By Carlos A. Iglesias (AKA Spic Racer)
The GReddy PRofec and HKS EVC (Electronic Valve Controller) are electronic
wastegate controllers that manage
engine boost. The PRofec is an expensive, "learning" controller that
uses fuzzy logic like the HKS EVC IV. The PRofec B is a more simple and
inexpensive non-learning controller. For more info on how boost control in the
RX-7 works, see the RX-7 Boost Control discussion.
Wheres the fuel regulator vacuum hose located?
Dont bother. Just buy a vacuum T, and plumb the smaller diameter hose off of
either of the nipples on the upper intake (extension) manifold. These nipples are where
the stock blow-off valve and where most people connect their boost gauge to.
Where did you mount your control box? (stepping motor)
The manual says to mount it somewhere relatively cool, so I mounted it just in front of
the cooling fan relays rack which is inside my cool air induction "space". If
youd like, I can scan a picture and send it.
Where do the other two hoses on the control box go?
Ill call the vacuum hose nipples on the PRofec, "Y", "E" and "G"
after the letters of the GReddy logo on the stepper motor which the nipples are in-line
with. What you need to do is remove the short vacuum line thats between the
front turbo outlet nipple and the wastegate (WG) actuator. The short hose that
you need to remove is the one that contains the "wastegate boost orifice/pill" and
where you would install a manual bleed valve for manual boost control.
Connect the hose
from nipple "E" (the center large diameter nipple) to front turbos outlet
nipple. You can now remove the line that goes to the other WG actuator nipple. Put a
vacuum cap and zip tie on the nipple and plug the line you just removed to keep the vacuum system from getting
The "G" nipple on the PRofec gets connected to the left over WG nipple, and
provide the actuating pressure to open the WG.
Connect the "Y" nipple to the extension manifold where a boost
gauge is normally connected. If you already have a boost gauge just insert a
"T" into the boost gauge line and connect the "Y" nipple to
that. The "E G & Y" nipples are labeled on the diagram above.
In summary heres how it works
1) The smaller diameter line provides manifold pressure info to the controller via the
stepper motor (Nipple "Y").
2) While building boost, the pressure (from the front turbo outlet nipple) being
received by the unit (nipple "E") is vented out to atmosphere by the relief nipple
on the bottom of the stepper motor, therefore the WG remains closed and boost
3) When the preset boost level approaches, the boost pressure is rerouted out to the WG
actuator via nipple "G." Since the WG actuator is now open on only the nipple
that goes to the Profec, the pressure in the actuator builds to the point at which it
overcome the closing force applied by its 7psi internal spring -> the actuator begins
to open. The Profec regulates the WG to maintain the desired boost levels. Make sure to
securely zip-tie or secure all of the associated nipples and hoses. Unfortunately, if the
systems pressure integrity is broken, the wastegate will not open. Long story short,
the system "Fail-safes" to BUY-A-NEW-ENGINE (fails in the wastegate
Along the same line, start to
program the system as if the WG ISNT going to operate properly. By that, I mean
expect the worst, just incase. Make sure it's working before turning going to
full throttle or turning up the boost. Being too aggressive right off the bat might buy you some really great performance for a
few seconds, followed by a very expensive post climax. For programming info, GReddy has a
great page at http://www.greddy.com/profecguide.html.
Ive always been able to program the Profec on the first or second try while in 4th
gear. In 3rd gear, its not as easy to program. Of course, running through
7500 rpm in 4th gear can make for some really interesting highway driving.
Kids, please dont try this at home ;-).
Flyin and Racin Rotary Beasts,
Carlos A. Iglesias (AKA Spic Racer)
More PROFEC B Install Tips
Hey I have a PROFEC B. Listen up:
1. Remove air box and intake piping so you can access the waste gate.
2. remove the 4 inch piece of hose going from the turbo to the wastegate. This
tubing contains the pill which you don't need now.
3. mount the stepper motor or little black box somewhere around the headlight under the
4. run a piece of hose from the turbo to the "IN" on the black box, then from
the "OUT" to the waste gate. It just acts as a bridge between the two.
Then reinstall the air box and intake hoses.
5. run the power cable coming from the black box inside the car near the drivers side kick
panel. I took it through the steering wheel boot or follow through where your boost gauge
hose goes into the cockpit.
6. Mount the the Profec B somewhere where you can access the dials on it. I Velcroed it to
the kick panel to the left of the clutch.
7. Now take the vacuum tubing for the boost gauge and cut it near the back of the Profec
and add a T connector. Take a small piece of tubing and go from the T connector to the
back of the Profec B.
8. Find where you want to add the power to the Profec B and there ya have it. Make sure to
keep the settings all the way down at first. That would be the LOW setting. then play with
it and have fun.
Hope this helps
Any questions email me at email@example.com
Jason 93 touring 351HP ATW
You may want to add to step 2 and disconnect factory
bleeder solenoid hose from the second nipple on the wastegate actuator. Plug this nipple
on the actuator. Also add that you need do nothing to the pre-control actuator. Many
people have y'd the PROFEC to both the pre-control and wastegate, not good.
I have my car setup with the Profec B controlling only the
wastegate and you are correct, you only get 10 to 11 lbs. of boost of the first turbo and
then a full 14 lbs. or what ever on the second turbo. (but what a kick!)
I talked to Luis at Pettit and he has adjusted his car's pre-control rod to give him 13
lbs. of boost on the first turbo. He enjoys it, because he can hang with those of us that
are running 10lbs. on the first turbo, off the
I am going to try and adjust mine this weekend, as I would like a little bit more
"kick" in the lower rpm....
I have a question for you though. If you adjust the pre-control arm to give you more
first-turbo boost, will the Profec adjust the boost level (via the wastegate) if you have
the Profec set to give a lower boost level than is
Theoretically it should. My concern is, I like to keep my boost down when it is wet
outside (so I don't go sliding through turns when the back end break loose). Plus I like
to keep it lower to improve the longevity of my motor