I've just done a brake upgrade on the 1200. I'm now running S13 front brakes. I already had U13 bluebird rear brakes. I've taken her out for a test drive, and I think it stops better. (I haven't driven it for two months) There's a bit of front end dive when I get on them hard. And the front locks up before the rear. But the ass is jacked up, and the front is a bit lowered. Plus I don't know how good the front shocks are. So how do I know for sure that the bias is good? I'm a bit concerned that the dive might be as a result of too much front end bias.

What can you tell me?

if the shocks are in question it's kind of hard to tell if the bias is correct. the fronts should lock up before the rear ... slightly.

i never changed my bias, i just use the pedal reasonably, stomping it really hard will take a lot of weight off the back wheels in most cases anyways...

I would have said bias is correct if the front locks up a bit before the back, at least thats how I've set mine up.

I think the best way is to find a wet road, and bias for that.

Even though currently the front locks first, You may not have anything going to the back. If that is true, then buying a bias valve will not help with that. You'd need a different master cylinder.

I'm guessing the U13 rears are probably similar enough to the s13 equivalent and it's probably ok.

The front dive can certainly be reduced with decent shocks.

Yeah, a front suspention upgrade is on the cards. It's taken me 5+ years to upgrade the brakes though. It was a real handfull to haul up with the standard stoppers. Had some VERY close calls. lol

the warrent of fitness place up the road from me has the whole rolling road brake test thang going on which reads the braking amount on each tyre. Might be interesting to see what that says.
Atleast if the front is locked up and the rears are free you can pull some hella skids

its easy going back to my formula ford days where i learnt this:-
Jack all four wheels of the car off the ground.
Have a helper apply the brakes for you.
Get them to gently apply the brakes whilst you spin the front wheel by hand. Keep applying brakes until the wheel just lock (ie you can no longer turn the wheel by hand anymore).
Check the other front wheel has got the same pressure. If you can turn it your caplier needs attention.
right if thats ok then go to the rear wheels.
On a normal road car, braking is around 80% front and 20% to the rear. So the rear wheels should turn. The percentage bias depends greatly on the suspension setup on the car, the softer the setup the less bias to the rear, conversely the harder the setup go to the rear more in the dry. On an open wheeler in the dry we try and get it 55% front 45% rear (in the wet we set up 45% front 55% rear!!). so in a race car (tin top) which has alot more weight transfer over the front, youd want around 65% front 35% rear. You can feel this with spinning the rear wheel. Get you helper to adjust the bias controller accordingly.
Anyway thats how we do it.
A much more accurate way is to have gauges setup in your brakes lines. When you get it on the road you will have to fine tune for your driving style.