Silo

iTrader: (1)

Thanks a lot!

MEGA_BB6_Turbo

well guys...i decided to go with the HKS FCON V pro since i'm close to SP Engineering....the thing is that i won't buy it until my engine is built which won't probably be done till next year. Good thing though....i got quoted at $1600 for the ECU!!! =(

winNvegas

i noticed not very many people here use AEM FIC (piggyback). Thats what i have installed in my car and ive had no problems. It just took a long time to tune the open loop, but i finally got my car to run great. The only problems is my idle is unsteady and i think its because of the larger injectors and not being able to give or take away the right amount of fuel to hold the idle steady. I wanted a professional to tune it, but there are none in las vegas. I tried three different places. One was "aem certified" prob was the worst of the three. Anyways, my car runs great, but Im sure would run better if tuned by someone that has experience. I also have to add that I'm not looking for huge power, which is different than most others in this forum. Piggyback may not be a good choice for people wanting higher boost.

djamps

iTrader: (1)

Idle 'bounce' is pretty common with larger injectors on stock ECU/piggy. You need to reflash (and tune) the stock ECU for your injectors, because piggy's don't have enough control. Took quite a bit of work to iron mine out with Osiris.

str8dum1

iTrader: (11)

i think the AEM is as much a piggy-back as the haltech is. I dont think its like a UTEC that uses the stock ECU for start-up, vacuum.

winNvegas would have to confirm. Any supra shop could easily tune your AEM though. I bet there are a few good supra shops out your way.

winNvegas

Yes, the AEM FIC is a pure piggy back. It takes the voltage and modifies it during open loop to trick the ecu to think its at a given voltage. Then you adjust the fuel trim to make sure the ecu is happy. There is also an AEM standalone but thats not what i have. And it does use the stock ecu for startup, but again you trick it into thinking its at a certain voltage and you feed it fuel based on that. I'm not sure about the vacumn. I didnt adjust anything there so ill assume the stock ecu controls this.

str8dum1

iTrader: (11)

So its just like a UTEC then. Then ya, anything larger than 600cc maybe hard to get dialed in under vacuum. 600cc and smaller should be easy and be pretty much like stock at all areas under vacuum. I ran my stock ecu with 600cc injectors all the time and the only thing it didnt like was fast pedal transitions. So it shouldnt take much to dial in the AEM

djamps

iTrader: (1)

Like he saidthe piggy version of the AEM modifies MAF voltage and trims timing/fuel, which makes it more like a unichip / emanage blue. On the contrary UTEC takes complete fuel and timing control in boost, which makes it like a MAP tuned standalone but only in boost.

str8dum1

iTrader: (11)

ahh, i thought that it only modified values under vacuum.

regardless, still should be able to get it dialed in

winNvegas

The aem fic does take over when the car boosts. As far as I can tell it is "complete control of timing and fuel" It goes into closed loop and whatever I want to adjust the afr to is easy. Its the open loop thats hard to tune because the ecu still uses the o2 sensors. The fic doesnt adjust the MAF voltage, it modifies the voltage coming from the o2 sensors so that no matter what voltage your o2 sensor is reading, the fic will add or subtract from that value to keep the stock ecu happy. so lets say i want my car to have an afr of 12 before it goes into boost, i plug in a value into the voltage table which will trick the stock ecu to think its at 14.7 (which is what stock ecus aim for, i think..) then i can add or subtract as much fuel as i want and the ecu will always be happy thinking its 14.7. The main goal is to keep the ecu happy because if it thinks the car is too rich, it will subtract fuel to the long term fuel trim even in closed loop then boom! because you are too lean. Keep in mind that Im an ametuer at this and whatever i say should be taken with a grain of salt. I did however spend alot of time reading, and when i went to the dyno, the tuner was impressed with my tune

djamps

iTrader: (1)

If the AEM had full fueling control it wouldn't need to trick the stock ECU. That's the cool part about the UTEC, it basically disconnects the stock ECU's ignition and injector wires at a specified manifold pressure and takes over completely, so the stock ECU can do whatever it wants and it won't matter. There's no adding/subtracting, you punch in the exact injector pulse width and timing values. The downside is the 'transition' can be felt like a brief misfire.

winNvegas

The fic does the same thing at boost. It takes over and no longer needs to trick the ECU. Only during vacumn is when you have to adjust the voltage and fuel trims. At boost, i ignore the voltage table and put in the amount of fuel to attain 11.0 afr. The units sound like they are similar once the engine reaches boost.

djamps

iTrader: (1)

Interesting. In boost what units are you using for fuel and timing? With UTEC, you use actual IDC (well, it's a value from 1-255 corresponding to 0-xx millisec) and for timing you use actual BTDC e.g. 18 degrees so there's no guesswork.

winNvegas

Ill have to connect to the ecu in my car to check. You might be right though, because with the timing i remember I put -1 degree for every psi over 0. So maybe the fuel was adjusted the same way. I just know that after the car reaches boost, i no longer have to worry about the ecu adjusting the fuel values that i inputed. I remember entertaining fic vs utec initially, but from what i read or what people told me, the fic was more advanced than the utec. Whether thats true or not, i dont know. But at this point, my car runs pretty good, except idle... and my car smells like gas when my windows are open.