VACUUM DIAGRAMS 944 TURBO
One of the most common problems we find with the 944 Turbo is vacuum line related, whether it's old and leaking hoses, or mistakes in the plumbing of
your updated vacuum lines. We have
Vacuum Hose Kits to replace those old
lines and recommend doing so. Below are several diagrams that should aid
you in the correct method for your particular set-up. Mistakes can cause
a lean condition, lack of boost, lazy boost onset and throttle hesitation and in
some cases engine damage.
Most of these cars are 2 decades old. Chances are there has been many sets of hands on the engine, repairing or replacing parts over the years. Even if you already have, or are about to replace your
vacuum lines, don't assume that they were plumbed correctly. Most of the
customer cars we have a chance to view have things incorrect. The difference when corrected in how the car runs can be night and day. NOTE: It can also
require engine re-tuning with the hoses now in the correct configuration since the car was tuned with the wrong configuration, in particular, if you
have adjustable fuel regulators, MAF systems with controllers or EMS controlled cars.
On some of the diagrams below, we show some lines to a Dual Port wastegate and Manual Boost
Control. The wastegate pictured is the Lindsey Racing wastegate. If you're using
a TIAL, and perhaps other brands, the two hoses at the wastegate need to be
swapped or opposite what we picture.
On all of the diagrams pictured, we have used the later model Idle Stabilizer hoses, sometimes referred to as the venturi delete
hoses. This eliminated the problematic "venturi tube" system on
the '86 and sometimes early '87 model cars. If your car is an '87 onward
model and has had replacement engine, it may be an early engine and
has the venturi tube. Our strong recommendation is that you
remove and update it with our
Venturi Delete hoses. How do you determine that? If the hoses are not
the ones linked, and the diagram does not agree, then you have a venturi tube.
86-88 944T w/Stock Intake (1 vac port), Stock WG, Venturi Delete
Vacuum Lines
/
Venturi Delete Hoses
/
Wastegate Control Lines
/
Bypass Valve Hoses
86-88 944T w/Stock Intake (1 vac port), Dual Port WG w/MBC, Venturi Delete
Vacuum Lines
/
Venturi Delete Hoses
/
Wastegate Control Lines
/
Bypass Valve Hoses
88-89 944TS w/Stock Intake (2 vac ports), Stock WG, Venturi Delete
On this set-up, we have
added a longer 2 port vacuum banjo bolt, fitting and sealing rings allowing us to reduce the number of Ts and put more devices on their own vacuum line.
If you don't add that 2 port bolt, then you would T - in the bypass valve to the fuel regulator and fuel
damper lines like the 86-88 drawings.
Vacuum Lines
/
Venturi Delete Hoses
/
Wastegate Control Lines
/
Bypass Valve Hoses
88-89 944TS w/Stock Intake (2 vac ports), Dual Port WG w/MBC, Venturi Delete
On this set-up, we have also
added a longer 2 port vacuum banjo bolt, fitting and sealing rings allowing us to reduce the number of Ts and put more devices on their own vacuum line.
If you don't add that 2 port bolt, then you would T - in the bypass valve to the fuel regulator and fuel
damper lines like the 86-88 drawings.
Vacuum Lines
/
Venturi Delete Hoses
/
Wastegate Control Lines
/
Bypass Valve Hoses
944T w/Lindsey Racing Intake, Dual Port WG w/MBC, LR Fuel Rail, Venturi Delete
Vacuum Lines
/
Venturi Delete Hoses
/
Wastegate Control Lines
/
Bypass Valve Hoses
