Cheap Electronic FCD - Revised

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

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NICO
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Post by NICO » Fri Nov 25, 2005 5:37 pm

sorry for posting, it was a vacum line that poped of the map sensor and i didnt see it.

bye the way VRG3 your fcd is the best, i tried 4 other ones and they where all shit big names 2

Simon Lines
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Post by Simon Lines » Fri Dec 02, 2005 1:41 am

Hey VRG3,

Care to build me one of these? $25 sound ok?

Simon

free5ty1e
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Post by free5ty1e » Thu Jun 01, 2006 2:57 pm

Hey everyone,

After moving to the mountains from sea level, my FCD stopped preventing fuel cut. After running a shielded cable into the cabin and installing the FCD there, I was able to adjust it as I drove (I used a 20-turn pot instead of just resistors) and get it to do it's job again, which I'm happy about (more than 3 seconds of full boost is a good thing).

I also reread the design and have some things to note. 4.3 volts is said to be the point at which fuel cut occurs on the pressure sensor reading, yet I was already clamping below that (I drove with a Fluke meter on the FCD's output signal) and fuel cut was still a problem. Even clamping down at 4.1 volts didn't stop fuel cut. It wasn't until I set it down at 3.9 volts or so that I got pure, uninterrupted boost.

Anyone want to take a stab as to why that is? Higher elevation / less humidity? But the pressure sensor sees absolute pressure....

Anyway -- if that guy earlier in this thread never got around to producing this FCD to sell.... I think I'll be doing that shortly. With a bypass / activation switch and two LEDs (power on and voltage clamped) on a printed circuitboard. With the military-grade LM124's, and 20-turn pots for full-range adjustment. I'll post up here when I've got some available for purchase. (not set up enough yet to work on the LegacEBC but definately can make these without much effort...)
-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

vrg3
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Post by vrg3 » Thu Jun 01, 2006 4:29 pm

Interesting. I guess maybe the fuel cut threshold is at a gauge pressure rather than an absolute pressure?
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212

rallysam
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Post by rallysam » Thu Jun 01, 2006 4:40 pm

Weird. Damn car is too smart. I guess it remembers the reading it got the last time the valve selected atmospheric, then subtracts that out from the real time boost readings... at least when it is calculating the fuel cut voltage. Hmm... I wonder if the internal fuel and timing maps are based off atmospheric or gauge?
'00 Impr RS - sold
'91 Legacy Turbo 5MT - mothballed
13psi, TurboXS TBE, WRX IC, Hallman MBC, TurboXS FCD, KYB AGX, Phil's STI seat, SPT short shifter, David Carter hood, Zeitronix widebandO2, Kuhmo rally tires, STI IC spray, thanks:gearboxtech.com

free5ty1e
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Post by free5ty1e » Thu Jun 08, 2006 1:55 am

Update: Just ordered the printed circuitboards for Vikash's Mk II FCD with power/clamp LEDs and a bypass switch. They should be here in a couple days - I'll be ordering the parts necessary probably tomorrow, and by next week should have some available for purchase.

I'll set the price after figuring out all the costs, but it should be around $25 - $30 or so. That includes a little profit for me, and of course some skimmed off the top for you V. I wouldn't dream of selling your design without recompensating you. I'm sure you wouldn't mind some royalties :)

Edit: I'll also offer an FCD kit, complete with parts and instructions, for slightly less money in case some people would like to assemble on their own, upon request.

Edit: And of course, V, you'll get one to test out and evaluate... that's a given.
-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

Legacy777
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Post by Legacy777 » Thu Jun 08, 2006 3:46 am

I may be interested in one.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm

vrg3
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Post by vrg3 » Thu Jun 08, 2006 4:12 am

Thanks, dude!
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212

free5ty1e
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Post by free5ty1e » Thu Jun 08, 2006 4:27 pm

V - no problem man. I'd feel like a total ass if I didn't :)

Josh - I'll put you on the list.

Also, our discussion on shielded signals in the LegacEBC thread got me to thinking that it would be a good idea to include the proper length of shielded wire with the FCD. This way, people don't go just hooking up single wires through the firewall. I'm also considering a male/female connector set so that the FCD can be removed and re-installed from the vehicle without having to cut wires. That's currently how mine is set up and I've found it very convenient in quite a few instances. I guess I can make the connector an option, but I think the shielded wire should be part of the package.
-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

Legacy777
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Post by Legacy777 » Fri Jun 09, 2006 2:13 am

Chris,

I'll have to take a look at this thread a little closer. I read bits & pieces way back, but really don't remember the in's & out's of hooking it up, and all that jazz.

Does this guy eliminate fuel cut all together, or does it raise it?
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm

free5ty1e
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Post by free5ty1e » Fri Jun 09, 2006 2:31 am

Eliminates it altogether. It will have a 20-turn precision potentiometer for adjusting pretty much anywhere in the range for versatility.

It clamps (limits) the MAP's output voltage at wherever you set it so the ECU will never see above that pressure. A handy LED will tell you when it's clamping the voltage so you can roughly tell where it's set (with a boost gauge's and possibly a buddy's help), make full-throttle runs and adjust it in between until fuel cut no longer occurs.

And if you want to re-enable the stock fuel cut just toggle the bypass switch and it won't mess with the signal at all.

Hooking it up is simple, all the wires you need to tap into are right there at the MAP sensor. (+12V, +5V, Gnd, MAP signal) -- you pretty much pass the MAP signal through this unit and then connect it's output to the wiring harness for the ECU.

http://www.graphics.cornell.edu/~v/fcd/

I just added a power LED, clamp LED, and bypass switch (with necessary support parts) to Vikash's design, and laid out a printed circuit board for small-scale production.
-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

rallysam
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Post by rallysam » Fri Jun 09, 2006 3:26 pm

If you think about it - you can't really raise the fuel cut because the sensor doesn't go a lot higher anyway.
'00 Impr RS - sold
'91 Legacy Turbo 5MT - mothballed
13psi, TurboXS TBE, WRX IC, Hallman MBC, TurboXS FCD, KYB AGX, Phil's STI seat, SPT short shifter, David Carter hood, Zeitronix widebandO2, Kuhmo rally tires, STI IC spray, thanks:gearboxtech.com

free5ty1e
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Post by free5ty1e » Fri Jun 09, 2006 8:50 pm

Yeah, the stock MAP sensor will only sense 1psi over fool cut anyway.
-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

free5ty1e
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Post by free5ty1e » Wed Jun 14, 2006 1:20 am

Got the first production run of PCBs back today and stuffed one of the FCDs with parts we had lying around... tested it on the bench.... works great!

Gotta love getting a circuitboard back with no errors :)

Image

Obviously it still has to be cut away from the others, and then tested in the car... but here it is!
-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

mikec
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Post by mikec » Wed Jun 14, 2006 2:00 am

That looks sexy! :)
"That shouldn't be a problem, since I do regularly visit the realm of subatmospheric manifold pressures." -- vrg3

free5ty1e
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Post by free5ty1e » Wed Jun 14, 2006 2:27 am

Thanks - it says "Fuel Cut Defend" there too but my camera didn't want to focus that close...

I opted to not waste board space with the bypass switch - that can be at the connector or on the wire. Still have to work that out, and get a parts order together to stuff the remaining boards, and then I'll be able to figure out how much I need to charge for them to turn a profit (and pay royalties to the V man)
-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

ultrasonic
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Post by ultrasonic » Wed Jun 14, 2006 3:38 am

Nice ground plane implementation.
-steve-

03 Legacy L Wagon
91 Legacy Sport Sedan - SOLD
94 Legacy Touring Wagon - SOLD
00 Impreza L Sport Wagon - totaled!

free5ty1e
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Post by free5ty1e » Sun Jun 18, 2006 10:38 pm

Thanks. It makes for good shielding and it looks good too :)

Got a few of them built up for testing, and decided to add some protection so that plugging them in backwards won't cause any damage.

I'll be working up an installation procedure and getting everything together for a complete kit in the next couple days, using my stock silver SS to test the ease of setup.

I might have to end up charging a little more than we initially thought in order for these completed units / kits to be profitable, but will also offer a less expensive package with just the circuitboard, instructions, datasheets, and list of parts / suppliers for those who'd rather do it yourselves.

With the assembled complete kit, you will literally be able to install the FCD in a matter of minutes and be operational without having to go find anything else.

More soon...
-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

thehookeup
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Post by thehookeup » Mon Jun 19, 2006 12:22 am

so funny thing happend. well i mad a fcd and it didnt work. and then i made another one and it didnt work, and then i made another one and it kind of worked but had a intermediate short. so i made one more, and it worked, but only after i fixed some wiring problems with my car.

so i decided to check the rest of them to seem if it was the car or the fcd's that were not working right.

well it seemed to have been the car. so now i have 2 fcds that i dont have a need for. so if anyone wants then they can have them.

and the funny thing is that all four that i made. only cost me a total of 10 bucks.

vrg, bad ass buddy really bad ass
-93 2.2T (RIP), 93 N/A best car on earth.
-00 legGT, 18" PIAA sport mesh wheels, front/rear Rallitek sways, lowered whitelines, coming soon: 2.5L sti internals, 20g heads P&P, twin charged. motor is almost ready to go in.
Andrew

free5ty1e
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Post by free5ty1e » Mon Jun 19, 2006 1:54 am

Well don't that just beat all? What was the problem with the car, MAP sensor hooked up wierd?
-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

thehookeup
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Post by thehookeup » Mon Jun 19, 2006 6:02 pm

no the map sensor was hooked up correctly, but there seemed to have been some sort of short at one point cause the there was a lot of melted wire. so alot of the wires were heated up. subsiquently there was a lot of resistance in the ground and the 12v and the 5v supplies going into the ecu. so i went ahead and pretty much rewired the a lot of the wiring leading into the ecu.
works great tho, and i am hoping to pull a 13.8 in the qt.
-93 2.2T (RIP), 93 N/A best car on earth.
-00 legGT, 18" PIAA sport mesh wheels, front/rear Rallitek sways, lowered whitelines, coming soon: 2.5L sti internals, 20g heads P&P, twin charged. motor is almost ready to go in.
Andrew

FuJi K
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Post by FuJi K » Thu Jun 22, 2006 7:57 am

So I was wondering.....I'm going to get a TDO4 WRX turbo shortly, but I wonder if I'll hit this fuel cut with the WRX turbo.....I'll be running the WRX TMIC as well. This is off of 02+ WRX.

So would I still be under Fuel Cut running a TDO4 WRX turbo?
MY99 GF4 5spd DIY Modified

thehookeup
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Post by thehookeup » Thu Jun 22, 2006 8:42 am

well. the answer is yes and no fuji......i fyou are using the stock electronic boost controller no you wont. but you might have some quick spikes that will hit around 14.7 psi and then back down to 9psi. most likely this will not happen. but it is possible.....

the boost cut is at 13 psi, and you have to maintain 13 psi or higher for more than i think its 3 seconds... so most likely you will not run into boost cut

but if you do not use the stock boost controller and use a manual boost controller which is generally more accurate you can go as high as like 12.5psi without boost cut, just make sure that you have the intercooler on or you might detonate.

and if you want to go higher than 13 psi which i recommend you will have to use this FCD or something like it.
-93 2.2T (RIP), 93 N/A best car on earth.
-00 legGT, 18" PIAA sport mesh wheels, front/rear Rallitek sways, lowered whitelines, coming soon: 2.5L sti internals, 20g heads P&P, twin charged. motor is almost ready to go in.
Andrew

FuJi K
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Post by FuJi K » Thu Jun 22, 2006 5:46 pm

so....I guess we'll find out when I put on the Turbo and TMIC. I believe the boost will taper down more with the 2.2L 22T compared to the 2.0L WRX when at higher revvs. I don't plan on running a manual boost controller at all...just run on the stock waste gate, unless I want to in the future, but i The WRX turbo is as big as I'll go on this stock setup.

The WRX turbo does peak boost at almost 14psi...should be 13.5lbs average. SCARY! Right at the limit.....*sigh*

....I just still have to figure out what the two "Select Monitors (Rx/Tx) are...and if I need them or not. Then add 2 more wires for ignition; prepping it for the Power FC.
MY99 GF4 5spd DIY Modified

free5ty1e
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Post by free5ty1e » Mon Jun 26, 2006 1:37 am

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.
-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

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