My civic 90 SI had rear disk brake 9.5" with HP+ pads

the front his 11" Corrado Disk with integra caliper and HP+ pads

I need more power for the rear brakes

the actual Proportionng Valve 3540 (I don't know if if OEM or not because my DX 91 had a 2530 PV)

 

nobody know which one I should use?

 

3540 isn't the stock valve on the civic. 3540 is usually screen on the 88-89 integra, and some early preludes. Both these cars have 4 wheel disc. I personally use the one from the 90-93 integra which is labed at 4040. I don't know if it there is difference, but I figured that's my rear is off an 90-93 integra, and my booster and Master cylinder is from an 90-93 integra, I'd use the same.

 

the fact are that actually I have too much power on the front

soo I want more pressure on the rear brakes

but it's hard to find the good PV

 

go 4040.

3540 also came with 90-91 EX with larger front discs and drums in the rear.

although, its never a good situtation to have your rears lock up before your fronts. i wouldnt try to achieve that.