[1BAD6T6]

I've been collecting parts over the past summer and fall to build a turbo kit for my vert. My hotside and coldside materials are in route. 80mm ITS turbo is sitting on the shelf. Basically, it's time to begin the build. I've had more than one person ask me when I was going to buy a stand alone (XFI, DFI, etc.). I actually hadn't considered it. I was going to buy a PMAS pro tube to match my 83# injectors and keep tuning as usual. The main argument right now is the stand alone systems can tune much better, have much great processing power and will also do away with MAF. I've asked the simple question that no one can seem to answer; What can a stand alone do that my QH can't? I don't plan to twist this set up over 6000 and make more than 800 horsepower. Is that enough to warrant ditching the EEC-IV?

[decipha]

you have to excuse their ignorance, they just don't know any better

[1BAD6T6]

HA! Right?! I grabbed low z 83's and a AEM box to run 'em with my current set up. The only real difference I see is that the DFI comes with features like boost builder, 2-step rev limiter, etc. I can't see paying close to 1k for that especially when my QH is bought and paid for and is familiar as well.

On the flip side, I see a lot of guys on turbomustangs running stand alones. Hell, you're running over 800, what do you see as limitations with the EEC-IV? Or are you running EEC-V?

[decipha]

i'll excuse your ignorance as well

time to read up

[1BAD6T6]

Damn it man! Maybe your 408w doesn't make 800. Ha! In all seriousness, I have researched. The major difference that I've found is that these stand alones are V/E based. Those that have actually responded to this say its much easier to tune, especially on a boosted application.

[cougarnut281]

Six of one, half dozen the other. Both ways will work for what you are doing.

[dualdj1]

The major difference that I've found is that these stand alones are V/E based. Those that have actually responded to this say its much easier to tune, especially on a boosted application.

This is, in my experience, the eternal argument in for forced induction. A lot of the turbo guys claim that MAF doesn't work as well, etc. To me, knowing how much air is going in is always going to be more accurate, and therefore give you better results, even if it's more difficult to tune. On the other side, maybe that extra accuracy isn't necessary for forced induction, and you're simply spending a lot more time tuning for minimal gain. Haven't taken on FI yet, so can't give you an answer

[cougarnut281]

The major difference that I've found is that these stand alones are V/E based. Those that have actually responded to this say its much easier to tune, especially on a boosted application.

This is, in my experience, the eternal argument in for forced induction. A lot of the turbo guys claim that MAF doesn't work as well, etc. To me, knowing how much air is going in is always going to be more accurate, and therefore give you better results, even if it's more difficult to tune. On the other side, maybe that extra accuracy isn't necessary for forced induction, and you're simply spending a lot more time tuning for minimal gain. Haven't taken on FI yet, so can't give you an answer

Why is tuning a maf any more difficult than a VE table? What has more granularity, a maf curve or a 16x16 VE table? What about if it is a 31x31 table? Does it matter for forced induction? How much experience do these people have with maf and VE that say one is easier? Is calculating air mass really less accurate than measuring it with a sensor?

I don't have concrete answers to any of these questions, just my own opinions. My point is to make others think about it and make your own decision.

[Chucko]

Remember that the more intake plumbing you have, the bigger the lag between what the engine is really doing and what the MAF sees. Also, a MAF is an intake restriction. In a max-effort combo you might gain a few HP without a MAF. Those are some of the arguments I could see for dropping a MAF on a blown or turbo'd application.

[cgrey8]

I've never tuned an SD system. So take this with a grain of salt since I am NOT speaking from personal experience. That said from what I understand, going with a MAF allows you to go with a more aggressive cam that may not produce stable vacuum...something that SD systems require. That's the biggest benefit of a MAF over SD is that MAF is outside the vacuum and is sensing actual intake airflow, not the vacuum produced by the engine and then interpreting the vacuum along with RPM with airflow and load. So MAF gives you freedom in performance cams. SD gets really erratic at low RPMs with aggressive cams because of reversion. The SD system interprets low vacuum as high engine load, which isn't necessarily the case with an aggressive cam at low RPMs.

[cougarnut281]

I personally think that is a myth. I think it comes from oem systems that have had problems in the past, like old speed density mustangs. The aftermarket systems are much different and in my experience do not have any problems.

example from personal experience: I tuned an lt1 based NHRA stock eliminator car a few years back that had bigstuff 3. For those that don't know about stock eliminator the basic jist is the the engine must be stock displacement, the heads are supposed to be stock and the cam must have stock lift but there is no rule on duration. As such most cars in the class have huge duration cams and this one was no exception. With an intake duration of over 260@.050 I was able to get an acceptable idle at 1200rpm without much trying. I wish I could remember the vacuum reading but it has been too long, it wasn't very high though I do know that.

[cgrey8]

Are aftermarket SD systems more stable/better because they do a better job of "averaging" unstable vacuum? Being they know the RPMs, I could see how more advanced algorithms could do a better job of "seeing thru" the bouncing vacuum. Or perhaps they capture the high-vacuum spike and reference based on that, basically ignoring the low-vac spikes. Is that possible?

[cougarnut281]

You are over thinking it. I have not tuned a ford speed density setup but after just looking at a few of the files for them I think they are goofy. The Da1 eec looks very rigid in its tune-ability and that is ok since it was not designed to control anything but a stock 5.0. An aftermarket pcm is designed to be very flexible so that it can fit a variety of applications.

All I did to make the stock eliminator car idle was set the VE table and spark timing to the same values in the range that the idle was bouncing effectively locking the fuel and spark to one value no matter how the vacuum bounced. The tricky part was blending the tables for the return to idle but even that was not overly complicated.

[1BAD6T6]

Cougarnut - Would you consider tuning a boosted application with an aftermarket stand alone easier than using the stock eec and Tweecer or QH?

[decipha]

here is my thoughts about mass air and speed density

speed density is based off the fact that the ecu is tuned to the engine and it assumes the engine is not going to vary far from when it was tuned, you CAN NOT tune a speed density car n/a then go throw boost on it and expect the engine to be optimal under both conditions, it will not happen, you either tune the engine so its optimal for the n/a setup, or so its optimal for the boosted setup, if you tune it boosted and take the boost out the equation you will not be optimal when n/a, you'll be under advanced and over fueled, if you tune it n/a and then decide to throw boost on it after the fact, don't be surprised when it comes apart

mass air is based off the fact that the ecu is tuned to its peripherals, it doesn't assume anything other than the injectors and maf staying constant, as long as fueling is dialed in and you know how to utilize mass air as factory equipped, you can tune an engine n/a and make it ready for boost. you can then run n/a with fuel being at 12.9 with 36 degrees of timing, then 2 months later the client can run 15# of boost on it through a turbo and the tune will automatically drop to 11.5 @ 24 degrees of timing just because your moving more air so your using a higher value in your tables, as long as your not a dummy you would set your tune this way and all is well


AFAIK there is no aftermarket mass air setups to be had, if the good lord should allow then hopefully i can get one out there with self tuning capabilities putting efficiency at its finest

[Snkepit]

Preach brother preach!

[cougarnut281]

you CAN NOT tune a speed density car n/a then go throw boost on it and expect the engine to be optimal under both conditions, it will not happen, you either tune the engine so its optimal for the n/a setup, or so its optimal for the boosted setup, if you tune it boosted and take the boost out the equation you will not be optimal when n/a, you'll be under advanced and over fueled, if you tune it n/a and then decide to throw boost on it after the fact, don't be surprised when it comes apart


AFAIK there is no aftermarket mass air setups to be had, if the good lord should allow then hopefully i can get one out there with self tuning capabilities putting efficiency at its finest

This is bullshit statement. It's called a 2-4 bar map sensor. Tune the entire range of the VE table and Spark table and you are optimum for all conditions just like a maf.

As for maf systems in the aftermarket I am pretty sure Motec and possibly Pectal offer them but they are a little more money than a big stuff or FAST for the nice units.

[cgrey8]

Is it at least true when talking about Ford EECs, not aftermarket offerings?

[cougarnut281]

Cougarnut - Would you consider tuning a boosted application with an aftermarket stand alone easier than using the stock eec and Tweecer or QH?

Short answer: yes just because you have a lot less to play with. All the essentials are there and nothing more. People say you lose some features to get the engine driving perfect but in my experience most don't notice or just don't care.

Personal opinion: I prefer the stock eec because I like to fiddle around and I am anal about how my car drives and runs under every condition but I am not everyone else and I am not like most everyone else either.

[cougarnut281]

Is it at least true when talking about Ford EECs, not aftermarket offerings?

Not sure, I have not tuned a speed density ford. The topic was more aimed at aftermarket offerings so I would assume that is what he was referencing.

[cougarnut281]

Rereading that I don't feel I answered you adequately Chris. Assuming that the ve table has enough range in the cells you would need to rape the top row for boost making it inaccurate at 0 vaccum. So in reality it would not be optimum for boost or NA at that point since you must tune for max boost only making anything between max boost and 0 vacuum rich.

This all assumes a stock 1bar map sensor.

[EFI-Unlimited]

AFAIK there is no aftermarket mass air setups to be had, if the good lord should allow then hopefully i can get one out there with self tuning capabilities putting efficiency at its finest

AEM and Megasquirt will both support Mass Air. I bet others will too, but I know for sure off hand those will.

Brian
EFI-Unlimited

[cgrey8]

Does AEM and MegaSquirt support running full-time Closed Loop using a Wideband as feedback? I've heard aftermarket setups can do that. In other words, they can trim-n-respond the fuel even at WOT to attain the target AFR...something Ford EECs can't do since their code doesn't support Wideband feeback as fuel control feedback.

[EFI-Unlimited]

Chris,

Yes, AEM and MS are both capable of WB and NB feedback, including at WOT. I have mixed feelings about its effectiveness, but I know a lot of race car guys use at as a crutch instead of getting it actually dialed in.

Brian
EFI-Unlimited

[jetenginedoctor]

I seriously wouldn't rely on a sensor that spends its life in the torturous environment of an automobile's exhaust to influence fueling under high engine loads. Most all of the ECUs I've ever sold were capable of doing it, though I steadfastly refused to enable this function on a customer's car, even if they insisted that I should. None of my customers ever hurt a motor with my setups (barring mechanical over-revs, not engine control related.)

If somebody really wants to go standalone, I've got a few "discressionary use" boxes that I'd be willing to sell for a fair price. Since I'm currently working a "day job" and not doing a lot with car stuff other than my own, I don't have a lot to gain by hawking one brand versus another. I'll tell you what I like and don't like about certain systems. I'll say that I'm especially partial to Autronic, but will also admit that I took the Autronic box off the Junkstang and replaced it with the OEM controls, but not for the reason you'd think.