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@Graham Bates , that's awesome! Thank you for sharing. Looks like a very rewarding conversion.
Good point on the power and ground connections. Absolutely critical to get those right.
I am by no means an engineer so forgive if this is a dumb question but I'm all about raising the quality of inputs where possible for the LH/ EZK. so would it be possible to improve the quality of current by something simple say running dedicated power / something to condition the current to also smooth spikes. This sounds like a worthwhile upgrade to me.
I looked at the pinout for the LH for my car and wasn't able to make a quick easy way to do it...my mind is wondering is it possible one or more (if correct) incoming signals are also providing power for the unit and if yes would that connection then benefit from a similar solution to mitigating the current draw on our AC electrics with the under hood relay. I think if this is real I'd go with solid state relay(s) and pull directly off the top of the CE panel.
Would be really grateful for any recommendations and of course will do some pictorial documentation of anything done with a results report.
Early on when I was conducting some auto-tuning of the fuel maps the car suddenly came to an abrupt stop. I was driving around town not far from my home when it happened, fortunately. The car would not start and I looked at the tune on the laptop and it was rubbish. A spike from the alternator had upset everything. I opened a recent tune and used this to get home. I immediately started on a separate power supply. Since then it has been perfect.
Early on when I was conducting some auto-tuning of the fuel maps the car suddenly came to an abrupt stop. I was driving around town not far from my home when it happened, fortunately. The car would not start and I looked at the tune on the laptop and it was rubbish. A spike from the alternator had upset everything. I opened a recent tune and used this to get home. I immediately started on a separate power supply. Since then it has been perfect.
A have a couple of drives done now. Everything is working very well. Overall, the throttle is more responsive than with the OEM ECU's, the AFR targets are hit right on, idle targets are hit, everything just works. And the more data that I collect for analysis, the smoother it gets.
Following up on the knock posts above, here is a log from my most recent drive. It shows what I believe to be a legitimate light knock. Nothing catastrophic, just edging into the knock area of timing.
There are three line graphs in the image. The top one has the knock signals for all 8 cylinders in various colors (top right has the color index). The blue line is the knock threshold that I set. When it is crossed, the ECU considers the cylinder to be knocking. The middle graph has RPM in red, throttle position in purple, spark advance in pink, and knock retard in yellow. Bottom graph is the knock detected indicators.
I've select the point in time that the ECU considers the knock to be real on cylinder 4. The signal is at 54%, compared to roughly 25% for the other cylinders. Prior to the event, cylinder 4's signal was comparable to the other cylinders. If you look at the middle window, you can see the yellow knock retard line jump up. And shortly after, the cylinder 4 knock signal drops back below the threshold.
For perspective, the graph is zoomed in to where the time from when cylinder 4 was down with the other cylinders, to after the second peak where it has dropped back below the threshold, is 0.2 seconds. From second peak to when it dropped back down is 0.1 seconds.
It's very interesting looking at the knock signals. You can really see which cylinders are more noisy at different points in the RPM and load ranges.
Anyway, the knock detection and reaction capabilities in MegaSquirt are real.
Here is a view of most of the 30 minute long drive. You can see how the blue threshold line follows the contours of the cylinder knock signals. And then that big peak in yellow.
I'm giving this a lot of attention because knock detection is very important when tuning.
Initially I took the power from the fuse panel to the ECU relay/fuse panel. The 928 has an unusual set up where the panel is fed 12v from the alternator via the starter motor instead of from the battery. In the early 1970's Porsche did not know anything about ECUs! After my problem, I ran a cable direct from the battery + to the add on relay/fuse panel shown in the photo. I also ran a negative cable the same diameter to the earth bar in the engine bay. The earth bar is an aluminium bar 40 x 10mm bolted across the back of both cylinder heads. To the earth bar I connected all the sensor earths and the ECU earth. All the sensor wires have to be separate and the same diameter as the positives and if possible the same lengths. Everything is 0-5v and these voltages have to be very accurate. If you're
not using GM sensors they have to be carefully calibrated.
If you choose to use a MAF with MegaSquirt, either straight MAF or blended MAF/SD, you'll have to figure out what the MAFload axis range should be. It is similar to MAP, but scales differently (e.g. I'll see 95 MAP while my MAFload is 33). The formulas that MegaSquirt uses to convert the MAF g/s input into a MAFload # is based on engine displacement, RPM and intake air temperature. And some other things that aren't as clearly documented.
To make things easier, I've created a spreadsheet that will get you in the ball park. You will still need to load test the engine with your specific configuration to see what the actual maximum MAFload value is, but the spreadsheet will get you started.
Also on the spreadsheet is a linear axis scale calculation for the three row counts found in MegaSquirt (16, 12, 6). You can use the axis interpolate feature in MegaSquirt to do this for you, but then it also forces you to interpolate your existing map as well. If you converted a known good map, like an original map from the ECU, you may not want to rescale the map itself, or have to repopulate the fields. In which case you can use the spreadsheet to come up with the axis for you. It's just a minor aid, use or ignore it at your convenience.
When figuring out your MAFload number, you need to know the anticipated maximum grams per second of air your motor will use and at what RPM you'll hit that. A general rule of thumb is your crank horsepower equals the g/s. Very general, it's not exact and can easily miss the mark by a lot if you have poor ignition timing or other factors. So, put in your maximum hp at the crank in the g/s field, and the RPM you hit that at, and you'll get the likely MAFload # that MegaSquirt will see. The axis calculations automatically add 10% to that, because you want a row above your maximum for safety timing/AFR's.
Using 120 for MAT is a pretty safe number to use to get you close.
Figuring out what "MAFload" means in MegaSquirt can be confusing and feel like you're chasing your tail. Hopefully, the spreadsheet helps.
Things are going very smoothly. The autotune is really phenomenal on this generation of the software and ECU. There isn't a whole lot of improvement to be made after it's adjusted a cell
For example, when starting with a flat VE map and flooring it, the AFR's on boost were way too low for the first pull, which I can see on the gauge as I do the pull. Do the pull again and the AFR's are right on the nose of the target I defined in the AFR map. It's like that for all areas of the map. The more data you feed it, the more accurate it is.
Smoothing the surrounding cells by hand, as always, is critical to smooth load transitions.
One feature that I'm very happy about is the long term fuel trim. Once enabled, it constantly watches the fueling adjustments needed to hit your AFR targets, and creates an adjustment map that it applies to the base VE map. Just like a modern car.
The ignition map that I translated from my tune on the SharkTuner PEMS is working well. The translation seems to have been pretty accurate. Knock sensing continues to function very well and is invaluable in analyzing what's going on with the motor.
The car is driving very well. I want to dial in AE a bit more, and adjust the threshold when I'm just barely off of idle and cruising/coasting. But, I'm probably being overly particular. It really does drive great as is. It's already much better than with the SharkTuned ECU's. Instant response (not AE, just responsive to throttle and load changes), idle is very smooth, it starts very fast, just...so nice in every way. It really transforms the car.
The built in continuous logging to a memory card on the ECU is very nice. It doesn't capture as many fields as the computer does when the computer is hooked up, but it's more than enough for analysis and tuning for after I'm done driving with the laptop hooked up.
The tablet that I'll be using for my extra gauges will also capture logs for all drives, and automatically upload them to our private cloud. A very convenient way to have logs available from my desktop if I want to see how things are going, or investigate an issue from a previous drive.
It's also very cool to have the wheel speed input from the factory sensor. Boy, is it noise to just get 8 pulses per revolution. That needed a lot of smoothing. But, with that input calculates what gear I'm in, and can adjust settings based on the current gear (like limiting power to prevent wheel spin in lower gears).
I doubt if I'll have a lot more to post on this from here on. It's basically done and working, with nothing but data collection and map smoothing to finish things out. I'll post my tune once I feel that I've got it to a point where I'm no longer bringing my laptop with me on drives.
I run speed density with my Microsquirt, I'm only interested in performance, not fuel consumption though the fuel consumption now is a fantastic improvement. The autotune is superb for tuning the 928 though the idle settings are best done by hand. I lock out the cells below 1000rpm. The Microsquirt does not have a stand-alone data set up so I can only collect data with the laptop in the car. I recently bought a Windows tablet for Tunerstudio and that normally resides in my Fiat race car. The Fiat also has a Microsquirt which controls the supercharged engine. 10psi of boost and runs exclusively on E85. I use Tunerstudio autotune on the circuit and on the hillclimb events and run a data log at the same time. Later I use Megalogviewer HD to review the tune. I bought the HD version in particular to check my 928's tune with the histograms and correction tables but found that the autotune was nearly perfect. There are lots of excellent videos on Youtube but I find Andy Whittles hard to beat.
MS3Pro with TunderStudio Ultra has a separate idle VE table that you scale to cover the idle load/rpm range. Autotune works beautifully on that dedicated table and keeps the main VE table intact for off idle.
Megalogviewer HD is outstanding. I've also been digging into custom channels for things like displaying a resettable knock counter on the dashboard and adding itnto the logs so it's easy to find where events occur. The flexibility of TS and MLV is very good.
I spent many hours hand tuning the SharkTuner. It's a valuable skill and still necessary in conjunction with autotune. But, modern autotune algorithms save countless hours of analysis, data collection and testing.
Initially I took the power from the fuse panel to the ECU relay/fuse panel. The 928 has an unusual set up where the panel is fed 12v from the alternator via the starter motor instead of from the battery. In the early 1970's Porsche did not know anything about ECUs! After my problem, I ran a cable direct from the battery + to the add on relay/fuse panel shown in the photo. I also ran a negative cable the same diameter to the earth bar in the engine bay. The earth bar is an aluminium bar 40 x 10mm bolted across the back of both cylinder heads. To the earth bar I connected all the sensor earths and the ECU earth. All the sensor wires have to be separate and the same diameter as the positives and if possible the same lengths. Everything is 0-5v and these voltages have to be very accurate. If you're
not using GM sensors they have to be carefully calibrated.
Had you given any thought to powering the whole panel directly from the battery and doing away with the supply coming in from the hot post? I am thinking of trying that and disconnecting the lead from the jump post (at both ends; no need to decide to accept additional risk when not necessary)....I may be mis-remembering but my brain wants to believe I can safely shoehorn a 10Ga wire through where the O2 sensor goes in or nearby snake it up behind and attach to the same place the hot post lead went...
Nice handiwork on everything there, like the rig you have there for power distribution
The power from the hot post still supplies the power to everything other than the ECU, O2 sensor, coil packs and the fuel pump. This car had mechanical fuel injection so the add-on panel has the fuses for the injectors.
I've converted my 1987 928 to MegaSquirt. It was previously running and tuned on SharkTuner PEMs, with a mid-mount turbo and 11.6 psi of boost.
Attached is a spreadsheet with all of the LH/EZK to MegaSquirt wiring connections. Along with my personal notations on pins, letter codes, resistors, MAF/TPS/VSS/Hall/etc pinouts. And more.
Also attached is my initial tune. It does not include VE table adjustments from tuning under load. AE tuning is also not complete in the tune. And, most importantly, the fuel and ignition tables are scaled for 11.6+ psi of boost, which won't work well for most people. However, I came up with a method for converting stock ignition maps. Worst case, converted maps may need a little rescaling after some dyno/road logging.
I've attached these files for those who convert to an aftermarket ECU in the future and need to know some of the critical settings that work. Or, someone who just needs confirmation of OEM wiring. I tested every single wire of the OEM harness, and confirmed the OEM wire colors. The WSM is wrong on a few of them, but my spreadsheet has the correct colors, confirmed personally by me. Given that my OEM harness didn't match the factory documentation, I recommend that anyone else doing this also personally confirm the wires on their specific wiring harness. The WSM wiring diagrams can also be misleading, or difficult to interpret, as to which ECU connector some wires come together at. In general, if a connection goes to both ECU's, it is split/joined at the LH connector. It's all in the spreadsheet. But, confirm it for your situation, don't just rely on how my specific car was wired.
The car started on the first attempt and idled well.
A few highlights:
MS3Pro Ultimate (Made in the USA).
PMAS MAF and wrote my own program to convert their 37 point curve into a 64 point curve.
Switched the stock trinary TPS to a standard infinitely adjustable (potentiometer) TPS.
Came up with a method for converting stock ignition maps to work with MegaSquirt (or any other aftermarket ECU).
Works with OEM CPS and CAM/Hall sensors.
Adjustable tach output to get the dash tach dead on accurate.
Full sequential injection.
Dual CAN Bus wideband O2 sensors, one for each side of the motor.
Supports dual factory knock sensors.
Custom dashboards for both the PC and Android applications.
CEL and limp mode capability.
Flexible logic loops to control any device based on any parameters.
Fully customizable AFR target table for entire fuel table and supports closed loop for all AFR's/cells.
The MicroSquirt could probably be made to be plug and play and quickly/easily replace the LH/EZK's. At some point, that may become a necessary path for some cars or situations.
For me, the top tier MS3Pro Ultimate was the way to go. The feature set is impressive, build quality is excellent, and support is very good. Plus, it's one of very few ECU's that natively support MAF, allowing me to have a blended MAF/SD tune to get the best of both.
Bottom line...it works well. And it's very satisfying to have it fire up smoothly on the very first attempt.
Great install, I love Megasquirt!
We used MS3-pro for the 928-V12/6spd car.
The engine, a Toyota 1gz-fe v12 with sequential injection , wasted spark ignition, variable valve timing, variable intake manifold. dual knock sensors and dual wide band O2 sensors.
We had to design the management software for the engine. Megasquirt tech support was amazing! They even helped us troubleshoot and tune the engine.
Ms3-pro has been trouble free for 7 years and I couldn't be happier!
Cheers
08-11-2022, 10:05 PM
