LTFT on eManage Blue

[lamcote]

Presumably you could test your theory for removing fuel with the EMB by entering a different injector size by noting your current LTFT,  entering a 5% bigger injector size than you have, then after a few days checking if the LTFT has gone up by 5%?

If so, your theory should work.

[jonbill]

Not sure if you've seen this?
 m http://www.spyderchat.com/forums/showth ... &_k=834io4 m

It seems to suggest you can fix this squabbling by adjusting the air map.

[shnazzle]

True. Now I wish I didn't sell the 2zz injectors

[lamcote]

What would you be doing with the 2zz injectors?

[shnazzle]

Never mind. Was multitasking yesterday and not thinking haha

[lamcote]

Oh, I thought you'd spotted something in the post jonbill had linked to (which looks excellent!)

[shnazzle]

Oh, I thought you'd spotted something in the post jonbill had linked to (which looks excellent!)

I didn't see that actually but I've had that bookmarked for a good while as it really gave a good start point for emanage on the 2.
The problem is that the images that his example/tutorial are around are missing and it's aimed towards boosted cars.

Here's a link I've found a bit more relevant. I intend to do this once I can be arsed to hook up a wideband.
 m http://www.newcelica.org/forums/showthread.php?t=264746 m

Basically he's saying that it is possible to keep the tune as long as you over-compensate in the cells where LTFT is adding/subtracting fuel. The part I don't get is; do I always want to aim for 14.7 in closed loop areas like the ECU does?
Would I just be changing values to do exactly what the stock ECU already does? I wouldn't really be gaining anything if I "tuned out" the LTFT. I would just be doing what the ECU already does automatically.

[lamcote]

My thoughts about what he is saying are :

1. Yes you would want to aim for 14.7:1 in closed loop, ANYTHING other than 14.7 at any point in closed loop is likely to result in the standard ECU undoing your open loop mapping (by introducing a LTFT)
2. Yes you are doing exactly the same as the standard ECU would do, but there is a good reason for that;
3. If YOU tune closed loop to keep the AFR at 14.7, thereby preventing the standard ECU from having to do it, the standard ECU won't then create a LTFT (so it can't then use the  LTFT to undo your open loop performance map) so this should mean your remap isn't destroyed
4. That's the theory, will it work? I don't know.

I would say however, it would seem to me to be FAR easier just to make sure you ONLY remap fueling in open loop in the first place. I think I may have said this once or twice before.

[stupink]

This whole thread hurts my brain!!  

I've tried to read and catch up but it's not happening.. but I am curious..

Could you give a brief summary in one place to make it easier to wrap my head around (and others who may be thinking the same..)

A. What engine/mods are on the vehicle..
B. What are the "problems"/symptoms you're trying to fix.

I know the informations all there, but its scattered about so much I can't gather it all together clearly  s:) s:)

[shnazzle]

Ah. Yes I see the thinking.
So basically what you're saying is that it uses closed loop as a means to determine fueling in open loop?
So if closed loop is sorted to 14.7 in part throttle conditions, then the ecu (theoretically) wouldn't see th need to interpolate those same trims to open loop areas.

I like the theory...
Now to test it. Just need a wideband  s:) s:)

[lamcote]

Yes that's exactly how I am interpreting it.

But as I say, if your mapper knows what they are doing and avoids changing any fueling in closed loop in the first place,  that should be job done.

[lamcote]

Stupink, what exactly are you asking? Are you asking what mods shnazzle has on his car or are you asking more generally about the issue of open/closed loop and fuel trims?

[stupink]

Shnazzles' car,  I can't quite put together what the setup is, or what the problem is..  too much information spread over too many posts/threads plus a busy life on my part  s:) s:)

[shnazzle]

There are no problems with my car Stu  s:) s:) ... That I know of.

The thread is about piggyback ECUs and how to tune the closed loop area.

I.e. My emanage has been mapped by Noble and drives more aggressively when I reset the ecu, indicating that the stock ECU is using LTFT to basically undo what Noble has done in some ranges.
It's not until WOT that I notice any gains over a stock 2.

So the question is, can a piggyback be tuned to provide some improved performance where you want it without the stock ECU undoing your work?

So if I want to run a bit leaner during cruise for a bit more efficiency, can I do this? Or is the stock ECU already well on it?
It may be well possible that I tune it to 14.7:1 at cruising speed but Toyota has found that 15:1 is actually better for efficiency.
Inversely if I want to run 12.5:1 at WOT, will the stock ECU also modify the closed loop table so that it goes back up to 13 or whatever it is stock

[stupink]

Ahhh.. I see.. that is probably why I was struggling to suss out what the problem was then haha!!

Trust stock ecu for part throttle stuff totally imo, logic behind that is if you want more power you push more pedal.. the limiting factor on part throttle to power isn't fueling or ignition its the fact theres a hoofing big bit of metal blocking the inlet, so theres no real point (unless mods you've done have ruined running) to adjusting anything other than full throttle  s:) s:)

I tried to reply to some of your other points, but I've got a bit of a head cold and I just confused myself even haha..  but basically you wont want to run leaner than stock ecu, and if you change it, it will reset to 14.7 anyway, if you want more efficiency, change the efficiency of the engine mechanically, so better cams/inlet/exhaust etc  s:) s:)

[shnazzle]

I definitely see the "issue"  with the part-throttle scenario. And I don't expect much in the way of performance increases.

What I do find interesting is the prospect of making the car more aimed at a flatter torque curve and less aimed at efficiency and emissions.

Can't help but wonder if I'm getting all out of the stock setup that it has to offer. Bearing in mind that it is designed to be stable across tons of different real world scenarios. But the car is never going to California or Norway so, can I not just get it mapped to its best for the situation it is in?

[stupink]

Ìn theory.. and its a big in theory, Toyota already did map it best for here..  inlet temperatures etc are taken into account during the running, so the ajustments made by the ecu to compensate should be pretty good.  but I agree you could probably sway away from efficiency and emmissions more.. Just not sure it would make enough difference to make a noticeable difference... if you want flat torque... add a turbo  s:D s:D    mines within about 20lflb from something like 3800rpm to the rev limiter.. i'd need an iron to make it flatter  s:D s:D   but I apreceate that's not what this is about.. I just like turbos.  s:D s:D

[shnazzle]

You know I had no idea you like turbos... Who knew..  s:) s:)  hehehe

Temps etc are taken into consideration but via calculations. General calculations.
Maybe I don't have enough faith in Toyota's fine work in making these ECUs auto-calibrate. Which is furiously arrogant of me; doubting a couple dozen highly trained engineers with a seemingly unlimited budget.
Hey ho.
 s:) s:)  

Yeah the turbo thing definitely plays on ye olde nugget. But so does built 1zz and 2zz and built 2zz...and turbo 2zz....and 1.8t....

[stupink]

I think it comes down to whether you trust the airflow meter or not.. its more of an Air Mass/flow.. so if its doing its job, the engine knows what airs going in accurately regardless of temperature. the operating temp of the engines going to be similar so I don't think much else changes other than air density?   I feel sure they dyno tested the engine at different inlet temperatures to map the ignition rather than guessing. or maybe now i'm being naïve!

[lamcote]

Personally I think there are five reasons why it is potentially worthwhile remapping a naturally aspirated engine:

1. Toyota has mapped the engine to run on 91 octane fuel. If you remap to 95 octane or even higher, there must be gains to be had, mainly from ignition timing changes?
2. Mass production inevitably has some tolerances built into it. Toyota must map their engines to take account of the odd engine coming off the production line with all the worst case tolerances and therefore the lowest power potential. So their mapping must be done towards the lowest power output likely. The chances are your engine will be better than that worst case so there are gains to be had from a remap.
3. Toyota must assume that some people won't bother servicing their engine very often or very well. To avoid problems they will use a very conservative tune to minimise stress in all the engine components, again there are gains to be had. Any engine produces most power at AFRs c.13.5:1, however Toyota use full load AFRs around 12:1 because the overly rich mixture cools the combustion process and protects the Cat from overheating under prolonged load. (If they didn't do that and some bloke living in the Alps who spends all his time thrashing up long 1 in 4 hills finishes up burning his Cat out within 6 months, it's Toyota that carry the can.) Reducing stress on the engine maximises reliability but that inevitably means you aren't maximising power. Toyota, understandably, aren't prepared to take risks with reliability, if you are prepared to risk reducing reliability (from Toyota's very high standard), you should be able to get more power. It's all about balancing risk and your personal attitude to that risk, and having an engine set up to match your own usage scenario. (Of course if you do actually maintain your engine correctly you should get the best of both worlds by maximising power while still getting excellent reliability.)
4. Toyota have mapped the 1zz for maximum economy, not power. If you've watched Formula 1 you will have seen there can be a big difference between power and economy engine maps even when they were running naturally aspirated engines.
5. If you have installed any engine mods, a remap will get the best out of them, if it's done properly.

Overall there must be potential for noticeable gains from a remap, even in a totally standard engine, never mind a modified one. This is why it's such a shame that your remap can finish up being undone.

I'm quite certain that if Toyota's mapping engineers had exactly the same goals as shnazzle, the 1zz would have been a very different engine, even if the only thing that changed was the software mapping.

By the way I totally agree with the point about only needing the power towards full throttle. Maximum low end and mid range power is no different to top end power in that it's still only achieved at full throttle. This really does reinforce the point that remapping fuel for power shouldn't (and doesn't need to) be done anywhere in closed loop. This would then avoid any need to mess about trying to hold on to the map you have paid for. (Of course, things probably get a bit more complicated when big injectors and boost are involved.)

[shnazzle]

Well those 5 points pretty much sum up the "why" for this post  s:) s:)  Spot on.

To bring this home to me;
Mods are markiii pipe and K&N filter, decat manifold and TTE exhaust and emanage to support changes with injector and ignition control.
The current map has fueling changes only in the open loop areas (over 50% throttle only) and timing changes seemingly aimed at freeing up some power (using 97 ron fuel) in low-load areas and also high-load/high-rpm.
The airflow has also been slightly adjusted upwards using the dials on the front of the unit. When turning down the airflow increase in the idle <2000 rpm range, idle begins to stumble as it did before I had the emanage.

So;
1) The car was mapped for anything from low to higher RON fuels with timing being conservative to satisfy points 2 and 3
2) The extra fueling and timing advancing does suggest that Noble thought the same and found areas on the dyno where the car would easily and reliably tolerate some more power
3) Don't have wideband so can't verify the fueling conditions. But as the EMB doesn't allow for leaning out fueling there's only one way to go. So if Toyota has chosen 12:1, there's nothing the EMB can do about it. So any power I could squeeze out from going to 13.5 (assuming I service the car as I do), is out of the question unless I go standalone (or EMU?). All power Noble has managed to extract (allegedly) is brought in through advancing the timing. Granted some of the timing advancing will be because the fueling was increased.
4) Point used in above
5) My mods are similar to Dave's car, where the EMB was mapped, but the engine is not the same and the mods aren't identical.

So I basically need to get my self kitted out with a wideband and a private road at the very least and see if I'm losing out on some potential power. Also, I could do with making sure that in the closed loop areas, I change the map to fuel to 14.7:1 so that the ECU does as little as possible. As per the CElica thread on LTFT.
If I manage to tune out LTFT changes, there;s a good chance that the ECU will think that there's nothing to change in the open loop areas.

Sound about right?

[lamcote]

I would agree with pretty much all of that. The only comment I would make is that I strongly suspect (but don't know for sure) that you can still be in closed loop well past 50% throttle, so you may well have quite a bit of closed loop fuel mapping that will cause you problems. Presumably that's why you eventually experience the power reduction after a reset that you have mentioned?

[shnazzle]

I would agree with pretty much all of that. The only comment I would make is that I strongly suspect (but don't know for sure) that you can still be in closed loop well past 50% throttle, so you may well have quite a bit of closed loop fuel mapping that will cause you problems. Presumably that's why you eventually experience the power reduction after a reset that you have mentioned?

Yes I thought the same. I think we agreed somewhere else that there's a hell of a lot more to closed/open loop than just load. I'll log my morning run in the 2 tomorrow and make sure i;m logging open/closed loop. Maybe we can come to some kind of understanding of when it goes into each.

Wouild be good to put it alongside an emanage log as well. So I'll monitor both

[lamcote]

That would be great, I would love to see the logs, I can't quite work out what data you can get and how it's presented so seeing some would be really interesting.

[shnazzle]

Torque Pro can produce some pretty spiffing charts and data.
I usually monitor:
- LTFT
- STFT (all banks)
- Fuel Rate
- IAT
- MAF reading (translated from voltage into volume)
- Timing
- rpm
- Fuel state (open/closed loop)
- Coolant temperature
- Throttle position
- O2 sensor voltages (all 3, particularly interested in pre and post cat to get cat efficiency)

And now on emanage
- rpm
- throttle position
- FUeling (stock ecu, EMB addition and total)
- timing (stock ecu, emb addition and total)
- airflow changes

What I'll do is start the EMB log and then OBD2 log, and then rev the engine to 3k-ish 3 times so that I can see where the logs should sync up.