Programmable ECU on 20V

[Useless]

:shades_smile: U don't need 2 replace 2 d programmable type Ecu 2 advance d 20v timing. U can just rotate yr. distributor if u require more advance ignition.

Would b wonder what type of fuel u use? :shades_smile: If yr 20v mods really need that much ign. It means this engine having a very in-efficient combustion frame front.

It is definitely not the proper way of making power via advancing the static ignition mark from the distributor. You are merely shifting the entire ignition point up a few degrees throughout the rev range. You might have better mid range, but at some point, the ecu will detect knocking at peak rpm. Thats just the cheap but inappropriate way of making power. Ping might not be audible to human ears but piezo-sensors are pretty sensitive. But agreeable that these stock ecu have been "conservatively" mapped hence making power upgrades a great potential.

It cannot be merely stating that the engine has inefficient combustion flame front. If the 4age engine has very inefficient flame front, it would not be able to push another 20 to 30 horses easily from NA tuning on top of the stock condition. Flame front propagation is has to be identified whether in laminar or turbulent state, which then is affected by Pressure, Temperature, Composition of unburned gases, and Engine speed.

 

[speedchaser]

Well said, Useless! Funny I should call u that.

Combustion flame front efficiencies has nothing to do with what we are talking on this topic. Flame front efficiencies are better discuss in the designed of the combustion chamber.. ie the position of the spark plugs and so on... The progression and propagation rate of the flame front is also totally independent of the ignition spark.

 

[Useless]

Lets not be quick to diss the std ecu of being from a weak nature in providing power to the driver. there are so many aspects put into consideration when programming a factory std ecu. But most importantly factory will always focus on longevity of the engine, then only engine performance will take the second spot.

I believe, when we begin to push engine tuning beyond the envelope of equilibrium (lifespan, power, emissions, etc), something(s) will suffer at an exponential rate.

 

[Acoustic]

Our mechanical engineering graduate has spoken

Industial placement was something like become James Bond, i.e. SPY Brand A ECU internal coding for Company B

Then uni final year project was something like engine air flow combustion, or was it using fluid-dynamics studies coupled with finite element analysis ???

Wei you not yet expose you secret report and project to me wei ......

 

[Useless]

chin,

no secret project la. since no source for cheap 4age anymore *ahem*:cry_smile: , have to settle for sr20 blacktop into the old celica. got a rollcage already. next would have to sort out the seam welds and chasis strengthening. things are slowly falling into place. just no time to concentrate on so many cars. somehow am more into the handling aspects of the car rather than speed. sorry guys, out of topic.

a very useful thing to check prior to starting to fiddle around a programmable mapping is to determine base points, i.e. static ignition at idle and also fuel pressure. notice that alot of ppl out there aways overlook the fuel pressure.

cheers.

 

[fandango]

hi fandango

from the few posts you made, I am worried you confused yourself between timing and ignition timing...

etc etc etc

we have to think in multiple^multiple dimension, cannot think in one dimension

many people are ignorant of this - hence you often only see people talk about fuel map. they would spent 99% on the fuel map and not border much about ignition map

hope this help, and sorry if I was wrong about you being confused.

Chin, thanks for explaining that. I am clearer now of what ignition timing/timing map means. Like what Speed sed, it will make a lot of difference to power. No wonder just getting an ITC will not go very far, since that is still static, regardless of other sensor inputs.

great discussion guys. sorry if my questions sound like a noobie's, that's because I AM one...:regular_smile:

 

[fandango]

Hmm...let's see...if the biggest gain is to be made via the ignition map, then how will the programmable ECU handle any related impact to the other maps, e.g. fueling (what other maps are there?)? Does the human tuner have to change all the other affected maps one at a time, or does the ECU have some fuzzy logic to help? This is assuming that the programmable unit already has some kind of base maps for the car. What if it doesn't? :retarded:

 

[TauhuTauhu]

fandango, there are only 2 maps in an ecu.
only fuel map and ignition map.

the 'map' is actually juz like a table...a graph

this 2 maps has their own values according to 2 main factors...
called the load sites and speed sites.

speed site is the speed on the engine(according to crank sensor/distributor and such), while load site is the load of the engine (according to TPS, afm/map sensor/hot wire).

whn the signals are accpeted from the sensors telling tht the engine is at certain load sites + speed sites, the ecu will look up the 2 maps (or u can call it tables/graphs) and then apply them on the injectors and ignitors...

other than the load sites and speed sites....factors such as enginetemp, air temp, batt voltage, AFR frm o2 sensor, knocking condition, sudden throttle opening/closing, cranking condition and such will also affect the "map" values.
but the basic fuel map and ignition map are still there. the ecu will only add or deduct the appropriate values from the basic maps to suit the engine condition.


it's not correct to say tht the ignition map is going to affect other map. because the maps are set according to the speed, load and also the small factors. so only speed, load and those small factors will affect the 2 maps.
each map will not affect one another.

it's like u set the fuel map for different speed + load + engine condition correctly with correct AFR. and then u work on the ignition to get the most advance ignition for every speed + load + engine condition juz before pinging/knocking to get the most out of the engine.

people seldom work on ignition mapping simply because fuel mapping is allot easier to be done according to the AFR and they do not bring instant or massive damage to the engine during the tuning process although small mistakes are made like a little bit too rich/lean.

hope this helps :)

 

[Acoustic]

fandango, keep asking....... you have good instincts to questions, people will be glad to answer. I don't know about the others, but I don't consider you newbie, because we all know you online quite a few years already

 

[fandango]

:cyclops: This is interesting. So both maps (it's some kind of lookup table, rite?) are to be set independently then. I suppose different ECU may have different combination of 'small factors'.

How do these 'small factors' interact with the maps then? Is it a case where say, "if voltage = x AND o2 reading = y, then + or - ignition timing by z deg at rpm=4000 and load = a? Or it's just one reading at a time, where say "if water temp = x deg, then increase AFR to xx:1?

Chin, you are too kind.

 

[Acoustic]

Hi fandango

You are right, it's all readings at once. The final is a total of the sum and minus of all big and small factors.

Speaking from MoTeC software and FREEDOM software point of view, there's TWO main maps, then allot allot more other maps, nearly all in 3D, they include air-temp, engine-temp, O2, vehicle speed km/h, gear estimation, etc.

Even ISCV in FREEDOM is 3D mapped and if I didn't remember wrongly, double of it. i.e. ISCV over vehicle speed and TPS........

Don't know this factor I remember correctly or not ....... need cuscostrutbrace to confirm......

I only clearly remember when open ISCV for adjustment, why appear 3D map.... then I pengsan already.... but not yet give up, go to another sub-sub-menu for ISCV and another 3D map appear, then I straight away give up ... .ha ha hah ahh a


Then VVT also another 3D map....

kau kau lah.... allot of maps ....... that's why I said, multiple dimensions all at once.

 

[cuscostrutbrace]

HI

Acoustic..ISCV where got 3D maa..hehe,maybe u enter other map,FREEDOM have six 3D map,that is:-

1.FUEL map = normal la,all ecu 3D nowadays(main map)
2.IGNITION map = also normal(main map)
3.THROTTLE map = Some ecu have,some dont have
4.AIR FUEL RATIO map = Some also have,some also dont have
5.ALTITUDE COMPENSATION map = Most aftermarket dont have,only few
have this map (or feature)
6.VVT map = Also most aftermarket ecu dont have

It also have so many other parameters which would take too many posts to explain here,normally main parameters are water temp and air temp.The ecu calculates its final injection time using multiplication factor,some other ecu's using addition,which adds or substracts to the base injection time,however both ways to produce same results,which is to add or substract fuel.I prefer multiplication though,:regular_smile:

Example:- During cold idle the base injection time 2.5 mS,water temp multiplication factor is 1.8,air temp multiplication factor is 1.5,throttle is 1 hence we get=6.75 mS

Then after warm up,base injection time still same,but water temp factor have drop to 1.1,air dropped to 0.9,throttle is 1,hence we get=2.475 mS,see the final injection time is lower than the base.All the other factors determine the final value and of course all these factors value can be changed accordingly.There is also other factors,but lazy to write,tired..haha

The factors only affects on fuel injection time(i think),ignition is not affected,whats written on the ignition map directly applies to engine,only corrected by knock control.

For ISCV,no map at all but it got 2 menu for controling the idle,one is idling stabilization revision and the other is idle speed control,iscv falls under the latter,which we can set what idle RPM we want according to water temp,and the ecu will play with the ISCV(and some others) to achieve the target RPM.

If what i explain is wrong,sifoo2 please correct:regular_smile:

 

[Acoustic]

Oooooooooooo itu macam..... but what was the thing that day I saw ???? got me to confused, immediately give up one ????

if not 3D, 2D table ar for the ISCV? two of it also ??

 

[Useless]

Chin,
Take a 3d map for example; you will most likely have RPM, throttle angle and ignition advance angle comprising of the respective 3 axes. A 3d map basically helps a tuner on a dyno to pinpoint the relation of two variable towards a constant. Again the scenario above, assuming throttle angle as a fix value at a particular instant, the tuner can adjust either/simultaneously the other two values to suit the required output. Trying to make a simple illustration here.


Fandango,
To further understand map/sensor relations, i suggest u download available softwares e.g. motec/haltech to have a clearer understanding.

Why the OEM ecu is always superior in final product output is because of the response it can produce towards varying factors. Put in other criterias such as stringent air quality legislation, sudden climate changes, varying cam profiles and timing etc. Standalone provides tuners the oppurtunity to squeeze out any potential horses from the engine but sacrifices flexibility in operations. Take a peek into the available maps in a normal daily driving economical car and be amazed of the amount of corelations that exists.

 

[cuscostrutbrace]

2D table according to water temp,called ISCV count value,it's like how much the ISCV will open,and 2D target RPM value depending on water temp also,and RPm feedback control,integral,proportional and derivative,both above and below target RPM goal..and some others..not important since we are more interested in idle speed control here :-)

 

[speedchaser]

Wooo.. haven't been here a few days and so many posts. Might as well chime in into my favourite subject. :)

First thing is I will never compare a standalone with a OEM ECU because the advantages of the OEM had been mentioned countless of times. I believe this topic comes from upping more timing on the Toyota with a standalone and squeezing more power out of it. No offence meant, if reliability is an issue then we should be keeping everything stock standard.

My first 4AG 16V (TVIS) was fired up in 1993 with all the go fast bits like cams, Webers ‘45s etc.. which I’ll not go into and it lasted me all this years with RPMs to 8k everyday (not everytime though). No re-builts or overhauls. That was before standalone was popular. I changed to GZE in 2003 for the sake of changing not because the old engine was bust. That’s what Toyota reliability is to me.

There was a saying way back then, “If a part of the engine needed a 20mm bolt, Honda will put 20mm and Nissan will put a 25mm but Toyota will put a 40mm!” Look at the GZE con-rods and you’ll see what I mean.

As for a standalone, do not confuse 3D maps with overlapping 2D or 3D maps. A 3D map is built upon 2 constants, ie; the RPM vs Load and the value on it is the 3rd which is the variable that constitute a 3D map. Start your excel and built up one and you’ll know what I mean. On the RPM vs Load, at a constant of 3,000 RPM there will be different Load points, that’s 2D and at a constant load point with you can have different RPMs, that’s another one. Intersperse it together and you’ll get your 3D map for RPM vs Load. Do that with RPM vs Ignition and you get another 3D map. Do that with RPM vs Throttle angles and you’ll get another one. Intersperse it together you will have overlapping map points for references.

No offence meant again, a standalone 3D map is a reference to pinpoint a variable against 2 constants and not the other way round.

Take a look at this chart and you'll see what I mean.

http://www.speedchaser.net/misc/rpm%20vs%20load.jpg

 

[Acoustic]

hi guys - don't worry about me .... I know ...... but to make matters interesting, hence the abuse of the keyword 3D :) aahahahhaahaha

 

[cuscostrutbrace]

I think it's assumed 3D because we can see the graph in sort of 3D mode,like what speedchaser attached photo,rather than on one plane,in the ISCV case.

 

[fandango]

Fandango,
.... Take a peek into the available maps in a normal daily driving economical car and be amazed of the amount of corelations that exists.

Use,

I get the picture. What you're really saying is that standalone base maps for any particular car is unlikely to have enough fail-safe compensation as OEMs. OEM ECU would have done probably hundreds of maybe even thousands of simulations and tests before confirming those equations between input variables. Something which an aftermarket tuner may not have the resources or time to emulate. Focusing just on power may result in other drawbacks that may appear over time. :retarded:

So for real-world applications, OEM is likely to be best, unless one is going for purpose-built machines, in which case programmable will be the way to go since the operating parameters will be much narrower and more focused. :shocked:

Then again, I wouldn't learn much if I didn't dabble in a programmable...:regular_smile:

 

[wllim5]

Speed,
Your explaination is good but don't go too deep. Not everyone can take it and understand it so easily. kekekeke

Fan,
There can be a lot of 3D maps. Its just how you wanna set it up.
Even on a very good standalone ecu. Not everytime the maps in there is fully utilised coz it will take too much time. Unless you got a very good resources and do it in a very very fine manner.

It is not to say that aftermarket ECU is not a match with standard ECU but its just the matter of the tuner and the $$$ you have to tune up an ECU. Just an example how many tuner actually go air temp. compensation into full detail, barometric/altitude correction and etc etc.

For a street car is actually harder to tune than a car that is meant for circuit race. Why? Will explain on TTT lah. So lazy to type liau. ahhaaha

Regards,
William