How to plumb vacuum for MAP on older TPI plenum.

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Jan 20, 2008 | 07:22 PM

scuzz

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From: Beautiful Tunnel Hill Georgia

Car: 67 Firebird Convertible

Engine: LB9

Transmission: 700R4

Axle/Gears: 3.55

How to plumb vacuum for MAP on older TPI plenum.

I am using a 85 plenum on a SD setup, and I'm not sure if it makes a difference what source I tap into for the MAP vacuum supply.
Any opinions?
I've looked around and can't find answer, and have been given several opinions, but not from you guys. The answers are here!
Help
Ron

Jan 20, 2008 | 08:19 PM

Jay

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From: Newington, CT

Car: 88 IROC

Engine: 5.7 RamJet

Transmission: T56

Axle/Gears: Dana44 4.10

Re: How to plumb vacuum for MAP on older TPI plenum.

On mine I used a T and tied into the supply for the HVAC control.
Probably not ideal. I'm not sure if the HVAC could interfere and cause a false reading at the MAP.

Jan 25, 2008 | 08:08 AM

roachjuice

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From: Tulsa

Car: 86 Omni GLHT

Engine: 2.2 Turbo/Intercooled

Transmission: 5 speed

Axle/Gears: 3:85

Re: How to plumb vacuum for MAP on older TPI plenum.

anywhere it's getting good vacuum like where the fpr gets it vac.

Jan 25, 2008 | 10:26 AM

Mongoose

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From: Monroe,NC

Car: 90 Formula

Engine: 305

Transmission: 700R4

Axle/Gears: 9 bolt/3.27

Re: How to plumb vacuum for MAP on older TPI plenum.

I used an '89 TPI on my conversion and had to drill and tap for a third fitting as things weren't operating as they should. MAP needs it's own vacuum source as did my FPR, mine ran really bad with any sharing of vacuum. The third line feeds the HVAC and the accumulator and all is well.

Jan 26, 2008 | 08:14 AM

scuzz

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Joined: Aug 2005

Posts: 615

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From: Beautiful Tunnel Hill Georgia

Car: 67 Firebird Convertible

Engine: LB9

Transmission: 700R4

Axle/Gears: 3.55

Re: How to plumb vacuum for MAP on older TPI plenum.

You know, drilling another hole for it makes a lot of sense.
I was afraid I might split off the MAP or FP vacuum.
I did that on my marine ramjet intake. The marine unit didn't have a vaccum port for brake booster. Who needs power brakes on a boat!
Thanks guys.