FridgeFreezer Posted March 27, 2007 Share Posted March 27, 2007 After a wander round the scrappy in the sunshine today I bagged a twin fan setup from an Audi that is a perfect fit for my radiator. It had a pressed ali resistor pack attached to it so I pulled that too, on getting it home it turns out to be a resistor pack that offers three fans speeds. So, given a standard X-Eng fan switch, which has two temperature switch points, can anyone see a useful/practical/simple way of using the full three speeds? I'm not sure I can be bothered with making a three-level adjustable fan switch sensed from the coolant but it may come to that, if only for the bling value Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted March 28, 2007 Share Posted March 28, 2007 Yes, use the MS fan control output as a programmable master and then use a twin Rad switch for higher temps. Remember, cooling control on a 4.6 is much more important & critical then the 3.5 / 3.9 Ian Quote Link to comment Share on other sites More sharing options...
jules Posted March 28, 2007 Share Posted March 28, 2007 Freelander td4's have three speed fans but there controlled from the ECU I think but surly DH can coble somthing together. Saw his truck down at stunning yesterday, Mike did a very nice job ot the Ibex's roof. Quote Link to comment Share on other sites More sharing options...
simonr Posted March 28, 2007 Share Posted March 28, 2007 John, are the resistor values arranged such that it would form a digital to analog converter (resistor ladder)? If so, your thee speeds actually give you 8 combinations. You could put a little keyboard on the dash and play tunes on your fan - think how you could impress the girls with that! Apart from that, can't see the point myself - I'd just go with single speed. Si Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 28, 2007 Author Share Posted March 28, 2007 Simon, no they're in series so you have: (SLOW)----[==]----(MED)----[==]-----(FANS) So if you apply 12v to the "slow" point it passes though two resistors, the "MED" point only one and for full speed you connect directly to the fan. I suppose using Ian's twin fan wiring you could get another three speeds but that may be overkill If I wanted to play tunes I'd use F/V converter and PWM drive, got some big power darlingtons here (ESR6065) begging to be used for something silly Quote Link to comment Share on other sites More sharing options...
Ex Member Posted March 28, 2007 Share Posted March 28, 2007 Variable Speed!!! Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 28, 2007 Author Share Posted March 28, 2007 Variable Speed!!! I see what they're doing and it would be easy to implement with MegaSquirt, you just steal the PWM drive for the idle valve and add a power transistor to the end. Or you could do the same with a 555 timer for about 50p: Obviously you may need to beef up Q1 a little If I ever get round to putting in the electric water pump I may well do something like that, if the MS can't do it all on-board by that stage... Quote Link to comment Share on other sites More sharing options...
Ex Member Posted March 28, 2007 Share Posted March 28, 2007 Wellllll, 35 Amps is a slightly different ballgame. If you could put it all in a sealed package for less than the $80 USD that he sells them for, let's see it!!! Quote Link to comment Share on other sites More sharing options...
nicksmelly Posted March 28, 2007 Share Posted March 28, 2007 Using 2 relays - Have the twin fans wired in series to run all the time in slow speed and use the two stage temp switch to cotrol medium and fast. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted April 4, 2007 Share Posted April 4, 2007 My heater-blower has three speeds now - ever since the 'slow' resistor packed up I'm back to 'on', 'off' and 'Lucas'. Quote Link to comment Share on other sites More sharing options...
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