Performance Capacity of Stock SD EEC-IV System?

Anything about Ford EEC tuning. TwEECer and Moates questions dominate, but there's some SCT and OBD-II knowledge too.

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silver70
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Performance Capacity of Stock SD EEC-IV System?

Post by silver70 » Tue Mar 10, 2015 7:40 pm

Hey, guys. My name's Eric and I'm brand new here. Basically, I'm here to try to learn how my SD EEC-IV system operates a little more in depth than I have been exposed to in other forums. Months of searching the net has led me here. I have a basic understanding of how the system operates, but, am still very much a newb when it comes to the technicalities, so, please be patient with me. I am trying to write a very basic synopsis for the capacity of SD system modification for another forum I'm a member of in order to help some of the other members. However, I would like to make sure I understand more technical aspects and verify that some of my correlations/comparisons are accurate.

So, to start off, I have read that the Adaptive Control feature of the EEC-IV can adjust for certain changes, about +/- 12.5% (some sources say 25% over-all). What functions, exactly, can the computer "adjust" by 12.5%? Fuel trim? Timing maps?

Also, if I were to add performance parts (i.e.- heads, cam, intake, headers, etc.), how would the EEC compensate for the increased VE? At what point can the EEC no longer compensate for the increased VE, assuming MAP is kept at an acceptable level with a mild cam?

Basically... how far can I take the stock SD EEC-IV before the engine modifications are outside of its ability to compensate?

I'm not sure if I'm even wording my questions correctly, but, this forum is my last hope to obtain an understanding of how my system works. I have been through, several, other forums and the guys tell me, "Just go ahead and bolt your parts on. You'll be fine." However, nobody has been able to tell me why the parts will work okay. I am looking for a technical response and to understand how my computer reacts to modifications. Tuning is beyond my capability, but, I would like to know the capacity of the stock system.

Thanks very much for your time. I hope I find my answers here. This forum, I believe, is my best (and last) shot.

Thanks again,
Eric

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Re: Performance Capacity of Stock SD EEC-IV System?

Post by LeadHead » Tue Mar 10, 2015 11:04 pm

Spark can only be compensated if the engine is equipped with a knock sensor. Some Fords of this era do, many do not.

Ford EFI systems (and most others) have two systems in the EEC that work together in order to manage fueling. Short time (closed loop) and long term (adaptive) fuel tables. Your short term fuel trim works pretty much in real time. It responds fast (but not instantly), and its goal is basically to keep the engine at stoich. It can pull - or add quite a bit of fuel in a very short amount of time.

Now on the other hand, you have the long term fuel trim system. Basically it watches what the short term fuel trim is doing, and looks for a trend. If it sees that at say 40% load, between 2000 and 3500 RPM, the short term is consistently needing to add 15% fuel, it will take note of that. It will then apply a 15% fuel multiplier at that load/rpm point, so whenever you hit it, you'll no longer need to wait for the short-term closed loop fueling system to catch up.

In general, without tuning, the SD systems can compensate a bit for go-fast parts using the adaptive fueling, but it isn't really ideal. So things like headers, mild (very mild) cams, and better factory head castings (think like GT40 vs stock pickup heads) are fine for the most part. Big intake manifolds, lumpy cams and high-flow aftermarket heads will just run super lean.

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Re: Performance Capacity of Stock SD EEC-IV System?

Post by ranga83 » Wed Mar 11, 2015 2:03 am

Lumpy cams run super rich ( not lean), atleast on my sd based eec due to the fact of less vac at certain rpm the eec thinks it is under load

decipha

Re: Performance Capacity of Stock SD EEC-IV System?

Post by decipha » Wed Mar 11, 2015 4:00 pm

correct, less vac in a speed density setup = more fuel due to more 'assumed' volumetric efficiency I.E. more load

a speed density ecu is tuned to the engine, you have a VE table that looks up the MAP reading of the sensor and is scaled by RPM

the ecu then interpolates the VE value from that lookup table and calculates how much air the engine is sucking down based on that, it then comes up with a fuel requirement and fires off the injector

no eec-iv ecu has closed loop spark control that I'm aware of, even those that have knock sensors do not advance timing only allow retard, keep in mind there could be some probably euro and aussies since they get the good stuff but to my knowledge none of the US eec-4s do, to further that, even if it was programmed to allow advance it wouldn't be near enough to be efficient, spark tables require manual adjustment by the tuner for optimal results, spark is where the power is to be had

most stock tunes have closed loop fuel clip limits of 25%, I've never heard of 12.5% nor have I have ever seen 12.5% clip limits in any stock tuner ever.

short term fuel trims are based on the hegos, the ecu constantly adds and removes fuel to make the hego switch, it does this in an endless "closed loop" thus the terminology.

once the hegos are controlling fuel and all the crap is set for adaptives to learn the fuel trims are saved so the next time your at the load/rpm (cell) the ecu already knows how much correction is needed

as long as your happy idling near the stock idle rpm with near stock vac then the stock tune is ok, with speed density you can run any cam any other EFI system can run but if you idle with much lower vac than stock you'll need to tune it, you simply reduce the VE at the lower vac ranges near the idle rpm to lean it out

with no tuning, your limited to the stock tune of 19 lb injectors, thats good for approx 245rwhp safely, many have gone much further even tickling 280rwhp but its not safe at all and not recommended

you can swap heads/cams/intake all you want, just make sure the setup gives you enough idle vac that the ecu is happy, you can go twist the distributor to adjust timing and make things work

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Re: Performance Capacity of Stock SD EEC-IV System?

Post by silver70 » Wed Mar 11, 2015 6:40 pm

Awesome! These are, EXACTLY, the type of responses to my questions I was looking for. I had lost hope, there, for a while. You guys are great.

First, I read, in an article by Tmoss, that the EEC is capable of 25% but active testing showed 12.5% +/-, or, 25% over-all. That's where I got that number from. I'm not even sure what the number signifies.

You guys are spot-on with the assumptions, too. My vehicle is an '88 Ford Bronco 5.0L and I'm replacing it with a 5.0 HO, GT40 (F3ZE-AA) heads, a Comp cam with 114* LSA/.479 lift/264* advert. dur., and headers. I'm using the stock intake because the runner volume is enough to support the motor, IMO. My ballpark figures are ~250HP/~300 Lb.-Ft.TQ at the flexplate. I'm, also, going from 3.55 to 4.56 gears to help with TQ multiplication.

Follow-up questions:

1.) What is "fuel-clip"?
2.) So, the injectors are the main limiting factor of the stock system, providing MAP is close to stock?
3.) How close to stock do I need to be with MAP?
4.) Can the EEC tune out excess fuel if I install larger injectors and don't tune for them?
5.) Is an adjustable FPR an acceptable "Band-Aid" for the stock injectors?
6.) Is there a limit to the stock programing's VE tables? Is "VE" just another way of saying "load/vacuum" when it comes to EEC programming?

Again, thanks so much for the responses, guys. This is, already, far more than I've gotten from any other forum. I may end up tuning in the future, but, I just want to be comfortable with my knowledge-base on the stock programming, first. Most of the stuff I've read focuses on MAF systems, but, I really have a hard time believing the SD system is as crappy as people say.

For my synopsis, I have a "correlation" between two factors that I'm trying to establish to simplify this entire thing for others. That is where all these questions are leading. I have pages upon pages of notes and just need to make sure all my other ducks are in a row, first.

Thanks,
Eric

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Re: Performance Capacity of Stock SD EEC-IV System?

Post by ranga83 » Thu Mar 12, 2015 2:09 am

none of our aussie SD eec iv's have closed loop spark control that I know of, our eec v's do tho.

decipha

Re: Performance Capacity of Stock SD EEC-IV System?

Post by decipha » Thu Mar 12, 2015 8:05 am

yeah ranga thats what I suspected, and even at that its not an optimal means of spark control in lieu of custom tuning

speed density isn't crappy, it works, the older ford stuff isn't exactly coded to be optimal for boosted applications and even near 0 vac but it does work

1> a CLIP limit is the maximum allowable correction the ecu can calculate, the fuel clips can be opened up with the KAMMIN/KAMMAX and LAMMIN/LAMMAX scalars
when it clips the fuel limit it gives up trying to compensate sets a check engine light and disables the fuel corrections
2> correct, the injector will only supply so much fuel before they "go static" which means they are opened 100% of the time pissin the barn down
3> only idle vac will be the most significant as far as idle control is concerned, anything other than at closed throttle or very low load creeping, say 1200 rpm with the
clutch out barely on the throttle will be effected, all other aspects of the engine should be ok
4> sure can, up to that -25% correction
5> sure is, thats basically the same as swapping injectors since your changing their actual flow rate based on fuel pressure, in fact in all of my custom tunes I usually shoot for 55psi fuel pressure for those with smaller injectors, it gives you just a touch more headroom in your injectors and I find it helps atomize fuel better to give you a touch better fuel economy
6> not exactly, you can always "scale" your tune to be able to compensate for as much VE as you need, in most speed density strategies, there's a VE multiplier scalar that multiplies the VE table to do this for you up to a point

The reason why many advocate MAF is because its a peripheral tuned setup. You program the ecu for the injectors/maf and your fuel is good to go. With speed density, you have to tune the fuel to the engine, so anything you modify engine wise that changes airflow/vac will need to be re-tuned where as with MAF thats not a problem.

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Re: Performance Capacity of Stock SD EEC-IV System?

Post by 85GT » Thu Mar 12, 2015 8:35 am

Follow-up questions:

1.) What is "fuel-clip"? - preset values in the tune for how much the fuel trims can self adjust to, both up and down. For the OEMs, these are safe guards that will alert you that something is malfunctioning that needs to be addressed as a stock setup should be well within the limits. If the limits are reached and enough correction can not be added, the HEGO's will not be able to switch. This will be detected by the EEC and eventually throw a code (CEL).

2.) So, the injectors are the main limiting factor of the stock system, providing MAP is close to stock? - them and the fact the eec only knows the stock size of them. The eec only knows it's working injectors that are stock to the original tune. It calculates how long to fire the injector based on knowing how much they flow. If you change them, it will not know without telling it so in a new tune, it will still calculate/fire the same length of time (pulse width) rather then shorter for bigger ones.

3.) How close to stock do I need to be with MAP? - in a simple sense, your actual VE needs to be within the correction range (fuel clips) of the programmed VE table. With tuning, you can enter your new actual VE's

4.) Can the EEC tune out excess fuel if I install larger injectors and don't tune for them?

5.) Is an adjustable FPR an acceptable "Band-Aid" for the stock injectors? - with tuning, it can provide you effectively larger injectors. Without, you'll just be driving your fuel trims more in one direction. Same for #4. At some point, the trims will hit the clips.

6.) Is there a limit to the stock programming's VE tables? Is "VE" just another way of saying "load/vacuum" when it comes to EEC programming? - without looking at the strategy not sure of the particular ranges, but there is numerical limit to ranges of VE that can be entered into the table based on the EEC's programming code.
In the simplest sense, LOAD is VE - the amount of air entering the cylinder vs the amount it can hold. So instead of having a MAF to actually measure that air, the EEC uses the table to predict the air. The look up table has RPM on one axis and vacuum on the other. The cells are VE(Load).


There is much more discussions/info on SD tuning on gearhead-efi.com This is a GM site, but the concepts still apply. A few good threads on how to 'tune' an SD system.
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Re: Performance Capacity of Stock SD EEC-IV System?

Post by silver70 » Thu Mar 12, 2015 8:21 pm

If you guys could only see the smile on my face as I read your responses. Again... EXACTLY what I have been looking for.

1.) So, is VE an, actual, product of the RPM vs. Vacuum multipliers that the EEC calculates, or is it just a reference value for injector pulse-width that comes "pre-written" in the cells from the factory?

2.) If it is "pre-written" at the factory, how do I find out what those numbers are?



The question I'm trying to base my synopsis around is: "How much power can I add to my engine before it has problems?" This is an, extremely, frequent question on the other forum I'm a member of. NOBODY has provided a technical reasoning and response to this question, though. The most typical response is, "As long as you use the right cam, you'll be fine.", or, "Just do it. It should work."

However, the younger generation showing up on the forum has a desire to learn about the programming aspect and why the parts will work and what makes certain parts work poorly. I'm trying to find a way to present how the SD EEC-IV system works and keep it as, brutally, simple as possible. Also, what it can compensate for/adapt to. I, really, like the forum and want to contribute something. Problem is, most just want to work within their stock programming's capability and are afraid to tune (myself included :oops: ). Here is an idea of what I'm trying to tie up and finalize the synopsis with:

During my research, I have read that, during dyno sessions, the TQ curve of the motor is, almost, identical to the VE curve. They both peak at very near the same RPM. They run parallel with each other. Is there a way to relate an increase in TQ (easier to understand) to what the stock SD EEC-IV programming can compensate for with its VE tables (more complicated to convey this concept) and 25% fuel clips?

I want to be able to provide a definitive answer like, "If you increase your engine TQ by "x" amount, the adaptive control feature of your computer will be able to compensate, assuming your engine vacuum is kept near stock parameters. So, tune for torque, not horsepower"

Almost have this thing all tied up, so, please bear with me. As always, thank you for your time and responses. I know it takes a while to type them.

Eric

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Re: Performance Capacity of Stock SD EEC-IV System?

Post by cgrey8 » Fri Mar 13, 2015 8:10 am

If the only thing you wanted to do is WOT on a N/A engine, I expect SD could probably work for that. But most people need sane engine control from idle to WOT and from cold to warm. When you consider this wide dynamic, it makes "tuning" much more difficult even for MAF. Depending on the engine, it can be down right impossible with Ford's implementation of SD on EEC-IVs.

My very limited 2nd hand understanding of Ford's implementation of SD and it's shortcomings come from:
  • The code never considered boost and neither does the stock MAP sensor
  • The resolution of the MAP sensor code isn't that great so it makes handling "tiny" changes in pressure difficult
  • I can't say this with absolute certainty, but my feeling is the processor doesn't oversample intake pressure. So if you have a really radical cam that produces reversion, you can get vacuum spikes and troughs in the process of 1 cylinder charge. If the processor only samples once per cylinder charge, this only gives a limited view of what's actually going on in the engine. So basing what fueling should be based on that is just working with averages.
  • But something even more complicated gets in the mix...again this is just my take, based on nothing other than my very limited understanding. Fresh air is one temp. Reversion air being shoved back into the intake from a cylinder due to low RPM overlap is a different temperature. But as we all know SD is very temperature dependent. So this makes trying to get fueling during engine warm up a challenge since you only have 1 ACT. Historically it's mounted right at the #5 cylinder port (older stock intakes) or relocated to the intake track before the Throttle body (newer stock intakes). And I don't believe the learning aspect of EEC-IVs is sophisticated enough to apply learning to "warmup" conditions. It certainly isn't in the MAF EEC-IVs.
So it's not that SD engine control is a bad technique. It's actually a quite valid and accurate way of engine management when properly sophisticated to handle the dynamics a street engine will have to operate under. It's Ford's implementation that is over simplified and just has shortcomings that their EEC-IV MAF control strategy improves on. And as decipha said, MAF is a little easier to understand how to tune for. You have measured air coming in, known injector flowrate, RPM, cylinder count, and engine displacement, so you abstract away a lot (not all) of the engine's characteristics to calculate fuel delivery. With that, now you can run radically different intakes/cams/exhaust and a number of other mods/addons that may or may not require radical changes to the tune. The tune actually has a chance of responding close to intended and the areas where the tune might need some tweaks is in the transient conditions, command different AFRs for newly attainable loads, run the idle differently for cold-to-warm conditions, and change spark advance at specific RPM/Loads if detonation is occurring. Obviously still not simple, but simpler and a bit easier for people to get their heads wrapped around.

Again, take my comments about SD with a gain of salt. I've never tuned an SD system. I've only listened to people talk about their experiences and formed my own opinions which could be off the mark. But those are my thoughts on Ford's EEC-IV SD implementation.
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decipha

Re: Performance Capacity of Stock SD EEC-IV System?

Post by decipha » Fri Mar 13, 2015 1:23 pm

VE is airmass, the volumetric efficiency of an engine at any given state is another way of saying how much air its moving

the VE table is programmed from the factory for the engine, anytime you make changes you should update that VE table to keep it as close to accurate as possible

In order to see your VE table we need to see your tune, what is the catch code on your ECU ?

The issue with adding power is that eventually it will lean out, the point at which it leans out will depend on how much kam's have learned +/- 25% and if those kams are being used at WOT or at the condition where its going lean, then you have to factor in the actual AFR offset from the injector modeling being off and try to cross calculate the commanded lambse during that condition, multiply it all together and you have a predicted amount of VE you can exceed from stock before going too lean, and that too will be limited by the injectors

post back with the catch code and i'll try to do a quick calc for you

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Re: Performance Capacity of Stock SD EEC-IV System?

Post by silver70 » Fri Mar 13, 2015 8:41 pm

To cgey8:
Thanks for the input. That's a new aspect of the system I had not taken into consideration (the data sampling). It seems, kind of, crude and tuning would be the ideal approach. Unfortunately, I have to work within the confines of the stock programming capability in order to relate to my audience for my synopsis.

We have an "EEC Tuning" section that seems to have, mostly, crickets and tumbleweed with nowhere near the information presented on this forum. Also, the only SD tech-oriented thread is about how to select a cam that'll maintain MAP. However, despite this, there are at least 4 new threads started every month about, "What can I do to my Bronco's engine without lighting the CEL, and still pass emissions?"

So, basically, I'm catering to: "desire to modify... inability to tune." It's proving a tough crowd. Maybe, once people are comfortable with their system and how it works, then, they'll be more apt to try tuning it.


To decipha:

Thanks for the, additional, info. I will be happy to get you the catch code and very grateful for anything more you can tell me. But first:

1.) What is the "catch code"? Is that the serial number? If there is more than one number printed on the EEC, I want to make sure I provide you the right one.

2.) Also, what is "lambse"?

Eric

decipha

Re: Performance Capacity of Stock SD EEC-IV System?

Post by decipha » Fri Mar 13, 2015 9:54 pm

the catch code is most likey two or three alphanumeric characters printed on your ecu's main connector

for example it will have something along the lines of L0S, A9L, CU, DF, not those but something like that
if you post a pic of the connector we can verify

lambse is the AFR the ecu is commanding
http://info.efidynotuning.com/fuel101.htm

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Re: Performance Capacity of Stock SD EEC-IV System?

Post by ranga83 » Sat Mar 14, 2015 4:29 am

decipha wrote:the catch code is most likey two or three alphanumeric characters printed on your ecu's main connector

for example it will have something along the lines of L0S, A9L, CU, DF, not those but something like that
if you post a pic of the connector we can verify

lambse is the AFR the ecu is commanding
http://info.efidynotuning.com/fuel101.htm
just to throw a spanner in the works. The AUS catch codes are 4 digits haha

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Re: Performance Capacity of Stock SD EEC-IV System?

Post by silver70 » Sat Mar 14, 2015 12:57 pm

Okay, at the risk of screwing up what you are asking for, I will provide everything printed on the label:

Code: Select all

EEC-IV    EFI-SD20b    32k    PROM    8QP                          
                                      7J18
E8TF-12A650-AG2A                                                              

6EC2830F11      7614 - 243

decipha

Re: Performance Capacity of Stock SD EEC-IV System?

Post by decipha » Sat Mar 14, 2015 1:02 pm

8QP looks like the catchcode

Ill see if i can cross reference it and the hardware code to see what i come up with

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Re: Performance Capacity of Stock SD EEC-IV System?

Post by silver70 » Sat Mar 14, 2015 11:13 pm

Thank you sir. Much obliged. I appreciate your investment of time. This research is going towards a solid cause and will help many others. Hopefully.

Eric

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Re: Performance Capacity of Stock SD EEC-IV System?

Post by floodking88 » Thu Mar 19, 2015 2:32 am

having tuned an SD computer (fairly successfully), i'll give my opinion that the 3 biggest problems with it is
1. cam swapping to one with more overlap
2. it doesn't know how much air it's moving (goes lean)
3. it can't detect BOOST

for a N/A engine, it does a good job. but you have to tell it that you're flowing more air.

i learned that my stock fueling was off when my O2 sensors went lean under WOT, when they should be rich, so i figured out a way to shift the numbers on the VE table to the range they should have been. Now it knows how much air is flowing, and the major disadvantage of SD is fixed. the rest of tuning is similar to MAF.

decipha

Re: Performance Capacity of Stock SD EEC-IV System?

Post by decipha » Thu Mar 19, 2015 9:42 am

I just looked through my stack of bins and all I have is an 8QN no 8QP, the N appears to be of the same 32kb strategy as the P though so its just probably another catch code

this is what I believe the VE table to be
Attachments
VE Table.png
VE Table.png (22.89 KiB) Viewed 10781 times

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Re: Performance Capacity of Stock SD EEC-IV System?

Post by LeadHead » Thu Mar 19, 2015 2:40 pm

Ford did actually make a digital (frequency based) MAP sensor capable of sensing boost. It was used on the 1994.5-1997 powerstroke diesel trucks. They can sense up to around 25 PSI of boost. However, who knows if it's capable of sensing any kind of vacuum at all? It also goes up to around 250Hz, compared to the 150 Hz or so for the gasoline engine MAP sensors, so the hardware in the EEC-IV may not be able to count the frequency.

However, it might be worth a try for someone looking to tune a supercharged/turbocharged SD truck.

decipha

Re: Performance Capacity of Stock SD EEC-IV System?

Post by decipha » Thu Mar 19, 2015 2:48 pm

im pretty sure we had a discussion about that a while ago and sailorbob said the ecu cannot calculate boost even with a boost reference MAP so you would still be limited by the code

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Re: Performance Capacity of Stock SD EEC-IV System?

Post by silver70 » Thu Mar 19, 2015 9:36 pm

That's awesome! Thanks so much decipha. Wow... the elusive VE table that I've read so much about. I've never, actually, seen an example of one. That's pretty cool. It looks like the top of the chart is RPM, but, what are the decimal values on the left side? Are the figures in the middle the lambse, or, just "reference multipliers" of some kind that the EEC uses to help calculate lambse?

Also, thanks for the input floodking. My stock LSA is 116* and I'm switching out for a cam with 114*. From what I've researched, it seems like this is the smallest LSA I can use on my SD system. Basically, the cam has the gross lift of a stock '93 Cobra cam (with the 1.7 rockers), and the duration figures of a 5.0 Explorer cam. Best of both worlds. HP and TQ. Also, I want to add GT40 heads and full-length headers. I'm keeping my stock TB and intake manifold. I figure I should be okay with this set-up since it's, fairly, conservative. I'm going from 185HP/270TQ to ~250HP/300TQ and the parts will, probably, move the power-band peaks up about 1k RPM. The only catch to this whole thing is that I have to work within the stock programming. Probably, kind of counter-intuitive for most people, here, seeing as this is a "tuning" forum. :biggrin:

Eric

decipha

Re: Performance Capacity of Stock SD EEC-IV System?

Post by decipha » Thu Mar 19, 2015 9:46 pm

the Y axis is MAP

those values are VE which is the percentage of air in the cylinder

so a VE of 0.859 for a 302 cubic inch engine would mean

302*0.859=259 cubic inches of air is in the engine

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Re: Performance Capacity of Stock SD EEC-IV System?

Post by jsa » Fri Mar 20, 2015 1:07 am

Cheers

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Re: Performance Capacity of Stock SD EEC-IV System?

Post by silver70 » Sun Mar 22, 2015 11:22 am

decipha wrote:the Y axis is MAP

those values are VE which is the percentage of air in the cylinder

so a VE of 0.859 for a 302 cubic inch engine would mean

302*0.859=259 cubic inches of air is in the engine
Okay. Now, are the Y values the Hz frequency of the MAP sensor? I.E.- How do I interpret the Y axis numbers to correlate/compare with MAP?

Also, it's interesting to see the VE table allows for a 0.859 VE. That's kind of high for a street engine, isn't it? An 86% VE would involve some moderate performance improvements, wouldn't it?

Also, if it's not too much trouble decipha, would it be possible to pull up the VE table for one of these catch codes: 8CB, 8PU, 8PV, 8PZ, C9Z, GT, RG, RZ, U2D, W2J. The one you provided above, apparently, came from a 5.8 Bronco and I have a 5.0. I looked up a catch code list and these came from 5.0 Broncos/F-Series trucks. Again, only if it's not too much trouble. I don't, exactly, know what's involved in pulling up/accessing the VE table.

Thanks,
Eric

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Re: Performance Capacity of Stock SD EEC-IV System?

Post by olddog » Sun Mar 22, 2015 12:47 pm

In addition to decipha 's web site also see Moates https://www.moates.net/

Between the two you can learn a lot. Moates will sell you the things you need to tune.
Replica 1967 AC Shelby Cobra. 5.0/347 Edel Performer RPM heads. Cam 236/242 @ 0.50 .575 lift 110 LSA. Vic JR Intake with bungs welded in and 38 lb/hr injectors. PMAS slot meter in 3" OD aluminum pipe. PCV is only emissions equipment. O2s are in a single header tube, as collector is in side pipes a long way from heads. MassFlow EFI. It uses a Ford EEC4 A9L - I added a QH Chip - using TunerPro.

silver70
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Joined: Thu Feb 26, 2015 6:25 pm
Location: Phoenix, AZ

Re: Performance Capacity of Stock SD EEC-IV System?

Post by silver70 » Thu Mar 26, 2015 8:59 pm

Thanks for the link olddog. However, as mentioned, I have to stick with the stock tune. I just need to get some of the details sorted out.

Eric

decipha

Re: Performance Capacity of Stock SD EEC-IV System?

Post by decipha » Thu Mar 26, 2015 11:17 pm

why do you need to stick with the stock tune? I understand you want to tell people what their options are but your limiting yourself significantly.

if you can spend 1500+ on a set of heads it only makes sense to spend 300+ on a chip you can toss on it for it to run right

silver70
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Location: Phoenix, AZ

Re: Performance Capacity of Stock SD EEC-IV System?

Post by silver70 » Sat Mar 28, 2015 12:52 am

Actually, they're the stock cast iron GT40 Cobra/Lightning heads. Thermactor ports and everything. :mrgreen: Did some "horse trading" for them. Cost me a couple of parts I had laying around the garage for several years.

The main reason is because almost every vehicle I have owned in the past (mostly carbureted street cars) I have modified to the point of them being impractical for a, nice, daily driver. I had a, beautiful, bone-stock 1970 Maverick. Fresh emerald green metallic paint and chrome with 72k original miles, immaculate black-on-plaid interior, working A/C, and all the under-hood and interior stickers intact. Original bias-ply spare still in the trunk. Literally, owned by a little old lady and kept in the garage. Could've gone to Barrett-Jackson with it. Now, the interior is gutted, fenders shaved, 5 point harnesses on the racing buckets, and manual everything with no accessories. Turns mid-11's in the 1/4 on a N/A 302 with a shift light blaring in my face at 5,750 RPM and the Flowmaster 40 series thrumming my ears to death on the freeway.

I, absolutely, refuse to go down that road with this vehicle. "Know thyself." I am removing my own stupidity from the equation and forcing myself to, finally, have a decent vehicle. If I start to "tinker" too much, it just spirals and I need to keep it simple. I just wanna take it to where I think it should've been, performance-wise, from the factory and call it "good". Also, there are too many guys in the other forum who just don't care. They start bolting on intakes, heads, and radical profile cams and then post questions about why their truck no longer runs. Some guys want to know why certain parts don't work but need to be spoon-fed the information. I'm just trying to keep them from ruining their trucks and provide all my research material in one location. I, literally, have pages and pages of notes taken over the past ~6 months and several different drafts of the synopsis typed.

A chip is an option if I can't get the parts I have to work with the stock programming. A Holley carb is not unfamiliar territory for me. However, I am scared-to-death of electronics. Hell, I didn't even have a decent multi-meter until, about, 6 months ago. I just want to be comfortable with how my stuff works before I start changing what it does.

I don't mean to come off as difficult/stubborn, so, I'm sorry if that's what this thread is developing into. I have been bouncing around on several other forums prior to here and have not received, nearly, as much information. It's been very general advice from people who know next-to-nothing about their electronic system. It seems like they just figured, "Meh... I've got a few extra bucks laying around. I'll buy a tuner and start dinking with stuff. I don't care if I mess something up; this isn't my daily-driver." Then these people ask for answers from other people who are in the exact same boat and, eventually, take their vehicle to professional tuners who give them advice similar to what I am finding here.

I hope this answers your question. Again, I don't want to be difficult and I appreciate all the time everyone is investing into this thread. Especially, you, decipha.

Eric

olddog
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Re: Performance Capacity of Stock SD EEC-IV System?

Post by olddog » Sat Mar 28, 2015 12:04 pm

First the speed density EEC IV was only sold a couples years or so, before they went to MASS FLOW. SD was more than 25 years ago. So the target audience you are talking about is very small.

You can only increase the Hp a modest amount before you are going to need bigger injectors. You have to have more fuel to make more power. At that point, you have to alter the stock tune to make it run. With SD, I suspect, you will make it run like crap before you need bigger injectors.

So my point is, if you refuse to alter the stock tune on a SD system, the Hp gain is so small, why bother? To me, that change in power cannot be felt in the seat of the pants. It will be so small you will have to put it on a dyno to measure it. It's about as pointless as buying a faster computer that is only used to play solitaire. You might get a woody talking about it, but it was pointless in any meaningful way.

If I wasn't willing to modify the tune, I wouldn't change anything.

Making an extra 20 Hp on a 225 Hp engine does nothing for me. Gaining 50 Hp at the expense of an engine that runs like crap most of the time would not be worth the cost to me.

Now modifying that engine to make 350 Hp and have it running like a top is a whole different story. You can brag you did something, and you can feel it in the pants. You are not going to get there without changing the tuning.

You can make 350 Hp and have a very street friendly ride, if you do it right. You can also have a 300 Hp miserable, bucking, hoping, piece of crap, if you refuse to do it right.

That's one point of view. You are welcome to keep your own, if I failed to convince you. Good luck.
Replica 1967 AC Shelby Cobra. 5.0/347 Edel Performer RPM heads. Cam 236/242 @ 0.50 .575 lift 110 LSA. Vic JR Intake with bungs welded in and 38 lb/hr injectors. PMAS slot meter in 3" OD aluminum pipe. PCV is only emissions equipment. O2s are in a single header tube, as collector is in side pipes a long way from heads. MassFlow EFI. It uses a Ford EEC4 A9L - I added a QH Chip - using TunerPro.

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