Information contained above this line was not
contributed by the owner of this site
EFINI "Y" PIPE HARD PIPES
Efini "Y" Pipe Kit: "Y" pipe, Crossover pipe w/capnuts,
2 metal "Y" pipe to turbo gaskets,
1 metal "Y" pipe to crossover pipe gasket, 1 "Y" pipe
rubber o-ring coupling
The OE turbo outlet intake piping consists of an alloy turbo "Y"
pipe connected via a rubber coupling to a plastic cross-over pipe. The
plastic crossover pipe is held in place, bolted in two locations, by a
steel bracket mounted atop the air pump. Why am I telling you all this?
Because the failure points of this setup are numerous.
Comparison: '93 (left) '99 (right)
And the rubber coupling
has now been completely eliminated and is replaced by a flanged bolted
connection (see above left) using a metal gasket. And to top it off the OE "Y" pipe has a
design that has been improved upon for the '99 model year.
Specifically, the bung for the BOV on the older '93-'95 models protrudes
directly into the compressor discharge flow path. (see below left) The
'99 "Y" pipe has a flush
fit bung (see below right) which provides minimal interference
Comparison: '99 (left) '93 (right)
||The rubber coupling
commonly is blown off during high boost applications, the rubber itself
also degrades rapidly under the very high temperatures seen local to the
turbo's. The plastic crossover pipe frequently cracks at the bracket mounting
points and at the rubber couplings usually due to over torquing the connector
clamps, resulting in small hard to detect boost/vacuum leaks.
The Efini "Y" pipe eliminates all of these problems. The crossover
pipe (see above) is now aluminum so is not prone to cracking. This new aluminum piping
also has a larger radiused bend for freer flow.
There is one catch, the bracket used to support the old plastic
crossover pipe also supports one end of the pressure chamber. You can choose
to reuse the old bracket or do as I did and just fabricate a short bracket
to support the end of the pressure tank and not worry about reusing the
unsightly steel bracket. Overall I am pleased with the finished assembly and
will eventually get around to polishing the crossover piping to
improve the appearance.
The completed install
All this makes
for a more reliable configuration and a mild increase in intake flow efficiency.
Thus, the turbos don't need to work as hard to generate boost and one might
add quicker throttle response although I doubt you could feel the difference
while driving. The installation was fairly straight forward. Removal of
all the intake piping is required along with the air pump and possibly
the airbox and intercooler. The only difficult part of removal of the old assembly,
separation of the "Y" halves, is made easy provided the
rear half of the "Y" is also loosened from the secondary turbo compressor
outlet (rear hard intake pipe must be removed to do this) so the two halves can be separated.
Once this is done the '99 efini pipes can be easily installed. It is
advisable that nothing be tightened down until the intercooler and crossover
pipe are all connected as some minor adjustments are necessary to get everything
The "Y" pipe portion installed, New angle of BOV bung
required trimming of the respective hose to the BOV
TRIPLE-R MAIN PAGE
| THE HEART OF THE BEAST | STOPPING
AND TURNING | THE COMFORT ZONE
7-UP CLUB MAIN
OUR "LOCAL7" COMMUNITY
| THE WORLD OF THE RX-7
This page last updated April 17, 2001
rotorphiles have visited this page since April 17, 2001
If you would like to contact me and converse about my experiences
with my 7:
free to send an e-mail to firstname.lastname@example.org
Disclaimer: All images contained on this page are
the sole property of C. Regan or were collected from the public domain,
unless otherwise indicated. If any image contained on this page is considered
private property please contact Christopher
Webcounter supplied courtesy of