CamB

Thanks for the follow up. I am probably less worried about MAP vs baro and more interested to try it on a turbo car where it's MAP / Exhaust Mani Pressure as this could take into account backpressure change on a turbo charged car (i.e. Further flattening the fuel table). Of course if one isn't actually changing turbos this is arguably a fairly limited value add, but still ... it's got me curious.

While I don't have a working vehicle to test this, hasn't stopped me thinking about it. If one was absolutely keen to try IMAP/baro as a load axis for the fuel table table, could one: - set up a GP PWM on an Aux which outputs a frequency being IMAP / baro * 100 (i.e., one axis MAP, one axis baro, table populated appropriately) - feed the GP PWM into a DI - use that DI for the fuel table axis I plan to set mine up with an Aux linked into a DI anyway, as I have spare and there are other things that you can do. It does occur to me an easy way to implement this in the software might be to create a math channel (I am pretty sure I have seen this as a feature request anyway), and make that available for the fuel table axis. (Edit) Also to the discussion above I think Motec's "engine load normalised" is similar to Link's "Load (Abs)" (and not the same as IMAP / baro), which is good (probably) for ignition, but not fuel as it effectively requires VE as an input.

Try searching the G4+ help file for "Link Map Sensors" (its in the wiring section) - is that the right one?

I'm learning as much as anything through this process too. This is the best discussion I am aware of: http://injectordynamics.com/articles/gm-injector-characterization/ The minimum delivery of 1ul is an effective pulse width of <0.1 msec for your injectors (1/10.72). (would be great if someone checked my maths - I assume if the injector is 10.72ml/s this is 10.72ul/ms) Do you mean how does this relate to the Link setting "minimum effective pulse width"? Hopefully someone at Link reads this but my working assumption based on what the help file says is that this has two jobs - (1) to set the minimum recognising that injectors won't open at all below a threshold and (2) to stand in place of accurate short pulse width adders. For example, if my spreadsheet is correct (not guaranteed!) then the minimum could be 0.1 ms, but only if the short pulse width adder was right. If you had zero in the short pulse width adder table you'd want to have closer to 0.6ms (to account for the non-linear injector response down there). I guess if I was in your position I would put something conservative in there, like 0.2-0.3ms. Then if this minimum is kicking in at idle (which I am not good enough at maths to work out), based on logging, try lower and see if it still runs. Would be interested in others thoughts?

The ethanol sensors send a PWM (digital) signal with frequency indicating ethanol content and pulse width indicating temperature.

For what its worth, in the version below I have added the maths I think is right (shows deadtime pretty similar to the M800 style deadtime, and a mathematical attempt to work out what the short pulse width adder would need to be). Happy to be corrected if I haven't worked it out correctly - I am here to learn! 0 280 158 123 Customer sheet v2.xlsx

What injectors are they? Out of interest (and seeking data for my own injectors, although yet to use them with the Link so can't confirm if this works), in the past I took the data from Motec M1 Tune (which is what Nils' data looks to be) for my own injectors and put it into a spreadsheet and did some maths. BTW, I don't think the columns are labelled right - eg in 10v I think it should be 1.00ul of fuel requires 1.636ms of injector time. You can work out the dead time implied for each point given Motec's assumed reference flow (and pressure)At 10v - 1ul delivered in 1.636ms, should take [X]ms (depends on injector size) - difference between 1.636 and X is deadtimeRepeat for whole columnI then averaged the deadtime once it became more or less linear (about 8-9ul), and called the difference where non-linear the "short pulse width adder"I tried with the data ID supplies for ID1000s (for use with M1 Tune), and the deadtime using my method is a very close match to the deadtime they show for GM characterisation. The short pulse width adder less so (eg for effective pulsewidth of 0.25ms, my maths says to have a short pulse width adder of 0.075ms, whereas ID would add 0.134ms. Now I don't know if the above is accurate but it seems reasonable... use at your own risk, etc. Interestingly Motec's data for ID1000s is different to ID's data....

Sorry if I've missed it in the above, but does the engine have any form of idle control (Idle solenoid, stepper, ethrottle)? Are you using the idle ignition table?

Random update on this as I was putting in some quality time looking at axis options... and I wonder if a suitable measure is already there. - there is a parameter called Load (Abs) - if one googles "Load_ABS"and SAE, there is what looks to be an extract from the SAE standard saying its basically an estimation of cylinder fill (takes into account MAP, standard baro and temp) (click here if keen) - subject to engineering confirming, it is probably a good measure for ignition? - while it can be selected as a fuel axis, I can't see how it would work as I think VE is an input into Load (Abs).

If you had "30" as the number in the fuel table for both 50kpa and 40kpa rows, assuming the fuel mode chosen is Load=MAP then the fuel the ECU calculates will be multiplied by 40/100 rather than 50/100 as MAP is applied against the fuel table numbers. The simplified (traditional fuel) equation would be something like: Master Fuel (20ms) * fuel table number /100 * MAP / 100 However when the (hypothetical) engine was tuned, the 40kpa row had "25" in it as the VE is lower. So the relative change in MAP is applied against 2.5ms (which corresponds to "25"). The question is whether using MGP as a load axis for the fuel table (which fixes a problem with using MAP looking up the wrong fuel table number with a change of barometric pressure) is a less useful basis to lookup fuel at < WOT. There may be a difference between theoretical and practical too...

You can see the point that the discussion is getting at by substituting something other than WOT in the below (from the forum link you gave). I think I have this right...: Although its looking up a table row that is rich and not lean like a MAP lookup would be in para 2. Of course you might be doing something else in the fuel equation to address this and/or this may be practically of no consequence. Note: Using IMAP/baro when in boost would imply an MGP axis could look up a fuel table row that is too low lean (eg at 80kpa barometric pressure, MAP 180, MGP 100 (like MAP 200 at sea level), MAP/baro *100 = 225). I suspect this does not reflect your experience with aircraft / pikes peak / race to the sky.

Nice car, nice engine. Just to check - this is posted in the G4 not G4+ forum. A G4+ Storm has 8 injector outlets but a G4 Storm only 4. Assuming you want to go sequential, a G4+ Storm would be required.

Thanks. I am not looking to tread on any toes so feel free to delete the post.

I'm looking to tidy up / thin out a loom into a Subaru V3/4 plugin and have some queries. It's actually a G4 but I assume same on a G4+ (except the latter has knock input), and I hope to change to a G4+ in time. All pin numbers refer to the labelling in the help file / manual. I can give the pin numbers below by ref to B135 / B136 / B137 if needed. I have looked through various online resources to help come up with the questions, so this is specific to what is going on inside the Link. - The help file / manual has a pinout list that states pin 36 is Aux Inj 6. I assume this is actually DI 1 - VSS? - Are all the original loom's power / ground used by the Link? - +12V switched - pins 60, 61 - Ground - pins 15, 16, 26, 72 - sensor ground - pins 53, 71 - I assume the ECU hold power equivalent stuff isn't needed and not connected on G4? (pins 25 - battery 12v, 51 - ign on status, 62 - ecu relay control) - likewise all the test/monitoring stuff (34, 35, 63, 64), and anything else in the loom that is not Power, ground, trigger, Temp 1-2, AN Volt 1-4, DI 1-4, Inj 1-6, Ign 1-4, Aux 1-4 and 6 and 8, knock - with the dip switches set for option 1, which pin is crank sensor / trigger 1 (is it pin 52 or 54)? If it's easier I am happy to have a look at a V3/4 plugin schematic and come back with a shorter (or hopefully no) questions. Thanks in advance for assistance.

Question relating to using PWM being a hack. Is there any difference electronically (I mean from the ECU's perspective) between 100% duty cycle PWM and simply switched on?

Thanks - I thought that might be the case. If I remember (and finally get the thing going) I will report back with anything I find. The reason for considering it is I am thinking: - Boost table 1 is low boost, tps vs rpm - Boost table 2 is high boost, tps vs rpm - Rotary switch input drives "Interpolate between" table.

Have relooked at the help file and it appears to effectively continuously adjust? Suggests the fancier the boost strategy (eg by TPS) the more important an accurate base DC is?

Thanks Brad - and I presume it works fine. I'm still hoping to understand what it would do under Option 2, so hopefully Link can get back to me. It would be helpful to know how frequently the PID starts again by going back to the Base DC table. Eg, if the boost target changes because I back off the throttle, does it stick with PID to try and get there or does it start the algorithm again due to the target change.

I have a question on how the closed loop algorithm uses the boost target and DC table. I understand the expectation is that it takes the target kpa from the target table and looks up a base DC % from the DC table by reference to Boost Target on the Y axis (typically). This is as set out in the help file. If one was to set up a boost target table with TPS vs RPM, would it be preferable to: 1) go through and work out full throttle DC % and build the DC table on the "normal" basis described above; or 2) build a DC table on the basis of TPS vs RPM to match the desired kpa in the boost target table? Option 1 would (I think) look up incorrect DC % at less than full throttle? It seems to me that option (2) would better match base DC to the boost target required by a given TPS and RPM. But I am concerned that it isn't following the instructions (ie, does the algorithm need Boost Target as an axis)? Thanks!

What do you mean by this? Is that the wastegate pressure? Question for the experts - is there any point in a boost target (in the above case, 1 bar) so far below the wastegate spring (particularly with boost control active from 50kpa, which seems way too low)? I guess maybe it doesn't matter for this example as the integral clamp is only 3%, but generally?

Sorry for digging up an old thread, but directly relevant to the above. If wired up as below, and there was a need to run the engine without the cam sync temporarily, would be the best alternative be multi point, 360*, and halve the master fuel (hoping deadtime are accurate)?

Thanks - I thought it might be. Good work Team Link.

If I am not already a "+1" for this in another thread you should also consider me another interested person. Interested in 4D and overlay.

Thanks - appreciate the advice. It's a high overlap 2 valve engine with ITBs so it might be sensitive. I guess I will find out...

If you have this setup, how is it best to approach setting injection timing? The typical method is to tune by AFR but 1/2 the cylinders will be different? In my case, I may be looking at this on a flat 6 with two lambda sensors and ITBs, so can probably try and pick injection timing that matches (and I suspect it is slightly before valve opens on 1 / 3 / 5 which is 120 deg later on 2 /4 /6, although there is probably also an injection timing that would see both inlet valve "pairs" open if that was desirable).