MS2/Extra Alpha 3.0.3 20090507 (was 20090426)

[racingmini_mtl]

I sent you the BOM by email. The resistors listed in the BOM are 1/6 W or 1/8W but 1/4W resistors will fit. And the DB15 connectors are not included.

Jean

[KaPower]

When setting the injector timing for bank2, cyl's #3 & #2 Is the timing number in relation to TDC for cyl# 3 compression or for cylinder #1 compression.

I made this chart to help visualize where to set injector timing, in relation to intake valve timing, and piston position for all of the cyl's...

[racingmini_mtl]

The timing for the injection is exactly the same as for ignition. So for sequential injection, injector channel 1,2,3,4 timing corresponds to ignition timing for channels A,B,C,D so timing is with respect to TDC on compression/power (closed intake valve). Positive values are for advance (BTDC up to 360) and negative values are for retarding timing (ATDC up to -360).

For semi-sequential, again this will be the same as for ignition but wasted spark. So the injection for injector channel 1 will be timed with ignition channel A and with respect to TDC for both compression/power (closed intake valve)and exhaust/intake (intake valve opening) since there is one injection per rev (2 per cycle). For injector channel 2, it is timed with ignition channel B and also from -360 to 360 degrees.

So for 4-cylinder engines with the common 1342 firing order using semi-sequential, injector channel 1 is for cylinders 1 and 4 and injector channel 2 is for cylinders 2 and 3. So if you want to time your injection with respect to the valve opening, you can actually use 2 values because you can set it for the entire cycle but you will get one per rev. What this means is that you can set it to either 30 or -330 (if your valve starts to open 30 degrees BTDC) and cylinders 1 and 4 will have an injection at the same time on each rev at 30 BTDC and cylinders 2 and 3 will have an injection 180 degrees later (again 30 BTDC). For sequential injection, you'd have to enter -330 to have the correct timing for all 4 injector channels.

I probably put more information than you needed and wanted and I'm not sure that I answered your question but hopefully I did. If I was not clear on some aspect let me know and I'll try not to get lost (and lose you) on tangents.

Jean

[wrenchdad]

Guys,

I might be seeing a small bug, just doing some bench testing and looking. And when I turn on "include AFRtaget" I only see a change in the PW1 of about 0.2pw. It will match the PW2 when I turn it back off.

My question is shouldn't "include AFRtaget" effect both PW1 and PW2 the same?

just asking,

later wd

[racingmini_mtl]

I'll have to have a look at that. You're correct that both PW1 and PW2 should be affected equally (and PW3 and PW4). Can you post your msq?

Jean

[wrenchdad]

Jean,

Yes, I can post it, just keep in mind that this is NOT from a running engine but only from some bench testing I have just begun, OK?

Just saying that in case you find anything weird, thats why I said "might have found a bug".

let me know if you need anything else.
wd


edit
PS, I have one of your 4-channel Ign/inj driver boards, is there a parts list or diagram anywhere for how to connect it up?
I got it from KeithG, he said it order it but couldn't wait and made his own out of some perf board.
thanks wd

[racingmini_mtl]

Thanks for the msq. And no problem about it being only from bench testing.

As for the BOM, unless there's another wrenchdad, I did send it to you by email and you responded about a week ago. Let me know if you need another copy.

Jean

[KaPower]

I probably put more information than you needed and wanted and I'm not sure that I answered your question but hopefully I did. If I was not clear on some aspect let me know and I'll try not to get lost (and lose you) on tangents.

Jean

Thanks for the detailed response! The way I understand it now, if I had to explain it to someone, is that each injection timing setting corresponds to each cylinders ignition event in an engine cycle, with 0 degrees being TDC compression, and that each cylinder gets two squirts per cycle, or every 720 degrees of crankshaft rotation. Ok, nevermind... there is no easy way to explain it is there!

JM.

[wrenchdad]

Thanks for the msq. And no problem about it being only from bench testing.

As for the BOM, unless there's another wrenchdad, I did send it to you by email and you responded about a week ago. Let me know if you need another copy.

Jean

Jean,

Sorry, yes you did, just WAY WAY too much going on right now!!

thanks, wd

[md95]

To make sure i'm understanding your semi-seq code and how it works- We still get 2 injections per engine cycle, per each cylinder pair(1&4, 2&3), but ONE of the two injection events is 30 degrees BTDC for intake valve opening (as your example)? So each cylinder gets a squirt of fuel mid cycle, but one squirt at the "optimum" time at 30 degrees BTDC intake? I'd like to try this out on the 4g63..I run the release code now with semi-sequential but have injectors paired as 1&3, 2&4. I figured one cylinder of each pair gets fuel at 70 degrees Before intake valve open, and the other of the pair gets it 180 degrees later. This creates a "lean" pair of cylinders, and want to get fueling even between them all. I know full sequential will work just fine, just seeing how semi will work to start.

[racingmini_mtl]

You got it. It's done this way to make things as even as possible for all cylinders.

Now as to which timing is optimum for your (or anyone else's) engine, I can't say. You'll have to find out by trial and error (at least for now).

Jean

[md95]

You got it. It's done this way to make things as even as possible for all cylinders.

Now as to which timing is optimum for your (or anyone else's) engine, I can't say. You'll have to find out by trial and error (at least for now).

Jean

Thanks Jean. One more question- With semi- Lets say i want to inject fuel at 100 degrees BTDC right before the intake stroke/valve opens. All I would need to set is 100 value in the fixed timing box for 1&2? This then would give each cylinder fuel at 100 degrees BTDC and 460 BTDC? (2 squirt per cycle) I'm going to try this code out as soon as I get some time. I really want to try full sequential, but will do this first.

[racingmini_mtl]

You only need to enter 100 in the fixed timing box for timing 1. Timing 2 is for siamese-port engine and would take a bit too long to explain here so you can just ignore it (it will be grayed out anyway). With the 100 value, all cylinders will have one injection pulse at 100 degrees BTDC and one at 460 degrees BTDC. And unless you know differently, you can enter the same value for the cranking timing 1.

Now you have to know if you want the injection pulse to start at that point or to end at that point. If you want to start injecting at that point you select start-of-pulse as the timing trigger and if you want the injection pulse to end at that point, you select end-of-pulse.

By the way, fixed timing is a good starting point to establish what the engine wants in terms of injection timing. However, since the air is not moving at the same speed depending on load and RPM, the fuel will not necessarily reach the cylinder in the same number of engine degrees with a different load and rpm. That's why there's also the possibility of using a timing table instead of a fixed timing so you can fine tune the injection timing as a function of load and RPM. This may or may not be necessary depending on your setup.

By the way, most of this is available on my site here: http://jbperf.com/sequential/index.html. I would need to elaborate on what the timing actually represents as done in the last few posts here.

Jean

[md95]

Now you have to know if you want the injection pulse to start at that point or to end at that point. If you want to start injecting at that point you select start-of-pulse as the timing trigger and if you want the injection pulse to end at that point, you select end-of-pulse.

This is what is a bit unclear to me. What is the objective with these settings? Why not just start the pulse at the first point? If you need to adjust when it fires, why not just change the injector timing value? I guess I just dont understand this bit. I'm thinking these settings will have a greater impact for injection timing precision when using full sequential, not so much with semi.

By the way, fixed timing is a good starting point to establish what the engine wants in terms of injection timing. However, since the air is not moving at the same speed depending on load and RPM, the fuel will not necessarily reach the cylinder in the same number of engine degrees with a different load and rpm. That's why there's also the possibility of using a timing table instead of a fixed timing so you can fine tune the injection timing as a function of load and RPM. This may or may not be necessary depending on your setup.
Jean

Being able to tune the injection timing per load and rpm is really why I want to try this code out. I've been getting a few PM's and also one of the 4g63 installs I did complaining of a sudden power loss in the higher rpm range 5500-6000 or so..I've been trying to figure it out and have an idea it's with the fueling. I've been reading that link of yours, and have downloaded the code and configured MT to start a MSQ. Thanks for your time on this, it's pretty slick! I'll give this a go as soon as I can, and report back.

[racingmini_mtl]

Now you have to know if you want the injection pulse to start at that point or to end at that point. If you want to start injecting at that point you select start-of-pulse as the timing trigger and if you want the injection pulse to end at that point, you select end-of-pulse.

This is what is a bit unclear to me. What is the objective with these settings? Why not just start the pulse at the first point? If you need to adjust when it fires, why not just change the injector timing value? I guess I just dont understand this bit. I'm thinking these settings will have a greater impact for injection timing precision when using full sequential, not so much with semi.

It's useful to set timing on different engine events. For example, if you want (or need) to start injecting immediately after the intake valve has closed to give as much time as possible for the fuel to vaporize before going into the cylinder then you'd use start-of-pulse. On the other hand, if someone else wants to minimize the time the fuel spends in the intake but without injecting on an open valve to avoid cylinder washing, the end-of-pulse would be the one to chose and the timing would be set for the valve opening timing. Then, no matter what the pulse width is, the injection pulse will always end at the same timing.

To have the same thing using start-of-pulse, you'd need to compute the timing with load and RPM in such a way that with the pulse width given by your VE table you keep the same ending. That would be much more complicated, would need adjustment of the injection timing each and every time you adjust your VE table, and would not take into consideration all the aspects that affect the pulse width such as EGO, accel, etc. With end-of-pulse, you can just set a timing and the code will take care of all the adjustments so that the ending is always correct.

By the way, fixed timing is a good starting point to establish what the engine wants in terms of injection timing. However, since the air is not moving at the same speed depending on load and RPM, the fuel will not necessarily reach the cylinder in the same number of engine degrees with a different load and rpm. That's why there's also the possibility of using a timing table instead of a fixed timing so you can fine tune the injection timing as a function of load and RPM. This may or may not be necessary depending on your setup.
Jean

Being able to tune the injection timing per load and rpm is really why I want to try this code out. I've been getting a few PM's and also one of the 4g63 installs I did complaining of a sudden power loss in the higher rpm range 5500-6000 or so..I've been trying to figure it out and have an idea it's with the fueling. I've been reading that link of yours, and have downloaded the code and configured MT to start a MSQ. Thanks for your time on this, it's pretty slick! I'll give this a go as soon as I can, and report back.

I look forward to seeing your results. By the way, don't forget that you can also adjust the VE trim for each injector channel to have a perfect AFR distribution for all cylinders (in sequential mode and for cylinder pairs for semi-sequential). That could also play a role in the problem you mention.

Jean

[racingmini_mtl]

Guys,

I might be seeing a small bug, just doing some bench testing and looking. And when I turn on "include AFRtaget" I only see a change in the PW1 of about 0.2pw. It will match the PW2 when I turn it back off.

My question is shouldn't "include AFRtaget" effect both PW1 and PW2 the same?

just asking,

later wd

Well there was indeed a bug and it's also present in the beta 2.1.0 so I didn't introduce it. I have what I think is the fix but I'll wait for James or Ken to get back to me to confirm it. Then this fix will be in the next release (or something else if I was wrong about the fix).

Jean

[wrenchdad]

[/quote]
Well there was indeed a bug and it's also present in the beta 2.1.0 so I didn't introduce it. I have what I think is the fix but I'll wait for James or Ken to get back to me to confirm it. Then this fix will be in the next release (or something else if I was wrong about the fix).

Jean[/quote]

Jean,

Good to know I am not completely losing my mind!

thanks, wd

[Gerald O]

Jean, can you please elaborate on the injection timing scheme for sequential siamese mode? I have my MGB running on this now but I am lost when it comes to understanding how the timing settings apply to cam/crank-stroke position. I found settings that will run somewhat well by making random adjustments, but my AF ratios are very imbalanced between inners and outer cylinders. From your website I found this:

For sequential siamese mode, the timing is with respect to TDC on the intake stroke which is the start of the injection window for the outer cylinders. And the timing 2 values are only used in sequential siamese mode with the first timing value being for the outer cylinders (1 and 4) while the second is for the inner cylinders (2 and 3).

The timing for the outer cylinders seems to be explained clearly enough. What I don't understand is the timing for the inner cylinders. It seems, based on the default settings, that there is a different timing reference point for the inners - is this true? Or do the inners also reference to their own intake stroke TDC? Would a setting of 0 for both timing 1 and timing 2 mean that every cylinder would start injecting at 0 degrees relative to its own TDC?

I have my number of squirts set to 1 - simultaneous. Do you have any recommended initial settings for my engine?

[racingmini_mtl]

Gerald,

You're correct that 0 for timing 1 and 2 means that the injection pulse will start at TDC for all cylinders. By the way, for the siamese mode, the injection is timed with respect to TDC on the exhaust/intake stroke (as opposed to the normal sequential mode where it is with respect to the compression/power stroke).

The reason the timing should have different values is that the injection pulses are only separated by 180 degrees if the same timing is used so to leave some additional time between pulses, timing 2 is increased. This leaves the outer cylinders timing optimal (timing 1) for the injection window when the intake valve is open and moves the injection timing for the inner cylinder some time before the intake valve opening which is not an issue because all the fuel injected on closed intake valves go to these cylinders.

The additional time between the 2 pulses is needed to allow the largest injection pulse possible for the outer cylinders and still have time to have the injector close and reopen between the pulse for the inner cylinders and the one for the outer cylinders. If you have the same timing and you have a pulse width which is equivalent to 180 degrees (5ms at 6000RPM, for example) then you would have absolutely no time between the 2 pulses which would result in more fuel for the second pulse since the opening time would not be needed (but still used).

I know this is not obvious and my explanation might not be clear but if you think about what the injector has to do and read the above a couple of times you should get what I'm trying to say.

As for the different AFRs, even with a perfect timing you'll still get some AFR difference between the inner and outer cylinders because there is some VE difference due to the dynamic of the air going into the different cylinders. To completely balance the AFR, you need to go to the dual table mode which is modified when using the siamese mode. In this case, the dual mode allows you to have different fueling for the inner and outer cylinders with table 1 being for the outer cylinders and table 2 for the inner cylinders.

I don't have initial settings but you could contact Paul S on the turbominis forums who has a pretty good running engine. The problem is that his setup is quite different from yours so it will still require a complete retune but you should at least be able to see some trends.

Jean

p.s. It might be a good idea to start a new thread to continue this discussion. This will make it easier to follow won't confuse other people.

[PaulS]

This would be best in another thread, but here goes.

This is my injection timing table that gave me the best results using the sequential siamese option.



This was mid-pulse timing, using two 375 cc/min injectors on a 1030cc engine. Using the same timing table for inner and outer cylinders.

To be honest, once above 3000 rpm, the outer cylinders were starting to go lean whichever settings I used. I have subsequently managed to get equal AFRs on the inner and outer cylinders up to 5000 rpm by using a single pulse spread across the overlap of the two inlet valves of the siamesed port. I achieved the single pulse by invoking the second VE table and zeroing the settings across the map.

To take this further I've decided to use Jean's Quad driver board and have individual squirts per cylinder. I'm hoping to trail this soon.