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Cyclone solenoid Q

I have a EPROM ECU in my Galant that came with it when I bought it for about 1 year ago, and I have a question..

There is a chip (aftermarket, don't know who programed it) in this that is supposed to be programed to control a cyclone intake, so I was wondering, does it matter what solenoid I use for this intake? I have heard that some solenoids are different from the others but I'm not sure if that's correct or not /ubbthreads/images/graemlins/dunno.gif

I have the stock cyclone solenoid that I can use, but some say that mostly these chips are programed for the fpr solenoid /ubbthreads/images/graemlins/dunno.gif is there a difference between these solenoids, or can I use the stock cyclone solenoid?

I have heard that the stock cyclone solenoid works both ways and the fpr solenoid works only 1 way, and that there is different programing for both of them when using them for a cyclone intake /ubbthreads/images/graemlins/dunno.gif


Well-known member
Sep 10, 2007
Portland, OR
Talk to Keydiver ( Jeff ). It's likely his chip, if not I would spend the $$$ and get one from him.
He can also explain which solenoid is best ( FPR bypass or BCS ).

Yes, there is a difference between the fprs and the cyclone JDM solenoid. The cyclone JDM solenoid stops getting power when opening the cyclone, while the fprs gets power when opening the cyclone.. might be the other way /ubbthreads/images/graemlins/dunno.gif

I might be wrong so you better ask Jeff since he knows this alot better! /ubbthreads/images/graemlins/smile.gif


Well-known member
Jun 22, 2007
Mountain View, CA
There may be a physical difference, but not a functional one. Both the cyclone and FPR (and all the others, like the Evap and BCS) solenoids are two-way, like a Y-valve, not an on-off switch. When the solenoid is at rest, the connection is open to one leg of the Y, and when it has current, it switches to the other, so it just depends on how you hook it up (notice that each solenoid has 3 nipples)

When the solenoid is "off", the cyclone actuator is simply vented to the nipple that is open to atmosphere. When it is energized, it switches to the other nipple with the vacuum reservoir, which supplies vacuum to the actuator. If it is acting the other way, the vacuum hoses are not hooked up correctly.

Here is a good writeup with pictures
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the fpr one has a bleed off on the back side of it unlike the other solenoids. My setup runs from the manifold to the solenoid then from there to the vacume canister then off of the canister to the diaphram on the cyclone. I also use jeff's chip to control it.

the fpr one has a bleed off on the back side of it unlike the other solenoids.

Yes, that is the main requirement of any solenoid you choose, it MUST have all 3 ports functional. Many of the factory solenoids only have 2 ports, a COMMON, and either a NORMALLY CLOSED or NORMALLY OPEN port. You need all 3 for a Cyclone hookup.
The only real difference, besides the electrical connector, between a JDM Cyclone solenoid and the USDM FPR solenoid is that the port that normally has the vent filter on it is the NORMALLY OPEN port on the JDM, vs the NORMALLY CLOSED port of the USDM FPR solenoid. You can actually remove that vent filter and put it on the other port if you wanted to use the FPR solenoid on a JDM ECU, which de-energizes the solenoid at 4500+ rpm to activate the secondaries.
If you can't find an FPR solenoid, I have also had success with drilling a small hole in the rear of a solenoid that was missing the NORMALLY CLOSED port. If I recall, a 1/16" hole was sufficient to vent the Cyclone diaphragm to atmosphere when activated.
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