arghx7

If changing the table doesn't do anything noticeable, it doesn't do anything noticeable. But it's another **** you can turn to try and address driveability, idle stability, rough running, whatever.

aidandj

iTrader: (5)

Code is on msextra.

18psi

iTrader: (76)

Oh trust me, I appreciate all the input and feedback in this thread. If I come off frustrated, it's only because of the constant seemingly contradictory nature of the posts from the different users.

This is one of those things that I'm messing with now because I don't have much else to mess with in the tune, and want it even better than it already is

PS: I'd still love for someone to clarify once and for all what the extremes are,
0 = end of squirt?
360 = approx middle of squirt?
720 = beginning of squirt?

Or is it vice versa?

And finally for DIY to hopefully chime in with how they came up with their 90-120 values.

patsmx5

iTrader: (16)

Ok so I have one lingering question.

Is it better to spray the fuel at an open or closed valve?

If you test this at say, idle, and determine that one is better than the other, does that hold true for the entire RPM range?

Also I can't help but notice DIY's map seemingly maximizes the time the fuel "sits" after being sprayed at a closed valve. To me this suggest spraying at a closed valve, and letting the mixture site there, is best in their testing. This must mean it results in the fuel having more time to vaporize from spraying it on hot surfaces (intake port, valves).

deezums

iTrader: (3)

I think it would be different with every setup, even on the same motor.

If you've got old junk injectors I can see having the fuel sit to vaporize helping, but newer injectors might hinder modern spray patterns... or they might be so baller as to not be effected no matter when it's injected. If you were expecting heat to vaporise fuel I expect tuning would be slightly harder, I mean the intake runner can't always be the exact same temperature right?

If you had a hot supercharger setup I could see leveraging the injection timing to cool the intake valve, were that even possible or how it physically works while under boost is another hard to answer question.

Really, the best thing to do would be minimizing variables by testing on a day similar to when you made the VE table, turning off EGO and comparing different values to known baselines.

I would also still like clarification as to when the squirt is in relation to the valve timing for various stock cams. Something like...

0 = TDC?
360 = approx ignition?
720 = interlaced??

While using end-of-squirt or beginning shouldn't necessarily be better than one or the other, can we agree that using EOS is less math for our little heads compared to beginning, so's probably the best one to use?

patsmx5

iTrader: (16)

Another question, possibly a good question too: What does the OEM ecu do regarding this? Maybe someone (DIY?) has already checked this and modeled their map as so? I wonder how hard it would be to test/log this? I'm guessing you would need an O-scope on the cam sensor and an injector, and know the cam phasing to crank phasing from scoping those 2 previously. Or a 3+ channel O-scope and do them all at once.

patsmx5

iTrader: (16)

Also good news, tracking number now shows my MS3 PRO will be here on Saturday, today, not monday!

So, what should I test? What do we want to see?

deezums

iTrader: (3)

I remember seeing a video of a stock miata idling batch, then going sequential, then batch again, am I nuts? It was a jimstim or something.

If so, it would seem they only care in closed loop cruise.

DNMakinson

iTrader: (3)

18: beginning, middle, end is a separate setting. Once that is chosen, then select the crank angle for that event. If you choose, "beginning", then the squirt starts at the table value. If "middle" then half the squirt is before the table value, and continues for half the squirt afterwards. If " end" then the squirt is started the squirt length before the chosen table value, so that it completes at the table value.

There is no difference between "0" and "720". Both represent TDC between compression and power. Every number in the taxable should be between "0" and "719", for simplicity.

"360" would be TDC between exhaust and intake strokes.

All this is on a per-cylinder basis.

Deezums: I can't imagine using anything except EOS. I suppose there would be reasons, but agree it will complicate the discussion.

OK, I thought of a time to use Start. If I want to know I'm squirting into an open intake, I'm going to set 360* and Start is Squirt.

arghx7

I can say this. The 1.6 on Ryephile's car didn't like closed valve injection. It always ran better with open valve. Some engines run open valve injection timing under all conditions. Honda is a good example. Others have some kind of mix between closed and open, with a mix between end of squirt and start control logic.

If you look at a recent Honda port injection engine it's all fixed end of squirt with some slight changes at full load high rpm. Look at a Subaru Ej257 engine and it's closed valve fixed EOI in closed loop fuel control and fixed SOI in open loop mode (basically squirts at TDC compression). BMW varies PFI start and end of injection according to vvt, speed, and load.

Mapping injector timing in a useful way with a scope isn't easy. I've done it before. I had LabVIEW software written by a consulting company to calculate injection timing with stock crank angle sensors. You need a scope kind of interface and you need to set trigger thresholds that don't pick up false signals. The other option is to install a special trigger and use special combustion analysis software meant for lab and OEM use.

patsmx5

iTrader: (16)

I tested this at idle on my car. It's a 99 miata, but has a 2003 VVT motor that's built. I run ID 1000 injectors with the fuel pressure turned up, so they spray 1,175cc/min.

I turned off EGO. The test was done at idle when it was fully warmed up.

I tried -90, 0, 90, 180, 270, 360, 450

90* in the ITT gave me the richest AFR at idle. Usually 14.3-14.4. Going Higher or Lower resulted in leaner numbers, 14.4-14.5, some all the way to 14.6-14.7!

I'm now running DIY Autotunes map.

patsmx5

iTrader: (16)

Also forgot to post, I tested changing the setting for 1, 2 and 4 squirts/cycle. As was said eariler, as long as sequential is enabled these settings do nothing. I swear in the past it did, but 100% sure that now it does not.

DNMakinson

iTrader: (3)

18: Realized the possible cause that you don't see the setting for squirt basis.

It is on the Basic/Load Settings Tab, Engine and Sequential Settings

18psi

iTrader: (76)

Mine is and has always been set on end of squirt tho
You can even see in original post.
Or are you saying I should change it to beginning?

DNMakinson

iTrader: (3)

No, I was trying to understand why you were still asking questions about how timing and position were interrelated (post 63). I thought perhaps you had not seen where to set position, and so posted it up. I didn't remember the initial post info.

See Post 69 for my take on when Beginning would be of use.

I'm thinking now about how to put together a spreadsheet to look at available time vs RPM and then populating with Inj time (based on generic VE with Inj size as a variable), to be able to picture how the various methods overlap. Not sure I can make it beneficial or not.

aidandj

iTrader: (5)

<p>Megasquirt3_Setting_Up-1.3 page 77</p>

Braineack

iTrader: (62)

sometimes i feel like people dont listen...

Braineack

iTrader: (62)

see post #32.

y8s

iTrader: (8)

I made this chart to help with things like this. It is not 100% accurate but helps to visualize. Note the orange lines (there are two, one for min and one for 83%). That's a squirt. If you use "end of squirt" then they all end at the same place.



You can use this to estimate the rough valve position during your injection event. I believe I set mine up so that the squirt ends juuuuust before the intake valve opens. I don't know if that's "best" or not, but it is what I did.

Edit: I think convention uses TDC in my diagram as 360. I jsut chose it at zero. I see references to both. What is important is to know what the MS uses for zero.

patsmx5

iTrader: (16)

See post #71, I tested it myself.

But I did read 32. I think your post is right, and they are in fact spraying at the valve right after it closes.