Are you guys interested in cheap AFCs?
 

Hello boys,

Hey guys I am starting up a little project to make an AFC, I have looked around and it seems pretty doable with the skill that I have. Before I start dreaming and order the parts, does anyone know if there are sites already that tell you how to do it? what is the cheapest AFC you can get on the market. Basically my plan is that once I am done making it, I can sell them for cheap price. I am pretty sure I can make a basic AFC. What is a reasonable price point? I want to develop a quality product that is easy to use and the most affordable out there.

I am gonna use a microcontroller for the project, but seeing as how powerful these microcontrollers are these days I would hate to waste it on performing jsut 1 task. What other features would be useful to integrate into an AFC? NO displaying of sensor readings because LCDs are expensive.

VTEC
Turbo Timer
data logging (doable but will probally be a major headache)
abything else to add to the list.

BTW thanks to the guys who helped me out by giving me great information before. I even thought of a name for the ghetto AFC, "FULLBAR" or "FUBAR" for short. Whatever features you guys think are cool to integrate please tell me soon because I am ordering my Programmer on monday, depending on the complexity of the application I may need to switch to a more advanced microcontroller and get a different programmer.

Thanks guys, I really look forward to contributing back to HMT through this little project. Wish me luck.

Regards,

Alan To

Re:Are you guys interested in cheap AFCs?
 

The stupid ------- forum erased my nice thoughtful response to you "not logged in"

Arrrgh.

Anyways, suggestions:
-Cheap, backlit 16X2 serial LCDs can be had easily for under $30. No sexy VFD display, not even sexy bitmap display, but it works for displaying sensors...
-Check PGMFI.org forum/approaches/tools n toys for a project Mark Lamond did using a basic stamp to datalog to LCD.
-It would be really useful to combine such a logger with one of the many MCU-interfaced solid state projects so data could be logged to SmartMedia/MMC/CompactFlash/etc.
-It would be really useful to build an additional injector controller using a PWM output on the MCU and a handful of appropriate Darlingtons. Especially if the duty cycle could be set according to MAP... oooh that would be useful

*shameless plug* you'll find lots of info + like minded ppl @ PGMFI.org ... come check it out if you haven't already.

If you want help with board layout, let me know. I'm getting rather good at it and would love to help. Also willing to share some software... Email me.

peace
-Dave

Re:Are you guys interested in cheap AFCs?
 

Ignition control maybe?

I'm with the extra injector controller idea too...


*thinking*...


If the LCD's are gonna be too much trouble then maybe a nice housing with some cool looking green or red lights (maybe for injector signal? "engine being enriched" mode? on-boost? off-boost? WOT? open loop? closed loop?). Just some recs.

keep us posted :thumbs up:

Re:Are you guys interested in cheap AFCs?
 

would they be for any cars (toyota) or are they going to be just for honda's?

Re:Are you guys interested in cheap AFCs?
 

This site is so slow, I had such a nice long winded response written down when all of a sudden it timed out.

Oh well, Beggers can not be choosers.

Well i just ordered my microcontroller programmer today and I can pick it up from the bus terminal tonight, so hopefully by tonight I will be able to do so fun stuff. As for the extra injector that is a good idea I will look into it. Originally I wanted to use a laptop to configure and tune the thing but i just found out the software i wanted to use is not longer free of charge and it would cost 100 bucks. So ---- that. I think i will just be ghetto for now and use LEDs, a quality LCD would be too costly in my opinion since I am looking to get to a price point of less than $50 bucks each unit. But in the future I will probally add several variants to the basic design. But to make things easy for me I will just shoot for making a basic VAFC.

Thanks for the Suggestion of using the Basic stamp microcontroller, but they are very very expensive ($99) and slower than a criplled horse running up hill. I have worked with them before. I am going to to the PIC family of microprocessors they are fast and dirt cheap ($3). In fact the basic stamp is built on PIC series of microprocessors, it is slow because the STAMP has dumbed things down to make it easy to use and stuff.


As for data loggin what sensors are an absolute must and what sensors are just gravy?

OH BTW I also wanna make a WB O2 sensor reader, you can pick up a bosch WB sensor for like $50 bucks off ebay, the only thing is that the unit to read the data is like $400 bucks. Personally I do not see how hard it would be to make a reader, especially if you have a pwerfully microcontroller on your side. So maybe all in all $100-$150 for a WB o2 sensor and a reader. Would a product like this be of interest to you anyone?

Re:Are you guys interested in cheap AFCs?
 

OH if I am not mistaken in general AFCs are not car specific, so you should be ble to use almost any AFC in any car, mine should be no exception. However The only platform I have to test it on is my 93 Del Sol si with a greddy turbo kit and 380 CC injectors. I am going to taylor my design specifically for this engine and its setup. So if it does not work well for other engine types and setups please forgive me.

OKay please everyone enlighten me on 1 thing, I am %99 sure but I wanna be %100 sure. all an AFC does is output a fake MAP sensor reading at certain RMPs right? Nothing else, no other sensors cme into play. It is just that simple right?
Also once I run larger injectors should you start fiddling with an AFC before you first start the car? or do you just let it run pig rich the first time around and start tuning afterwards?

Re:Are you guys interested in cheap AFCs?
 

oh yeah what about ignition timing? does a typical AFC do anything for ignition timing? Does the ECu adjust the ignition timing itself based on the MAP sensor?

Re:Are you guys interested in cheap AFCs?
 

got my programmer lastnight everything works, currently relearning assembly code. thanks for everyones help. I still need some of my prior questions answered, with special emphasis on retarding timing, is there a direct electrical way to easily retard timing? How does the MSD work? Someone help me out here. Timing retarding and VFAC would be a killer bundle in one package. I am sure my programming skills and the addition of a more complex MCU would be up for the task, heck I will even work with BJTs if it calls for it. I really need info on timing, please help.


Thanks.

Re:Are you guys interested in cheap AFCs?
 

afc also uses the tps signal

Re:Are you guys interested in cheap AFCs?
 

had another idea to add... boost controller.
IMHO, you need some kind of simple display. several 7-segment LEDs are like a minimum.

As for timing, you're looking at a much more complex thing to mess with than the MAP sensor input. The ECU in our cars sends a pulse to the coil, and drops the pulse to ground when it wants the voltage in the coil to colapse (read: spark). You would have to read the distributor sensors (reluctor-style - look for the "swing") and then do a little math as to how much to delay the drop to ground in the ignition output in order to retard timing.

You really should email me. I have some info I can't post publicly that would make your life a lot easier.

Re:Are you guys interested in cheap AFCs?
 

Blundar you are the man, thanks.

BTW what do u think about me using an injector to control boost? Hey i still have timing questions, I posted them up at PGMFI.org in the general section. Any help is greatly appreciated.

Regards,

Alan To

Re:Are you guys interested in cheap AFCs?
 

much simpler: use a simple bleed solenoid. I raped a couple from my emissions box. Who needs that garbage anyways?

Turbo =====T=====Wastegate
|
bleeder
|


don't know if my ASCII art will work, but hopefully you get the idea. Use a normally-closed electronic valve. (AC, emissions, etc.) and T-it into the line between pressure and wastegate. When you want to raise boost, open the solenoid. In order to avoid overboosting, you're going to have to do some kind of velocity calculations ... figure out the rate at which boost is rising, and start feeding the solenoid a PWM signal with a duty cycle from some kind of lookup table trying to decrease the velocity of boost increase and get it to stabilize at the target without overshooting it significantly. After you hit the target, a closed-loop-like feedback system could regulate the PWM duty cycle and oscilate between slightly above and slightly below the target.

Re:Are you guys interested in cheap AFCs?
 

Some thing that could act as an AFC and read/convert/display a wideband O2 would sell very easily for $150...

The timing retard thing would just put it over the top !!!

Re:Are you guys interested in cheap AFCs?
 

yeah, patent it before you sell it. that would make a killing.

ill buy one.

Re:Are you guys interested in cheap AFCs?
 

i would buy one to ;D

Re:Are you guys interested in cheap AFCs?
 

dude u r the man! i wish i could do all that computer ----. and i would definately buy one too.

Re:Are you guys interested in cheap AFCs?
 

keeping it to the top

and you keep us updated.

Re:Are you guys interested in cheap AFCs?
 

Sounds pretty cool Alan. Good luck. :)

Re:Are you guys interested in cheap AFCs?
 

I'm going to be doing the same thing in the future. Its good to have competition. I also will be using a PIC microconroller.

Nick

Re:Are you guys interested in cheap AFCs?
 

It has been a few days, how is the project going Toalan?