filetofit

http://www.angelfire.com/ab7/diymapl.../ignition1.gif

http://www.angelfire.com/ab7/diymapl.../ignition2.gif

http://www.angelfire.com/ab7/diymapl...ages/fuel1.gif

http://www.angelfire.com/ab7/diymapl...ages/fuel2.gif

OK I finished the maps for the PR3 ECU last night. I compressed the stock maps down so that the last five columns are for boost. By running a voltage divider on the MAP sensor input to the ECU with the ratio of 2.9/5, MAP voltages of 5 volts (11 psi) are scaled down to 2.9 volts which corresponds to the last column in the maps. I figured I'd pack the most boost into the stock maps using the stock map sensor and 450cc injectors.

Notice that at the top of each map I have a number labeled "effective mbar". This is the actual pressure that is in the manifold. The row labeled mbar is what the ECU thinks it is seeing.

In the boost region of the ignition maps I've used an ignition retard of 0.75 degrees per pound of boost.

For the fuel maps, after compressing them from 15 to 10 columns, I applied an injector size factor of 0.5333 (the ratio of 240/450). I also applied opening time compensation factors of 20,19,18,17,16,12,8,8,8 percent to the first nine columns.

In the boost region I used a fueling map for 11.4 psi scaled it down a little for my maximum boost of 10.8 psi, interpolated for the in between boost levels, then increased the fueling by 20% to account for "the increase in brake specific fuel consumption characteristic".

Comments?


[Modified by filetofit, 8:35 PM 10/10/2002]


[Modified by filetofit, 9:55 PM 10/11/2002]

falcongsr

did you try it yet?

if i were you i'd want to go into open loop mode when boosting...are you going to mod the TPS signal into the ecu to go open loop?

SiRkid

good work!!!!!
you should try it though.... way to be trying this on your own

1.8T_EG

bump for innovation and creativity...

Ri5e

What about the injectors? If you use big injectors, say 550ccs, would the fuel maps let the car idle fine?

boomslang

I can't get the pics to work, but sounds good. Try it out!

ninesecrx

your bad ***

legendboy

Good job I'm very intrested in hacking honda ECU's but I am not a programer but I find it very interesting.

filetofit

Like a previous poster said, you have to copy the links and paste them. Angelfire won't let you link to their free pages. Sorry, anyone know any free imagehosting sites?

The idle should be fine because all the injector pulsewidth values wre basically cut in half to compensate for larger (450cc) injectors. And then fuel was put back in at low RPM to compensate for the longer opening time of larger injectors.

falcongsr

closed loop vs open loop? if i am stupid for repeatedly bringins this up please tell me.

filetofit

Oh yeah, closed versus open, good question. You think I should amplify my TPS sensor signal to go into open loop early? It's pretty easy to do.


[Modified by filetofit, 11:43 PM 10/10/2002]

falcongsr

i think you should make tps voltage = 4.5v when you cross 0psi threshold. otherwise ecu will be trying to maintain stoich air fuel ratio regarless of your entries in the fuel map. until map voltage got up to 2.85v or so. i know you'll be in boost at lower map voltage (at ecu).

you dont want 14.7:1 afr while boosting i dont think. a little too lean for me.

i did this with a cheesy relay circuit and a pressure sensor on a jackson supercharger setup for similar reason: part throttle boosting. you'll have the same problem since the ecu will think you're in vacuum when you're really boosting but not at wide open throttle.

edit - this WOULDNT be a problem if you always have the pedal to the floor when boosting, but with most turbos and SC's i am pretty sure there are instances where you're not at WOT and still making boost. if i am wrong here someone please tell me but i think this is important.

filetofit

That's a good point. I've got closed loop disabled on my ECU right now but for those who want to keep closed loop, I'd have to address that. I would probably just amplify the TPS signal so much that it hits 4.5 volts for anything more than a little bit of throttle. Off the top of my head that would be easier than pegging the TPS signal at 4.5 when MAP goes positive.

falcongsr

yes it would be easier, but is there the issue of part throttle and NOT boosting? now you're dumping too much fuel in vacuum. i am one of those people that are going to want it all - as close to stock drivability, emissions, and economy and safe boosting. but yeah if you're running with closed loop off then my point is moot.

filetofit

Doesn't the ECU go into open loop at 50% throttle anyway?

I suppose I could set up a comparator that, when the MAP signal reached 1.8 volts, biased the input of a TPS signal amplifying op amp in such a way that it forced the output up to rail voltage which would be 4.5 volts, for those of you who want everything.


[Modified by filetofit, 12:01 AM 10/11/2002]

falcongsr

seemed more like 90% based on watching my stock o2 sensor. thats when it stopped oscillating and went full rich.

also, now that that gauge is gone and i have an egt gauge, i see higher EGTs at part throttle than at wot, when the ecu starts dumping fuel. this indicates that the ecu is still in closed loop until i punched it.

but i have no idea where the actual crossover point is. it would be cool to watch the stock o2 and steadily increase the tps voltage to see where the ecu says ' ok this guy is trying to floor it' regardless of what the map sensor is saying.

legendboy

I read somewhere its 72%, I may be wrong.

speedymon

I thought it was 72% according to Liam (AFC hack guy)

boomslang

I just saw the screen shots.

Your chip programmer can take values straight from excel? That's too easy!

willyboyK20

just a general question as i am trying to learn.
what is the diff between closed loop and open loop?

DIRep972

iTrader: (1)

keep at it man. you are gettin it.

BudaKai

I have one question. Will this ecu hack be able to handle 3.0+ bar of boost because that's currently what I struggling with. That and I saving for the MONSTER snail to do it. Those dart blocks caught my eye and I wanna take Steph down. I love what he's done for use but someone's gotta stop him. Honda all the way. I don't wanna spend the money on A Motec or something when I live with a computer science engineer, and I'm majoring in mechanical engineering.


[Modified by tzsir, 8:40 PM 10/10/2002]


[Modified by tzsir, 8:41 PM 10/10/2002]


[Modified by tzsir, 10:32 PM 10/10/2002]

Drag_Dc2

Damn i only wish i knew what the heck you guys are talking about.


However I am curious to compare how you decided what values to plug in for fuel and ignition timing regardless of compressing stock values or not? Are you basing your values off a stock program? Looks like you have the ability to plug in any value for any of the tables. Is there a way to determine what set of values would work better for a given application?? Sort of like the old school DFI, just a table full of numbers.....

SOrry i know my questions do not use technical terminology, im just a stupid econ major, without any knowledge of electrical workings.

TurboedGSR

closed loop is when you're ecu is in "daily driving mode" and is constantly making changes to the air/fuel ratio to keep it as close to 14.7:1 as possible. open loop is when the ecu works off the pre-programmed maps, which i guess happens at 72% throttle as someone has stated before

Full-Race Geoff

thats AWESOME. great work! good to see someone doing more electrical stuff, not enough guys trying it out.

if you need a place to host some stuff, i can put it on http://www.full-race.com