simonjrwinter Posted December 19, 2014 Report Share Posted December 19, 2014 When I bought my TR6, I was told that the bonnet was one of three that had been sent to have louvred punched in. I've never seen another TR6 bonnet with louvred in the same place as mine. Is there anyone on here who owns or has seen another? Simon Quote Link to post Share on other sites
GT6M Posted December 19, 2014 Report Share Posted December 19, 2014 M Quote Link to post Share on other sites
simonjrwinter Posted December 19, 2014 Author Report Share Posted December 19, 2014 Picture in my signature, why would there be any need for pics until there's a reply? Simon Quote Link to post Share on other sites
GT6M Posted December 19, 2014 Report Share Posted December 19, 2014 Farr tooo smaaaallll to see on my comp M Quote Link to post Share on other sites
Don H. Posted December 19, 2014 Report Share Posted December 19, 2014 There are a number of images on Google. Take your pick. Are they like yours -- we have no idea. Quote Link to post Share on other sites
Don H. Posted December 19, 2014 Report Share Posted December 19, 2014 Picture in my signature... I guess I need better glasses. The thumbnail in your signature always looked sorta like a Sunbeam to me. Quote Link to post Share on other sites
simonjrwinter Posted December 19, 2014 Author Report Share Posted December 19, 2014 there you go..... Quote Link to post Share on other sites
GT6M Posted December 19, 2014 Report Share Posted December 19, 2014 No not like mine, But Tims MK1 2.5 PI has got em where yours are. should help with under bonnet heat Tip top Tip, if youve got a manual swith on an electric fan for rad, the put it on as soon as ye come into slow traffic, stop start it works wonders for the fuel lines M Quote Link to post Share on other sites
RobinTR6 Posted December 20, 2014 Report Share Posted December 20, 2014 Good PIC, looks nice and nope not seen another. BTW what colour is your car, rather tasty. Quote Link to post Share on other sites
simonjrwinter Posted December 20, 2014 Author Report Share Posted December 20, 2014 It's a Jaguar colour (from memory) I have the colour code somewhere....... Quote Link to post Share on other sites
Denis Posted December 20, 2014 Report Share Posted December 20, 2014 Perhaps they were to help De Ice the windscreen on a winters day! Quote Link to post Share on other sites
john.r.davies Posted December 20, 2014 Report Share Posted December 20, 2014 Simon, Any good bodyshop can insert louvres. They can pressed in, using moulds, rolled in using a special tool or even beaten in with enormous manual skill. When well done, they can look very period (and also very ****) see: http://www.sportscarmetalworks.com/bonnet-louvres/ or you can buy louvred panels to insert, but the panels always look ****: http://www.hoodlouvers.com/ Problem is that in the period, people didn't understand aero, and louvres ARE **** as air and heat extractors. While they will let out hot air at the traffic lights and in motion the first louvre is a useful extractor, it messes up the air flow for the second, which messes up the third and so on. Only the first and possibly the second of a bank of louvres actually work. So your louvres could have been put in at any time before its current respray. Triumph must have thought they were either necessary or looked good, as they put them into the contemporary GT6's bonnet, unfortunately right in the high pressure bubble area in front of the wind screen, doubly useless. So yours might have been an experiment, but do you have any evidence that your car left the factory with its louvres? Have you tried to contact the owners of the TR6s next to yours in VIN, in case theirs are in the three? John Quote Link to post Share on other sites
RogerH Posted December 20, 2014 Report Share Posted December 20, 2014 Following on from John's comments about airflow. If the louvres were upside down they may work better by drawing the hot air out due to skin effect(a sort of venturi) (not sure how multiple louvres would work though). In aerospace we have things called NACA ducts usually used to allow air in but could work in reverse. These use the skin effect of airflow to allow a quite decent airflow to go in without disturbing the airflow around them on the structure. They definitely wouldn't look good on the bonnet compared to the louvres though. Roger Quote Link to post Share on other sites
Motorsport Mickey Posted December 20, 2014 Report Share Posted December 20, 2014 Roger, If you look at many race cars they all use NACA ducts whether pulling air in or in the reverse function of causing the bypassing air to suck air out, depending upon how the duct is fitted. We even used them on the undertray of my racecar at the rear of the engine to pull the air out of there. Their shape is quite sophisticated and must be in the same proportions (looks similar to a typical delta wing plane profile) but can be scaled up or down to fit the space available on whichever panel you wish to fit them. Many of the motorsport suppliers have them in their catalogues, Merlin Motorsport,Demeon Tweeks etc in a standard sizing, probably about 150mm x 150mm. Mick Richards Quote Link to post Share on other sites
WELLSY Posted December 20, 2014 Report Share Posted December 20, 2014 Been thinking about bonnet louvrers for my weber carbed 6. Can be very lumpy in traffic, which I am sure is due to heat build up under the bonnet. Perhaps only one is needed above the carbs? Wellsy Quote Link to post Share on other sites
marko Posted December 20, 2014 Report Share Posted December 20, 2014 Remember if you're putting louvres in the bonnet right above the carbs that louvres can let water in as well as heat out!! You'll find this out when you first wash the car or put a hose pipe over the bonnet so beware!! Quote Link to post Share on other sites
john.r.davies Posted December 20, 2014 Report Share Posted December 20, 2014 (edited) Roger may know better than I, but I don't think that NACAs work, backwards. Their principle is that the curved edges with the sloped-down entry ramp cause the skin flow, the boundary layer, to fall inwards, allowing the ambient flow to do so above it. This entrains two vortices, that transfer energy to the boundary layer air to speed it into the intake. When reversed, the boundary layer will pass over the (rounded) lip of the intake with little disturbance, and what intercation it has with air in the intake will be blocked by the upright walls up to the curved edges, which close as the air passes, forcing the boundary air back out again. A better extractor duct has parallel sides, with a large aspect ratio (longer than it it is wide) with a rising ramp as the floor, similar to the NACA in reverse. The lip to the out-take should have a tripping lip, like a small Gurney flap. This projects the boundary layer upwards, causing another pair of vortices to form in the throat of the out-take, with a similar effect as in the NACA. Air in the outtake is energised but as it and the vortices are in the outside air flow it is drawn outwards. Examples of this design include cars with front radiators (as opposed to side pod rads), such as the GT40 - and my Old Blue Vitesse. See between 750 and 57 SofS (below) has a vent in the same place, copying the LeMans Spitfires, but it, and they, don't work! John Edited December 20, 2014 by john.r.davies Quote Link to post Share on other sites
RogerH Posted December 21, 2014 Report Share Posted December 21, 2014 Hi John, the NACA duct was originally designed to allow air in without disturbing the surrounding airflow - which is does very well. As for drawing air out - it is probably quite inefficient, but again does not disturb the airflow too much. Your square approach almost certainly would draw the air out a treat but would also cause drag and disturbance. So its a balancing act 'streamline V grunt' . Roger Quote Link to post Share on other sites
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