Its vacuum rack! Here's a great writeup I got from No7yet.


Okay, I'm finally going to get around to it :-) Keep in mind that "my"
version was/is the "tree-hater" version. FL has no emissions testing. If
yours does, don't do this without some thought :-) It's probably a pretty
general job, but my car's an 89 TII, so adjust accordingly. I did the TID
mod and TB mod at the same time, which eliminates a LOT of complexity. I
also haven't yet bothered with a catch can for the check-and-cut valve or
the PCV vent system. I will, eventually, but have omitted it here. I also
installed a Fiero fan, which I highly recommend. Not only does it give me
control over the fan, in conjunction with the TID, it REALLY opens up the
engine bay.

Corrections/additions are VERY WELCOME, since I'm going off memory here,
and I spent a month or so working on it. (and a million other things)

I bought an "Arospeed COLOR RACING HOSE" (*sigh*) kit from a local speed
shop. It came with 10ft 4mm, 6ft 6mm, and 2ft 10mm, which was enough. I
got all the hoses done, but didn't have much leftover for things like
washer fluid hoses or the overflow bottle hose (oh darn). Cost: $20

You'll also need ~7ft of high-pressure 5/16" fuel hose - get the best
stuff you can. You'll have some left over, but it's useful for little
coolant hoses and the like. Cost: ~$25

Go to Home Depot and buy 2 "AM" bolts. Can't remember the size of the
bolts, only the "code". They fit right in the 5/16" hose, and are for
plugging up the TB coolant lines. Also get 15 1/4" washers to use as
spacers for the next item. Cost: $5

Get an ACV block-off plate "set" from Mazdatrix. Cost: $17

Go to a local parts store and buy a WHOLE BUNCH of hose clamps in
various smaller sizes. Expect to return for many more. I replaced
every stock spring clamp I could find. You may want to do the same.
Also get 4ish 3/16" vacuum caps, and a pack of 100 small zip-ties. Get
some "bigger" zip-
ties if they've got a pack of 10 or something. Cost: $15+

Do you have a hose cutter? No? Go get a flat razor - they work great.
Cost: $0.20

If you want to be VERY ****, buy some 39 ohm resistors to solder in place
of the ACV and solenoids. That should (as yet untested) prevent the
ECU from throwing codes for those bits. It won't light up the check
engine light, but if you ever pull codes, you'll have to remember to
not freak out when you get 6 or 7. Cost: $4?

Some general tips:
- If you can't pull a hose off, grab some pliers. With the pliers, grab
the base of the hose, and twist side to side (yaw around the Z axis). It
should "break" the hose free, and make removal a bit easier. Don't be
afraid to use a "prying" technique to remove particularly stubborn hoses.
If a hose breaks or WILL NOT come off, use your razor to cut the hose
lengthwise along the length of the nipple. Carefully.
- Before you get started, depressurize the fuel system by pulling the
EGI
fuse while the car is running. You'll still spill a good deal of fuel,
but not as much.
- You can NOT use silicone hose to carry oil or fuel.
- I'd allocate a day or three for this job, as it's not hard, per se,
just
very tedious, and it's tough to make sure that you've got every single
part you'll need. Refer to your Haynes/FSM vacuum diagrams often.
- Zip-tie all the vac hoses with the small ties.
- STUDY THE ENTIRE WRITEUP FOR A GOOD LONG WHILE _BEFORE_ YOU GET
STARTED! :-p

1) Remove the IC. There are four hoses attached; one from the compressor
outlet, one to the throttle elbow, one from the AWSV, and one to the ASV.

2) Unplug and label all the electrical connections to things that are
attached to the UIM. IIRC, that's two connections for the ACV, the TPS,
IAT sensor, AWSV, ASV, and BACV. There may be more in the way, so go
ahead and disconnect those, too, if you need to.

2.5) Unplug the coolant line running to the BACV. It'll spill. Big deal
:-)

3) Unbolt the UIM assembly. There are 4 bolts around the periphery of the
UIM, and one in the middle. My dumb *** forgot about the middle one
and spent a long time trying to pull off the UIM with it still in.
There's a "bolt"-thing that holds the UIM to the IC mount that's a
caveat. Unbolt the throttle assembly from the UIM, and wrestle the
throttle cables off the TB - it's gonna take some effort the first time.

4) This is where an assistant is nice. Lift the UIM up and begin pulling
vacuum hoses. You don't need to worry about what goes where, since you've
got me and a Haynes. Unplug the 90 degree hose and curse mazda for it.
If you can't get it off "right", CUT IT. Remove any leftover bits of
hose.

5) Take a moment to admire the uglyness. Go get a beer. Begin to
contemplate removal of the hard lines. Note the location of bolts and
removal obstructions.

6) Pull the line coming from the fuel filter and going to the return
line. You'll be replacing these lines.

7) Remove the charcoal canister and all the lines going to/from it.

8) Unplug the solenoids, and think about how you're going to maneuver the
rack around the wiring harness. Remove the IC mount, again
labelling any/all electrical connections you unplug.

9) Unbolt the rack from the engine. Begin to lift it up. Remove any
still-
attached lines. If you haven't gathered by now, most everything is
coming off, so don't worry about it. Remove the rack. There's a bit of
hard line that runs underneath the alternator - don't worry about that,
as you can't remove it, since one section is an oil line. Remove the
passenger-side hoses that ran into the stock TID. On the S-rack side,
there's one line that runs to the Duty Control Solenoid (it
looks "different" - you'll know it). Remove the DCS, and store it.

10) Unbolt the ACV and the split air pipe. The ACV has three 10mm bolts,
one of which is a PAIN IN THE *** to get to. Feel around underneath and
unbolt whatever you can feel. You're removing the split-air pipe, too, so
go ahead and pull that. Hope that the bolts stay in, and save the
nuts. Attach the ACV and split-air block offs that you got, reusing the
gaskets if you can. Some high-temp RTV works great, too. Stack some
washers over the bolts, and tighten down the nuts in sequence.

11) Unplug the primary injectors. Unbolt and remove the primary fuel
rail, being very careful to keep track of the spacer. You're replacing
the hose that runs between the fuel rails, too.

12) Remove all the cooked-on rubber vacuum hose under there. Keep track
of the MOP spider splitter - you're reusing it.

13) First, we're replacing vacuum hoses. Now may be a good time to do a
quick test-fit of the UIM, so that you know about how long the silicone
hoses should be. You're running line from the following locations to the
BACK of the UIM, except the first:

- between the secondary injectors
- from the back of the secondary injector ports
- from between the primary injectors
- from each oil injector -> 4-way splitter
- from the fuel pressure regulator (on the secondary rail)
- from the brake booster hard line

The FPR line MUST go to the BOTTOM nipple on the back of the UIM.

14) After you've got the vacuum lines laid out, reattach the primary fuel
rail, running new hose between the rails. Now run line from the fuel
filter -> primary fuel rail, and from the secondary fuel rail -> fuel
return line. I double-clamped my fuel hoses, and recommend that you do
the same.

15) Perform the TB mod. Replace the IC mount.

16) There are two TB coolant hose issues that need to be dealt with. One
line comes from the water filler neck, and the other goes into the rear
endplate. Cut about 4" of hose (either fuel or coolant) and clamp it on
the respective nipple. Insert a bolt, and clamp the bolt. MAKE SURE that
your engine-side block-off is long enough to be bent out of the way of
the UIM. If it's not, the bolt will stick straight up, and prevent the
UIM from seating properly. Your fuel lines must also lay flat on the
engine, or they'll be in the way.

17) Now's a good time to replace the lines going to the Pressure Sensor
and BOV. You can use the stock tee. There's a stock nipple underneath the
BACV that you can use, having eliminated the ACV. Speaking of nipples,
cap the three on the front of the UIM.

18) Now you need to think about where you're going to mount the DCS (Duty
Control Solenoid). I mounted mine next to the alternator, on the throttle
cable mount tab. Use some 6mm hose and connect it to the correct sub-
alternator hard line (the one that comes from the wastegate line). I
imagine that there could be gains to be had from mounting it closer to
the wastegate, but I didn't bother.

19) So you've got the fuel lines redone, and the coolant hoses blocked
off. Replace the UIM, remembering to bend that little coolant hose out of
the way, making sure to not pinch any hoses or wires, and keeping track
of all your vacuum hoses. Attach the FPR to the bottom nipple, and the
other three as you can. The 6mm hose coming from the vac spider goes on
the bigger of the remaining three (duh).

20) Attach the line coming from the brake booster to the horizontal
nipple near the throttle cable attachment point.

21) Wind the AWSV and BACV wiring around whatever's necessary and
reattach them. NOTE: This can get difficult, as your fuel lines and vac
lines can be pretty in-the-way. If needed, pull the UIM again and reseat
things to make room. You'll get pretty good at pulling the UIM eventually
- I know I am.

22) You should have been reconnecting things as you went along. Don't
worry too much if you've got "extra" connectors. There are many around
the engine bay, and you've just removed 5ish electrical connections. Go
ahead and start reconnecting things.

23) Reinstall the IC and anything else you need to before you start the
car. Prime the fuel system and check HARD for leaks.

24) Don't be surprised if the car won't idle right away - the TB mod does
that. You'll probably also need to adjust the throttle cable slightly.
You may also flood the engine (I did). Now's a good time to change your
spark plugs/wires.

I'm tired and hungry (and it ain't even noon), so I'm going to stop here.
I think I covered it all, but welcome comments, questions, and
corrections (especially the latter).

I've got a few more writeups, as well, but they won't be this long...

Brandon
(Zzzzzzzzzz...)
---------

A few things I neglected to mention in my writeup...

- This mod (or series of mods) requires the removal of the cat. You can
remove the airpump, too, since all it'll be doing is spinning and making
funny noises.
- If you remove the airpump, you'll need to re-work the water pump belt,
as it'll probably slip. You've got a couple of options. RP and a few other
places sell double-sheave alternator pulleys. Mitsubishi sells a stock-unit
double-sheave pulley that will work, as well - check the RX-7 Forum in the
2nd-gen section. Rob Golden says that you can use a 3L220 lawnmower belt,
and wrap it around the empty pulley.
- You'll probably want to do the TID mod (writeup to follow soon) at the
same time.
- You can remove the airpump dump hose the runs toward the front of the
car.
- If any of your preformed hoses are cracked (as my BACV->AWSV hose was),
now's a good time to replace them. If you use some silicone hose to do so,
you'll have to remember to keep it from kinking (i.e. use plenty).

That's all for now. :-)

Brandon

---------


--

 

NICE Write-up. For those that are interested I have the Double Alternator Pulleys for 18 shipped.

 

Banzai- do you have alot of this or just one?..PM me!..might be interested

 

The duty control solenoid is S5 only. Its a stock boost controller. Its blue and red with an electrical connector and 2 vacuum lines leading from it. I would think this write up is compatible for an S4, the only concern I would have is how the S4 controls boost.

 

The S4 doesn't control boost - there's just a straight line going to the WG.

Everything else is the same.

Brandon

P.S. Damn you turboGXL for stealing my post! Must... increase... post... count... Thanks for the creds, though.

 

No mention of the twin-scroll turbocharger solenoid valve(switching actuator). Free download of the factory manual at hppt://fc3s.org

 

S5 turbo all the way. Twin scroll is next-to-useless and the S5 turbo has a better wastegate anyway

Brandon

 

I missed the part about you putting a series five turbo on your car. If thats the case, forget about the switching actuator. The switching actuator controls a metal flapper in the exaust stream(in the exaust manifold) and by doing so helps direct the air for a quicker spool up. The solenoid valve controls the flapper from the left side of the engine. Below 2700rpm the flapper closes off part of the exaust path to the turbine, but after 2700 the flapper opens fully. Something like that. Real close to like that.