Just a thought here, maybe totally unnecessary.

Has anyone tried running these motors with higher voltages as an experiment to see how much faster can they go without failing?

I thought of experimenting with this myself but I don't have any spare motors and would hate to ruin mine.

I think I speak for many when I say that the Gen 1 system is plagued with issues to begin with. The thought of possibly adding more potential failure issues seems less than attractive. Just my two cents here.

-Van

I used a battery charger to test a motor and at 12 amps, it popped a small spring metal piece on the points, rendering the limiter switch useless.

Adding volts often won't help them and can make worse problems. "12v systems" should have 14-15v when the alternator is on and "12v" DC is already hard on relays and switches. Problems w/ Fiero PW switches are a good example. 10-15 years back was a push for 42v systems in cars but stopped because is multiply harder to make contacts to handle higher DC volts. Several are trying again w/ 48v but don't hold your breath for being common soon. (Note that most switches etc you buy have AC amp ratings on them but if you push same amps on DC then you will fry them and likely very quickly.)

Even If Gen1 motors get full power, They are slow because of motor gearing vs Gen2 at same volts.

Cardone New Gen2 motors open/close the HL in about 2/3 of 1 second. OE Gen2 ones are around 1 sec. Working Gen1 are notably slower but passes FMVSS 108 3 sec limit for hidden HL.

But...
If motor's have ground and/or power problems, they will be slower then that and Gen1 can "fail" that limit. Worse Power/ground often means motors run at low volts and try to pull more amps and often can't w/o burning relays and switches.
See my Cave, Electric Motors

quote Originally posted by fierofool: I used a battery charger to test a motor and at 12 amps, it popped a small spring metal piece on the points, rendering the limiter switch useless.

If you mean blows the motor circuit breaker? No surprise. Most 12 amp charger will putout more then 12 amps to a inductive load until something shuts off or fries. Most charges if they even have a fuse/breaker is on 120v AC side so when the charger dies the Building won't dump 15-20a @ 120v AC. Building Breakers/Fuses won't blow when a died thing have some resistance but same died thing often will melt or catch fire w/o smaller fuse and/or thermal cutout built into them.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

quote Originally posted by fierofool: I used a battery charger to test a motor and at 12 amps, it popped a small spring metal piece on the points, rendering the limiter switch useless.

If you mean blows the motor circuit breaker? No surprise.
[/QUOTE]

It burned a small arched piece of spring metal that's located at the points contact pads. It flips direction to solidly open or close the points. It burned that piece in two. The blue arrows point to the area in this photo I grabbed from PFF.

ouch but same issue as said above...
Charger can burn anything that can't handle current, inductive loads often eat power to Start and Run and more so at End of Travel causing high Stall current.

Limit switches are often dirty/burn making more contact resistance and your "testing" likely can't shut off fast enough by hand and burn the switch(es) or whatever is weak.
Gen1 Relays are old tech but faster switching then any human.

Example: Fiero Starter motor is rated at 1.5kw = ~120a @ 12.6v (= typical full charge battery) but only part of the power story...
Starters can easily draw 300+ amps when you turn the key. This is "inrush current" and this issue isn't only to motors.
If engine won't or slow to turn over or battery is low then starter will draw more current often 200 − 300+ amps and can fry starter motor, solenoid and even the big cables to the battery. Battery can have a short life too.
To see inrush current, you need a scope or DC amp meter w/ peak hold function. You can't read it w/ normal amp meters because happens too fast to register.
Most normal digital and analog meters max at 10A and often too low to read Stall and other types of current draw for most motors in a car. Just reading Run current for many motors in a car are near or over the 10a limit for most meters.