88V8 Posted December 28, 2008 Report Share Posted December 28, 2008 Does anyone happen to know the output, in cubic feet per minute, of the heater fan? I have in mind replacing it with this, at 104cfm, http://www.frozencpu.com/products/7907/fan...amp;id=QgoaZGiq or this at 254cfm http://www.frozencpu.com/products/2571/fan...ml?tl=g36c15s73 but no point if it's less than the existing. Ivor Quote Link to post Share on other sites
RogerH Posted December 28, 2008 Report Share Posted December 28, 2008 Hi Ivor, be careful you do not push too much air through the heater as this may lead to cooler rather than warmer air coming out. The original fan normally gives an adequate flow and the lack of heat being water problems. Happy new year Roger Quote Link to post Share on other sites
Richard Crawley Posted December 28, 2008 Report Share Posted December 28, 2008 Does anyone happen to know the output, in cubic feet per minute, of the heater fan?I have in mind replacing it with this, at 104cfm, Unless you have a blocked heater matrix, the standard heater should be very good even by today’s standards. With an earlier CP car, the vent flap must be open or the heater will never work as it’s the only way for air to get into the unit; no air in = no air/heat out. I believe you have a CR with plenum grill so, I guess, the heater matrix is stuffed or you have another problem; either that or your getting to an age where your beginning to feel the cold! Quote Link to post Share on other sites
88V8 Posted December 28, 2008 Author Report Share Posted December 28, 2008 be careful you do not push too much air through the heater as this may lead to cooler rather than warmer air coming out. That's a very good point. However, the OE half-blocked demist vents indicate a potential to use more airflow, and when I compare the air volume with the output of the fan in our 205 shopping trolley, it suggests that more could be done. Even cool air in sufficient volume will demist pretty well. With an earlier CP car, the vent flap must be open or the heater will never work as it's the only way for air to get into the unit; no air in = no air/heat out. I believe you have a CR with plenum grill...... your getting to an age where your beginning to feel the cold! Er, age, yes, perhaps.... The grille was there. Now it's in a box on the shelf, and I have a flap thing which is firmly sealed and screwed down and going to stay that way. Whoever decided it was a good idea to ventilate the heater by a means that involves letting water into a steel box doesn't get my vote. I've seen the pics of the consequent rust, a restorers' job creation scheme. So the air will be allowed in in via a different route. But while the heater is out for the necessary mods, I would like to fit a bigger fan. Guess I could check it by setting up a blowing competition. Ivor Quote Link to post Share on other sites
Richard Crawley Posted December 28, 2008 Report Share Posted December 28, 2008 The grille was there. Now it's in a box on the shelf, and I have a flap thing which is firmly sealed and screwed down and going to stay that way. Whoever decided it was a good idea to ventilate the heater by a means that involves letting water into a steel box doesn't get my vote. I've seen the pics of the consequent rust, a restorers' job creation scheme. Therein lies your problem! If it’s screwed down, you won’t be getting any air into the heater & no air in = no air/heat out! I’m not saying the plenum flap was the best of ideas as far as potential rust was concerned (&, lets face it, BL didn’t exactly care!) & the later “open grill” affair just made things a whole lot worse. It was fitted, presumable, because some owners couldn’t actually figure out that you had to open the flap to get air circulation through the heater in order to allow it to work! Any heating/ventilating system has to circulate air in order for it to function correctly & in our “more enlightened” age, it’s just a question of not opening the flap if it’s raining! So the air will be allowed in in via a different route. What route did you have in mind? But while the heater is out for the necessary mods, I would like to fit a bigger fan. Guess I could check it by setting up a blowing competition. Whatever capacity fan you fit won’t make any difference unless you can get the same amount of air in as you wish to pump out. The standard heater doesn’t require much air displacement for it to function more than adequately, just unblock the vent & it will work. It’s a basic fact that unless a heating/cooling system has a > equal supply of air, it won’t be efficient! Quote Link to post Share on other sites
msport Posted December 28, 2008 Report Share Posted December 28, 2008 Sorry to be thick about this (forgive me as I don't know much about cars and have only had my TR6 since August 08) but are you saying that in order to get hot air into the car you have to raise the flap behind the bonnet on the earlier CP cars? Would be interested in knowing as my fingers were about falling off whilst out driving mine today! Quote Link to post Share on other sites
Richard Crawley Posted December 28, 2008 Report Share Posted December 28, 2008 Sorry to be thick about this (forgive me as I don't know much about cars and have only had my TR6 since August 08) but are you saying that in order to get hot air into the car you have to raise the flap behind the bonnet on the earlier CP cars?Would be interested in knowing as my fingers were about falling off whilst out driving mine today! Yes; open the flap when your heater is on & it could prove to be a revelation! Quote Link to post Share on other sites
Tony Millward Posted December 29, 2008 Report Share Posted December 29, 2008 So the air will be allowed in in via a different route. Ivor Ivor, I too, would be interested as I've been pondering that myself... Tony Quote Link to post Share on other sites
88V8 Posted December 29, 2008 Author Report Share Posted December 29, 2008 Ivor, I too, would be interested as I've been pondering that myself... Hi, Tony, having bought a spare heater I find that the design isn't as I expected so Plans A & B have been binned, and Plan C is upcoming. I did run the heater with the grille in place when first I bought the car, but the air output was feeble, so a bigger fan has to be on the shopping list.... Also, one that takes up less space in the casing. If you can wait until I've bought the replacement fan, I'll do the mod - not difficult with the heater out - and post about it but basically I'm going to turn it into a good old fug-stirrer and take the air from inside the car. With a saloon I would be less inclined to do that, but under a soft-top one isn't exactly hermetically sealed even with the hood up, and now we know better than to smoke in our cars the need for 'fresh air' is somewhat diminished. The other benefit of recirculating the air is that it will reheat that which it has already heated, thus getting even hotter..... Mind you, as BrianC has pointed out, if the car leaks then it will recirculate the damp all over the screen, but I'm sure your car won't be allowed to leak even if it had any rain to leak in Ivor Quote Link to post Share on other sites
peter f Posted December 29, 2008 Report Share Posted December 29, 2008 (edited) I did run the heater with the grille in place when first I bought the car, but the air output was feeble, so a bigger fan has to be on the shopping list.... Also, one that takes up less space in the casing. Ivor What fan motor are you considering as a replacement, and which supplier? I need to replace mine and I'd be interested in looking at alternative options. Peter Edited December 29, 2008 by peter f Quote Link to post Share on other sites
ianhoward Posted December 29, 2008 Report Share Posted December 29, 2008 What fan motor are you considering as a replacement, and which supplier? I need to replace mine and I'd be interested in looking at alternative options.Peter Me too!! Brgds Quote Link to post Share on other sites
Tony Millward Posted December 29, 2008 Report Share Posted December 29, 2008 Hi, Tony, having bought a spare heater I find that the design isn't as I expected so Plans A & B have been binned, and Plan C is upcoming. I did run the heater with the grille in place when first I bought the car, but the air output was feeble, so a bigger fan has to be on the shopping list.... Also, one that takes up less space in the casing. If you can wait until I've bought the replacement fan, I'll do the mod - not difficult with the heater out - and post about it but basically I'm going to turn it into a good old fug-stirrer and take the air from inside the car. With a saloon I would be less inclined to do that, but under a soft-top one isn't exactly hermetically sealed even with the hood up, and now we know better than to smoke in our cars the need for 'fresh air' is somewhat diminished. The other benefit of recirculating the air is that it will reheat that which it has already heated, thus getting even hotter..... Mind you, as BrianC has pointed out, if the car leaks then it will recirculate the damp all over the screen, but I'm sure your car won't be allowed to leak even if it had any rain to leak in Ivor I actually considered (and still am), bringing fresh air from the inner front wings...where the plenum tube goes out. This would mean having a pipe each side connected to the plenum (enlarge the drain tube holes) and seal the air intake on the scuttle. Hope I explained that well enough. Tony Quote Link to post Share on other sites
88V8 Posted December 29, 2008 Author Report Share Posted December 29, 2008 What fan motor are you considering as a replacement, and which supplier? I need to replace mine and I'd be interested in looking at alternative options. Probably this one, allied to a controller so I can turn it down. Obviously this will replace the motor and the fan. If I find it won't fit, then perhaps the smaller one I mentioned initially, but further rummaging on the Net may turn up other options. These Case fans are designed for a very long life. http://www.frozencpu.com/products/2571/fan...ml?tl=g36c15s73 I actually considered (and still am), bringing fresh air from the inner front wings...where the plenum tube goes out. This would mean having a pipe each side connected to the plenum (enlarge the drain tube holes) and seal the air intake on the scuttle. Hope I explained that well enough. Absolutely. However, the inner wings are or should be pretty sealed up once you fit the baffle plate, so I question whether one could really get significant air volume from there. In any case, the underwing is pretty well full of water mist when driving in the wet. Also, the intake hole on top of the heater box is 4" dia so that's 12.5"sq, to get that collective aperture through the ends of the plenum would require significant surgery. I had pondered taking air from the engine bay but I think on principle that's not such a good idea. I wonder how other classic car designs addressed this issue? My first seven cars didn't have a heater... Ivor Quote Link to post Share on other sites
RogerH Posted December 29, 2008 Report Share Posted December 29, 2008 Hi Msport, the earlier TR4A has an excellent system. You can either have 'fresh' air from outside through the bonnet vent. Or, with the vent shut, through the facia vents as the dreaded fug stirrer. Progress and change isn't always a good thing. Happy New Year Roger Quote Link to post Share on other sites
Tony Millward Posted December 29, 2008 Report Share Posted December 29, 2008 Absolutely. However, the inner wings are or should be pretty sealed up once you fit the baffle plate, so I question whether one could really get significant air volume from there. In any case, the underwing is pretty well full of water mist when driving in the wet. Also, the intake hole on top of the heater box is 4" dia so that's 12.5"sq, to get that collective aperture through the ends of the plenum would require significant surgery.Ivor Aah... very good points which I didn't consider..thanks Ivor. Back to the drawing board Tony Quote Link to post Share on other sites
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