Cheap Electronic FCD - Revised

That spinning thing that makes all of the cool noises. OE and Aftermarket.

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dzx
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Post by dzx »

Vikash, when you said you could change out the legacy sensor for one with a higher range, like one from a GM vehicle, what all would be needed to make it work on a legacy?
///M
'93 Legacy SS - part out
Cynt
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Post by Cynt »

free5ty1e wrote:OK - the kit is complete and ready for sale!

http://fcd.chrispaiano.com/

Anyone from Legacy Central gets a discount of $5 off. I had to charge a little more than I originally thought in order to cover costs for a true quick-install kit with everything needed. Remember, each purchase also provides Vikash with some cash for his original design... and will assist me in developing the LegacEBC and LegaCU products in the near future.

I did a sample install on my stock '92 SS and it took all of 15 minutes with no problems.

So if anyone's still struggling to get their own FCD up and happening, consider the plug and play kit I've put together.
This site is down, any of these still available? somehow i just dont trust my mad soldering skills :roll:

Mahalo - Dave
free5ty1e
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Post by free5ty1e »

Wierd, when was that site down? I just checked it and it was up. PM me if you still want an FCD built for ya.
-Chris
91SS 4EAT stock
91SS 5MT awaiting engine rebuild and VF36...
92SS 4EAT - RIP :(
94SS 5MT4.11+rLSD 289k km: RobTune550,TD05-16g @ 18psi,FMIC,3"TBE,Forester lift
biggreen96
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Post by biggreen96 »

So has a solution to the high altitude fuel cut been found? Here in Moscow, ID ~2600 ft, I run into it at around 13.5 psi with the vrg3 FCD. My vf39 and 440's are dying for more boost!
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rockethound
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Post by rockethound »

well, it looks like the fcd that chris was building/selling is based on the vrg3 unit but with a potentiometer for adjusting the boost cut threshold pressure. If it's still for sale, I'll take one. :D
'92 Legacy SS ej20g mugged, desnorked, TD04, , MBC, CAI,v2 i/c, JDM STi v2 close ratio 5sp w/4.11's, short shifted.
vrg3
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Post by vrg3 »

Long overdue, but...

If you want to lower the threshold of the FCD, replace the 10K resistor with a higher resistance. If you have an already-built FCD of this type, an easy way to do it would be to just wire a resistor in series with the wire that goes to +5v.

So, you're at 2600 feet... so barometric pressure is somewhere around 13 psia? Assuming the overboost threshold is still about 13 psig, that'd mean we'd want to clamp below 26 psia. Plugging that into the sensor transfer function says we'd want to clamp below about 4.1 volts. We'd want a little wiggle room too though...

So. If you haven't built your FCD yet, or can modify it, use a 15K resistor instead of the 10K resistor. That'll clamp at about 3.8 volts, or about 24 psia.

If your FCD is already built and you don't want to (or can't) modify it, try putting a 4.7K resistor in series with the +5v wire for the same effect.
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212
ciper
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Post by ciper »

Would anyone be interested in prebuilt FCD of a similar (though slightly better) design?

I had a bunch made YEARS ago with the intention to sell them to you's guys but then my life got flipped turned upside down.
Last edited by ciper on Thu Dec 06, 2007 10:33 am, edited 1 time in total.
beatersubi
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Post by beatersubi »

ciper wrote:Would anyone be interested in prebuilt FCD of a similar (though slightly better) design?
Yes.
93 legacy wagon L, 22T swapped (TW imitator) now with five forward speeds. (Gone, but never forgotten)
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ciper
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Post by ciper »

I will try to track down the details and then dig them out of my friends storage shed. I outsourced them to India and they came back looking great :)

edit: Dang! Although the design is pretty different the function and installation is nearly exactly the same as VRG3 LOL. I guess a price war is in order with Chris Paiano ;)
SubaruNation
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Post by SubaruNation »

ciper wrote:I will try to track down the details and then dig them out of my friends storage shed. I outsourced them to India and they came back looking great :)

edit: Dang! Although the design is pretty different the function and installation is nearly exactly the same as VRG3 LOL. I guess a price war is in order with Chris Paiano ;)
i need one :D
Zach - Legacy Frankenstin
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All_talk
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Post by All_talk »

Just FYI, I built one of these this weekend... Works great!

Gary
No matter how broke I am... I always seem to find two cents.
SubaruNation
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Post by SubaruNation »

All_talk wrote:Just FYI, I built one of these this weekend... Works great!

Gary
you mind sharing with me/ the class how you did it? :)
Zach - Legacy Frankenstin
93forestpearl wrote:Keep up the good work. You'll never know what you are capable of unless you push yourself.
All_talk
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Post by All_talk »

Well I just followed the schematic, I used that Radio Shack universal IC board and they didn’t have a 20K trim pot so I subbed in a 10K. By my math that gives me 3.5V to 5V adjustability. I bench set the reference voltage to 4.1, then road tuned it up to fuel cut, then back 1 turn (about 1 to 1 1/2 turns above the bench setting). I didn’t take any pictures, but I sure wouldn’t wanna show off my soldering skills, its been years since I did any board work and its not so pretty. Front side looks real nice though. Its wired and mounted under the hood at the MAP sensor. I put it in a “sealed” package (super ghetto), if I can figure out a way to keep the adjusting screw open (not that I really need it now) I might pot it in some epoxy. I can take a pic of the finished install if ya like.

Gary
No matter how broke I am... I always seem to find two cents.
SubaruNation
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Post by SubaruNation »

that sounds way too intense for me... :shock:
i mean i installed my own fog lights but... I'm kinda worried about this one.

could somebody build on of these for me and i'll send them reasonable fundage? please? :-D
Zach - Legacy Frankenstin
93forestpearl wrote:Keep up the good work. You'll never know what you are capable of unless you push yourself.
All_talk
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Post by All_talk »

Here's a couple of pics, the "packaging" is the plastic lid from a can of turttle food, the board is isolated with foam on both sides, then the whole mess wrapped in tape. If fuel cut is what ails ya, this big black pill is the cure. :P

Image

Image

Gary
No matter how broke I am... I always seem to find two cents.
asc_up
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Post by asc_up »

Any chance you could make some of those 'big black pills' and sell them?
-Aaron

2000 Audi S4 - 2.7L Twin-turbo, 6 Speed

[quote="evolutionmovement"]It was me. And those are my balls. Happy Sunday![/quote]
SubaruNation
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Post by SubaruNation »

asc_up wrote:Any chance you could make some of those 'big black pills' and sell them?
PLEEEEEEEEEEASE!!!!!!!! :smt088
Zach - Legacy Frankenstin
93forestpearl wrote:Keep up the good work. You'll never know what you are capable of unless you push yourself.
All_talk
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Post by All_talk »

Isn't Chris selling them here?

http://fcd.chrispaiano.com/
No matter how broke I am... I always seem to find two cents.
SubaruNation
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Post by SubaruNation »

i was hoping to get one cheaper than that :roll:
i will look into it though, thanks for the link :D
Zach - Legacy Frankenstin
93forestpearl wrote:Keep up the good work. You'll never know what you are capable of unless you push yourself.
asc_up
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Post by asc_up »

Are those still available?

I just don't want to send money and find out later that he went out of business or something...
-Aaron

2000 Audi S4 - 2.7L Twin-turbo, 6 Speed

[quote="evolutionmovement"]It was me. And those are my balls. Happy Sunday![/quote]
SubaruNation
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Post by SubaruNation »

and better yet, +1 i'd like to know
Zach - Legacy Frankenstin
93forestpearl wrote:Keep up the good work. You'll never know what you are capable of unless you push yourself.
farfrumwork
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Post by farfrumwork »

I had the VRG FCD (like version 1 or something) that I bought used here and when I installed it I still had the dreaded cut (around 13-14psi)

I removed it and installed a mechanical valve (releases at 10psi), and that worked ok..... but it would still hit cut when cold, and I was unsure of the effect it had on the MAP sensors ability to monitor boost.

So enter Vikash and his recommendation for modifying the FCD for altitude (I live at 5500ft ASL). I soldered a 4.7kohm resistor in series with the +5v wire as described above and resintalled the unit. So far (1 week) I have no fuel cut, the car runs smoother, and I'm getting better mileage (not sure if this is the FCD, but it makes sense if the mechanical unit was messing with the MAP sensor readings).

So thanks again Vikash!!

-Chad
Old - '93 T-Leg - 14.693 @ 92.68 at 5800ft ASL (Bandimere Speedway)
New - 07 Spec B/stg 2

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Boostedballs
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Post by Boostedballs »

Would it be better to just install the GM 2.5bar MAP I have laying around? What would that do for me?
Air-to-Water Intercooler, VF-39, 550 injectors, AEM FIC, stainless race header, 3" stainless exhaust, 75hp Nitrous, 150psi H2O injection, intake mods, stock: long block, 4EAT, ecm.
Legacy777
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Post by Legacy777 »

It wouldn't do anything for you since the ECU isn't calibrated to use it.
Josh

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Boostedballs
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Post by Boostedballs »

All of the schematic links are dead!

I have my car running great now and I want to up the boost a touch.

I even bought the components to build it and I deleted the schematic from my work computer (because I'm quitting on Tuesday) because I assumed I could just download it at home. OOOPS!


please help!
Air-to-Water Intercooler, VF-39, 550 injectors, AEM FIC, stainless race header, 3" stainless exhaust, 75hp Nitrous, 150psi H2O injection, intake mods, stock: long block, 4EAT, ecm.
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