Programmable ECU on 20V

[Useless]

fandango,

i have always been a purveyor of piggybacks. the convenience and ability to produce satisfactory outputs with todays advance piggybacks is a plus point for your amateur car tuning enthusiasts. i am convinced that with the correct setup, these latest piggybacks are able to provide a more satisfactory result for a daily driven performance car; as compared to standalone.

about the limitations of the oem ecu to accept modified signal depends on the generation of which the ecu firmware was produced. it all depends on how "tough" the rules and conditions of the codes have to be met upon input/output. but with the ability to perform lambda feedback correction is a great disadvantage to prevent check engine light occurance. that itself is a very huge pluspoint.

i was able to run very excessive and stupid ignition figures on euro2 standard ecus without any check engine light. i strongly think that that lambda has a greater precedence for that genre ecus. many ppl have succeeded with running excessive mods with modern day standalones. i think their notion of going piggyback is because their monsters are daily driven and dont want it to be a bitch to drive in traffic :P

ITC have intervals of 800, 2400, 4000, 5000 and 7200 rpm with interpolated values in between. but i dont know how much does the knob actually adds to advances/retards. all i know is that it works and its pretty simple to operate :P

just my poor 2 cents,
useless

 

[S.W.Yap]

ATW hp is about 20% losses for FF manual car and 25% losses for FR manual,
I have seen Altezza dyno at 155whp and EP3 at 160whp(both manual gb).

 

[fandango]

.... about the limitations of the oem ecu to accept modified signal depends on the generation of which the ecu firmware was produced. it all depends on how "tough" the rules and conditions of the codes have to be met upon input/output. but with the ability to perform lambda feedback correction is a great disadvantage to prevent check engine light occurance. that itself is a very huge pluspoint.

Don't quite follow you on the lambda part. Maybe you meant a great "advantage"? So are you saying that if I were to get a piggyback, I should also install a wideband lambda sensor to "fool" the oem ecu?

By the way, would you mind sending me a PM on what you think are decent piggyback makes?

 

[Useless]

fandango,

sorry my bad. it should be "advantage" and not disadvantage as stated earlier :P surfing zth during office hours is a risky affair. haha. pls dont mind my typos.

due to the coding of ecus used on newer cars, we are faced with a tighter tolerance for emission output during close and also open loop operating conditions. hence there are some piggybacks out there that can manipulate the feedback o2 signal to the ecu. to my understanding, the lambda curve (narrow band) has a strong position at lambda=1, but these piggybacks can shift the position to lambda=0.9 for example; so now the car close loop operation can be at 0.9 instead of 1. this is to cater for modern cars which try to maintain a very huge close loop window for virtually all engine operating conditions. however, there are limitations to those who want to tune the lambda.

the narrowband is surprisingly sufficient if u plan to run mild mods. coupled with a egt sensor+gauge it is good enough to counter check the readings.

but do take note of how each manufacturer code their ecus. different makes react differently when a piggyback is employed.

just my poor 2 cents,
useless

 

[fandango]

Went to check out a certain piggyback tuner last week. Saw some nifty continentals including a really hot looking Integra. Now I am really tempted to have a go at it...:regular_smile:

 

[Useless]

fandango,

did try to pm u but ur mailbox is full.
mind to share ur experience of ur tour-de-piggyback lastweek?

pls do check with other toyota modders and their experience with piggybacks. i gather that there are problems with introducing fuel map changes. But i think that the ignition changes should not be a problem. but then again i might be wrong.


sidetrack abit. i am puzzled on how we (i too) can conclude a percentage of losses when taking atw dyno reading? do we really know how the original factory spec dyno was performed? (i dont)...
on a thinking note, are the bases/condition of the local modders cars during these dyno tests the same? so is it correct to introduce a standard correction factor to all ff cars? i think we should all stick to atw readings and not try to convert them :P after all, that is what is being put to the ground.

just my poor 2 cents,
useless

 

[fandango]

Use,

I've cleared my inbox, please try again.

Well, this tuner showed me a few dyno charts, including a few for Toyotas. Looked impressive. One was a lumpy curve with high cams, and then it had the dips leveled and overall curve extended upwards with the piggy.

I forgot to ask him: if the timing map was so called optimised, what will happen if the engine encounters a condition that requires retardation, e.g. water temp goes up, or bad fuel quality? The oem ECU should be trying to retard timing, but will the piggyback let it? If not, what will happen?

I see your point about fueling being possibly problematic...no doubt the original fuel map had lots of other correction factors tied in...trying to fool it may result in "limp" mode...

 

[samuelccy]

bro, I've got an offer for E-manage include installation n tuning .. cost me RM1.5k .. is it a good price or can b lower

 

[S.W.Yap]

bro, I've got an offer for E-manage include installation n tuning .. cost me RM1.5k .. is it a good price or can b lower

If it's include tuning on ignition timing as well , I think it's a good deal.
I got my few weeks back at 1.6K.

 

[fandango]

Another thing about piggybacks, they all seem to have different map resolution (load-y, rpm-x). For example, e-manage ultimate has 16x16, fcon sz has 16x24. So by default, does this mean the fcon sz is better? It should cost more definitely...tuner also has to do more work...16x16=256 variables, 16x24 = 384 variables! that an additional 128 variables for the tuner to figure out!

I wonder what resolution unichip has...

 

[Useless]

fandango,

haha. I thought u disappeared. Please wait awhile for me to pm u. i saved the msg somewhere. need to look for it.

btw, what ecu are u running? do u have some specs?

i think the minimum one should go for is 16 square resolution. from my experience, for daily driving with the ocassional spirited driving, meddling with the mid range would give the most feel. coupled with playing the cams, optimizing the power band to one's driving style is highly achievable. you would be surprised to see that eventhough having more than 16 square resolution, it will have somewhat similar regions with the 16 square changed values. then there is also the interpolation resolution which exist between surrounding cells. but that would be to technical and dwelling into firmware development. lets not get there.

as again, piggyback capabilities always fall back on the embedded values within the fuel maps on the ecu. e.g. i did try running ultra lean on my car (4g91) with safc and itc before. no error code. was practically pushing to the limit of lean fueling and high ignition timing from low to mid range. surprised that there was no error code or check engine light. fuel consumption was better (obviously) but the risk of running lean did crack the coolant rubber stopper, small problem. other than that, no knock at normal city driving conditions. i dont know how far the toyota ones can be pushed with a piggyback before it switches itself to run on a different map. hence, my conclusion is that the my mitsu ecu is "flexibly dumb".

best way is to always rechip the fuel map or to re-flash the fuel map. but i havent seen it being done on small cc cars. too expensive for low level enthusiasts.

maybe the cheapest way to make instant changes to the fuel map is to add a variable resistor to the absolute pressure sensor. old-skool style. haha. but i dont know how many 80s-90s genre ecu will react to that. changing altitude pressure readings can alter fueling.

cheers

 

[fandango]

Please send me your recommendations.

I have not installed any piggy back yet...still searching for more actual user experiences on each type.

I just found the resolution for Unichip - its 12 load x 17 rpm. so:

1. Unichip - 12x17
2. emanage ultimate - 16x16
3. fcon sz - 16x24
4. Haltech interceptor - 16x16
5. SMT?
6. ?

It would appear that the interceptor does not handle close loop operation. That might cause higher fuel consumption during cruising. I read that Unichip handles closed loop.

"you would be surprised to see that eventhough having more than 16 square resolution, it will have somewhat similar regions with the 16 square changed values."

so the benefit of higher res maps is not readily noticeable, esp for lightly modded cars? do you consider this to be lightly modded:

1. Metal gasket (1.2mm - 0.8mm)
2. Shaved head (0.5mm?)
3. Balanced crank and rods
4. Aftermarket flywheel
5. Adjustable fuel pressure regulator
6. Stock cams and pulleys (intake vvt only)

will consumption improve if I install a wideband lambda sensor with a compatible piggyback? Or it's only good for a standalaone?

 

[fandango]

Here is some interesting info on piggybacks that I managed to dredge up from a celica forum in the US. The email was written by a gm of a piggyback ecu maker:

Summary by the original post-er:

Basically the chip must be tuned to not do too much in closed loop mode. In closed loop, the car should be tuned to just level out what needs to be leveled out within OEM specs (such as adding fuel at low RPM for a CAI). If you are driving around in closed loop, that means you are at low engine load, and by definition not asking the engine to make much power... so they leave closed loop operation MOSTLY up to the stock ECU. The stock ECU will not "learn" anything in closed loop because they are not changing anything drastic fot it to learn while in closed loop. When the car enters open loop (ie. when you get on the gas and put the engine under more load) they are free to tune any way they want for max gains because the stock ECU is out of the picture in open loop. People who think piggybacks don't work probably tried to tune them too heavily in closed loop, where you wouldn't gain much by agressive tuning anyway, and the stock ECU saw those drastic changes and took action on them. Here is the email...

------------------------------------------------------------------------------------

The problem, I think, is people don't understand the operational areas that are closed loop and those that are open loop. Closed loop is essentially when you're just cruising... there is no requirement to make power in closed loop. Rather, closed loop is
about good mileage and emissions. Closed loop can and does occur at ANY rpm and is defined by load... for all practical purposes on a normally aspirated engine you can take load as how far are you depressing the gas pedal. Regardless of rpm, if you're not getting on it, the engine's in closed loop. Regardless of rpm, if you are in it, the engine's in open loop... i.e. at full throttle and 2,000 rpm the engine is in open loop, but at that same rpm when you lift the throttle, you're in closed loop. At 20% throttle and 7,000 rpm, the engine is in closed loop, but as soon as you push the pedal down, you're in open loop. Think of a spread sheet with the vertical axis labeled rpm and the horizontal labeled load; every point your engine operates at is defined by some rpm and some load. However, any rpm can exist at any load (a single row in that spread sheet) and any load
can exist at any rpm (a single column). Open loop is essentially the right quarter of the chart (high load, all rpm) while everything else is closed loop. If you follow that logic through, there is no reason to look for power gains in closed loop... by definition, you're not asking the engine to make power. Your foot is
asking the engine to be efficient not make power. There is no value to making power at 50% throttle... but don't confuse that with 50% rpm because the two have nothing to do with each other and are frequently confused. Without spending a lot of money, heavily modifying the car, and getting a guaranteed bust on any emissions test, there is no way to make more power in closed loop because it is a closed solution around 14.7 - 1 A/F ratio as mandated by the federal government. That's where all the learning occurs, and the only place it can learn. The problem comes when you make "coarse" adjustments to the car by adding
something like a CAI to the car. Virtually all CAI's make power not by flowing more air, but by changing the field conditions in the vicinity of the sensor... they fool the car into injecting less fuel, which is generally the correct solution for virtually all
production cars in an essentially stock condition. Unfortunately, air's response isn't linear so what might be fine a 5,000 rpm
absolutely isn't fine at 2,500 rpm and vice versa. The result is most CAI's do produce a power gain... over part of the rpm band (where the coarse correction is proper). Most also produce a power loss over other parts of the rpm band (where it isn't). The biggest problems, however, is that CAI's and other bolt on components make changes only in relation to rpm and have no capability to change with respect to load. That means they make changes in closed loop WHERE THOSE CHANGES CAN BE DETECTED AND CORRECTED BY THE OEM ECU. Those corrections - known as fuel trims - are what are commonly known as "learning."
The *piggyback* works differently... we don't make coarse corrections. Rather we have individual data points (over 53,000) which correspond to both a rpm and a load at which we make precise corrections. If we make a series of changes in open loop, that's the only place they're made... they aren't occurring in closed loop, so the stock ECU can't see them, so it doesn't ever realize it should learn. That isn't to say we can't make changes in closed loop, we can. However, those changes are always back to the desired 14.7 A/F ratio because that's the only logical solution when you're loping around town. With precision electronic control, we can make both a smoother running and efficient engine (in closed loop) and maximum power (in open loop). That's what I'm talking about when I say we can keep the stock ECU happy. If the OEM ECU is learning because of a modification on the car, we can correct the A/F ratio so the OEM ECU doesn't see the change and doesn't make any corrections.

Conclusion? Hmm...

 

[LoWPrOfiLe]

Hey Guys.. Interesting discussion here...
I humbly believe that stock ECU's can never be replaced by any standalone ECU's. Having said this, I would also like to stress that car manufacturers spend millions on R&D with countless number of hrs getting the optimum a/f and timing vs coolant, air, battery volt and yadda yadda yadda...BUT after mods are done it would not be the same situation. I would also say that generally, stock ECU's are developed to be fuel efficient and not compromising the emissions test with conservative timing hence restricting potential horses.

I'm not FOR standalone EMS but I feel that if the few criterias are met ($$$$ not a prob, mods where the engine needs more fuel... higher boost... cams... ITBs... yadda yadda yadda, and finally a good knowledgable workshop which would not slaughter you) Go for it..

Having said that, Piggybacks are also usable up to a certain extent and it would be up to the owner and workshop to advice if its sufficient enough for the engine to be safe and unleashing the full potential of the already done modifications.

A simple example would be recondition cars from Japan say ermm... a EvO 7?
I'm not too sure what the octane level is there...anyone?.. we're pumping 97 here. Since the discussion of blowing engines due to map vs correction map..I again humbly ask u, is the weather and climate similar to Malaysia's? I doubt so. I'm only Assuming that our Octane levels are higher(comparing to the States, 92 there) enabling us to make full use of it and running higher timing curves that is of course if we have a programmable EMS. Its how much experience and knowledge the workshop has, to play with the variables.

Having said all these, you can only apply so much (experience & equipment) when tuning on the road. Tuners would only be able to tune maybe ...65 % to 80% out of the full safe potential of the car. Dyno tuning is a necessity and even choosing the right dyno's to tune is Important.

I'm also gonna go off topic abit by saying this, A good tuner would not tune above the engine's threshold and limit although he can. However good a tuner(since not all are his/her customers), certain unseen and only assumable variables like stock internals not meant to take that type of horses.. bad condition engines would be his/her biggest challenge.

I think i've ramble too much.. Good night and happy modding!!:regular_smile:

 

[Useless]

fandango,

wil reply shortly, stuck with work.

the gm of the piggyback manufacturer did not mention anything on short term/long term fuel trim/adaptation, open/close loop trigger conditions, etc...interestingly diagreeable?

rgds
useless

 

[fandango]

I think he is saying that the adaptation wont happen since the piggyback is only intercepting signals during open loop. His contention is that the ecu will only adapt/learn during close loop. Because during open loop the ecu will still fall back on lookup tables for the appropriate values, and if the piggy intercepts those signals and sends its own back to the sensors, then the car will run according to the parameters of the piggy.

This is all fine if the ecu will revert to close loop if an error code pops up, meaning the piggy will not interfere. So what if an erro code pops up during open loop operation that requires fuel trim or timing retardation? Will the piggy recognise this and let the ecu take over? :retarded: If not, will the engine go kaboom??:shocked:

 

[Useless]

fandango,

from my personal experience, the piggyback does not know when it is open/close loop as of the ecu operations. most of the piggybacks out there are upstream modificators in the control system. i do get instant response if i enrich maximum fuel or retard maximum ignition on several systems i have tried. and these were done at sub 4000 rpm range.

i believe why we cant feel much changes in close loop is because the tolerance till error code is quite huge. and the range of correction is somewhat large for a particular operating condition.

i think that ecu will continue to 'learn" be it in open/close loop. just that the "amount of things being input" differs. but than again i might be wrong.

if there is an repeatable errorneous log detected by the engine ecu, it will revert to an open loop.

"So what if an erro code pops up during open loop operation that requires fuel trim or timing retardation? Will the piggy recognise this and let the ecu take over? :retarded: If not, will the engine go kaboom??:shocked:"

if i gathered correctly, there are lesser fuel trim changes in open loop as compared to close loop. ecu switches maps depending on load and other factors. timing retardation is determined by knock sensor in open loop. and the final part, piggyback cannot recognise anything; its just a dummy inserted to perform addition/subtraction between sensor and ecu. yes, engines do kaboom even with piggybacks installed.

"so the benefit of higher res maps is not readily noticeable, esp for lightly modded cars? do you consider this to be lightly modded:

1. Metal gasket (1.2mm - 0.8mm)
2. Shaved head (0.5mm?)
3. Balanced crank and rods
4. Aftermarket flywheel
5. Adjustable fuel pressure regulator
6. Stock cams and pulleys (intake vvt only)

will consumption improve if I install a wideband lambda sensor with a compatible piggyback? Or it's only good for a standalaone?"

i think ur mods are light. an adjustable fuel pressure regulator is ur greatest safety tool. generally, raise the entire fuel curve up when CR is increased, then optimizing fueling with piggyback is the easier path.

narrow band lambda is built for the ecu to see 14.7. wideband informs about upstream exhaust gas mixture. i cannot see how can consumption be significantly improved when narrow vs wide is applied; given that both are of the same condition. consumption is governed by the obedience of the right foot, engine specs, engine condition, etc. WB is used with standalones because its the only thing to tune with easily.

at this point after re-re-re-re-reading the email u posted, i think what he tried to say is that piggybacks can alter both open and close loop conditions. "With precision electronic control, we can make both a smoother running and efficient engine (in closed loop) and maximum power (in open loop)"

p/s- i think things are getting very subjective already. will try hard to revert back to the original topic. hehe.:_:

rgds
useless

 

[fandango]

hehey dude - thanks for your post. I needed to understand that a little better. So far I only know of one other fellow Toyotarian that has installed a piggyback. haven't got a chance to interview him or drive his car yet...:regular_smile:

We should catch up one of these days.

 

[Useless]

It would be beneficial if ppl who have used early generation types of piggybacks (eg safc 5 button, safc blue screen, apexi itc, smt advance, unichip, etc) with success on the 4age generation engines would kindly share their experiences in this thread. I am sure that many have done it before.

Cheers,
Useless

 

[foolat]

got a newbie question to ask... I was reading on bill sherwood's place that the 4age has no mechanical advance for the distributor...

In that case, why have a distributor in the 4age 20v at all? I'm a bit confused... since 4age 20v ecu controls the advance, why have distributor?