Can anyone tell me how to get the front tires to lock up at the same time when braking in a straight line?

Corner weighting? Or is it a usually problem with the brakes/tires/alignment?

 

I'm assuming no ABS, so with a factory system, I'd say that if the brake system is working properly the fronts should lock up simultaneously.
After driving, use an infrared thermometer to check the rotor temps. L/R front should be the same, as should the L/R rears.
If too different, problem with the caliper, brake hose.

 

As long as the tires have the same grip at that moment.

How many degrees should they be within?

 

When you drive your car in a laboratory on a perfectly clean and flat surface and have the car perfectly corner balanced and aligned, the wheels will lock up at exactly the same time.

Do you have one wheel that always locks up and the other does not?

The answer to your question is yes. Verify your alignment and corner balance settings, Then do some brake testing on a straight road and check temps, they should be similar.

 

The front left, but that's probably because the driver is a fatass.

I tend to get the same problem with my MR2 as well.

 

Unless your car is RHD that is the opposite of what I would expect. As others suggested corner balance and alignment settings. If those check out, dunno what to tell you other than it is almost impossible to get them to lock up at the same time consistently. Too many variables. As long as the car isn't pulling to one side or the other during braking, why are you so concerned about the lockup being equal?

 

My car is RHD.

My concern is that I'm leaving a LOT of stopping power on the table.

I know it's hard to get them to lock at exactly the same time, but I don't want one tire to lock up at 70% of the brake pedal pressure of the other tire.

 

Unless you have calipers that are starting to seize, that is highly unlikely. Plus, you would most definitely feel the car pulling hard to one side or the other under hard and light braking if the balance was off by that much. I think you're over thinking it :P

 

Well, even a few percent would be leaving upwards of a few feet of stopping distance on the table...

 

All I'm saying is that there are other variables that will likely have much more of an effect on stopping distance (notably the homosapien behind the wheel) than whether or not your calipers are exerting EXACTLY the same stopping power. If it was enough different to be an issue you would be able to tell through feedback through the vehicle when braking hard. Unless you want to plumb in some pressure sensors right at the calipers, your best bet will be to use a color changing based on temperature paint on your calipers or trying to jump out quick with an IR heat gun to measure caliper and rotor temps but this will be quite difficult to get good numbers since while you are measuring one side, the other is cooling. Ultimately if the car stops straight and feels like it has enough stopping power to lock up whatever tires you are running, your time will be better spent elsewhere (perfecting alignment settings, adjusting tire pressures, or just plain putting in more seat time).