Thread: sdv6 alternator failure

And here's a page with a helpful description of what the pulley is and how it helps:
Dayco - Overrunning Alternator Pulleys

These two came off the links in the video posted by DiscoJeffster.

Overrunning Alternator Pulley OAP - YouTube

The INA Overrunning Alternator Pulley OAP the Technology Film Schaeffler - YouTube

Originally Posted by DiscoJeffster

It’s this simple, by example.

Solid pulley vs NULINE Overrunning Alternator Pulley, OAP - YouTube

That doesn't really explain much to be honest - what load was on the alternator during each run, what was the acceleration and deceleration or speed at the time of each test? I could make a belt wobble like that or run smoothly just based on those variables.

I'm not saying it doesn't work, but based on what I know about alternators, engines and what manufacturers have been doing for decades without issue, it just looks to be a bit of snake oil is all.

That or something that's only needed by D3's 4's due to a design flaw? If that's the case it makes more sense.

Homestar I’d suggest you do some of your own research then or accept it as snake oil. If you do the research you’ll see it’s across many vehicles, not just LR.
My understanding is that with the increase in alternator output, the force as each coil passes a magnet has increased to the point that the force fluctuations are great enough to need something to take out the shock.
Back in the day alternators were 80-100A, whereas now they’re upwards of 200A in the same package. That means more coils, more magnet strength, more force fluctuations as alternators do not produce an even output.

Just asking...

That bit about force fluctuations isn't quite correct unless the alternator is at almost max load which it wouldn't do very often. Even then, say the alternator is loaded heavily and the engine is doing say - 3000RPM. That would mean the alternator is spinning at least twice that, and as there are 3 windings in the unit, that's 300 pulses per second - I couldn't actually see that creating the wobble on the belt like the video shows, but who knows...

I deal with alternators every day - just not the cute little 12 volt, 200amp jobbies you're talking about here - ours are 3 phase, 415 volt 2000 amps per phase jobs, so I do know how an alternator works - it's my job, hence my scepticism here.

And just because they fit a 200amp alternator, that doesn't mean it pushes that out all the time - the load on an alternator is completely load dependant, they don't 'push' amps out, they only supply what the load is at a given time, it's just how they work. - a lot of people don't get this bit. I'd actually like to know how much the vehicle uses while running without lights, etc on - just the base vehicle load - anyone know that? I'm genuinely interested.

But hey, if it works - that's great, or if it doesn't and it's just a placebo effect - that's fine, just doesn't make much sense to me.

I'm not saying they don't - I've never said that in any of my other posts, so again, if it does that's super, but to me it sounds like a Hiclone, fuel polariser or HHO generator sort of thing is all. I thought OEM's had alternators sussed decades ago.

Agree, exactly, so I’d suggest it’s only an issue at high output. I tend to think a manufacturer wouldn’t include something they don’t feel there is a benefit/need for. Costs them money after all.

Maybe it's just the modern passion for serpentine belts, vee belts have more damping. My 1994 Merc has a serpentine belt and they fitted an actual shock absorber style damper to the tensioner. I can tell you that without a working damper it does indeed make an unhealthy sounding racket.

The video stated 750 rpm so plenty of time to feel the pulsing. Alternators are often at maximum output at idle - they have to be to keep blinkers, headlights, air-con, electrically heated/cooled seats working whilst the engine is idling as slowly as possible to juggle adequate power output from the alternator against minimum exhaust emissions.