Motorsport Mickey Posted March 26, 2021 Report Share Posted March 26, 2021 "Great fun to build but did they work - basically no. As for the WW electric piano." Didn't that WW electric piano exceed trhe emissions...or am I thinking of something else ? Mick Richards Quote Link to post Share on other sites
RogerH Posted March 26, 2021 Author Report Share Posted March 26, 2021 4 minutes ago, Motorsport Mickey said: "Great fun to build but did they work - basically no. As for the WW electric piano." Didn't that WW electric piano exceed trhe emissions...or am I thinking of something else ? Mick Richards you can take the micky Mickey Roger Roger Quote Link to post Share on other sites
ntc Posted March 26, 2021 Report Share Posted March 26, 2021 But when od 2 is the same as none od 3 you gain nothing same for 3/4 Quote Link to post Share on other sites
RogerH Posted March 26, 2021 Author Report Share Posted March 26, 2021 Hi Neil, that was one of the designers (of the OD) issues. However there really is an asset. When driving n a very twisty road in the Black Forest the hairpins were comfy in 3rd gear. But the straights needed a bit extra gearing. 4th would have been fine but you had the constant faff of changing gear every 10 seconds or so. However a simple flick of the switch on 3rd OD did the trick. No clutch or gear stick waggling. Just a flick f the switch. And then another flick to get into 3rd to flow around the hairpin. Roger Quote Link to post Share on other sites
ntc Posted March 26, 2021 Report Share Posted March 26, 2021 Roger Thats my point useing in one gear yes but you gain very little when changing gear you will spend more time flipping in and out Quote Link to post Share on other sites
Tim D. Posted March 27, 2021 Report Share Posted March 27, 2021 Really appreciated OD when we did the 10 countries. With the supercharger it 4th and OD 4th worked great up the passes. I fitted the logic unit before the trip. I agree, it is not a perfect solution but I do like the fact that it prevents me inadvertently using OD3 when when I change down to third in a hurry. Tim Quote Link to post Share on other sites
ianc Posted March 27, 2021 Report Share Posted March 27, 2021 ntc: on a TR2/3/4 gearbox (and probably for TR5/6) with the 22% overdrive, O/D 2nd is certainly NOT the same as 3rd - it is almost exactly halfway between and therefore an excellent gap-filler ratio when going up the box, especially on hills. For example, at Kop Hill I use 2nd to about 5500, then, on the ever-steepening slope, O/D 2nd to about 5500 in order that when selecting 3rd I am at the peak of the torque curve and can hold it in 3rd for the rest of the Hill. Were I to select 3rd from 2nd (missing O/D 2nd), I would be a lot slower. Ian Cornish Quote Link to post Share on other sites
Hamish Posted March 27, 2021 Report Share Posted March 27, 2021 I have a tr6 box and 22% od and 3rd od is now the same as 4th since I went to 4.1:1 diff. Quote Link to post Share on other sites
ntc Posted March 27, 2021 Report Share Posted March 27, 2021 8 minutes ago, Hamish said: I have a tr6 box and 22% od and 3rd od is now the same as 4th since I went to 4.1:1 diff. Exactly yes as I said the odd occasion I wonder why most serious competition cars do not have od fitted Quote Link to post Share on other sites
Motorsport Mickey Posted March 27, 2021 Report Share Posted March 27, 2021 40 minutes ago, ntc said: Exactly yes as I said the odd occasion I wonder why most serious competition cars do not have od fitted I don't know if you mean other cars than TRs Neil, but from memory Christian Marx uses his TR4 with an overdrive, and he's pretty seriouds about competing. Mick Richards Quote Link to post Share on other sites
BlueTR3A-5EKT Posted March 27, 2021 Report Share Posted March 27, 2021 2 hours ago, ntc said: Exactly yes as I said the odd occasion I wonder why most serious competition cars do not have od fitted Weight saving? Power consumed by the overdrive epicyclic gears? Something else to go wrong? Knowledge of the circuit and the engine to road speed combination for all conditions? Quote Link to post Share on other sites
RogerH Posted March 27, 2021 Author Report Share Posted March 27, 2021 As far as I am concerned the OD does a good job for the type of driving that I do. I like touring and it suits the OD very well. I also like fiddling about with electrickery and if I can change something, then I will. I have a nice pair of brake light repeater LED;'s on the dashboard to show if a filament has failed - now how do they work without robbing the brake lights of volts. Roger Quote Link to post Share on other sites
stillp Posted March 27, 2021 Report Share Posted March 27, 2021 28 minutes ago, RogerH said: I have a nice pair of brake light repeater LED;'s on the dashboard to show if a filament has failed - now how do they work without robbing the brake lights of volts. I'm named on a patent for something that does that. Pete Quote Link to post Share on other sites
Lebro Posted March 27, 2021 Report Share Posted March 27, 2021 The normal way would be a low value series resistor, with a voltage comparator sensing the voltage drop across it (which need not be more than a few millivolts.) Or, you could install some light sensitive diodes in the lamp housing, & feed that back to a circuit which would apply current to your dash leds. Or install an extra wire from the lamp to the dash & compare the volts on that wire with that on the brake light feed wire (i.e measuring the volts drop along the feed wire) Bob. Quote Link to post Share on other sites
RogerH Posted March 27, 2021 Author Report Share Posted March 27, 2021 too complicated Roger Quote Link to post Share on other sites
Charlie D Posted March 27, 2021 Report Share Posted March 27, 2021 How about a length of fiber optic cable that touches the stop lamp at the rear end and comes out through a hole in the dashboard. at the other end, pointing at your eyeball. Simple and no electricity needed. Charlie. Quote Link to post Share on other sites
RogerH Posted March 27, 2021 Author Report Share Posted March 27, 2021 Too complicated Quote Link to post Share on other sites
Ian Vincent Posted March 27, 2021 Report Share Posted March 27, 2021 Put a two way relay between the brake light bulb and earth. When the filament fails the relay loses it's current and pops across to the other circuit lighting your LED indicator. Rgds Ian Quote Link to post Share on other sites
RogerH Posted March 27, 2021 Author Report Share Posted March 27, 2021 45 minutes ago, Ian Vincent said: Put a two way relay between the brake light bulb and earth. When the filament fails the relay loses it's current and pops across to the other circuit lighting your LED indicator. Rgds Ian That will take volts from the filament during use. Roger Quote Link to post Share on other sites
Lebro Posted March 27, 2021 Report Share Posted March 27, 2021 Inductive pickup from feed wires (ferrite ring, lots of turns, drive LED directly) Bob. Quote Link to post Share on other sites
RogerH Posted March 27, 2021 Author Report Share Posted March 27, 2021 Would that work with DC Roger Quote Link to post Share on other sites
Lebro Posted March 27, 2021 Report Share Posted March 27, 2021 It's not DC when you start to brake ! (or stop braking) It can be done (think clamp on current meters) but would involve some circuitry, & geuss from your response that was not what you did. Bob. (still thinking) Quote Link to post Share on other sites
Lebro Posted March 27, 2021 Report Share Posted March 27, 2021 Hall effect device in conjunction with iron (or ferrite) core with the feed wire wrapped around it. Bob. Quote Link to post Share on other sites
Tim D. Posted March 27, 2021 Report Share Posted March 27, 2021 Ask friends to drive behind you and flash their headlights if your bulb blows. Its what all my many many friends allow over the country do for me. Tim Quote Link to post Share on other sites
RogerH Posted March 27, 2021 Author Report Share Posted March 27, 2021 Hi Folks, the answer is simple (sort of) - see the attached drawing. The brake bulb filament is fed 12V via the coil of a reed relay - apart from the initial pulse there are no looses to dim the bulb. When the coil is energized the contact closes and powers the LED. Thanks for playing. Tomorrow it will be a DIY Nuclear Power Plant. Roger Brake repeater.docx Quote Link to post Share on other sites
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