Quicker windows

inovermyhead

inovermyhead

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So, sick of my slow windows l was talking to a friend who is a retired electronics engineer and he suggested using a DC to DC converter and upping the voltage to the motors. We jury rigged a converter and checked out what sort of amperage the windows draw and what effect increasing the juice might have, and behold....speedy glass at 19volts.
The converter was $100 at Jaycar (an electronics shop) and is used to charge laptops etc and bumps 12v to 24 v with adjustments
Simple to wire up, power to the cable that had the plug in cigarette lighter, then power to the switches, earthed and enough cable that the unit can sit in the glove box. Works a treat.

Cheers. John
 
John,

What is the up and down speed of each window now? That data would give us a comparison with the data from the replacement with the later window motors. THANKS
 
Interesting, had you already cleaned and regreased the mechanisms? This usually works wonders and would lower the current draw and resistance. This plus simple relays at each motor worked wonders on mine. There are threads on cleaning and relays.
 
Is there a chance of burning the motors out putting 19v to them? Shoot a video so we can see the results.
 
adawil2002 said:
Is there a chance of burning the motors out putting 19v to them?
Click to expand...

There is that risk. I suppose the saving grace here is that window motors only run intermittently, so they don't get that hot. Using a voltage converter to speed up your heater blower would likely result in a fried motor.
 
But I like hitting the switches one by one blocks from home so that way it's good to go by time I get to my garage.
 
It takes more than just the motor, tracks need a good cleaning and lubrication too. And mid-73 already has the e28 style motor.
 
Hopefully it will work ok for you long-term, I have only had very poor results with high-current DC-DC boost converters. DC-DC buck converters, no problem, but boost converters have always failed me.
 
All the tracks and guides were cleared and greased as well as any moving parts in the operation. I spent a lot of time getting the movement of the glass right before tightening everything up.
My buddy with the knowledge looked at installing the extra relays but seemed to think that what we came up with would work fine and was 'less work', I don't know, I just go along with anything he suggests electrical.
He also seemed to think as long as it's one window at a time it will be fine, time will tell but at least it's in the glove box if it needs replacing.

Just timed them, measured by the tried and true method of 'one and two and' and seems to be approximately Fronts 7 secs up and 6 down Backs about 5 secs up and down at 19 volts.

Hope this helps. John
 
So, the time is essentially the same with the high voltage system compared to the e28 motors. I also cleaned everything, installed the e28 motors and have 6 sec up and down on all, without the engine running. I have done two at a time, using two fingers for the switches - same time. I haven't tried it with the engine running and the alternator adding voltage to the system, as the car is not yet drivable (no front seats!).

So - now we have at least three options for getting the windows up or down in less than 3/8 of a mile when driving 60 mph! This voltage increase, the relays mentioned by Steve Hose, and the e28 motor transplant. Pick your poison!!

By the way, the late '73+ motors are not the same as the e28 motors. They have the same mounting bolts/holes but the OE motors are larger and heavier than the e28's. I also don't think they run as fast with no load. Can't say for certain how fast they would be with a cleaned/re-greased regulator system, as I didn't try that.
 
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The fused/relayed windows are very quick since full 12v goes directly to the motor, with the added benefit of low amps/volts going through the switches. Similar benefit as low beam relay mod.
 
I have a slight update on window motors. I have a spare '73+ motor and a spare e28 motor, so decided to experiment a little. Since I'd changed my windshield wiper motor from non-functioning to perfect functioning by removing all the old grease from it's transmission and replacing that semi-hardened grease with new SuperLube, I decided to see what difference it would make in the '73+ window motor. The back panel on it's transmission is held on by three screws (just like the windshield wiper motor), so it is easy to remove it, clean out all the old grease and install fresh SuperLube grease.

So - I did that yesterday. I timed the rotation of the gear on the transmission that drives the window regulators at 1 rev per second with the old grease. Cleaning the trans thoroughly and installing new grease resulted in: ONE REVOLUTION PER SECOND!! So, nothing gained there, at least on this motor, but on the other hand, the 'old' grease was actually not very hardened. The designed motor rpm at 12 V is just slow.

When I've timed the gear rotation on the e28 window motors, I always get about 1.8-2.0 revolutions per second. Those 'next generaton' motors are just designed to run at nearly double the speed of the OE motors on the later cars. But, their transmission case back side is riveted on, not fastened with screws. Therefore, more difficult to change the grease.
 
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Teahead - yep, I'm sure you could do that. I just said 'it was more difficult'.

runner - If you have a well stocked local wrecking yard, might be a good source. You need just the REAR window motors. 2 of each side for all four coupe windows. (same motor does LR and RF, and other motor does RR and LF on the e9's). That is probably the cheapest way to get them. You might search Craigslist as well.


Alternatively, do an eBay search for e28 REAR window motors - frequently they are still attached to the regulators, so you might search for those as well.
For Example, today 8/6/16, there are four on eBay 2 lefts and 2 rights. Link: http://www.ebay.com/sch/i.html?_odk....TRS0&_nkw=bmw+e28+rear+window+motor&_sacat=0

As several have said - straight plug and play for the late '73+ cars (well, you have to cut the plug connector off the motor wires and install two male spade connectors). There are some mods needed for earlier cars, and they are well described on this forum, just search for 'e28 motor' or something like that. ~6 seconds up or down, what a pleasure.
 
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