kreator33

hi,i'm installing a tuned port set up in my car,,,i'm dealing with all the vacuum lines now,, i wanna know what to keep and delete, tell me if im right so far,,,,
i removed the egr, and all the pollution stuff,so, whatever vacc going from egr is gone since i have a block off plate on the intake,,and egr solenoid is gone as well,then from there it used to go under the throttle body,,t off to the canister,,, so do i just put a cap ont the tro body port?,, cannister is gone as well... then from the side of throttle body,,big hose going to cannister,, plug that as well? , then the other big one that goes on the valve cover, i keep that right? as well as the pcv on other side. then i keep the brake vass too, and the one from plenum to fuel regulator i keep, now im left with the one on the rear corner of the plenum,,,form what i read, it seems to be for cruise,,and hvac,,now, i dont have cruise,and i dont know what hvac is,but i assume it has to do with heat or ac,, but i removed heat and ac as well,,so can i plugthat port,or is it used for something else as well?

Brando5641

iTrader: (-1)

correct me if im wrong but, i think all you need is brake booster,map ( not sure how they are mounted on tpi), and pcv. vac. wise.

vetteoz

iTrader: (13)

How do you plan to vent the pressure in your fuel tank?

Plug it ; your vents inside just won't change position without vac

kreator33

there is that white plastic breather/vent on one of the lines,,isnt that what that's for? i plugged the one going to canister

kreator33

and i dont have a pump in the tank,its external inline pump

1983Chimaera

You sound like you have a similar setup to mine. I have an '85 Corvette TPI setup on a .040 over 4 bolt main roller 327, run by a Megasquirt-I programmable ECM. The MS-I has a built in MAP sensor running speed density, and doesn't control spark so I use a 4-pin HEI with mechanical and vacuum advance, triggered by a Mallory Hyfire 6A. The MS-I also does not support IAC control, so mine is removed and a block off plate installed in its place with 3 vacuum ports custom fit in it. Two are currently blocked (they were used with a stepper motor in place of an IAC, but this is a poor substitute and ultimately deleted). I am running a fully functional heater vent system, have removed the heater diverter valve, and do not have cruise control or any emissions equipment installed. My vacuum routing is as follows, from the front of the plenum working towards the rear;
- The third port on my IAC blockoff plate is routed to the HEI vacuum advance.
- The passenger side of the throttle body has a large vacuum port that supplies vacuum to the passenger side PCV on the valve cover.
- The EGR is deleted with a block off plate installed.
- The vacuum port on the driver side of the TPI base is supplying vacuum to the driver side PCV in the valve cover.
- The driver side rear upper plenum vacuum port is supplying vacuum to the power brake booster, with a check valve installed.
- The first rear passenger side upper plenum vacuum port is supplying vacuum to the HVAC controls and fuel pressure regulator, with a check valve on the supply to the HVAC and a vacuum canister on the firewall.
- The second rear passenger side upper plenum vacuum port is supplying vacuum to the MS-I on board MAP sensor.

The fuel line formally run to the charcoal canister is left vented to atmosphere. I also have an external fuel pump, as my car was originally a 4 BBL 305 Z28 with no provision for in tank mounting. The white fuel tank vent is still installed, and my fuel pump is an MSD 2225 mounted on the rear firewall with fuel injection rated fuel line and fuel injection hose clamps going from the original stainless steel fuel lines, braided hose between the fuel pump and 5/8 threaded inlet fuel filter, and fuel injection rated fuel line run back to the stainless steel fuel feed line. I'm using a non-vented gas cap. I also insulated the fuel pump on the rear firewall with rubber spacers, and used insulating self-stick aluminum duct insulation from the plumbing section of Lowe's to sound deaden and heat insulate the floorboard and rear firewall under the carpeting. It's dramatically cheaper than Dynamat, is substantially the same thing, and comes in a roll 12" wide by 15' long, and 1/8" thick for under $20.