Brake system "upgrades" end in spectacular failure

Any puddles of brake fluid under the car?  Did the rod fall out of the master cylinder?  The brake pedal still connected properly?

When in doubt start with the basics.

You need a larger master cylinder.

We went to 4 wheel discs on the Karmann Ghia before the last race. The day before leaving for Louisiana, we took the car to MSRH for some testing, and realized that we had no pedal. It was firm for about the inch before it hit the firewall. Changing from a 19mm to a 21mm master cylinder changed everything. We managed to do that Friday at the track, and had great breaks all weekend. It made a much bigger difference than I thought.

Even if the MC is slightly smaller than you need, this will not cause the problem you are experiencing.  It might not give you enough volume to work properly, but it will not cause a completely dead pedal.  It sounds to me like you have air in the MC.  Did you bench bleed the MC before bleeding the calipers?  If the MC has bleed ports, attach a 6" long hose from the bleed port and insert the other end in the reservoir under the fluid level.  Slightly crack the bleeder just enough for fluid flow and SLOWLY pump the pedal until the bubbles stop coming out of the hose.  Tighten the bleeder while the hose is still submerged and repeat the process for the other bleeder.  Now rebleed the corners in the following order:  RR, LR, RF, LF.  You should be back in business.

You might still have the wrong MC size for optimal system function, but I'm almost positive air in the system is your current problem.  A slightly undersized MC bore will make the pedal stroke feel long since you have to push farther to get the same amount of fluid to the corners.  It will feel lighter as well.  It might work perfectly fine other than the long pedal feel and is sometimes actually easier to modulate without locking up.

Is it an abs car perchance? I had trouble with a b13 se-r with the abs doing the same thing. Took a few tries and a bad master I think was the problem

Did you get the rotors for Nissan NX2000 2.0 liter Made in Japan 10.125" (257mm).

In any case I am guessing that is not the problem.  If you are goin got replace the Master Cylinder go with a larger one from a 90's Altima.

Dunno if it will help you, but i've got an S14 bmc I don't need.  I think its 7/8".

Modern systems have a pressure differential valve typically. That means that if you push down hard on the pedal, if it senses no even pressure split between front/rear, it will block off the rear with a little shuttle valve and divert all pressure to the front (or vice-versa). My best advice is to use a very low pressure eezi-bled (like 20psi pushing in the master) and open 1 front and 1 rear nipple-- or have 1 person sitting in the car and 1 person on a front nipple, 1 person on a rear nipple and go like so:

Person at pedal says "Open" and people at nipples open bleeders and when open repeat back "open". Person at pedal pushes down v-e-r-y slowly like taking 5-6 seconds to have pedal reach the floor. once pedal reaches the floor the person at pedal says "close" and people at bleeders close nipples and repeat back "closed" when they are closed. Person at the pedal lifts foot off of pedal at a similar 5-6 second pace to reach the top and upon reaching the top repeats the process with "open", and so on.

most people are used to the typical old school pump up the pedal 5 or 6 times then open a bleed nipple. This will just block off the half of the system with the least pressure and possibly lock that pressure differential valve permanently. Once at rest for a long enough amount of time, the system equalizes pressures from bleedback to the master and then the differential valve pops open, introducing air pocket back to system.

BTW, for pads, check out this thread:

http://www.sr20forum.com/road-racing/26 … ost2526426

Did you start that thread?

I did.  We used the Mitsu Hawk Blues on the NX calipers last race and they were awesome.

Yeah, but then the men in blue probably think, Do I want to stop this nutjob? We know we are nutz to race $500 cars.

Glad we could help.  That braking setup has been an SE-R road racing staple for eons now.