Do you guys know about the idle advance table? I just found out about it from Peter last night.

Sam

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So I filled in the timing map with Ed's numbers. EVerything below 65 KPA got maybe 10 degrees added. Then I drove the car. It drives fine, but I actually thought maybe I lost a little torque. This is just a seat of the pants thing, and may not actually be true. I watched the laptop timing needle, and it followed correctly, so know timing is being controlled correctly by the ECU.

I think since Ed developed these numbers by stopping just short of detonation, they may be, as MAtt alerted us to, just a few degrees beyond peak HP.

Later, I will take just a few degrees out of each cell, and take another run. This is not really very objective, or scientific. But, right now without a dyno, it is the best I can do. Stay tuned.

If you look at George's numbers, you will see they are lower than Ed's. So maybe the peak HP is just a tad below his.

I sent a copy of the file to Ed, and he returned it in 3D from. That was cool. I hope he posts a screen shot of this for us all to see. You will not be able to rotate it more than likely, but it is still cool. Thanks Ed. Actually I hope he fills in the blank cells first.


Sam

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You really need to know MBT and borderline knock. MBT is the spark that gives maximum brake torque and borderline knock is the maximum spark to prevent knock when running 14.64:1 air/fuel (or lambda = 1) at a given coolant temp and inlet temp. These are typically mapped by the OEMs in a test cell. There are modifiers to these tables. Without this data, you will have to determine a good working spark map experimentally - which can be very time consuming. Typically, you make peak power with spark several degrees away from detonation because while you may run spark low enough to prevent knock, you can still at the same time have spark too early and this will make peak cylinder pressure before the engine reaches maximum mechanical advantage - and you'll end up fighting the piston motion at the end of the compression stroke.

Mitch

So maybe my seat-of- the-pants sensation was correct? I have seen this dyno process done, and it is amazing. Finding someone who knows how, has the right type of dyno equipment, and won't charge an arm and both legs, and is also responsible, and honest is a challenge.

Thanks. Sam

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This typically is not done by outside independent tuning shops. What they do is find what works best for WOT. The OEMs map all areas of speed/load so you know MBT not only for WOT, but for part throttle as well.

Mitch

What you say is true. You cannot get max HP out of an engine without optimizing timing in each cell. You must hold the engine at a steady state, RPM and MAP, and adjust timing until max HP is reached. This must be done again and again in cells all over the timing map.


There was one guy here locally who had a steady state dyno, and claimed he could tune all cells for max HP with timing. I learned the hard way NOT to trust this guy. He kept my car over a year, and did NOTHING. He claimed he did something, and charged me for what he claimed he did. But in the end, I do not believe he really did anything. Certainly he did not tune the ECU. By then I was just glad to get my car back. His name is John Behe. Steer clear of him for sure. Fancy web sites do not a trustworthy, competent tuner make.

Oh he tuned up Corvettes and GTO's fine, but my car sat. So, I am really afraid of that route for now, unless I get a rock solid, gold plated reference from someone. You know what they say, if it sounds too good to be true, maybe it is too good to be true.

Sam

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Ed, I have to apologize for my poor analysis of the results when applying your timing map to my engine. I said it seemed like it had less power. So here goes a retraction of sorts. True, it did have less power, but after fooling around with tuning today I discovered the reason it had less power.

This is big. Because the engine was winding up further in the RPM range with less throttle, and thus a lower KPA, the engine ended up operating in a section of the fuel map it had never been in before. And, this new section was tuned too lean. Once I really started paying attention, I found the engine wanted and could use far more timing than I thought previously. So the better tuned it gets, the more easily it gets into the low KPA, high RPM sections of the Map.

As I tuned timing, I had to keep looking at the fuel map, and the AF ratio gauge and adjusting things as the engine got into those new areas. My timing map now looks a lot like Gunpilot's. And, it feels much livelier under the right foot.. ACtually it is kind of a combination of Ed's and George's.

I wish I had a steady state dyno. If I were to take the car up a steady straight incline and could maintain constant RPM and MAP, how could tell when I had advanced the timing too far? Would there be a bucking or missing? Would the vacuum start to drop perhaps? I know it cruises at higher vacuum now than it did before adding timing back in. I can tell this is where the real economy and real HP resides.

Thanks again Ed for your hard work before, and willingness to share. And thanks Gunpilot for posting your map. How do I go about posting a printout of my timing map here? Can I turn it into a JPG and put it on photobucket with the photos?

Sam

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You are welcome Sam. As I said in another thread, my map is not fully refined yet, as I quit tuning once I was at the track.

To grab the image of your timing map, I use a thing called Jing (http://www.techsmith.com/jing.html) to capture the image I want. I use the free version. They have free hosting of the images too. If you don't want to install yet more software, you can send it to me and I'll post it again for you.

-G

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It's a Slant thing. Even I don't understand.

1974 Duster, EFI /6 soon to be turbo...

Get that Monkay! Get that nasty thing!!

I thought maybe I could get the table screen copied within the windows capabilities. So far I have not been able to get the image of the table copied in any way. I thought print screen key stroke would get it captured enough to copy it into a word doc, but no go. I exported it using the export command under the right mouse click, and went through that, but then I could not find the file after that. I do not know where it saved it, or exported it to. I went to "file" open, and all it displayed in the menu were complete tuning files. Any help as to where the exported table went to?

Thanks, Sam

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Here is the current timing map. My daughter showed my how to copy the screen to paint shop, and then save it as a jpg.



The plan is to raise the timing further in the lower KPA cells between 1900 and 3000. Aggressive Ted says he has his timing pushed to 50 BTDC at 2000 RPM at high vacuum without problems.

This map provides good crisp throttle response, and no preignition on mid grade fuel. It is important to realize that there is an idle map that actually reduces the timing to lower levels until the throttle is cracked, and then the timing jumps to the figures shown in the table.

It is also important to know that MSII provides an adjustable table for more advance when cold, and I have almost 10 degrees added when cold. This increases idle speed, and improves cold drivability. Enabling this feature means you have to use good sense and not push it when cold, or likely it would be into pre-ignition.

I will post my fuel table for Jari, our Finnish friend, soon.

Sam

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What's with the 32 in the lower right corner?

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Good question. Just an oversight. I do not expect the engine will ever see that cell. But, I will correct it. Also, Those two lower left 12's can be raised to 20. The idle timing table has them set at 10. Thanks.

Any thoughts or advice is welcome. I am no expert. I just write and post a lot. I do fiddle with the car a lot too. But it is always with a sort of naivete that wonders not only why things took the turn they did, but if there is a better way. Comments from the forum have been an enormous help.



Sam

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