[5.0Rick]

Hello
I am running a turbo with with 42# Bosch injectors and had problems with elevated temperature and part throttle driveability issues. My car now starts, idles, and runs cooler (where it should 180 degrees or so). I believe these problems were caused by incorrect load calculations which lead to retarded timing hence the poor driveability and higher than normal temperatures.

My approach to tuning is a bit different to what most are doing. What I wanted to achieve 1st was a stock tune with the correct settings for injector slopes, battery offset, breakpoint, etc. I wanted my changes to be based on factual data rather than trial and error. Since I am running the stock cam, I decided to put the stock MAF back in and work on getting the driveability dialed in. I tried the Lightning battery offset, breakpoints, and injector slopes of 40.6 and the car ran better than ever (from a driveability standpoint) I also divided the values by 1/2 on the Cranking Fuel Width vs ECT function.

Once I was pretty sure that these settings were workable, I replaced the MAF with my Pro-M 42# bullet and used the MAF transfer that I generated using the Excel spreadsheet and the data sheet standard numbers. Right away I could tell that something was not right. The car would start bucking at 1800 rpm in 3rd or 4th at light throttle. At 1st I thought it was the accel enrichment multiplier function but after playing around with the fuel, I decided that it had more to do with load calculation rather than fuel since this bucking was not present with the stock MAF meter.

I then started looking at the MAF transfer and playing around with the numbers. I figured that Pro-M calibrated their MAFs by scaling the values so I started trying to determine by what quantity. I did a little more research on what numbers to use from the Pro-M data sheet and found a write up indicating that the Calc numbers were what Pro-M shoots for when calibrating a meter. I took the stock MAF transfer and put it in Excel along with the Calc numbers from the Pro-M data sheet and created a graph. I then started multiplying the stock MAF values until the graphs were overlaid (the same). What was interesting was that the multiplier was 2.21. This is the same result as 42/19 or the ratio of injector change. At that point I changed the MAF transfer to the stock values multiplied by 2.21.

Unlike the MAF transfer generating Excel spreadsheet results, the lower values were much larger. These larger values are workable with the 40.6 low slope and I have a rock solid stock idle.(BTW, I have both low and high slopes set to this)

After these changes the car started and drove better, however the 1800 RPM stumble (bucking at light throttle) was still there (sometimes, not as frequent). I was still dealing with a load calculation issue. That was when I decided to experiment by increasing the Engine Displacement Scalar. I started with 400 and the bucking disappeared. I increased it again to 450 and the throttle response at low rpm improved dramatically. I then decided to use the same ratio multiplier on the Engine Displacement Scalar that I had used for the MAF transfer values (2.21). This change made a HUGE difference. The car drives like stock at part throttle. I believe this brought the load calculation back down to match that of a stock calibration. I did take some safety precautions by lowering the boost (5 psi - waste gate as loose as possible) and altering the fuel and spark tables as well as the WOT fuel and spark functions just in case I was totally off base.

I am now fine tuning by altering the fuel & spark tables. Every now and then I will get a slight ping at part throttle while under boost. I believe this is caused by the 14.64 commanded A/F in the Stabilized A/F table. I will need to experiment a bit on how much to enrichen the commanded fuel A/F at a given load.

Update: I altered the Stabilized A/F table by adding fuel starting at .3 load and the detonation has disappeared.
Misc settings

Fuel pressure - 39 psi with no vaccuum

70mm throttle body - all ISC settings and TB settings untouched.

Injector breakpoint values - 1.949

base timing 10 degrees

Valve cover air inlet connected to intake pipe of turbo after the MAF (very important - this air has to be accounted for or the idle will be too lean. Possible problems starting a cold engine)

All emissions equipment present


I wish I still had my Tweecer RT so I could datalog :(

Tuning via a chip is a PITA

Let me know if you find this information useful.

Regards,

Rick

[JuiceSC]

Essentially, your approach is the same as mine except for 2 small details. Crank PW function IMO is irrelavent. So with 42s you get twice the fuel at cranking. Once you release the starter, this function is not used. Using the stock values, I crank my starter half as long! Seriously, if the tune is right, this does not matter since its only used during cranking.

Second, you got too agressive with the CID scalar (my opinion once again) and you ended up with a little ping. What I did was match up 80% load with about 1 or 2 inches of manifold vacuum.

[5.0Rick]

Essentially, your approach is the same as mine except for 2 small details. Crank PW function IMO is irrelavent. So with 42s you get twice the fuel at cranking. Once you release the starter, this function is not used. Using the stock values, I crank my starter half as long! Seriously, if the tune is right, this does not matter since its only used during cranking.

Second, you got too agressive with the CID scalar (my opinion once again) and you ended up with a little ping. What I did was match up 80% load with about 1 or 2 inches of manifold vacuum.

My car actually fires up right away. Not only that but I would think that the extra fuel that is dumped in at cranking would affect the A/F enough to trigger the adaptive technology to begin making unnecessary adjustments.

On your second point, I am not really trying to bring the load down low enough to work with the current fuel and timing values, I am trying to bring the load down to where it belongs (Y axis on the tables). I will work on the values at the particular load rows to work with my combo. But like I stated, the slight occational pinging seems to occur at a very slow rate of increase in throttle input & RPM while under boost, that is why I suspect the stablilized fuel table. It is essentially leaning the A/F to 14.7:1 while under boost (under load - not a good thing)

[JuiceSC]

I have no starting issues either. Adaptive won't kick in for some time after startup, so, extra fuel on start will not affect learned fuel trims.

[2Shaker]

5.0Rick,

interesting approach, and you are right, to me it seems vastly different than most of what I have done. However, I do agree with the Crank PW. In my own experience I had to lower the Crank P/W function by about 50% because the thing was flooding when warm. Starts perfectly now, hot or cold.

[Cougar5.0]

Essentially, your approach is the same as mine except for 2 small details. Crank PW function IMO is irrelavent. So with 42s you get twice the fuel at cranking. Once you release the starter, this function is not used. Using the stock values, I crank my starter half as long!

When my engine was hot, I would crank it for 30 seconds with no response. I had to hold the pedal down to dry up the excess fuel to get it to start at all. I cut the crank PW values and the car starts every time. Consider that others may have different experiences with identical injectors & slopes etc. when you make such broad-brush statements.

[JuiceSC]

Consider that I have helped several others getting their tune dialed in, and my experience has been the same each and every time.

[Cougar5.0]

So the two of us in this thread who had an issue don't know what we are doing?

You have a tendency of sounding like an arrogant ass hole at times.

[JuiceSC]

IMO=In My Opinion,


Out.

[5.0Rick]

Hi Guys,

1st of all, it is not my intention to flame anyone but this type of discussion is exactly what adds an incredible amount of frustration to someone who is just starting out with the Tweecer. There are lots of opinions and only one right answer.

My take is that we should be able to make changes that apply to every engine (with new injectors, MAF, cam) much like the stock A9L code applies to all stock 302s with a stock cam, stock MAF, stock injectors, and stock fuel pressure. At least close enough for the adaptive technology to dial in the rest (25% variance).

All settings are relevant, if they were not necessary, Ford would not have included them in the EEC period. I understand that all engines have different fuel & spark requirements, but that is handled by altering the tables. (matching fuel & spark needs to volumetric efficiency)

If I had a dollar for all of the opinions that people swear by and all of the tunes that degrade over time, I would be a billionare.

With that said, I posted this information to help the new guys that are just starting out. I am tuning via a chip and cannot datalog. I would be most appreciative if someone with a Tweecer RT could test my theory out and post their findings so everyone can benefit. There are 3 parts to my theory and they are as follows:

1. With a change in MAF, the stock MAF values can be multiplied by the injector ratio- in this case 42/19 or 2.21, these numbers closely match the Calc Pro-M datasheet values.

2. Also required to bring the load down to where it should be, you have to multiply the Engine Displacement Scalar by the same ratio - actual CID*2.21 -- for 42# MAF calibration - I have a 317 so mine is set to 700.73

3. The Stabilized fuel table aims for 14.7:1 at all load values. This table needs to be enrichened as load increases.

Please keep in mind that safety precautions need to be taken on boosted applications, the stock fuel and spark table values may be too aggressive and will need to be adjusted. Remember, this is not an issue with a car that has matching MAF and injectors because the calculated load is wrong (too high=more fuel and less timing) As stated earlier, the Stabilized A/F table will also need to be adjusted.

Regards,

Rick

[MaddMartigan]

From what I have experienced and learned so far, the MAF is a big part of getting all of this to work correctly. The problem with Pro-M seems to be that their calibrations and data sheets are sometimes off and you then have to fine tune your MAF transfer to work that out. Also, those of us with 42# injectors also need to think about what Ford did with the Lightnings that use these same injectors. The Lightning supposedly has it's injector slopes at 40/46 which would leave me to believe that the ECM would be constantly trying to compensate for those of us that used 42/50. I know that I ended up having to modify the MAF curve for my 90mm Lightning MAF as a result of this. This kind of issue would certainly explain why a tune degrades over time. If we do indeed have the wrong injector slopes then we are trying to make the computer compensate for a wrong setting and, while it will do it, I am willing to bet that it will continue to struggle to make that correction.

Also, if you have a Pro-M that was calibrated for injectors that are anything but stock so that it can trick the ECM then I think that will be one more thing you will be fighting.

[5.0Rick]

The problem with Pro-M seems to be that their calibrations and data sheets are sometimes off and you then have to fine tune your MAF transfer to work that out.

I disagree with the statement that the Pro-M datasheets provide erroneous data. They have (had, since they are no more) some very accurate expensive equipment used to calibrate their meters and they aim to achieve a scaled up MAF transfer (calculated values).

I believe that the reason tunes degrade over time is incorrect MAF transfers (tweeked) and the resulting incorrect load calculations.


Regards,

Rick

[Cougar5.0]

Pro-M flowed their meters with associated inlet components attached to simulate the system they'd be used in - panel filter, cone filter & blow through were popular calibrations. People even sent their system to them to get an accurate calibration to their actual setup. There is no such thing as a meter that is accurate, it is only as accurate as the system you install it in is like the system it was calibrated in.

If you think you can fine tune your car without an "RT" version to take datalogs to analyze, you are going to be doing a LOT of guessing. Nevermind that nobody really knows what the battery offsets & slopes are for "Green Tops" used in an A9L application.

I agree that there should be only right answer for each input, but without someone with expensive equipment testing these things (never mind statistical variations from batch to batch), we are going to have to hodge-podge the best we can - thank God for the datalog. I can't imagine how you are doing tuning without seeing the results of each change.

[5.0Rick]

Pro-M flowed their meters with associated inlet components attached to simulate the system they'd be used in - panel filter, cone filter & blow through were popular calibrations. People even sent their system to them to get an accurate calibration to their actual setup. There is no such thing as a meter that is accurate, it is only as accurate as the system you install it in is like the system it was calibrated in.

I am not trying to argue with you but I believe they are accurate enough. I mean, there are no absolutes only close enough. How many decimal points are used to determine accuracy? Not only that, but the number rounding that occurs when entering values would not be so drastic. In my opinion, if it was really that important to have it as accurate as possible, Ford would have had values like 13.000001 and not 13.000. Not only that but I believe they would have used different units like g/s instead of Kg/hr to gain more granularity.

Just food for thought...

Rick

[Cougar5.0]

Pro-M flowed their meters with associated inlet components attached to simulate the system they'd be used in - panel filter, cone filter & blow through were popular calibrations. People even sent their system to them to get an accurate calibration to their actual setup. There is no such thing as a meter that is accurate, it is only as accurate as the system you install it in is like the system it was calibrated in.

I am not trying to argue with you but I believe they are accurate enough. I mean, there are no absolutes only close enough. How many decimal points are used to determine accuracy? Not only that, but the number rounding that occurs when entering values would not be so drastic. In my opinion, if it was really that important to have it as accurate as possible, Ford would have had values like 13.000001 and not 13.000. Not only that but I believe they would have used different units like g/s instead of Kg/hr to gain more granularity.

Just food for thought...

Rick

I wish it was just a matter of round-off error. The ProM42 cal versus C&L 76mm 42lb cal are close. At 4.8V the ProM is 7.5% higher airflow but at 2.8V the ProM shows 20% more airflow. Two nearly identical diameter meters cal'd for the same injectors are not linearly related. My meter is off by up to 25% at higher flow rates from the manufacturers curves. Air does not flow uniformly through the meter BUT the sample tube is in only one location near the outside diameter of the tube in the case of C&L & the ProM bullet. Anything that effects the uniformity of flow before and after the meter will effect the accuracy of the results. Any bend near the meter effects the results - putting a cone filter where a bend used to be can dramatically effect the uniformity of flow through the meter.

If that's not enough food for thought, read the following post: http://forums.corner-carvers.com/showthread.php?t=8535 . Not only is the post rather entertaining, it will REALLY open your eyes WRT to the ProM bullet that you are using. :D

[5.0Rick]

Your statement about two nearly identical meters is inaccurate. One is a C&L and the other is a Pro-M. The Pro-M is electronically calibrated to match a scaled stock transfer and the C&L uses the stock electronics.

If you take the stock MAF transfer and multiply the values by 2.21 they are almost exactly the same as the MAF curve that is produced using the Calc Pro-M numbers (same throughout the voltage range). I am assuming it is not so with the C&L from your observations.

As for the example that you posted, there is not enough conclusive data on that particular cars tune. The fact that one car may make more peak power does not prove that one is more realistically matched than the other. Now if the torque and HP curves showed more power throughout the rpm range then that would be a different story, but I have not seen such data. (Also, more power with improved driveability as well.)

My meter was calibrated by the late Mr. Atwood (rest his soul), so I am confident that it is accurate. I don't want to make this a C&L vs. Pro-M discussion. I am sure they are both good meters and of course results will vary based on different variables.

[Cougar5.0]

If you don't read that entire thread that I linked to (not just the mindless first post in it), then you entirely missed my point. I knew something was up since you posted back too quickly.

READ. THE. ENTIRE. THREAD.

http://forums.corner-carvers.com/showthread.php?t=8535

There is an awful lot of information in that thread from people who knew the inside players at ProM. I especially love this quote in that thread:

The Bullet is for all intents and purposes is a fucking fluted exhaust pipe with a molded plastic "sampling tube" with a draw-through slot cut in the back of it shoved into the pipe. While it’s probably something of an unquantifiable improvement over a stock meter on a near-stock application, if you’re looking for any real performance gains, forget it.

It takes at least a half-hour to read that entire thread - trust me, you'll be glad you did.

[5.0Rick]

Interesting read, however it is more of the same. Theories and rambling...

Not to mention one very opinionated moderator with bad manners.

Again, nothing concrete just hear say. Nonetheless, whether or not this guy was an insider or knows what he is talking about.. don't know, sounds like more BS to me. I'll keep my Pro-M, I like the fact that the calc values are almost identical to a scaled up stock MAF function. Seems right to me.

Regards,

Rick

[Cougar5.0]

Anyway, the real point wasn't to criticize ProM (though the bullet really is a budget meter that is very sensitive to the system it's in), it was to show how important the "system" is with respect to the meter's accuracy. If that point isn't clear after reading that thread, then I don't know what else to say. Would it help any if I told you I was a mechanical engineer and that I do windtunnel testing at work and have helped design windtunnel? We use a "filter" before the area of interest that looks like a pack of straws glued together. This helps to laminarize the flow in the area of interest. We also have to ensure that the area after the measurement area has no changes in cross-section or bends or any obstacles for a significant distance as air "stacks up" and can have an effect on the flow uniformity for some distance before the obstacle in the tunnel. You saw all the grief that guy was causing himself because he had his TB just after his meter - totally bad idea.

I can't stop you from believing that a MAF is a precision instrument that is not affected by the system it's in (nevermind variations in calibration accuracy, electronic drift & cleanliness of the measurement elements) & that fuel injectors have no statistical variation to their electronics & they don't vary mechanically (the reason for "matching").

Anyway, have fun - though I really think you should get an "RT" version of TwEECer so you can more easily correct your issues through the datalogs. I can't believe you are trying to tune a turbo "by the numbers". Have you looked at the GUFB document yet? Everything you need to know about the A9X programming is in that document. BTW, your adjusting of the fuel & spark tables to "fix" you issues seems as "trial and error" as any approach I've seen here.

[5.0Rick]

Anyway, the real point wasn't to criticize ProM (though the bullet really is a budget meter that is very sensitive to the system it's in), it was to show how important the "system" is with respect to the meter's accuracy. If that point isn't clear after reading that thread, then I don't know what else to say. Would it help any if I told you I was a mechanical engineer and that I do windtunnel testing at work and have helped design windtunnel? We use a "filter" before the area of interest that looks like a pack of straws glued together. This helps to laminarize the flow in the area of interest. We also have to ensure that the area after the measurement area has no changes in cross-section or bends or any obstacles for a significant distance as air "stacks up" and can have an effect on the flow uniformity for some distance before the obstacle in the tunnel. You saw all the grief that guy was causing himself because he had his TB just after his meter - totally bad idea.

I can't stop you from believing that a MAF is a precision instrument that is not affected by the system it's in (nevermind variations in calibration accuracy, electronic drift & cleanliness of the measurement elements) & that fuel injectors have no statistical variation to their electronics & they don't vary mechanically (the reason for "matching").

Anyway, have fun - though I really think you should get an "RT" version of TwEECer so you can more easily correct your issues through the datalogs. I can't believe you are trying to tune a turbo "by the numbers". Have you looked at the GUFB document yet? Everything you need to know about the A9X programming is in that document. BTW, your adjusting of the fuel & spark tables to "fix" you issues seems as "trial and error" as any approach I've seen here.

I never said that the MAF is a precision instrument. I said it is close enough (how can "close enough" be confused with precision?). Did you read my posts? You seem to be a bit more concerned with forcing your view point rather than engaging in a constructive discussion.

Yes, I have a copy of the GUFB document and have been reading it. It is very long :)

Also, I am not adjusting the fuel and spark to correct issues, I am adjusting fuel and spark to achieve a good tune. That is how tuning is done, by providing the right amount of fuel and spark at a particular load.

lastly, nope it does not make a difference that you happen to be an Engineer. I am an Engineer (Systems Engineer) as well. I work with lots of Engineers, and guess what, we engineers are not always right :)

Yes, I know it may come to you as a big surprise, but I have been wrong before and believe it or not I am sure that you have too.

Seriously though, I appreciate you taking the time to respond to my post and make me think deeper about my theories. It's all good.

Regards,

Rick

[Cougar5.0]

Well, all this discussion of the "right" numbers made me decide that since I was already very close to the Lightning injector slopes & battery offsets, I mine as well just go the rest of the way & dial it in to exactly the same. Perhaps the injector drivers are the same, who knows. I changed them, took a drive then recalculated the breakpoint and I can say the car can't run much better. The transition from coasting/decel to tip-in & light accel has never been smoother. I was already at 40.68 high slope, but I changing the low slope from 44.8 to 46.8 seemed to dial in just a little more fuel going from high to low so that after a transition when the transient fuel is drying up, the recovery is very smooth & it only overshoots slightly above 14.64 - not even noticable under any conditions.

Edit: note that the tip in lean came back again worse than ever after the engine cooled off after the above changes. Makes me so mad sometimes trying to make changes & offer help here - you have to go through several engine cycles to completely verify any changes made.

I'm being firm because a turbo has a non-stock MAF tract (usually) and I have seen variations of 20% at high flow rates from one inlet setup to another using the same MAF! I don't want you to blow up your motor. I mean, you're not actually dialing in a turbo car without logging AFR are you?

[5.0Rick]

Well, all this discussion of the "right" numbers made me decide that since I was already very close to the Lightning injector slopes & battery offsets, I mine as well just go the rest of the way & dial it in to exactly the same. Perhaps the injector drivers are the same, who knows. I changed them, took a drive then recalculated the breakpoint and I can say the car can't run much better. The transition from coasting/decel to tip-in & light accel has never been smoother. I was already at 40.68 high slope, but I changing the low slope from 44.8 to 46.8 seemed to dial in just a little more fuel going from high to low so that after a transition when the transient fuel is drying up, the recovery is very smooth & it only overshoots slightly above 14.64 - not even noticable under any conditions.

I'm being firm because a turbo has a non-stock MAF tract (usually) and I have seen variations of 20% at high flow rates from one inlet setup to another using the same MAF! I don't want you to blow up your motor. I mean, you're not actually dialing in a turbo car without logging AFR are you?

I am running a wide band O2 (AEM), so I am keeping tabs on the A/F and I am slowly (baby steps) increasing the boost. My spark is also very conservative. I am running 20 degrees max. My plan is to run approximately 8-10 psi max on premium pump gas.

BTW, wouldn't an increase in slope actually decrease the amount of fuel delivered since the ECU expects the larger injector to flow more, it cuts back the pulse width?

Rick


Rick

[Cougar5.0]

BTW, wouldn't an increase in slope actually decrease the amount of fuel delivered since the ECU expects the larger injector to flow more, it cuts back the pulse width?

Rick


Rick

Yes. The ECU thinks the injector is larger when the low slope is set higher, so it will use a lower pulsewidth. The only time the pulsewidth is less than 2ms where it would transition to low slope in my car is when the car is coasting/decelerating, thus when you tip in, the ECU will be transitioning from a larger to a smaller injector (in it's little head) and thus it will dial out the pulsewidth during a transition from low to high. This is the way I am thinking of it today - does it make sense to you?

[sailorbob]

Started off well this thread, and then lost it's way at bit :D Adding my observations;

Larger injectors do require smaller cranking pulsewidths, simulating larger injectors by increasing the pulsewidth shows this. As an aside, my guess is that the MAF signal isn't reliable enough at cranking speeds to calculate a desired A/F ratio and therefore a simple injector pulsewidth based upon ECT is used.

I consider that the MAF transfer should always indicate true airflow into the engine, the scaling of it to compensate for different sized injectors is a 'fudge' and because of the complexity of the eec any scaling inevitably causes driveablility problems (I think the sheer number of posts on the various boards about MAF transfer problems bears this out). The eec calibration data should always reflect what's actually fitted to the engine and unless you are developing more than 200% LOAD then the eec will cope with all your modifications. Only if you are exceeding 200% LOAD would I advocate rescaling the displacement to cope. You should rescale your tables to cover the LOAD range your engine produces.

[5.0Rick]

BTW, wouldn't an increase in slope actually decrease the amount of fuel delivered since the ECU expects the larger injector to flow more, it cuts back the pulse width?

Rick


Rick

Yes. The ECU thinks the injector is larger when the low slope is set higher, so it will use a lower pulsewidth. The only time the pulsewidth is less than 2ms where it would transition to low slope in my car is when the car is coasting/decelerating, thus when you tip in, the ECU will be transitioning from a larger to a smaller injector (in it's little head) and thus it will dial out the pulsewidth during a transition from low to high. This is the way I am thinking of it today - does it make sense to you?

Yes that makes perfect sense. I thought you had indicated that you had added fuel by increasing the slope.

Rick

[2Shaker]

One thing I overlooked when I was in this area is the minimum pulse width. It is a scalar in CBAZA, do you have that? With bigger injectors the EEC may be commanding a value less than the minimum PW scalar and indeed the car ran a lot better when I reduced this number by half.

Also, FWIW, I am convinced the MAF plays no role in crank.

[5.0Rick]

One thing I overlooked when I was in this area is the minimum pulse width. It is a scalar in CBAZA, do you have that? With bigger injectors the EEC may be commanding a value less than the minimum PW scalar and indeed the car ran a lot better when I reduced this number by half.

Also, FWIW, I am convinced the MAF plays no role in crank.

Hi 2Shaker,

Unfortunately the A9L does not have that scalar (at least it does not appear on my version of Caledit - I have a binary file producing version)

Rick

[MaddMartigan]

Sorry to interrupt the exchange but I figured I may as well respond to back up my Pro-M remarks.

There was a lot of people (here, and other places) that discovered that Pro-M had a bunch of kids doing their flow bench work and that they weren't always doing a good job calibrating the MAFs.

Secondly, it has been said already but it seems that it should be mentioned again that calibrating a MAF to "match" a certain size injector is just crap. The whole reason we are all doing our own tuning is so we can do it the right way. A MAF flows what it flows. The transfer table just tells the computer what voltage is being required and the corresponding air flow. There is nothing there that tells the computer what size injectors to use. If you change those numbers to modify the amount of fuel required it is because you are giving the computer erroneous data and making it change the amount of fuel it is sending. If you give the computer wrong numbers then it is going to calculate incorrectly. I don't think any of us are smart enough to calculate all of the variables involved with this. Again, you are going to cause the computer to constantly fight itself.

In the end, knowing the actual tranfer function table for the MAF, the appropriate injector slopes and minimum pulsewidth is the first major step towards making this all work. I got my car to idle and cruise just fine by setting the appropriate values in those areas and then "tweaking" the MAF curve ever so slightly to compensate.

FWIW, the 90mm LMAF curve that comes with CalEdit does not match what the Lightning ECM has in it. The Lightning ECM apparently also uses injector slopes of 40/46 instead of the 42/50 that I originally started using. I am still experimenting to see if that is the reason I had to modify my MAF transfer.

Also, this isn't an argument or fight of any kind. Just an opportunity to learn.

[5.0Rick]

Hi MaddMartigan,

You are correct the MAF has nothing to do with the injector size. The MAF is used for load calculation. In turn, the load calculation along with the entries in the tables are used to provide the appropriate amount of fuel and spark.

Please note, the MAF transfer by itself is not what is adding or removing fuel.

If the MAF is off, then the load calcs are off. If the load calcs are off, then the tune degrades over time (changing temp, barometric pressure, humidity, etc).

This is why I am focused on getting the load calcs right. So far the changes that I have implemented have had consistent results. The car runs the same (driveability) every time after many on/off cycles and a few weeks elapsed now.

If I had an RT I would test (datalog) the following:

1. 19# injectors with stock MAF - datalog to profile the load - what load range while driving (non aggressive driving)

2. 42# injectors with Pro-M MAF with the Calc flow values in the MAF transfer, along with the Lightning injector settings and the scaled engine displacement (engine displacement*(42/19) or 2.21

Then I would compare the datalogs to see how similar or dissimilar the loads are. This would help me determine whether or not my theory is correct.

Regards,

Rick

[MaddMartigan]

Rick,

I think that's a good way to go about it. The only thing I would add is that, from what I have read, Ford based most of their loads on a VE of around 65%. In your case and even more in mine, that number is no longer accurate since we are using more displacement than stock and we have a much better flowing system. When I used a Load Scaling setting of 2, I was seeing loads in excess of 150% on my 347. Now, I realize that this would be considered normal for a forced induction application but I am NA and it lends even more credence to the idea that we are far exceeding Ford's original design. I think you are on the right track by modifying the Cubic Inch Displacement scalar but I think you may be using the wrong calculation. You really need the RT function to see the results of this however. If I understand all of this correctly (and I'm not guaranteeing that I do), I would say that if you figured out the correct VE for your engine combo and then figured out what percentage more than the Ford 65% baseline, you may be able to use that factor to modify the CID scalar and then have a correct result. My calculation would be something along the lines of CurrentComboVE/FordFactoryVE*CurrentCID=CID Scalar.

Now, I think you can figure out Ford's base VE by taking the Sea_Level_Load_Scaling vs. RPM function and comparing that to the actual load numbers you datalog. By using that you could figure out the average higher percentage and then multiply your current CID to get the appropriate CID Scalar.

Of course I could be way off too. :?

Hi MaddMartigan,

You are correct the MAF has nothing to do with the injector size. The MAF is used for load calculation. In turn, the load calculation along with the entries in the tables are used to provide the appropriate amount of fuel and spark.

Please note, the MAF transfer by itself is not what is adding or removing fuel.

If the MAF is off, then the load calcs are off. If the load calcs are off, then the tune degrades over time (changing temp, barometric pressure, humidity, etc).

This is why I am focused on getting the load calcs right. So far the changes that I have implemented have had consistent results. The car runs the same (driveability) every time after many on/off cycles and a few weeks elapsed now.

If I had an RT I would test (datalog) the following:

1. 19# injectors with stock MAF - datalog to profile the load - what load range while driving (non aggressive driving)

2. 42# injectors with Pro-M MAF with the Calc flow values in the MAF transfer, along with the Lightning injector settings and the scaled engine displacement (engine displacement*(42/19) or 2.21

Then I would compare the datalogs to see how similar or dissimilar the loads are. This would help me determine whether or not my theory is correct.

Regards,

Rick