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Posted: Sun Aug 31, 2008 4:05 am
by corsair
I posed you a link to the schematic in your other thread balls.

here it is for anyone else interested

Posted: Wed Sep 03, 2008 5:41 pm
by Legacy777
I'll try and get to putting the files I pulled down from the internet archive.

Posted: Sun Feb 08, 2009 6:54 pm
by Grayguy
IS there a parts list somewhere for building this, short of paying the $25 to get one? I kinda thought there should be since Vgr3 posted this up as free info to begin with...

Posted: Sun Feb 08, 2009 7:35 pm
by magicmike
Grayguy wrote:IS there a parts list somewhere for building this, short of paying the $25 to get one? I kinda thought there should be since Vgr3 posted this up as free info to begin with...
I don't think there is access anymore to any of his stuff. The guy is a genius and created/invented new techniques or circuits on many different occasions only to have his hard work stolen or used without even giving credit to him which I think is what hurt him the most. The fact that some people proffited from his designs and offerend no monitary payback makes me ill, you know who you are and shame on you.

Posted: Tue Feb 17, 2009 3:43 am
by 94legacy2.2
so just wondering on this FCD

Ive made them before for a dodge. Its a 3 wire electronic module. Much easier then above.

So the one I have or have built needs the 5volts in, ground and signal.
Would this work for the subie aswell?
If so All I need to hook up on the Subie wires are the red, white and black wires
Red= 5volts
White= Signal wire
Black= ground

Ill post a diagram of it here in a few

Posted: Tue Feb 17, 2009 3:48 am
by 94legacy2.2

Posted: Tue Jun 09, 2009 8:29 pm
by vrg3
The original page is back up, now hosted on Josh's server:

Posted: Mon Jul 27, 2009 8:05 am
by Boostedballs

I think this will push my car into the 13's!

Now 14.1@95mph

Posted: Wed Jul 29, 2009 7:36 pm
by Boostedballs
Ok, I built a couple of the FCD's. Pretty easy, thanks everyone, especially Vikash!

I'll post the results as soon as I get it installed and tested!!!

Posted: Fri Jul 31, 2009 2:44 pm
by cj91legss
vikash do you have a part # list for your fcd?

Posted: Sun Aug 30, 2009 11:28 pm
by cj91legss
Well i finally boght components, made, and installed mine today... not bad at all. Actually im pretty pleased with it.

Posted: Mon Aug 31, 2009 5:14 am
by cj91legss
Any idea of a safe boost level? I'm running stock injectors with a front mount


Posted: Sat Sep 12, 2009 7:01 pm
by Boostedballs
Boostedballs wrote:Ok, I built a couple of the FCD's. Pretty easy, thanks everyone, especially Vikash!

I'll post the results as soon as I get it installed and tested!!!

Ok, I installed Vikash's FCD and a home-made brass manual boost controller. My boost is rock solid at 14psi even with a 70hp shot of NOS going!

No more fuel cut!

I'm gunna try to take it to the track tonight and see if I can get into the 13's!

Thanks Vikash! :D

TIP: i assembled mine on a small board and used a 14 pin socket for the op amp. I covered both sides of the board with liquid electrical tape. The holes in the board are open so it makes it easy to tiewrap it to something.

Re: Cheap Electronic FCD - Revised

Posted: Thu Jul 08, 2010 3:54 pm
by cj91legss
Just randomly posting in here... im running 16lbs now with a td04 stock ecu 440s and this fcd and no problems...

someone should make some of these...

Re: Cheap Electronic FCD - Revised

Posted: Mon Jul 12, 2010 7:08 am
by Mattheww044
id buy one in a heartbeat. if someone wants to make a spare, ill buy one

Re: Cheap Electronic FCD - Revised

Posted: Fri Jul 16, 2010 4:33 pm
by cj91legss
matt i might take you up on that.

Re: Cheap Electronic FCD - Revised

Posted: Wed Nov 10, 2010 6:49 pm
by Florin1
Bump. Does anyone local have any of these?

Re: Cheap Electronic FCD - Revised

Posted: Sat Mar 12, 2011 2:27 am
this little guy would really come in handy if someone is building some...

Re: Cheap Electronic FCD - Revised

Posted: Sat Mar 12, 2011 2:36 am
by cj91legss
Someone is, just had a small bump in the road...

Re: Cheap Electronic FCD - Revised

Posted: Fri Jul 29, 2011 6:06 pm
by cj91legss
i finally got one to work, the 2 i made previously had a cross in a wire, so im going to break those down and rebuild them. :)

Re: Cheap Electronic FCD - Revised

Posted: Thu Oct 27, 2011 1:55 am
by mazda ej22t
how high of boost can you use with this defender? only to 14 or can you go higher than 20 per say?

Re: Cheap Electronic FCD - Revised

Posted: Sun Oct 30, 2011 9:05 pm
by Legacy777
Typically a FCD will completely eliminate the fuel cut since it clamps the boost voltage at a certain level. They would need to be designed slightly different to still allow for fuel cut, but at a different/higher level.

Re: Cheap Electronic FCD - Revised

Posted: Sun Jul 01, 2012 5:02 am
by keithmoilanen
Still being made?

Re: Cheap Electronic FCD - Revised

Posted: Tue Jun 18, 2013 7:37 pm
by free5ty1e
The schematic is still up at - they are still for sale but there would be a delay as I am currently completely out of the printed circuit boards and most components from the recent relocation to oregon. If there is still interest I will order another run of boards and parts and be able to fill orders again.

I also wanted to clear something up; theres been a lot of talk about taking advantage of vrg3's designs for profit. I made a deal with him when I started laying out the circuitboard to provide him with royalties for each unit I sold. After I gathered enough of a payment I sent it to him via PayPal and am currently caught up on these royalties; its not often I sell an fcd and I don't make much profit. I mainly wanted to offer other enthusiasts a "ready to go" fcd solution if they didnt want to fudge around with building one.

I also offer warranty and tech support, although I didnt have to. Ive provided troubleshooting tips and replaced a handful of units that I was able to determine were shorted out by plugging in offset by 1 pin. I put reverse voltage protection for reversed connectors but couldn't catch all the bad situations in such a simple design.

I can dig up the parts list and post here too, I see there is some interest in that.

Sent from my SAMSUNG-SGH-I337 using Tapatalk 4 Beta

Re: Cheap Electronic FCD - Revised

Posted: Tue Jun 18, 2013 8:45 pm
by free5ty1e
I just got a PM question for help with an inoperative FCD (complaint is it raises fuel cut slightly but does not eliminate it). As this could be several issues, I figured I'd copy my response here for reference in case others have similar issues to troubleshoot:
free5ty1e wrote: Hi!

Are you getting a Check Engine light along with this issue?

Hmm... usually at this point I'd recommend grabbing a voltmeter or multimeter, turn your ignition to ON (no need to start the car), then reading the voltage at the following pins to see if things are hooked up right (not sure about his wiring or pinouts or coloring so I'll use pin names you can reference):

12V power - should read same as your battery voltage, this provides power to the voltage clamp chip. Ensure this voltage is also seen at the yellow with red stripe wire on the pressure exchange solenoid as this is where it is typically drawn from. If this voltage is no longer at your solenoid, you will have a Check Engine light on with a code for this solenoid.

5V power - should read somewhere between 4.8V and 5.2V. On my schematic, this is taken from the pressure sensor's red wire. Ensure again that the voltage is still getting to the pressure sensor as well as the FCD. This voltage is used to create the voltage divider circuit that clamps the output at 3.9v (anything above this and the ECU triggers fuel cut after 3 seconds).

Input - Should be the signal from the pressure sensor. This is the one wire (pressure sensor, white) in the car that you will want to CUT and separate instead of just tapping into. This signal should be from the SENSOR side of the wire. This signal should read somewhere near the mid range of 0 - 5V... maybe somewhere in 1.5 - 2.5v? (with the engine off)

Output - Should be the altered signal from the pressure sensor, on its way out to the ECU. This should mate up with the CUT white wire from the pressure sensor, on the ECU side of the wire. If you want to test this signal out, take a short piece of spare wire and connect the 5V power to the Input pin. Watch the Output pin voltage on your meter, should go up to 3.9v and not get any higher. If it goes above 3.9V then this is why you are still seeing fuel cut; if there is a way to adjust this FCD clamp voltage this is why you need to do it. On my units I include a little potentiometer (knob) that can be used for adjustments if necessary, although I pre-set them all at 3.9V before I send them out.

If your FCD cable has a shield or ground, connect that to the pressure sensor's green wire. Verify this reads 0V or has continuity to other grounds in the system.

If you aren't able to get any voltage clamping action on the output, or if the output is just 0 at all times, you may have a blown / faulty LMx24 chip. You can order a replacement from DigiKey for very cheap, and if you opt for the military grade LM124 you will have increased durability and temperature operating range. (LM224 is standard operating range).

Since this may help others with similar FCD issues, I'm going to also post this in the FCD thread for reference.

Hope this helps! :)

Edit: Here is a link for DigiKey's product page for the mil-spec LM124 voltage clamp chip in case you need to order one.
I also note that Vikash's original FCD page is down but Josh has it hosted on the surrealmirage domain here:
...I will have to update the webpage in order to reflect this. It is still referring to the old page on I'm sure I'll get to that at some point.

Edit2: In case DigiKey's website backend changes and the above link is no longer valid, you can search on DigiKey or other electronics components sites for "LM123" and drill down to the ones that match in the Op-Amp category (you'll want a PDIP or DIP package -- you don't want to get a tiny surface-mount chip with no through-hole pins!). Or, even better, the DigiKey part number is 497-6984-5-ND for a direct look-up. Current price for 1 chip is $1.79.