouble via u2u. So now I'm banned, never to return again. They should have done it years ago!
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JAG
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| posted on 18/6/03 at 12:43 PM |
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How much of the screen needs to de-mist for it to pass the test??
Would you get away with just a single blower vent in front of the driver??
Anyone care to offer an opinion??
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Spyderman
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 posted on 18/6/03 at 03:29 PM |
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I thought the SVA manual specified the amount that had to be cleared.
Can't find the details at the moment though.
Terry
Spyderman
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JAG
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| posted on 19/6/03 at 03:45 PM |
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I've just looked at this site;
http://www.jpmast.nl/svaChapters.htm
The page on demisting/defrosting simply says that the system must clear an adequate area of the screen
What the hell does that mean??? It means Mr SVA Tester can make his own bloody mind up 
Justin
Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!
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Ian Pearson
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| posted on 19/6/03 at 07:53 PM |
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quote:
What the hell does that mean???
I would imagine it means that you make sure you have plenty of hot air blowing onto the screen, and don't have your hood on your car when you go
for your SVA test.
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greggors84
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| posted on 19/6/03 at 08:02 PM |
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Does the air have to be heated by an element, or can it just be heated by the hot air from the engine?
Chris
The Magnificent 7!
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Ian Pearson
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| posted on 19/6/03 at 08:28 PM |
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Just hot. These guys do an electrical blower.
NF AUTOS
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jmbillings
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| posted on 1/8/03 at 09:16 PM |
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We used a small 12v hairdryer mounted behind the dash, then in the top of the scuttle we cut 4 thin long holes. On the underside of these we mounted a
drainpipe tube (inch dia) cut in half lengthways, then a small rubber pipe from the hairdryer to this.
It was crap, but it passed SVA.
Trust me, after driving through Belgium in the pouring rain, you get more rain on the inside of the screen than out, and no demister will get rid of
that! The 2 inches of water in the footwell gets kinda annoying too, but amuses the foreigners when you sponge it all out at a service station...
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Browser
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| posted on 2/8/03 at 07:58 AM |
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Call me a wuss but I'm fittin' heater vents for me feet as well as me 'screen 'cos I don't want cold tootsies. I know,
I'm a big soft southern shandy drinkin' poof but at least I'll have warm feet!
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Lightning
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| posted on 3/8/03 at 09:32 PM |
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I bought a Caterham windsceen from Redline Racing in Caterham. It has built in heating element and I think cost £115, but that was a couple of years
ago. Nice quality as well.
Steve
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Mark H
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| posted on 4/8/03 at 01:21 PM |
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quote:
Call me a wuss but I'm fittin' heater vents for me feet as well as me 'screen 'cos I don't want cold tootsies. I know,
I'm a big soft southern shandy drinkin' poof but at least I'll have warm feet!
My locost cooks my feet - with gearbox and engine inches from your trainers, this is the least of your problem!!
Of course you may still be a sssdp, but you wont have cold feet.
Mark Harrison and
Q986 KCP back from the dead...
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ChrisW
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| posted on 4/8/03 at 02:14 PM |
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Other option is to have a folding screen.
Chris
My gaff my rules
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Dave Ashurst
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| posted on 8/8/03 at 08:45 PM |
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The SVA man puts his hand over the vent to check.
However:
On a really cold foggy day, and I don't have a roof, the ice forms on the screen faster than the screen vents melt it.
Then you need an electrically heated screen, or in my case plenty of lukewarm washer fluid. It makes piles of blue slush. (yummy)
Ice condenses on your hat, hair, clothes, face etc too.
Cool.
Dave
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