Calculating brake line pressure?
A decade ago (!), @NissanEgg worked up some great information on brake pressures supplied by various proportioning valves on the old forum. A few months back, I linked to that information in The Brake Thread.
Unfortunately, he isn't sure any longer on how these numbers were arrived at. Part of the data was taken from in the FSM for these cars at the end of the Brake section, but in looking up several of the cars listed I've been unable to duplicate his numbers, and he thinks that some data may have come from other sources.
I couldn't figure a good way to paste my data in this thread, I have it saved here as an Excel spreadsheet. Here's what I was able to gather from a few FSMs.
For comparison, here is similar data from the other thread:
BRAKE PRESSURES
B13 cars
1.6L ABS (F)711 (R)284-341
SE-R ABS (F) 924 (R)498-555
1.6L (F)1067 (R)640-697
SE-R (F)782 (R)356-412
NX2000 (F)995 (R)569-626
Most interestingly, the NX was the only model I came across so far that had a Variable proportioning valve, so right off the bad that throws a wrench in my trying to match up the proportioning valve. Unless the FSM I have is incorrect for the NX, it was the international version that also included the DET, and the numbers I have may not have applied to the US version.
Everything I've read up online seems to want to include brake pedal force in the calculations, and there was no other brake data in the FSM that gave a PSI rating, so I'm not sure where to go on trying to calculate brake pressures.
My original goal was to add to the original table some newer models that weren't included so that there may be a better listing of ,suitable parts for brake upgrades.
Unfortunately, he isn't sure any longer on how these numbers were arrived at. Part of the data was taken from in the FSM for these cars at the end of the Brake section, but in looking up several of the cars listed I've been unable to duplicate his numbers, and he thinks that some data may have come from other sources.
I couldn't figure a good way to paste my data in this thread, I have it saved here as an Excel spreadsheet. Here's what I was able to gather from a few FSMs.
| Year | Model | Engine | ABS | MC Bore Diameter | Proportioning Valve Split Point | Reducing Ratio |
| 1994 | Sentra | GA16 (Base) | No | 3/4 | 569 | 0.2 |
| 1994 | Sentra | GA16 (GXE/XE) | No | 13/16 | 569 | 0.2 |
| 1994 | Sentra | SR20 | No | 7/8 | 284 | 0.2 |
| 1994 | Sentra | Either | Yes | 7/8 | 213 | 0.2 |
| 1991 | NX | SR20 | Yes | 7/8 | Variable |
For comparison, here is similar data from the other thread:
BRAKE PRESSURES
B13 cars
1.6L ABS (F)711 (R)284-341
SE-R ABS (F) 924 (R)498-555
1.6L (F)1067 (R)640-697
SE-R (F)782 (R)356-412
NX2000 (F)995 (R)569-626
Most interestingly, the NX was the only model I came across so far that had a Variable proportioning valve, so right off the bad that throws a wrench in my trying to match up the proportioning valve. Unless the FSM I have is incorrect for the NX, it was the international version that also included the DET, and the numbers I have may not have applied to the US version.
Everything I've read up online seems to want to include brake pedal force in the calculations, and there was no other brake data in the FSM that gave a PSI rating, so I'm not sure where to go on trying to calculate brake pressures.
My original goal was to add to the original table some newer models that weren't included so that there may be a better listing of ,suitable parts for brake upgrades.
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