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?
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.
there were five different cars, none of which had any demist....
Does anyone have pictures showing how they've done demist on their car?
Remember that cateringham is made up of very expensive pork. The windscreens may well be electrically heated screens, so no need for vents.
Hmmm hadn't considered the pork option!
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.
Europa, but they a'int cheap
is that the top bit or the under neath bit?
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]
Yep,
I used the complete Mini heater.
Had to build the bulkhead out for it tho....
Cheers
Chris
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??
I thought the SVA manual specified the amount that had to be cleared.
Can't find the details at the moment though.
Terry
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 
quote:
What the hell does that mean???
Does the air have to be heated by an element, or can it just be heated by the hot air from the engine?
Just hot. These guys do an electrical blower.
NF AUTOS
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...
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!
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.
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!
Other option is to have a folding screen.
Chris
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