That was the idea, to start another 'weight of driving shoes' type thread! The windage I am talking about is the drag cause by the air on the actual rotor as it rotates inside the stator, not the fan on the front, which you are correct in saying will cause losses. So if a smaller alternator has a smaller fan, it will help reduce losses due to windage caused by the fan itself. This is the kind of pedantic stupid stuff I wanted to post on an alternator weight type thread. Shall I start one, and ask BBB to move our rubbish over? ps. The magnetary magicy drag is what left coast thingy was going on about regarding the drag as more current is generated. His bit is scientifically true but not banter at all! Thus, not really relavent, nor, perhaps, relevant?!
right i see. mk3 doesn't have a fan at all, so i assume the drag loss from bigger internals will be more than made up by the lack of wackin great fan spinning about on the outside. lots of surface area on one o them
Surely there's a fan inside the casing, how else does it keep cool enough? And the leftcoast man is right, alternator output isn't constant, it's demand-led, so really you want the smallest, lightest alt that doesn't result in your battery ever going flat.
actually yeah it does: http://rangerovers.net/repairdetails/electrical/boschaltrepair.htm looks like no other option but to fit a 2.0 bottom end if you want to use a mk3 alternator setup
I'm so confused right now. So the MK3 alternator setup doesn't work on a MK2 but the rest of the ancillaries do?
Makes **** all a difference to your car. As said if you run, heated windscreen, mirrors, can bus and central electric module, A/C, **** warmers in chairs, big sounds blaring PIAA lights and so on and all these must run at the same time, then alternator current matters. MK3 stuff over MK2 KR 16v stuff w/HPAS is one solution to get rid of the crappy slider pulley found on water pump and peharps improve PAS pump grip on crank pulley. The other option is an 8V GL Single VBelt set up. 70 amp alternator from 1.6 8v MK4 or MK3 1.6-2.0 is more than enough in a MK2. A/C will not add much more current draw to this. As said the later alternators have the collong fan inside and rob the engine of less parasitic loss. In real terms this means very little to you and your possible 400+ g/km of CO2 car.
ignore all of the above, just banter MK3 setup does and will fit a mk2 perfectly fine, the reason to do so isnt really for the upgrade in amps, its because the tensioning system is way better, the mk3 stuff is lighter, plus its newer. also, how many mk2s do you see in scrappies now, vs mk3s? way easier to get mk3 spares. main advantage is the pas setup, mk2 tensioning system is a huge pile of cack. mk3 setup is much better, i could replace 3 mk3 pas belts in the time it takes to do 1 mk2 belt i recon
I'm actually thinking of getting it all new. I want to "rebuild" my MK2 with as many new parts and possible, and new MK3 parts are much more readily available than MK2 new. Cheaper as well I would imagine. I assume since I'm getting the a/c setup I'll need the up-rated amperage of a bigger alternator anyway, right?
ideally yes, 90amp one required. luckily finding a 90amp alt in the separate tensioner style is easier than for the earlier non-ac setup. you can get the bits you need from any mk3 1.8-2.0 8v or 16v, just as long as its the type with the seperate tensioner wheel. the only ac specific bits are the compressor, the steady bracket on the back of it, plus the waterpump pulley. also the crank pulley is 8v/16v specific. getting the above new though will cost a pretty penny from VW!
More torque is required to accelerate the higher mass of the 75 amp rotor. So, the car itself will accelerate more slowly. Once accelerated, power is constantly lost. Energy is used all of the time, at any given speed, due to I x W2 (I X omega squared). Thus, the heavier rotor will need to be run at lower speeds to compensate. I would think that a larger pulley is used on 75s? The 75 should produce 55 at lower revs and parasitic power loss, due to rotor mass, will be compensated for! As will some other parasitic losses. But, the larger pulley will impose higher friction losses due to the longer contact area around the periphery. And, larger bearings will also cause more friction losses! Energy will be lost due to the extra windage drag of the longer belt, the length of which will lead to catenary losses, as the belt is pulled straight from the curved condition. There is an advantage though! On deceleration, the extra stored energy, due to heavier masses, will be fed back into the engine, via the alternator belt. But, parasitc losses will mean less energy is fed back. All of this, of course, I got from Wikileaks! None of this takes into account the energy loss effects of: Centrifugal, Centripetal or Coriolis Forces.
Ah ha! You obviously need to attend one of my seminars! The one entitled: "Pie-in-the-sky, paper engineering, bull5hit banter" Would probably suit?
whould it help if you polished and/or chrome plates all the moving parts, less air resistance that way? if so all those ed38ers with the bling parts will have the last laugh
What's the deal with water pump? No need to swap? What if I'm going A/C, do I need the MK3 a/c water pump or just the pulley?
yep, mk2 crank pullet is for a v belt, you want the mk3 item as it uses a ribbed belt. but like i say, you need to get the right one for your car as the mk3 8v and 16v pulley is a different offset due to the different thickness of the timing belt
So what would be the right crank pulley, alternator, water pump setup to get for a 1.8 16V KR then as the mk3 8V and 16V pulleys are different?
