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Posted: 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

Posted: Fri Dec 02, 2005 1:41 am
by Simon Lines
Hey VRG3,

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


Posted: Thu Jun 01, 2006 2:57 pm
by free5ty1e
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...)

Posted: Thu Jun 01, 2006 4:29 pm
by vrg3
Interesting. I guess maybe the fuel cut threshold is at a gauge pressure rather than an absolute pressure?

Posted: Thu Jun 01, 2006 4:40 pm
by rallysam
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?

Posted: Thu Jun 08, 2006 1:55 am
by free5ty1e
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.

Posted: Thu Jun 08, 2006 3:46 am
by Legacy777
I may be interested in one.

Posted: Thu Jun 08, 2006 4:12 am
by vrg3
Thanks, dude!

Posted: Thu Jun 08, 2006 4:27 pm
by free5ty1e
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.

Posted: Fri Jun 09, 2006 2:13 am
by Legacy777

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?

Posted: Fri Jun 09, 2006 2:31 am
by free5ty1e
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.

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.

Posted: Fri Jun 09, 2006 3:26 pm
by rallysam
If you think about it - you can't really raise the fuel cut because the sensor doesn't go a lot higher anyway.

Posted: Fri Jun 09, 2006 8:50 pm
by free5ty1e
Yeah, the stock MAP sensor will only sense 1psi over fool cut anyway.

Posted: Wed Jun 14, 2006 1:20 am
by free5ty1e
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 :)


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

Posted: Wed Jun 14, 2006 2:00 am
by mikec
That looks sexy! :)

Posted: Wed Jun 14, 2006 2:27 am
by free5ty1e
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)

Posted: Wed Jun 14, 2006 3:38 am
by ultrasonic
Nice ground plane implementation.

Posted: Sun Jun 18, 2006 10:38 pm
by free5ty1e
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...

Posted: Mon Jun 19, 2006 12:22 am
by thehookeup
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

Posted: Mon Jun 19, 2006 1:54 am
by free5ty1e
Well don't that just beat all? What was the problem with the car, MAP sensor hooked up wierd?

Posted: Mon Jun 19, 2006 6:02 pm
by thehookeup
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.

Posted: Thu Jun 22, 2006 7:57 am
by FuJi K
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?

Posted: Thu Jun 22, 2006 8:42 am
by thehookeup
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.

Posted: Thu Jun 22, 2006 5:46 pm
by FuJi K
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.

Posted: Mon Jun 26, 2006 1:37 am
by free5ty1e
OK - the kit is complete and ready for sale!

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.