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supraman
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Discussion Starter #1
This is for a single turbo say T67 --
Exactly how much more power can one get using the AEM vs using the stock ECU+VPC+S-AFC.
How different is the ign timing map programmed by a pro-tuner on the AEM Vs The stock ECU ign map?Is the stock ECU able to advance/retard ign timing for a single set up according to knock? :)
 

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-Getting High on KAI-
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Randy, I do not know how much you can benifit from the AEM ( its also a question how good your AEM tuner is )
when buying a AEM/Motec ecu, you can program a lot wider range in your car, its not only for horsepower your getting, your also getting the ECU world on a laptop, where you almost can se everything thats going on in your engine...

Im learning every day from my AEM about my car, logging diff stuff like my pulls trough the gears and so on...
 

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parting out
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the map on the aem can be whatever you want it to be. the stock maps are conservative due to people putting 87 in their cars. they can be as agressive as you want them to be, but be prepared to run race gas all the time.
dan
 

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namahs said:
the map on the aem can be whatever you want it to be. the stock maps are conservative due to people putting 87 in their cars. they can be as agressive as you want them to be, but be prepared to run race gas all the time.
dan
IMHO, the stock maps are pretty agressive (up to 22.5 deg) compared to what most folks are running on the AEM. It seems like most of those on the AEM run significantly less timing. The stock ECU with it's signal processing seems to do a lot better job of knock sensing compared to the amplitude based table approach of the AEM.

Mike
 
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namahs said:
the map on the aem can be whatever you want it to be. the stock maps are conservative due to people putting 87 in their cars. they can be as agressive as you want them to be, but be prepared to run race gas all the time.
dan
WTF? "Why the race gas all the time"?!

Thanks!
 

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Slowpoke said:
WTF? "Why the race gas all the time"?!

Thanks!
It's a timing/boost/octane relationship. Get very agressive with the timing at even low to moderate boost and the octane has to go up. At least, that's what I assume was meant.

Mike
 
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So, low timing versus low octane and the other way around right?

What is the diff with low/high timing then?

Thanks!
 

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Slowpoke said:
So, low timing versus low octane and the other way around right?

What is the diff with low/high timing then?

Thanks!
Assuming you're at the knock threshold, you can supress detonation by raising octane, lowering boost pressure or retarding timing. Cooler intakes and richer AFRs also help but the effect is less. Lowering the compression ratio helps big time but is a *little* tougher to do :)

Remember there are practical limits to how effective each of these is. You're not going to be able to retard timing enough to run 35 psi on 91 octane as an extreme example.

You might want to read some of these links;

http://www.sdsefi.com/tech.html

I'd start with;
http://www.sdsefi.com/techcomb.htm
and
http://www.sdsefi.com/meltdown.htm

There's also a number of other good links off the main tech page (first link).

Mike
 

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This is why many people make such insane numbers from stock ECU'd Supras after going single. They do this without enough octane sometimes are are getting timing retarded as they knock their way to a couple of quick dyno runs. Resetting the ECU and then dynoing is what most people do so it's really easy to do it.
 

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Mike_Austin said:
IMHO, the stock maps are pretty agressive (up to 22.5 deg) compared to what most folks are running on the AEM. It seems like most of those on the AEM run significantly less timing. The stock ECU with it's signal processing seems to do a lot better job of knock sensing compared to the amplitude based table approach of the AEM.

Mike
Or they're knocking and don't realize it. I'd also point out that no one really knows what timing map is in the stock ECU other than staring at a slow speed Tectom display. Those don't datalog do they? If someone has the stock mapping by all means share it. I'd also be interested in someone documenting how th eOEM ECU signal process signals from the knock sensors. So far all I've ever heard in the past is anecdotes about how OEMs process knock signals. No one has been able to document how the Supra EMS does it - by all means share this too please.

One thing you'll gain from a properly tuned AEM is a consistant A/F. Put a W/B on an alphabet soup car and watch the A/F day to day - I'm told it's quite entertaining.:eek:

You'll also gain a great number of other features the piggyback stuff cannot do. I don't feel like detailing them all but a search here will find previous posts.
 
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Mike_Austin said:
Assuming you're at the knock threshold, you can supress detonation by raising octane, lowering boost pressure or retarding timing. Cooler intakes and richer AFRs also help but the effect is less. Lowering the compression ratio helps big time but is a *little* tougher to do :)

Remember there are practical limits to how effective each of these is. You're not going to be able to retard timing enough to run 35 psi on 91 octane as an extreme example.

You might want to read some of these links;

http://www.sdsefi.com/tech.html

I'd start with;
http://www.sdsefi.com/techcomb.htm
and
http://www.sdsefi.com/meltdown.htm

There's also a number of other good links off the main tech page (first link).

Mike
Thank you very much for the great reply, appreciate it!

Is there some kind of thumbrule in order to set and tune the AEM on this whole timing/boost/octane ordeal?

Also, which is better if you concider the longevity/lifetime of your engine; low timing/high boost or high timing/low boost? In other words, which is better for power versus having a safely tuned car?

Once again, thanks Mike!
 
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BLKMGK said:

One thing you'll gain from a properly tuned AEM is a consistant A/F. Put a W/B on an alphabet soup car and watch the A/F day to day - I'm told it's quite entertaining.:eek:

You'll also gain a great number of other features the piggyback stuff cannot do. I don't feel like detailing them all but a search here will find previous posts.
BLKMGK,

Sounds good to hear the A/F dont vary in a day-to- day basis :) I was really worried about that happening and maybe result in blown engine just because the weather goes hot/cold and other suff like humidity...

Also, the other features you talk about; How come there is so very few people using the launch caontrol and ALS with their AEM EMS? Is it hard to get dialed in perhaps, shouldn't tuners like Sean or Justin be able to fix this up?
I mean, the sound from a singled Supra with open WG building more than 1 bar boost off the line is strictly porn :D

Thanks!
 

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I've used the launch control, works fine. Just a 2-step is all. I've not gotten the anti-lag "right" but Justin has posted settings that I'll try. It's a bit noisy to test in the driveway with 4 dogs running around:p

The A/F will be consistant if it's tuned right, the IAT setup is right, and in my case I also use closed loop full time. If it's a little off the closed loop takes care of it :D
 
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BLKMGK,

Sounds good to know there is no problem with your A/Fs :)
I would hate the idea of having someone tune my car and that I would have to do all theese changes afterwards all the time. I just want to be able to set the boost on my EBC and use the right fuel for the boost I'm running, that's it!
No such thing as a hard-to-understand computer hooked up to the car all the time and no differences in A/F ratios and stuff like that :)

I would also love to hear from some people with the anti lag function hooked up and working. Anyone?

Thanks again!
 

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supraman
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Discussion Starter #15
Has anyone dynoed a stock ECU+ piggy back stuff single turbo with A/F perfect with race gas and then swapped the stock ECU for the AEM and done a back to back dyno? Just to see what gain if? can be had with programmable EMS?
It would be awesome to see how the stock ECU controls timing/fuel and knock!! I am not sure about U.S spec cars but Jap-spec ECU cars have apparently more aggressive timing maps to maximise power as 100 octane gas is available freely in Jap! :)
 

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Sooooooo JDM
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randy said:
Has anyone dynoed a stock ECU+ piggy back stuff single turbo with A/F perfect with race gas and then swapped the stock ECU for the AEM and done a back to back dyno? Just to see what gain if? can be had with programmable EMS?
It would be awesome to see how the stock ECU controls timing/fuel and knock!! I am not sure about U.S spec cars but Jap-spec ECU cars have apparently more aggressive timing maps to maximise power as 100 octane gas is available freely in Jap! :)
First off, there is no "Perfect A/F".... Everyone has their own ideas what a conservative/aggressive tune is.

Secondly, the AEM (or any EMS For that matter) will not gain you any power over a stock ECU if it ran identical settings (even if we knew). It's a very simple formula, a given engine @ "X" A/F, with "Y" timing @ "Z" boost will give you a set amount of power. An AEM won't magically pull any more power out of it's ass than a piggyback or stock ECU. That's not why (or shouldn't be why) people buy an EMS. It's not all about "numbers", it's about driveability and making a combo properly perform outside of how Toyota intended. Using the stock ECU and piggybacks is a compromise, period. "But I read that soandso just made 1278 RWHP using a stock ECU and piggback!" Dyno numbers don't tell the whole story. Ignorance is bliss though, if you haven't been on the "other side" then you wouldn't know any better. I concur with Blkmgk's earlier musings about having a WB and watching A/F swings day to day, hot to cold. Very entertaining and downright scary in some cases.

Thirdly, 100 Octane gas.....as you know it...is not freely available in Japan. In Japan, it's rated at the pump by it's Research Octane number or RON. At a pump here in the US, we rate our gas by RON + MON (Motor Octane) divided by 2. It is a blend of two numbers that result in a AKI (Anti Knock Index). There is no direct conversion between the two because of the way it's rated. I traditionally run Sunoco 94 for example, which has a rating of 99 RON. 1 Point below the coveted "JDM" gas :rolleyes: FWIW, our rating system is the more accurate one when it comes to fending off knock.....the whole point to running higher octane gas.


Ryan
 

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supraman
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Discussion Starter #17
Ryan23 said:
First off, there is no "Perfect A/F".... Everyone has their own ideas what a conservative/aggressive tune is.

Secondly, the AEM (or any EMS For that matter) will not gain you any power over a stock ECU if it ran identical settings (even if we knew). It's a very simple formula, a given engine @ "X" A/F, with "Y" timing @ "Z" boost will give you a set amount of power. An AEM won't magically pull any more power out of it's ass than a piggyback or stock ECU. That's not why (or shouldn't be why) people buy an EMS. It's not all about "numbers", it's about driveability and making a combo properly perform outside of how Toyota intended. Using the stock ECU and piggybacks is a compromise, period. "But I read that soandso just made 1278 RWHP using a stock ECU and piggback!" Dyno numbers don't tell the whole story. Ignorance is bliss though, if you haven't been on the "other side" then you wouldn't know any better. I concur with Blkmgk's earlier musings about having a WB and watching A/F swings day to day, hot to cold. Very entertaining and downright scary in some cases.

Thirdly, 100 Octane gas.....as you know it...is not freely available in Japan. In Japan, it's rated at the pump by it's Research Octane number or RON. At a pump here in the US, we rate our gas by RON + MON (Motor Octane) divided by 2. It is a blend of two numbers that result in a AKI (Anti Knock Index). There is no direct conversion between the two because of the way it's rated. I traditionally run Sunoco 94 for example, which has a rating of 99 RON. 1 Point below the coveted "JDM" gas :rolleyes: FWIW, our rating system is the more accurate one when it comes to fending off knock.....the whole point to running higher octane gas.


Ryan
Thanks for clearing that up!!:) Very well said!!:cool:
 

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Heh, what he said! There's no "magic" in an AEM. What you get is CONTROL and DATALOGGING. Two things you do NOT have with piggybacks. Piggybacks "fool" various sensors to try and get the OEM ECU to do what you want. Even the boxes that fiddle outputs after the ECU have their downsides since it's often possible for the OEM ECU to "see" the changes and react to them.

Take the VPC for instance - it's programmed to trick the OEM ECU into thinking that you've still got the OEM MAF installed. It does this with a MAP sensor and IAT sensor. If you go with bigger injectors there's a different "chip" for that. Simple right? Here's what's wrong with that - first the IAT on these things heatsoaks if you mount it where HKS tells you to. Several AEM users have tried to use VPC sensors and reported on this - you need to move it someplace to get an accurate reading. Oh and then hope that HKS didn't realize this and crutch the strategy with regards to the IAT.:eek: Now then, lets say you went to 800cc injectors or whatever the HKS box handle. How does it compensate? It compensates by sending a signal to the ECU that tells it there's LESS air flowing than there would be if it were a chip for 550cc injectors. This fools the ECU into using a shorter injector impulse which just happens to correspond to the right fueling for the bigger injectors. Mustang guys do this ALL the time with MAFs for bigger injectors - they're screwed too and don't realize it. Anyone see the problem with doing this? It's simple when you think about it - timing. Yup, when you get the computer to think there's less flow it will use more aggressive timing maps. Good thing the Toyota EMS has that super duper knock sensing strategy huh?:rolleyes:

That said I've not ever used piggyback stuff as I recognize the shortfalls. I'm not sure what folks do to trim timing or how some of the other boxes work but what I've said above ought to give you some ideas as to the possible pitfalls when you F*ck with the OEM ECU. Piggyback stuff can work, obviously, but it's playing with fire so far as I'm concerned. I wanted more control.

Datalogging - I can and do log data @ 250 samples a second. That's far faster than the OEM ECU spits out data and I can save and graph what I record. I can even plot HP with the data the AEM gathers. Datalogging tells you TONS of things and if you log EGT with A/F, timing, and knock noise you can get a good picture as to what's going on. Hell, I log fuel pressure, IAT, and other things too. There's real power in knowing what your motor is doing and not guess based on what little external indicators you get. It's kind of cool to know what your turbo spools at and not guess BTW. I've heard all sorts of wild claims about how a T78 spools for instance - I think I and other AEM users have disproven them.

A downside to the AEM is it's complexity. When you have all of this control you must actually understand what something does before pushing a button or pulling a lever. If you don't want to take the time to learn about how things work or how to use the AEM then be prepared to pay someone who already knows or stick to piggybacks and pray for the best. Oh and run a W/B O2 with a DISPLAY no matter which way you go! A W/B is a great indicator as to what's going on and while it won't do squat about knock it will show you if you're going lean - which usually leads to knock....

Okay, tired now ;)
 

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BLKMGK said:
Or they're knocking and don't realize it. I'd also point out that no one really knows what timing map is in the stock ECU other than staring at a slow speed Tectom display. Those don't datalog do they? If someone has the stock mapping by all means share it. I'd also be interested in someone documenting how th eOEM ECU signal process signals from the knock sensors. So far all I've ever heard in the past is anecdotes about how OEMs process knock signals. No one has been able to document how the Supra EMS does it - by all means share this too please.

One thing you'll gain from a properly tuned AEM is a consistant A/F. Put a W/B on an alphabet soup car and watch the A/F day to day - I'm told it's quite entertaining.:eek:

You'll also gain a great number of other features the piggyback stuff cannot do. I don't feel like detailing them all but a search here will find previous posts.
While the Techtom is the only route for OBDI cars like mine, OBDII (96-98) can use Palm based apps that offer better update rates. Grant just posted some info on what represents full timing vs rpm using an OBDII app that datalogs. There's also some runs from someone using toluene at various boost levels.
http://www.supraforums.com/forum/showthread.php?s=&threadid=156914

The stock ECU has a pretty good record of saving motors subject to way too much boost for the octane. The idiotic feat of the guy who dynoed HKS twins at 2 bar on 91 octane comes to mind along with all the BPUs running full boost on pump gas.

I took a look through the 93 NCF on mkiv.com and there isn't much info on the knock sensing and timing control although it indicates that the crankshaft position sensor, throttle position, airflow, coolant temp are used in the knock control logic.
http://mkiv.com/specifications/ncf/ncf93/ncf103.jpg

I'm not sure I believe the stock ECU does anything as sophisticated as an FFT to isolate knock although it's possible it could have dedicated DSP logic and do it. Personally I think it probably uses some analog filters to isolate the critical knock frequency range and then measures amplitude. Either way, IMHO, the empirical evidence is pretty strong that it does a better job than the AEM. Not too surprising given that the Toyota engineers designed it specifically for the application.

I've heard of folks running piggybacks seeing varying AFRs but mine are dead stable except for the rapid +/- .5 AFR cycling around 14.7:1 in closed loop that's done intentionally by the ECU for pollutant reduction. Course with the cats gone, it's useless but it should doesn't hurt anything or effect driveability. Under high airflow the ECU runs open loop and it behaves like the AEM without O2 feedback enabled.

I think most folks who see varying AFRs are either modifying their AFRs in the closed loop region (under 4k rpm with low throttle) or tuning after an ECU reset before it completes it's learning. I do neither and my AFRs are dead stable outside of about .4 AFR on long pulls due to the VPC temp issue mentioned in this thread. One of these days, I'll get around to moving it. I run the car rich for safety so having my AFRs only vary from 10.7-11.1 is pretty minor.

The AEM setups have definitely improved a LOT with time. I was very interested when it first was announced but the release delays concearned me and I decided to wait. Especially considering I have an auto, I'm glad I did. Even now, there's just not much incentive to change. Outside of the 3200 stall on my car, it runs as well as it did stock. Starts first time, every time and idles and runs like stock regardless of hot or cold ambient or engine temps. I'd love the datalogging but wonder how often I'd bother connecting a laptop to look at it. In the meantime, the Palm datalogging of revs, boost and AFRs with the FJO is super convenient and a handy check beyond a quick look at the FJO display.

I'm not knocking the AEM. It's an awesome value in a standalone for the money but even as a techie who's also worked hard to understand all the elements of tuning, I'm not sure it's worth the effort. It's definitely not for the folks who don't even understand the basics. In the meantime, I'm still on the stock ECU with all the nice diagnostics it does on the engines and the other subsystems like the ABS.

Mike
 

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silvino said:
This is why many people make such insane numbers from stock ECU'd Supras after going single. They do this without enough octane sometimes are are getting timing retarded as they knock their way to a couple of quick dyno runs. Resetting the ECU and then dynoing is what most people do so it's really easy to do it.
The really sad thing is that they're also often trying to tune their cars during the dyno runs. IMHO, until the stock ECU has a chance to learn it's long term closed loop settings after a reset, it's plain foolish and dangerous trying to tune WOT (open loop).

You can generally spot folks on stock ECUs who run too much boost for the octane. Their dyno graphs are usually really jagged due to the timing oscillating when the ECU senses knock.

That said, I still think the stock ECU does an excellant job of providing optimum timing for the conditions within any reasonable combination of boost and octane. I just don't understand why folks would knowingly yank it's memory to get back timing that was pulled for a reason. I suspect the same folks might just punch more timing into their AEM...sad.

Mike
 
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