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matty

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On 13th May, 2009 Paul S said:
The problem with big injectors is that they are supposed to be problematic at idle. Hence, I'm reluctant to take too great a step in that direction.

However, I've not had an idle problem with four large (480cc) high z injectors, although pulse widths were very low, less than 2mS.

I've just bought a set of four 630cc high z injectors for the 1293 turbo. So I could try those on the 1030 engine.


Paul, im running the 480cc injectors and on low idle (850-900rpm) the pulse width is well below 2mS. Mine idles really well only using the igniton timing to keep the idle steady.

Would it be an option to run the larger injectors but just increase the idle to a point where the PW are 'acceptable' then if they prove to work well in the rest of the rev range, have another look at the idle control?

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jbelanger

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On 14th May, 2009 Gerald O said:
What happens with the existing code when the timing for the two pulses overlaps? Does it effectively result in a single longer pulse?

If the overlap is small, what happens is that the second pulse start is delayed until the next wheel tooth and there is still a gap between the pulses.

When the overlap increases, the second pulse start is still pushed to the following tooth but the gap disappears and the resulting single pulse is no longer the sum of the 2 pulses.

This is a good way to handle overlapping pulses in a non-siamese engine since the pulses are evenly distributed. However, it doesn't work on the siamese engine with the 2 pulses one after the other followed by a large gap. Therefore this situation must be avoided by advancing the inner cylinder injection timing.

Jean

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Rod S

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Matty, two questions....

1 - as you are 8 port presumably you are running your injectors at the more normal 80-90% duty cycle ???

2 - are you using low z or high z - I really want to understand whether the "alleged" quicker response of low z at larger sizes is worth the hassle (setting up PWM on the basic MS as I haven't yet modified it for Jean's P&H board).

Schrödinger's cat - so which one am I ???


Paul S

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On 14th May, 2009 jbelanger said:
On 14th May, 2009 Gerald O said:
What happens with the existing code when the timing for the two pulses overlaps? Does it effectively result in a single longer pulse?

If the overlap is small, what happens is that the second pulse start is delayed until the next wheel tooth and there is still a gap between the pulses.

When the overlap increases, the second pulse start is still pushed to the following tooth but the gap disappears and the resulting single pulse is no longer the sum of the 2 pulses.

This is a good way to handle overlapping pulses in a non-siamese engine since the pulses are evenly distributed. However, it doesn't work on the siamese engine with the 2 pulses one after the other followed by a large gap. Therefore this situation must be avoided by advancing the inner cylinder injection timing.

Jean


When Rod has finished the bathroom, I'm hoping that he will get his new scope working and tell us exactly what happens.

The pulse from the MS is only one aspect, the ability of the injector to start flowing again is more critical in my opinion.

Matty, the problem we have is that two 375cc injectors only allow decent AFRs up to 3000rpm using the two pulse mode on my engine. So I could use four 375cc injectors, a total of 1500cc to get that up to 6000rpm in NA mode. But to then apply the turbo charger, I would need a total injector capacity of around 3000cc/min for one bar boost. The 480cc injectors are OK, but we need to go much bigger with the two pulse mode.

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Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Rod S

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On 14th May, 2009 Paul S said:

When Rod has finished the bathroom, I'm hoping that he will get his new scope working and tell us exactly what happens.


Ouch....

PM me your latest msq and I'll run it tomorrow on the scope - tell me what RPM etc you want to see it at.

No tiles today, I've actually had a break (not literally) at 78 to go, and been finishing soldering my wiring loom today...



What a pain..... It's a lot better now with all the heat shrink on.

Schrödinger's cat - so which one am I ???


Paul S

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Your soldering gets better towards the end *hehe!*

My latest .msq is single pulse. I did send you the best two pulse .msq some time ago.

By the way, my wife does the tiling. Only trouble is that she gave up when she got to the toilet cistern - too difficult. That was about two years ago and it's been like it since.

Minis take priority.......

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Rod S

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On 14th May, 2009 Paul S said:
Your soldering gets better towards the end


Yep.... but it looks worse to the left as the injector wires have to bridge two terminals and these Dsub connectors are supposed to have a single SMALL wire soldered into each individual teminal.....

Whilst doing it the word "VEMS" kept coming into my mind.... but I managed to push it away *happy*

I've still got the earlier msq files you sent so I'll try them both.

8 to go here (once the mirror is glued in place


and the final 70 here


over 350 in total.... Anyway, back out to the garage to finish the relay/fuse block...

Schrödinger's cat - so which one am I ???


carl talbot

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you should do a bath/shower/wet room with 100mm hand made french tiles , with a colour mosaic
not one straight edge or 90 corner !

you wouldn't be moaning about a bit of fiddly soldering !!


*happy*


Rod S

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On 14th May, 2009 carl talbot said:
you wouldn't be moaning about a bit of fiddly soldering !!


When you get to my age, you moan about anything and everything :)

Right, scope connected


I haven't bothered setting suitable scales etc. yet because it's triggering on channel A (quick and easy just to check everything works) but it can't make its mind up whether to trigger on the first or second pulse.

So I'm off to see how to get the external trigger to work (involves a bit more fiddly wiring....)

I want it triggering off our phase pulse (cam) as Jean says that is a constant engine degrees - then we can actually see the injection timing moving across the screen.

It's your msq Paul, hence the different pulse widths.

Schrödinger's cat - so which one am I ???


Paul S

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Great.

Can you wind up the revs to see how the MS handles the pulses getting close/overlapping?

Just really need to see one of the signals over one cycle.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


miniminor63

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looking at that sad looking connector I am glad I went for the VEMS ... It was one of THE reasons I chose one over the other. Still, MS is the choice for siamese port injection, so I am following with interest. You guys sure put down a lot of time in this, looks promising though!


Paul S

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The use of the DB37 is undoubtably questionable in this application. Plus there are better ways of doing it.

However, the are very few reported problems with it in use. I've been using the MS forums for a couple of years and don't recall any problems associated with it.

I've connected/disconnected mine dozens of times over the last 18 months as I've tried different code versiosn and setups - no problems so far.

I always buy the pre-made loom, that has been assembled by machine.

Another case of smoke and mirrors in my opinion.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Rod S

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On 15th May, 2009 Paul S said:
I always buy the pre-made loom, that has been assembled by machine.

Even assembled by machine (presumably crimped ???) the correct size wires are simply too large to fit in the teminal ends so I don't know what bodge they do to get around it... plus, as Jean says, with Extra/Siamese, the configuration is different anyway.

Anyway, back to business....

I haven't got the external trigger to work yet so I've just put the cam pulse on the A channel (red) and we're only looking at one port's injector.

I've left the timebase fixed so you see more and more cam pulses as RPM rise.

REMEMBER, the pulse is DOWNWARDS on the display.

3000 RPM


6000 RPM


7000 RPM


All as expected (I think) until 8000 RPM


The pulses merge but change in length every other (2X) RPM.....

Pulse end point looks the same, start point differs.

Schrödinger's cat - so which one am I ???


Rod S

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Right, I've just tried 6000 RPM and applied a bit of boost (syringe on the MAP sensor) and exactly the same - the transition as the pulses merge is really wierd but I can't capture moving images (yet....)

Schrödinger's cat - so which one am I ???


Paul S

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Whoops

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Rod S

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caught it just as it was changing to alternate short/long

I reduced the timebase to show more pulses.

6000 RPM and slowly adding boost




Once all merged, the short/long is totally uniform but during merging it's a bit random.

I may dig out my old scope over the weekend just to make sure it's not a glitch with the USB one.

Megatune shows nothing that suggests this....

Schrödinger's cat - so which one am I ???


Rod S

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For Jean - I'm just scoping off the INJ tags on the JimStim, would it be worth adding some dummy load resistors.

I'm just wondering if the lack of load is affecting the flyback ??? I have the full build standard everything you need for low z injectors - I haven't yet installed your P&H board - and this is with Paul's msq which is set for high z (I assume).

Schrödinger's cat - so which one am I ???


Paul S

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Rod,

Just check that it not the rev limiter coming in at 6000rpm.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Rod S

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Nice idea...... You did have the rev limiter set at 6K but on spark retard.

Just to be sure, I changed to 10K (so I now have to rename another "Paulxxx.msq" but just the same.
I also tried 5k and a bit higher boost and the same....

Schrödinger's cat - so which one am I ???


Rod S

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Of course I may destroy your engine at 10K RPM !!!

I'm going to try and get the external trigger working, I really want to see both injectors, a 3 beam scope would be nice though......

Schrödinger's cat - so which one am I ???


TurboDave16V
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Didn't we see this same randomness at the merging point with the MEMS mpi data?

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Paul S

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So, to summarise,

The pulses merge rather than get pushed apart which is good, as long as the total pulse length is correct.

But the inner cylinder pulse goes missing every other rev which is not good.

I don't think that this accounts for my problems with getting equal AFRs above 3000 rpm as I would have expected the inners to go lean......... or would I ???

On the subject of DB37s and looms, The premade looms use a single thin wire per pin, then splice them in the loom to a larger cable.

Anyways, I've cocked up as the loom I've just bought from DIYAutotune does not include a wire for the VR Sensor on pin 7 and there is no easy way of connecting the cam signal input to pin3 as there is no pin in the connector *angry*

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Paul S

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Rod,

Before you do any more can you disable the injection timing table and put in a fixed value. We will then see what it's doing with the timing as the pulses merge.

At the moment the mid pulse timing is moving, but that should be with the table.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Rod S

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Just to complete the picture,
5K RPM and 0.6 bar boost


Dave, re. the MPI, before my time (ie I haven't read all the very early threads) !!!!

Thin wire then thick..... so only a little bit melts *happy*

I've got some Dsub individual pins (for making connectors the easy way, ie solder wire to pin and then insert in back of connector) if you want me to post you a few - they are meant for specific "bare" shells - which I couldn't get in Dsub37 - but may push into the back of your Autotune one.

Schrödinger's cat - so which one am I ???


Rod S

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On 15th May, 2009 Paul S said:
Rod,

Before you do any more can you disable the injection timing table and put in a fixed value. We will then see what it's doing with the timing as the pulses merge.

At the moment the mid pulse timing is moving, but that should be with the table.


Any specific values - as I'd rather mess with your msq rather than try and reload one of mine and get even more confused......

Schrödinger's cat - so which one am I ???

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