Why not use the AEM F/IC for boost? - Tuning Forum
Forum Post / Reply
You must log in before you can post or reply to messages.
After doing a bit of reading the last 2 days on this product, I'm a bit confused as to why nobody has either brought it up or even tried to run it on a J-body.
It runs in parallel with the stock ECU... much like the S-AFC. It intercepts a signal, adds or subtracts to it, and sends it to the injectors/spark plugs.
It can control spark and fuel, but is limited by the stock PCM. It can only add or subtract to the stock PCM's limits... (i.e rev limiter, etc)
Of course, we have HPT so we can do something nifty like tell the PCM our rev limiter is 8500 rpm.....
The software for the AEM has 27 x 17 charts that are Scaleable... you want the charts to go from 3000 rpm to 8500 rpm? Set them up yourself. Both for fueling and spark retard.
The system has a built in 40 psia MAP sensor that reads atmospheric + 25 psi of boost.
It can add or subtract up to 100% injector duty cycle, and can only retard timing. (No big deal since timing can be added with HPT)
If you zero out cells they make no changes to the stock pcm. Since it works in tandem, if your pcm sees knock it will pull timing and the AEM unit will go along with it. If it wants to go stoich during closed loop the AEM will work with it. Anything you setup in the pcm will be followed by the AEM unit, and will be added/subtracted to only where you make +/- modifications above zero.
This is like a very advanced S-AFC (to dummy it down)... only it reads boost and can work with timing. It has its own injector driver box that can run high or low impedance injectors.
Looking at all that... my question is... why has nobody brought this up or tried to use one? It seems like it's truly feasible to use it for controlling fuel and timing in boost and have it do nothing below 0 psi boost and let the stock PCM do its regular job.
Comments or thoughts would be awesome.
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
Basically because it's expensive, and iirc, it's still a pretty new system.
I know a lot of the 2.2 Cobalt guys were talking about using it on their cars because of their dreaded e16 ecm. I guess we're just too cheap to do it.
For most of us, spending $800 on proper tuning equipment (HPT + wideband and install costs) and then adding another few hundred is just too much when a good tune can be had for our power levels with the J-platform ecms.
There is no way for a peripheral device to advance spark timing if it bases it's calculations on a current spark signal. The only way it could advance timing over a stock tune, is if it completely ignores the stock tune or guestimates from a previous known spark event. I really don't understand why you guys like to complicate things more than they need to be. What's so difficult about going to a standalone?
I have no signiture
Whalesac wrote:There is no way for a peripheral device to advance spark timing if it bases it's calculations on a current spark signal. The only way it could advance timing over a stock tune, is if it completely ignores the stock tune or guestimates from a previous known spark event. I really don't understand why you guys like to complicate things more than they need to be. What's so difficult about going to a standalone?
I think he understood that it can't advance it, but for a boosted motor you are not goiong to advance over the stock tables anways.
I see it being a plus because it is cheaper, less to hook up. Standalone is more costly, harder to hookup and usually requires more tuning. Since you can start off the stock tables it will be less tuning.
FU Tuning
^^^^^ Setting up a standalone isn't difficult in the least, just time consuming. I know the different megasquirt softwares (Megatune, MSExtra, etc.) have algorithms to set a base tune for the engine, so I'm sure higher end products like the TEC3 would have as well. Plus, if you are really serious about tuning, a standalone will allow for far more accurate timing calculations if used in conjunction with with reluctors that have more than 7 notches (or teeth). 60 degrees of crank rotation between notches means a great deal of uncertainty in spark timing during periods of acceleration.
I did just now noticed Chris said...
SweetnessGT wrote:
It can add or subtract up to 100% injector duty cycle, and can only retard timing. (No big deal since timing can be added with HPT)
...but I don't really understand why you say that's no big deal. Do you plan to just set all 100% TPS values to like 32 degree advance and dial back from there or something? What about non-full throttle events? How will you handle mid to high RPM and low map values (or low map to high map conditions like off-cruise spool-up) when the PCM dials in via TPS and the AEM uses MAP. It just sounds like a more convoluted mess than going with a full standalone.
I guess I understand the appeal, though, if you already spent the $650 on HPTuners and don't want to feel like you wasted your money by ditching it for a standalone. To each their own I guess.
I have no signiture
Quote:
Setting up a standalone isn't difficult in the least, just time consuming
That's what I'm talking about.
As for the timing I do not see you needing more timing on a boosted motor than a stock file already gives. I have nto even added timing to my N/A 2.4. If one was to need more timing give it more with HPT. Chris has it, so he can easliy do that.
FU Tuning
Whalesac wrote:^^^^^ Setting up a standalone isn't difficult in the least, just time consuming. I know the different megasquirt softwares (Megatune, MSExtra, etc.) have algorithms to set a base tune for the engine, so I'm sure higher end products like the TEC3 would have as well. Plus, if you are really serious about tuning, a standalone will allow for far more accurate timing calculations if used in conjunction with with reluctors that have more than 7 notches (or teeth). 60 degrees of crank rotation between notches means a great deal of uncertainty in spark timing during periods of acceleration.
I did just now noticed Chris said...
SweetnessGT wrote:
It can add or subtract up to 100% injector duty cycle, and can only retard timing. (No big deal since timing can be added with HPT)
...but I don't really understand why you say that's no big deal. Do you plan to just set all 100% TPS values to like 32 degree advance and dial back from there or something? What about non-full throttle events? How will you handle mid to high RPM and low map values (or low map to high map conditions like off-cruise spool-up) when the PCM dials in via TPS and the AEM uses MAP. It just sounds like a more convoluted mess than going with a full standalone.
I guess I understand the appeal, though, if you already spent the $650 on HPTuners and don't want to feel like you wasted your money by ditching it for a standalone. To each their own I guess.
I appreciate any and all responses to my question.... it's kind of a "new" product (18 months old) and it is really different from a regular piggyback like Emanage etc.
First off to clarify something for Whalesac:
Timing is calculated via Map vs RPM... not TPS. 
So out of boost, I can take care of any and all timing via HPT with the stock map. Should my lower compression motor need more timing for spoolup, torque, etc down low... I can add it no issue. Timing up until the point of boost has never really been an issue for me... it's the safety factor of not being able to pull timing when the motor sees positive manifold pressure. This product will simply take over when I pass the 0 vac threshold. (I would set it up to do ZERO while in vaccum so that the stock PCM can do the job it was designed to do - manage the car out of boost.)
At any point on the timing map that the motor starts to see boost that I've set it up for rpm-wise, the F/IC will pull timing for me. I can set it up to pull no timing for the first few PSI during spoolup to promote a faster spool (setting the F/IC cells at 0) and then start to pull timing above that area. Much like any other timing map...
What this will also allow me to do... is pull timing above the stock PCM's ability. 6800 is the max via HPT. Whatever # I put into the F/IC is the limit... so I can keep pulling timing if the need arises past 6800 rpm instead of using the last known good cell. I'm not too concerned about pulling timing above that level out of boost since, well... when I'm driving around partial throttle I shift at 2000 rpm. The only time I'll ever go above 6800 rpm is when I want to make power. It's not ideal but for what I *need* it for... it should work!
So it's not quite the convoluted mess you envisoned!
The same would apply for fuel. I'd do zero below 0 vac and let the F/IC do all the fueling above that threshold.
In fact since it has 6 injector drivers, should I *want* to (and I don't)... I could drive 2 extra injectors.
I agree 100% that a full standalone is better.... but 4 things stop me:
- Price of a good EMS...
- EMS hardware knowledge. What you wrote about the crank sensor.. I have NO idea about things like that. it's out of my scope.
- Wiring. This is probably the #1 issue over price and knowledge. I loathe the idea of all that wiring.
- Getting base maps setup, etc. The idea of it seems daunting to me.
As you said, I've invested in HPT... I like what the car does out of boost. It runs FLAWLESSLY... the car has zero issue out of boost. While i may not have as much control as with a standalone this piggyback with its unique ability to intercept the injectors and drive them itself while still remaining affordable... is really appealing.
Which is why I'm inquiring about it.
Keep sharing your thoughts I like discussions like this... they prompt forward thinking.
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
^^^^ OK. I take it you are then either running a 97 or 00-02 supercharged reflash. For whatever reason, I thought you were talking about using this in conjunction with Alpha-N, which to me seems like a horrifying mess. If both systems (J-body PCM and AEM) are running Speed Density, then I don't really see a problem with it.
What I was referring to with the crank sensor is that the stock reluctor has 6 notches spaced 60 degrees apart with one offset sync notch to give the PCM a reference for the exact position of the crankshaft. Of the 6 evenly spaced notches on the crank, only two of them refer to TDC (obviously for cylinder pairs 1&4 and 2&3), and based on the velocity and acceleration of the crankshaft and the spark advance tables, the computer must guess when to fire the spark plug. In a static event where the RPM is constant, you could do fine with just 2 notches and an offset notch, because the computer should be able to very accurately calculate crankshaft position due to no differences in time between the two notches.... but that's not how car engines are intended to operate. For periods of acceleration, more resolution via more notches or teeth means a more accurate prediction of crank position and spark timing. There is also a limit to the number of teeth as well based on RPM and the current technologies of crank pick-ups, Distributers don't have to worry about any of this because they use mechanical points which are perfectly in sync with the crank.
I have no signiture
I'm using it with a 99 pcm... which is alpha-N.
Timing is map based, fuel is TPS based.
So it'll be a mix...
How will it be a horrifying mess, when all this will do is add fuel when I'm in boost... but not in a linear way I can do it via RPM.
Let me know your thoughts on that aspect... I can see it being a bit difficult to get perfect but at the same time if I let the PCM take care of 0-14.7 psia and let the F/IC take care of everything above that... it shouldn't be brutal. Trying to convince my 1 bar pcm to see boost has been a huge pain in the ass... it's like teaching Calculus to a 3rd grader.
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
Due to the nature of a turbocharger: at mid to high rpms, throttle and map do not have a close correlation with one another for a given rpm like in a NA engine. A single throttle position at a specific RPM can take on different manifold pressures depending on whether the turbo is spooling, fully spooled, etc. When you have two systems telling the computer that the same condition is different, then you start to have a problem. I can't find any pictures of Alpha-N VE tables online anywhere to give a good example, so I'll try my best to explain it.
Assume you are cruising at 3000 rpm (engine under vaccum). You then open the butterfly to 100%, and fuel ratios are perfect, because you tuned the stock J-body PCM and AEM to handle this condition. However, let's say you only open the throttle to 70-80%, and the map values are the same as the 100% condition. Unless the 70-80% TPS vs RPM VE bins are the same as the 100%, your Air/Fuel ratios start to rise higher than the 100% TPS condition. This is because the AEM sees the same condition in both cases and attenuates the signal the same amount both times, but because the 70-80% J-body table assumed a lower VE, a shorter total pulse width was sent to the injectors and consequently the reason for the higher AFR.
I'm not saying this can't work with Alpha-N. It just seems like it will be very difficult to tune well for all conditions, especially if you intend to take it near the 25 psi boost pressure limit. Considering spark is controlled via MAP, spark advance should work flawlessly...I must have I had a brain fart earlier, because I knew spark is determined by manifold pressure
Anyways Chris, don't let me deter you from trying this if you really want to. I'm just trying to give some scenarios that might cause you trouble when tuning. I do agree, though, that this is infinitely better than trying to tune a turbocharged engine with straight Alpha-N...and even if the AEM doesn't work out well enough to your liking, I'm sure there are plenty of import guys who would be willing to buy it off of you.
I have no signiture
im running the aem fic on my 98 2.4. its been in for about 2 months. waiting for an intercooler, injectors and time to install my turbo. the resolution of the fic is amazing! it can't advance timing. but if your boosting thats not a problem. it is not a stand alone system. you wire in the fic and you start your car, it runs the same as stock. untell you chang peramiters to add or subtract fuel. the newer fic 8 has a built in boost controller with optional boost controll solenoid. you can log data and view in aemloger as a graph. you can fun 2 different fuel tables to switch between. it has and input for your wide band. to me running just the fic has great potential.
you can remap the map sensor signal to the pcm so when you hit boost your pcm sees wide open throttle and not boost wial sittill sitting in open loop. the fic also has and o2 sensor clam that can modify your o2 sensor signal to your pcm, so if in boost in open loop you can switch your o2 signal to the pcm. i recomend anyone with question get on aempower forms and read the install and operating instructions for the fic befor you down it.
It's nice to see some more options out there for us IMO. I know Chris and I were talking about this and he ran with the idea and did alot of research. I've tuned the AEM FIC on a couple Cobalts and found it to be very easy to use, great resolution, and it worked very well. Both car were custom boosted and run like stock. I was just curious to see or hear if anyone had ran one on a J and it's nice to hear someone has!
My thoughts would be not to run this solo but in conjunction with HPTuners to do as Chris mentioned. I'll be interested to continue hearing more input on this
President/Founder - 607 Motorsports
lyndon wixom wrote:you can remap the map sensor signal to the pcm so when you hit boost your pcm sees wide open throttle and not boost wial sittill sitting in open loop. the fic also has and o2 sensor clam that can modify your o2 sensor signal to your pcm, so if in boost in open loop you can switch your o2 signal to the pcm. i recomend anyone with question get on aempower forms and read the install and operating instructions for the fic befor you down it.
So are you saying once it sees positive pressure it ignores the J-body PCM? If so, that sounds like it might work pretty well.
I have no signiture
the fic has its own built in map sensor. witch it uses at referance for the maps. if you use the map sensor wire option on the fic it remaps your map sensor signal to your pcm. so when your in boost your fic revices the signal reads the map sensor map and sends an altered signal to your pcm, wial at the same time readings its own map sensor and rpm altering your fuel signal to your injectors.
Just a minor point...
Whalesac wrote:^^^^......, Distributers don't have to worry about any of this because they use mechanical points which are perfectly in sync with the crank.
Most distributors are driven by the cam, in some fashion. That puts them kinda in sync with the cam which is kinda in synch with the crank. With all the lash, torsional harmonics of the cam and crank and the dynamics of the timing chain/ belt tensioner - the 6+1 crank signal was a monumental step out of the dark ages. I can't tell you if 58 teeth will make more power than 7, but the higher tooth count is definitely needed for diagnostics.
^^^^^ Correct, but timing is measured in degrees of crank rotation before TDC, which is why I said it is in sync with the crank. The cam spins at half the speed of the crank, so both the cam and distributer are always synchronized to the crank. I'm not saying the 6 + 1 is crap either, just that you get far better resolution/certainty with more teeth when accelerating.
I have no signiture
yes and true. yes more teeth would give better resolution. helping detect misfires and other high priority conditions. but timing would not be effected by the 6+1 synk. it is only referenced for timing and fueling. the computer can calculate whats going on and when.
ohh boy!!
I gotta bump this becuase it sounds VERY promising! I've been finding the F/IC for $397.80 - $410 all day long. Not a bad invesment by the looks of it, good find Chris!
No need to reply chris...we have already talked about this. But to the rest of you. This is great for those that finally realize the massive crutch of HPT and want more like they could have had if they did a standalone in the first place. Unfortunately still not as good tho as there are many features you lack with HPT + FIC. However, the point I'm trying to make here is for the people who may read this thread and think this is a good tuning option. It is not, this is fine for those who have already bought HPT and want more. If you havn't bought anything yet, do yourself a favor and buy a true real standalone.
Chris, I thought about it more and why dont you just run a MS for fuel only. It's a terribly simple setup. As bad or easier than the wiring required for the FIC, and you can just grab the tach signal from the ICM..no big deal. Can be done for half the price. You would tho loose the ability to retard timing however. But you would gain the ability to run it as a standalone in the future when you can manage wiring it all up. LOL
Honestly not trying to stir the hornets nest here guys...just trying to set the record straight. That's all.
Edited 1 time(s). Last edited Saturday, May 16, 2009 8:54 PM
"Never argue with an idiot. They'll drag you down to their level, then beat you with experience!" -Anonymous
Buddy of mine just installed one of these in his MR2
Yes, I agree. For the cost of HPT + FIC we're looking at the price of a standalone right there, minus the wiring headache. Now that Nukkinfutz has released his MS-2 package, you get a MS2, wiring harness and a LC-1 for less than HPT + FIC.
With that said... if you already HAVE HPT, or somebody who is only charging you 2 credits for theirs, and you pick up an FIC... you are saving $$. You won't have quite as much control as a standalone, but it'll do the job if that's all you're asking for.
For me, at this point, I'm too far invested in other equipment to turn around and junk ALL of it for a standalone, so this is the route I will probably go unless some other miracle solution rears its head, lol.
I'll get this up and running the same way I got the FMU + HPT up and running - which is now being utilized by even some high powered cars on the .org - then it will at least be another option. Which, really - is all we can ask for.
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
Has any other person had any success with this unit??
Time to get it going again.....
Nobody else has considered trying it, from what i can tell.
I will be installing one next season, I have looked into this very closely and it is the best solution for me. Coupled with HPT this is just what I was looking for.
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
Forum Post / Reply
You must log in before you can post or reply to messages.
