[xr4x4ti]

OK here is my current combo:

331, R302 block
RPM2 intake
AFR 185 heads
PT67 Turbo, soon to be something bigger (Probobly PT74GTS)
Lunati cam (eventualy a more turbo friendly cam)
55lb Delphi injectors with low impedance driver
Soon to be Air-Water intercooler

I am currently running the AEM EMS with a crank trigger and 8 LS2 coils for the ignition.

The point of this car was to be a very driveable and reliable car that could be driven every day, not some weekend race car.

The AEM EMS is really starting to piss me off when it comes to day to day driveability. I can tune it one day and it runs great, next day it rich, lean, etc. I had in running well and making OK power, but I had it pretty rich all of the time. Now that I have tried to get it to run at close to 14.7 at cruise and not have birds fall out of the sky when I drive by is when it has been giving me problems.

So, I keep on thinking to myself that I am making this way to complicated and for the HP goals that I have (500-550rwhp), that an A9L with tweecer and a large Mass Air Meter would give me a reliable consistant daily driver.

What do you guys think? Am I crazy for wanting to go to stock computer from the AEM?

Should I basically just be able to change the Mass air transfer function, injector size, and engine size and have a pretty good running motor. I guess I will need to pull some timing out under boost.

Thanks,
Tim
XR4X4Ti

[cgrey8]

The one thing I can say about the stock computer is you'll get a lot more support if you have a TwEECer RT and a standard EEC like an A9L simply because it's what the rest of us have and we know it. I know nothing about the AEM, how it works, what your options are, or what you can expect from it. So all I can offer beyond universal-type problems is sympathy.

The other thing that stands out as a potential wild card are the low impedance injectors. Those are generally only used on serious racing applications. If you go with a stock computer, std high impedance injectors will be fine.

Another thing to note about injectors is anything above 42lb injectors is going to be increasingly more difficult to get tuned in for daily driving. Most mild stock engines come with 19lb injectors (24lb for older Cobras). The higher performance engines like the supercharged Lightnings and supercharged Cobras get larger (42s I think). The point is once you get too large with the injector, your ability to accurately control it at "cruising" loads is more difficult. Another post here recently summed it up pretty good...it's like trying to fill a bucket with a fire hose vs a garden hose. So even with a stock computer, trying to accurately control fuel delivery at light loads may be a challenge with anything larger than 42s. Can it be done? I think it can, and I think there are people here that have done it. But I'm sure it took some time to get everything sorted out and they may be "ignoring" some issues as a result...you'll have to ask them.

Being you have a 331 turbo and some good flowing heads, you have a need for larger injectors for sure. But I'm not 100% confident you need 55lb injectors. There are plenty of supercharged 347s that get away with 42s and an FPR to boost them up to act more like 45s. A benefit to you is turbos generally aren't quite as brutal when it comes to parasitic loads on the engine like superchargers, so your BSFC will be lower than what supercharged engines measure at. My gut feeling is 42s and an FPR will work for your setup. You may run them up around 90% duty cycle at max loads if you actually hit 500hp. And if you do boost the fuel pressure a little. That's better than oversizing them and having driveability problems needlessly...at least IMO.

But since I'm not running that combination, I can't say any of that with any absolute certainty.

[86GT]

Everything chris said is true. The only thing I would have reservations on is the size of the injectors. I think the 55 are good if you are indeed hitting 550hp. I would rather be safe on the top end than sorry.

Yes this will cause headaches trying to tune the low cruise and idle but it can be done. Your idle setpoint may have to be increased just so the injectors can be set right.

Just my opinion!!

[cgrey8]

Ah, so higher idle is the sacrifice you learn to "ignore" when you go with larger injectors. For a daily driver that doesn't have to see a lot of stop-n-go traffic, I guess that's not a bad trade-off to get a daily-driven 500+hp. But for the Atlanta driving I do on a daily basis, I'd have to sacrifice HP to get a better, more fuel efficient idle. Besides, there's no where in my commute that I could actually use that 500hp if I had it.

[86GT]

I have about 400hp and I use 42s. I am able to get it to idle at 760 without any issues. Since I do not have 55s, I can only assuming that the idle and tuning will be harder for drivability. If the only trade off is setting the idle higher than it is most likley worth it.

[cgrey8]

What %Duty do you see on your 42s and how much boost are you running when you see that?

Fuel Pressure still at 39PSI?

What is your high/low slope and breakpoint at?

With that setup, how much does the WB vary with your WOT LAMBSE setpt? I'm assuming different driving conditions and different tanks of gas will cause your WB to fluctuate from setpt.

[xr4x4ti]

Thanks for the replies guys.

I currently idle the car at 900 RPM, so that is not a problem:)

This is great information. I did not realize that it got more difficult once you went past 42lb injectors with the eec.

I went with low impedance injectors with an actual low impedance driver (not just resistors) to try and alleviate some of the low end problems, since the LI injectors open faster and more consistently.

I realize people on this board do not have any experience with the AEM, I am just looking for how hard is it to tune the A9L. If I am just going to move from one problem to another, there is no point is switching.

The example I have is my friend with a 414 stroker. He had a eec-tuner and all he did was change the injector size, engine size, and the MAF transfer function and the car ran great, got great gas mileage and put down 380hp to the wheels without any fuss.

Before the AEM, I had a Electromotive TEC3 on my old 2.5 liter motor and that was much easier to tune then the AEM. I think there is actually more documentation available for the EEC then the AEM!

My thought was to get a A9L, a Tweecer, either a C&L or a SCT high flowing MAF, and a MSD6AL and see what happens. Of course this is quite of bit of money and effort just to do the experiment.

By the way, the car is not a Mustang, it is a Merkur XR4Ti converted to AWD, 6 speed, etc.

Thanks!
Tim
XR4X4Ti

[cgrey8]

Nice conversion...a friend of mine used to have a 2.3L turbo XR. It wasn't that responsive off-idle, but once the turbo kicked in, it did pretty good.

About your questions and concerns, you are right to be concerned that you'll just trade one set of problems for another. You just have to decide the better of the two evils.

The interesting thing is, it isn't difficult to tune for max HP. To get the max HP is just a matter of having the components sized right, and getting the AFRs right at WOT. And if that's all you are looking for, that's a day at the dyno to get the fuel pressure dialed in, the dizzy twisted right, and you are good to go. You may not even need a special tune on the EEC.

However the "art" of successful tuning is not in getting max HP. Any Joe with a mild understanding of engines and a dyno can do that. The art is in getting driveability from your powerhouse...and that's not easy to do until you know all the various ways and reasons an engine might misbehave AND what all your options are to combat each condition. Therein lies the learning curve.

The one thing I will say for sure...without proper documentation and/or people to explain things to you, trying to tune alone is nearly an act of futility for the average person. It's that reason alone that I would highly recommend the stock EEC over the AEM....even with larger injectors. But that's just me...

[Dale McPeters]

Tim,

Since I have tuned both the A9L type EEC’s & the AEM I feel that I can give you an unbiased opinion.

If you are looking for something to tune a daily driven car and make HP in the range that you stated above then the A9L EEC-Tuner/TwEECer will work. But you will not have the WB feed back control and individual cylinder tuning as you currently do with the AEM. Also the A9L does not have the tuning control that some of the later model EEC-V's do as it is rpm based instead of load based. With a turbo car such as yours it is better IMHO to tune with a load based pcm of some kind. It could be the AEM, Ford EEC-V, Fast XFI, BS3 etc. etc.

So far I have not had any problems tuning with the AEM. Of course my car is no longer a daily driver either. I like the AEM better in my particular application as I have a lot more control over the engine and devices that I use and so far have not had any problems with documentation other than for the A-Tooth table. Mitch an AEM Engineer was kind enough to provide that and the jumper settings required for the change to a 12 tooth wheel.
By the way it is the one that I bought from you....

As stated by others above tuning drivability is always harder to tune than WOT. It can sometimes be time consuming on a power adder car with big injectors.

If I were you I would drop John Garner an email to get his suggestions on tuning the AEM EMS for drivability before ditching it and spending more money. He has his "superstang" running quite well with the AEM and a MAP setup. He is also a former EEC-Tuner/TwEECer user. He is also running boost and he is making quite a bit of HP with his car at this point and from our last conversation it drove like stock.

If you need John’s email or website address drop me a pm or email.

[cgrey8]

Now you've got my curiosity up about the AEM's capabilities. You say it has more control than the Ford EECs. That doesn't surprise me, but can you elaborate? So that I'm not as biased in my explanations in the future, I'd like to know more about AEM's and what you can do with it.

And as for your comment about being an RPM-based EEC, I fully agree. A load-based EEC like CBAZAs or the newer EEC-Vs probably do make for easier forced induction tuning. But since GUFB is what I got AND I don't have to deal with forced induction, it's never been an issue for me. The things that need to be load-based are. The only thing that's not is the WOT functions.

I guess if the RPM-based tuning really was getting in the way of tuning, you could always adjust the TPS voltage to transition to WOT above what the TPS puts out thus eliminating the WOT functions altogether. Then at high load you'd just enter OL, not WOT. Then things, even in GUFx would be pseudo-Load based like CBAZA since the Fuel and Spark tables are based on Load. I don't know anybody that's done that, but it'd be interesting to play around with if RPM-based tuning was just too inflexible. Thoughts???

[Cougar5.0]

I am curious what 'load based' & 'RPM based' mean. In OL or WOT, the AFR is determined based on load (which is defined as the intake aircharge - basically MAF output). The same table - FN1307 - is used either way.


Now the WOT spark is simply RPM based and this could be an issue for some. Then Chris' suggestion to only use OL (and not WOT) could be construed by some as an advantage since load would also be considered in the calculation. I actually have a half volt between OL & WOT. When I mash it to the floor however, my load is always between 140 - 170%. This would drive me off the top of the table anyway - which I think is why the Ford engineers deceided to have a separate WOT functions. Of course they knew the load characteristic of the engine at any given RPM, so this wasn't rocket science. The most 'unpredictable' power adder at any RPM may very well be the turbocharger - so I can see why I hear a lot of stories about tuning a turbo setup.

What other major differences besides WOT spark exist between GUFX & CBAZA w.r.t load usage?

[cgrey8]

...When I mash it to the floor however, my load is always between 140 - 170%. This would drive me off the top of the table anyway - which I think is why the Ford engineers decided to have a separate WOT functions...

Rescaling the columns in the tables using the Scaling functions should cure that shouldn't it? If the top row is 75 and needs to be 170, just scale it for 170 to be the top row. Once you are above about 80% load, I'd think the changes from 80-up when it comes to AFR and timing would be linear wouldn't they? So you could modify the top two rows so your load might go 10, 20, 30, 40, 50, 80, 160. Or is there a good reason this wouldn't work? It seems this would be the only way to do it on CBAZA or newer EEC-V tunes...isn't it?

[Cougar5.0]

...When I mash it to the floor however, my load is always between 140 - 170%. This would drive me off the top of the table anyway - which I think is why the Ford engineers decided to have a separate WOT functions...

Rescaling the columns in the tables using the Scaling functions should cure that shouldn't it? If the top row is 75 and needs to be 170, just scale it for 170 to be the top row. Once you are above about 80% load, I'd think the changes from 80-up when it comes to AFR and timing would be linear wouldn't they? So you could modify the top two rows so your load might go 10, 20, 30, 40, 50, 80, 160. Or is there a good reason this wouldn't work? It seems this would be the only way to do it on CBAZA or newer EEC-V tunes...isn't it?

There is nothing to gain in scaling over 100% in 95% of the tables in my experience. Of course, since the fuel table (which is the only one that that I really care much about) uses % load scaling and 100% is actually 130% - that's all the over-scaling that I've ever found necessary. The WOT function handles spark and I've never found that to be lacking. Functions that modify the spark based on ACT, ECT BP etc correct for any air-heating caused by the S/C.

I'm sitting here wracking my brain, trying think of anything that might be gained by extending the scaling above 100% in any other table. I do have injector timing scaled to 125%, but the top two rows are identical from 1500 RPM on. This is why I undid any scaling above 100% in any other tables as it is unnessasary and can remove needed granularity where it might still have a meaningful effect.

Now if I had a turbo and I found that the variablity in timing with load & RPM was causing me drivability issues, I would do as you suggest and convert to OL only and scale the spark table appropriately.

[cgrey8]

With an RPM-based WOT function to control spark, you can't control spark based on boosted PSI. As PSI increases, the load will increase. I thought the 1 thing that would make forced induction tuning easier on a non-RPM-based EEC would be the ability to pull timing based on load, which ultimately would be pulling timing based on PSI...which is independent of RPM. No?

It seems the indirect way you have to pull spark based on PSI with GUFx is the WOT spark vs ACT function. As PSI increases, so does ACT, so in an indirect way, that would sortof pull spark based on PSI.

Again, forgive the questioning. I don't own a supercharged engine, but I'm curious as to how they are tuned for in case I decide to go forced induction at some point.

[Cougar5.0]

I think the differences between tuning techniques are as different as the 4 major types of power adders (PD, Centri, Turbo, Nitrous). In my case, there is little granularity between about 75% load and 170% load. The biggest tip-in I can do before going open loop is about 75% load. I have all timers set to "0" so I go open loop almost instantly at heavy load. The top row of the spark table is close enough to the WOT function - so I just don't/wouldn't notice the diffference since I'm only in the intermediate loads (75% - 125%) for miliseconds at a time. A PD blower is almost like a switch - it's either on or off. Perhaps a KB is not a good example for what the O/P is looking for. I dunno...

Edit - as far as WOT timing, I have simply tweaked the factory curve based on where I have "touched" on a little pinging. Basically I have pulled 2 degrees timing from 1800 RPM on - lol. I have meth injection that kicks on at 3000 RPM and >3 psi boost, so there are other "things" that are affecting AFR, ACT & the amount of timing I can live with at a given WOT load/RPM point.

[86GT]

What %Duty do you see on your 42s and how much boost are you running when you see that?

Fuel Pressure still at 39PSI?

What is your high/low slope and breakpoint at?

With that setup, how much does the WB vary with your WOT LAMBSE setpt? I'm assuming different driving conditions and different tanks of gas will cause your WB to fluctuate from setpt.

I have seen:
88% duty cycle
39psi fuel pressure
7psi on the boost
5700rpm
139 load.

The 42 pound injectors are maxed at about 450hp with a supercharger and 500 or so on a N/A setup.


Lot of good info in this thread, I think Cougar50 is correct as far as the KB setups. The KB setups are like a switch so the scaling on the tables may not be required. I on the other hand, I have a centrifugal type blower so the rescaling is more efficient in my opinion. Since I have seen a max of 140 on the load I scaled my tables to 150 and turned off the sea level load scaling. I think a more gradual riching of the fuel mixture is better suited on the centrifugal. I also rescaled the load for the spark tables. It just makes more sense to me, but then again there are a million ways to skin a cat.

[Cougar5.0]

Yep Clint, that makes sense and shows some of the differences in tuning techniques between PD and Centri. If I had a centri I would be trying to optimize torque from 2000 RPM up to about 3500-4000 RPM where boost starts really building. This would mean more timing and less fuel at lower RPM's. Then I would gradually pull timing and add fuel as the boost comes on.

A turbo? Who the heck knows - every compressor set-up will have different characteristics. At times they are like a centrifugal, at other times they are more like a PD blower. I would enjoy tuning a turbo as a challenge, but I'm guessing it would likely take a year or two before I felt comfortable with what I was doing.

I just checked a log of a track run from last fall with my 42# injectors:

Max DC = 99%
Max Load = 170%
Boost = 11 psi

I suppose the 9.3:1 AFR was still a bit too rich (even w/meth injection)! The other issue with DC was the 26" tires which had me running at nearly 6200RPM at the top of the track.

[Dale McPeters]

I thought the 1 thing that would make forced induction tuning easier on a non-RPM-based EEC would be the ability to pull timing based on load, which ultimately would be pulling timing based on PSI...which is independent of RPM. No?

Yes.

This is one of the reasons that later model EEC-V's work so well with turbo setups. The code is a lot more efficient on the later EEC-V's than it is on the A9L type EEC-IV's in regards to running a turbo setup. "Everything" is load/temp based especially on the '03 & up EEC-V's.

The only thing is you do not have the same abilities to tune with like you do with an after market pcm such as the AEM, Fast XFI, BS3 etc. etc.

And you can not readily change things like the AD channels like you can in regards to the AEM 30-1400/1401 boxes. Unless of course you rewrite the assembly code. Which takes a lot of time. I know this one from experience.

With the AEM I can re-assign "most" AD channels at will just by setting it up in the software. This can not be done as easy with the Ford EEC.

Do not get me wrong the Ford EEC works very well for what it was designed for as I am still using an A9L & Moates J3 module on one of my own cars.

One thing to remember is that the A9L EEC-IV's while working well are almost like a dinosaur with today’s technology.

[cgrey8]

I fully agree with your comment about how antiquated the EEC-IVs are. It amazes me they can do what they can for late-80s technology. But then again, embedded systems don't need nearly the number-crunching ability that most computers need. But their abilities are still limited due to their age.

When compared to the newer 2003-up EECs, what has improved as far as EEC performance? What niceties have been added to make them more formidable? I've only gotten hints and glimpses of knowledge of what the latest EECs are capable of like the rumor about how newer cars will soon run Wideband HEGOs instead of Narrowbands so they can do a better job of response and learning.

[Cougar5.0]

It's funny because we are embedding a processor & memory that is about the equivalent power of the Ford EEC IV into modular power supplies that are only 1.3" x 0.9" in PCB area! I have found that looking at the Ford code gives me ideas for programming my power supply! I am wondering what a new processor/firmware could do for me as far as drivability and performance. A turbo is the only case that I can think of where it may offer some benefit. Can my car be made to drive better than what seems perfect to me? ...or is it the "newer must be better" glitzy showoff philosophy here?

[Dale McPeters]

...or is it the "newer must be better" glitzy showoff philosophy here?

Nope.

You guys use what ever works best in your particular application..

Definately no more posting for me.....

[cgrey8]

LOL, often what works best is what you have and know how to use. But I'm always open-minded to the possibility of something better.

[Cougar5.0]

...or is it the "newer must be better" glitzy showoff philosophy here?

Nope.

You guys use what ever works best in your particular application..

Definately no more posting for me.....

Same answer I got last time I asked.

You're too good for us now - we're just dumb rednecks using backwoods fuel injection.

[Dale McPeters]

You're too good for us now - we're just dumb rednecks using backwoods fuel injection.

You never heard those words from me.

[Cougar5.0]

You're too good for us now - we're just dumb rednecks using backwoods fuel injection.

You never heard those words from me.

True.

I was hoping for more than just platitudes followed by "well, if you don't like what I said, I'll just take my marbles and go home."

If you are so confident about what you are saying, why do you take such a tact?

[Dale McPeters]

You're too good for us now - we're just dumb rednecks using backwoods fuel injection.

You never heard those words from me.

True.

I was hoping for more than just platitudes followed by "well, if you don't like what I said, I'll just take my marbles and go home."

If you are so confident about what you are saying, why do you take such a tact?

What do you mean by "such a tact"? Need an explaination....

I think that I explained why I would use a later model EEC-V if tuning a turbo car....

[Cougar5.0]

I was talking about the "no more posting for me" type comments...

I was originally curious about the "dinosaur" comments since we control high-speed DC-DC converter feedback loops using similar processor speeds and like 16k memory & C programs that have similar code to the EEC IV. Granted all of this fits into a 6x6 mm chip with FET drivers are external 3x3 mm chips - lol. I just got the feeling that you were implying that the "new technology" was offering something other than some flexibility in tuning the occasional turbo engine.

[Dale McPeters]

When compared to the newer 2003-up EECs, what has improved as far as EEC performance?

Just about everything as far as tuning goes. Faster processor, better spark/fuel control just to name a few.

What niceties have been added to make them more formidable?

One of the main things is almost everything is completely load/temp based. Including spark and fuel, on the returnless fuel system setups. It is a lot easier to pull spark based in IAT etc. than it is on an A9L type EEC-IV.
If all the EEC-V spark tables are used correctly you have a lot more control over detonation. Also some of the later models also have knock sensors that really help in some cases.

IMHO it is easier to make power more safely with the later model EEC-V's vs. the EEC-IV's due to some items stated above.

I've only gotten hints and glimpses of knowledge of what the latest EECs are capable of like the rumor about how newer cars will soon run Wideband HEGOs instead of Narrowbands so they can do a better job of response and learning.

I also heard this but I do not know that this is a true statement. Will believe
it when I see it..

[Cougar5.0]

Poor guy started a post about A9L vs. AEM and we are having a pissing contest about EEC V...

[Dale McPeters]

I was talking about the "no more posting for me" type comments...

You should know me better than that by now.

I was originally curious about the "dinosaur" comments since we control high-speed DC-DC converter feedback loops using similar processor speeds and like 16k memory & C programs that have similar code to the EEC IV. Granted all of this fits into a 6x6 mm chip with FET drivers are external 3x3 mm chips - lol. I just got the feeling that you were implying that the "new technology" was offering something other than some flexibility in tuning the occasional turbo engine.

Well to be honest with today's technology the "dinosaur" statement is mostly true. The Ford EEC has come along way since the A9L was introduced. Including the after market stand-a-lone tuning systems.

For example not to long ago the AEM EMS 30-1400 that I have on the '93 would have been considered something like an F1 racing tuning device. Now that the newer systems such Fast XFI, BS3, DFI etc. have hit the market the AEM that I have is toward the bottom of the list for most people.. But it works fine for me and it plugs into my existing harness.

Technology is always advancing. Also remember that some of our cars are 15-20 years old now. Well except for my wife's 42 year old mustang....