rebuilding ka

[rally56]

I'm rebuilding a 91 ka for my 240sx and would like to get rid of all the vacuum hoses and valves that are not directly related to the engine running well. anyone know what i can take off and plug safely and what has to absolutely stay functioning? Also what are the 4 hoses running up into the intake close to the heads, one hose per runner? any info would be appreciated, thanks.

[R240NA]

The only vacuum lines you need to run and be safe are the FPR and the brake booster. Everything else is either emissions or SCV. Make sure though you take the SCVs out, otherwise you'll hit a wall at 4k rpm when they're supposed to open. The four lines under the runners are the PCV, you can plug those too and just leave the main hose vented to atmosphere. My car, a 96, is done the exact same way. Nothing looks cleaner than no extra lines and hoses.

[singlecamhonduhkilla]

R24ONA DO U HAVE A PICTURE OF UR ENGINE BAY WITHOUT THE WIRES?JOE

[R240NA]

Yes I do. Why are you yelling at me?

[rally56]

R240NA, thanks for the info, it's pretty much what i suspected, but what is it that you are calling the FPR? I take it the SCV are the set of butterfly valves up close to the head. I already removed those and plugged the holes where the rod went through. could you post the picture of your engine? Thanks.

[leper421]

The Swirl Control Valve is a vacuum diaphram behind the engine, by the EGR and BPT. Can someone explain exactly how and when and why it is used?

[R240NA]

FPR= fuel pressure regulator. You're correct on the SCVs. Leper, the SCVs were used on 91-early 93 KAs to 'build torque'. They are actuated open at 4k rpm, otherwise airflow has to force them open. They're stupid and useless.