petzzii Posted January 8, 2016 Share Posted January 8, 2016 Hi, My car has a heater, very good for cold mornings, but on summerdays it's getting really hot underneath the scuttle.. I'm thinking of putting a heat valve in the heater hose, and putting 2 bonnet vents on the side. Anybody has done this before? Is it worth...? Quote Link to comment Share on other sites More sharing options...
Captain Colonial Posted January 8, 2016 Share Posted January 8, 2016 I put a heater valve from an old Mini + cable w/dash knob in-line with my heater, works just fine and amount of heat is incrementally controllable to boot. Quote Link to comment Share on other sites More sharing options...
petzzii Posted January 8, 2016 Author Share Posted January 8, 2016 Hi Scott, That's exactly what I wanted to read..... 1 Quote Link to comment Share on other sites More sharing options...
Dave Eastwood (Gadgetman) - Club Chairman Posted January 8, 2016 Share Posted January 8, 2016 Yes, works so much better with one. Had it on the last car and fitted one on this one too. Quote Link to comment Share on other sites More sharing options...
petzzii Posted January 8, 2016 Author Share Posted January 8, 2016 Any tips for bonnet vents? Quote Link to comment Share on other sites More sharing options...
Dave Eastwood (Gadgetman) - Club Chairman Posted January 8, 2016 Share Posted January 8, 2016 Sorry if I've misunderstood you, are you talking about putting bonnet vents on the scuttle? For what reason? What do you want to achieve? Depending how good the heater valve is, and how you plumb it, you can achieve complete isolation of the heater, such that there's no hot water held under the scuttle and no heat build up... Quote Link to comment Share on other sites More sharing options...
petzzii Posted January 9, 2016 Author Share Posted January 9, 2016 Hi Dave, Sorry for my bad english, I wanted to put a bonnet vent on each side of the bonnet near the scuttle, to get the heat out under the bonnet. Quote Link to comment Share on other sites More sharing options...
Dave Eastwood (Gadgetman) - Club Chairman Posted January 9, 2016 Share Posted January 9, 2016 Ah, no problem, it's not the best or easiest way of getting heat out I'm afraid, especially if you have a windscreen. On a windscreened car, at anything above forty or so miles an hour, the end of the bonnet near the scuttle becomes a high pressure air zone, with pressure increasing further with speed. Thus any opening at that point will "tend" to see air pushed into the engine bay, NOT drawn out. The effect isn't quite so bad on an aeroscreened car. You can get air drawn out from under the bonnet by doing things like raising the rear edge of the bonnet slightly, to form a gap, (I'm told, I have t tried it myself). The most effective way of getting air out from under the bonnet and improving air flow in there is to split the tub sides, and flare them out. There are a number of threads around on the Boardroom at the moment showing this being done. (I'll try and find one or two of them when I get a chance!) Quote Link to comment Share on other sites More sharing options...
petzzii Posted January 9, 2016 Author Share Posted January 9, 2016 I wanted to put these vents outside, not on top of the hood. Anyway, if it's not worth, i will forget it. Thanks Quote Link to comment Share on other sites More sharing options...
Dave Eastwood (Gadgetman) - Club Chairman Posted January 9, 2016 Share Posted January 9, 2016 You mean low down either side of the bonnet - where Caterham have their air intakes? It may have been tried on a Westfield, but you'd need to do some experiments first, and still may find its not that effective. It shouldn't have as big a high pressure zone as the top, but I suspect it might be a bit turbulent. Why don't you try doing the wool tuft test? (Short lengths of wool, say 5 cm, stuck to the bonnet at one end, then drive about at a variety of speeds and see how they behave. (Ideally video them). That will give you an idea of what the air flow is like. As I say though, the proven method is the flared tub side. Quote Link to comment Share on other sites More sharing options...
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