H8 NL Pajero tuning - Findings . likely matches with 3.5 Magna ecu

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stumagoo
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H8 NL Pajero tuning - Findings . likely matches with 3.5 Magna ecu

Post by stumagoo »

Not sure if people are interested but having slapped a sc14 (a bit small I know but its cheap) on my 3.5 and deciding to tune it I thought I would share some of my findings as there was very little knowledge or more to the point Knowledge being passed on for this sort of thing.


first up fueling - the stock injectors were running around 50% duty cycle at WOT according to evoscan - Pulse width was around 12 ms, I am running 8 psi and the Pajero is stock 9:1 compression on the 6g74 so even though I expect to blow the engine eventually I am happy to play with it as it is. I think the Bosch replacement fuel pump was at its limits - I put an adjustable fuel reg on for safety sake and if I bump up any more than 5 psi the stock style pump wont keep up. Genuine is a denso and I have heard better things about them. I have the bosch stock style pump running as a lift pump and an external aeroflow 300lph feeding through 5/16 line to the injectors - overkill probably but its a cheap bit of insurance.

Tuning - the XML I have developed is getting more and more involved (thanks Wytwun for your help) I have altered the maps to run up to 160 load which seems to be fine as evoscan is only reporting WOT maxing out at 140 load - unfortunately I am not game enough to try and incorporate big maps (like some of you magna owners have) but it may be something in the future. I have modeled the maps after some other boosted stock maps which go up in increments of 20 and 15 depending on the load

I have found 2 areas that caused me grief and lots of detonation issues.... first was supercharger specific and not likely as big an issue for the turbo guys but the closed loop threshold was set with 2 triggers 1 is load the other TPS and it seems that while load is important TPS is actually overiding it.... with my supercharger I could be at >100 load easily at 40% throttle on while NA its closer to 80% this meant often at cruising situations if I was gently boosting and trying to overtake the ecu would stay in closed loop due to TPS giving low readings and not triggering open loop despite what the load was saying.... this was annoying and really meant I just needed to push the throttle a little harder....

the bigger issue is there is another small 1d map on the H8 ecu (not sure if it is on the newer ones) that sets max AFR rates at a given RPM - basically if you go over this it ignores the reading and leaves the load at what ever its set to---- the Paj one worked out about 3 psi or for me around 110-120 load it meant that the afr was going stupid if I went over that level of load ---- despite what the fueling Maps said.
I dont know if anyone really cares about these or other findings I have found over the time but if people want more info I am happy to pass on what little I have found

I want to add this has not been dyno'ed yet - I have some other aspects to finish before I book dyno time but it is running a wideband and AFR's at full boost are between 11.5 and 12.1

WytWun
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Re: H8 NL Pajero tuning - Findings . likely matches with 3.5 Magna ecu

Post by WytWun »

stumagoo wrote:
28 Jul 2019, 16:27
the XML I have developed is getting more and more involved (thanks Wytwun for your help)
You're welcome! 8-)
stumagoo wrote:
28 Jul 2019, 16:27
I have altered the maps to run up to 160 load which seems to be fine as evoscan is only reporting WOT maxing out at 140 load
Rescaling map axes is fine, but you just need to know which maps are using the particular axis table you rescale. In the SH2 ROMs I've disassembled, the fuel map (+ hi octane fuel map in knock sensor applications) has its own load axis table; the ignition map(s), ignition warmup trim map, the EGR trim map (which I don't think your Paj has) and another map whose purpose I've not figured out all share a separate load axis table; there is also a general purpose load axis table used elsewhere in the code as well.
stumagoo wrote:
28 Jul 2019, 16:27
unfortunately I am not game enough to try and incorporate big maps (like some of you magna owners have) but it may be something in the future.
Increasing the map dimensions requires care in patching the ROM, but not necessarily any program code changes for most maps (*) - you just need to make sure that you fix all the affected map structures. I think I missed something in an ignition related map on the one attempt I made at this and was able to detect pinging from too much ignition advance (later confirmed with logging). As I've not had any need for the big maps, I haven't gone back to this...

(*) there are exceptions where the code has hard-coded assumptions about size, but the main ignition map group and fuel map aren't affected by this.
stumagoo wrote:
28 Jul 2019, 16:27
the bigger issue is there is another small 1d map on the H8 ecu (not sure if it is on the newer ones) that sets max AFR rates at a given RPM - basically if you go over this it ignores the reading and leaves the load at what ever its set to---- the Paj one worked out about 3 psi or for me around 110-120 load it meant that the afr was going stupid if I went over that level of load ---- despite what the fueling Maps said.
In most of the Mitsubishi KV MAF ROMs there's a MAF frequency limit table which hard limits the reported amount of air, which definitely needs adjustment if airflow is increased over stock (either by FI or bigger engine and/or better intake plumbing). Most of the J series Magna ROMs don't seem to have any other load related limits, however all the L/W series MAGNA ROMs have some additional limit like this which limits achievable load to about 97. So far I've not succeeded in identifying where this is being applied :(.

stumagoo
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Re: H8 NL Pajero tuning - Findings . likely matches with 3.5 Magna ecu

Post by stumagoo »

You are spot on with everything you have said I think Wytwun. No the Paj has no egr and it also has no Knock sensor -which is why I am running pretty rich and pulling timing. I did find that if I was not careful and pulled to much timing combustion temps can increase as well and cause preignition/diesel style ignition when coupled with the too lean situations I was fighting.

I dont know how much this post will help others but as I said there is not a lot around detailing what changes should be looked at when tuning for boost - I just hoped someone may find this one day and not have the headaches I had trying to find why I was leaning out on boost when I thought I had everything right. (turns out as stated it was a combination of TPS/closed loop thresholds and more importantly the Maf max frequency table.... which was the last thing I altered and everything else just fell into place. Ironically I had the map specified all along and never bothered to even look at it

discostu
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Re: H8 NL Pajero tuning - Findings . likely matches with 3.5 Magna ecu

Post by discostu »

This is great Stu. I'm still mad keen to play with all this stuff, but at the moment I just need to get this car going. You've given me a lot of ideas and been very generous sharing the info you have. Most of all I would like the dual ignition timing maps and be able to switch between based on lpg or petrol being used, but in play with that later. Jobs are piling up in the garage....

BCX
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Re: H8 NL Pajero tuning - Findings . likely matches with 3.5 Magna ecu

Post by BCX »

Hey all,

If there is interest, happy to patch any H8 rom with switchable maps and bigger maps.

I've already done this (plus lots of other goodies) to my triton. I use switchable maps for lpg and petrol. I also added electric fan control as I deleted the clutch fan.

Just post up the rom and let me know what you want.

Cheers,
Bill
8th Gen Galant VR4
MK Triton [6G74 conversion]

discostu
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Re: H8 NL Pajero tuning - Findings . likely matches with 3.5 Magna ecu

Post by discostu »

That's very cool Bill. Very nice of you to offer this. I don't have my head around all of this stuff enough yet to try, but I'm very keen to learn. Just need to put the time into it, and I don't have a programming background at all

Did you see much difference with the greater advance on lpg?

How did you input a signal to ecu to use lpg map-spare pin?

WytWun
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Re: H8 NL Pajero tuning - Findings . likely matches with 3.5 Magna ecu

Post by WytWun »

discostu wrote:
22 Sep 2019, 09:13
Did you see much difference with the greater advance on lpg?
Can't speak for Bill's Triton but the couple of Magnas that were set up this way got LPG performance/response very near premium petrol performance/response, and on mixer system cars that were prone to backfire this was essentially eliminated.

discostu
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Re: H8 NL Pajero tuning - Findings . likely matches with 3.5 Magna ecu

Post by discostu »

Sorry for slow response. That is interesting, thanks for that.

Do the magna run knock sensor? What I'm wondering is if the ecu advances spark itself until it registers knock, and then backs off slightly. Therefore automatically advancing spark suitable for the fuel being used?? I guess I'm wondering the benefit of this in our falcon and camry running lpg also. We don't have many backfire issues, but I would prefer none at all

I looked at timing advance processors to do this job. I spoke to lpgshopuk, and they reckoned it wasn't worth doing with lpg, only with cng. There was a reasonably cheap option available there, might have been stagLPG, can't remember exactly

WytWun
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Re: H8 NL Pajero tuning - Findings . likely matches with 3.5 Magna ecu

Post by WytWun »

discostu wrote:
06 Oct 2019, 15:47
Do the magna run knock sensor?
3rd gen Magna/Verada (1996-2005) don't have a knock sensor (though the Australian made 1997-2004 USDM Diamante based on the Verada has the knock sensor).
discostu wrote:
06 Oct 2019, 15:47
What I'm wondering is if the ecu advances spark itself until it registers knock, and then backs off slightly. Therefore automatically advancing spark suitable for the fuel being used?? I guess I'm wondering the benefit of this in our falcon and camry running lpg also. We don't have many backfire issues, but I would prefer none at all
It will advance to the limit of the "high octane" fuel map, which in your Falcon and Camry are likely to be for 98RON fuel if the ECU mapping is for Australia (Falcon likely, Camry don't know). The problem is that LPG burns quite differently to petrol and requires a completely different ignition mapping strategy, as the petrol ignition mapping doesn't do the required job (it doesn't have large enough amounts of ignition advance where LPG really needs it). You really need custom LPG mapping (see here for some LPG ignition mapping info).

The custom mapping can be achieved several ways: with additional maps in factory ECU (as I've done for SH2 Magna ECUs and Bill has done for H8 ECUs) or with a piggy back processor. At least one member on here has successfully used a Jaycar kit of a Silicon Chip magazine programmable ignition controller to do this instead of a more expensive piggyback (aka interceptor) ECU. Note that with a mixer system, you need to also ensure that when you switch from petrol to LPG that there is sufficient delay before activating the LPG mapping, and when switching from LPG to petrol that there is no delay in activating the petrol mapping - the length of the switching delay in the petrol->LPG case depends on the system but can be 0.5-1.5 seconds with mixer systems (injection systems will be much less, perhaps not even needing any delay at all).

Note that while it is safe to the engine to run petrol ignition mapping with LPG (ignoring the effects of backfires), it is not safe to the engine to run LPG ignition mapping with petrol (even 98RON)!
discostu wrote:
06 Oct 2019, 15:47
I looked at timing advance processors to do this job. I spoke to lpgshopuk, and they reckoned it wasn't worth doing with lpg, only with cng.
That may be the case in the UK, but what I've seen here suggests it is worth doing with Australian LPG setups (mixer systems especially, because of the backfire reduction).

Note that the LPG injection (both vapour and liquid) systems shouldn't experience the backfire issue to any great extent as the LPG is only present in the intake manifolding close to the heads; mixer systems on the other hand have LPG right back through the intake to the mixer. A backfire is when the cylinder charge is still burning as the intake valves open so that the LPG/air mixture in the intake system is ignited and burns all the way back to the LPG source. When the ignition advance is properly mapped for LPG, the cylinder charge should be completely burnt before the intake valves open so backfiring doesn't occur.

discostu
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Re: H8 NL Pajero tuning - Findings . likely matches with 3.5 Magna ecu

Post by discostu »

Thanks for that. I'm getting a pajero going and installing LPG injection on it, just to give the idea of what I'm doing. The Camry and falcon are both running mixer setups. I'll have another look over those maps tomorrow to get a better idea

I did come across those Jaycar kits. The problem was, for what I could work out, that with running 3 coils I would need to run 3 of the jaycar kits, and there was only 1 left in the country, or something like that. Plus there was no more of the programming kits available, and I couldn't find any info on how to program it using PC. I figured that I was probably best just trying a different avenue given those issues

That all gives me a good idea about things that I need consider. What I'm still wondering is how is the LPG running signal sent into the stock ECU (running a separate ignition map)-is there spare pins that are available for inputting a signal? It has to be told somehow, but its my lack of knowledge of all this that struggles to understand how this part is achieved.

I am wondering if its just easier running the plug in module available from the UK. Price wasn't that high for at least one brand, but I think they just advance it by a certain amount, rather than run an actual map

WytWun
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Re: H8 NL Pajero tuning - Findings . likely matches with 3.5 Magna ecu

Post by WytWun »

discostu wrote:
15 Oct 2019, 22:11
What I'm still wondering is how is the LPG running signal sent into the stock ECU (running a separate ignition map)-is there spare pins that are available for inputting a signal? It has to be told somehow, but its my lack of knowledge of all this that struggles to understand how this part is achieved.
The multi-map ROM mods (both my SH2 version and BCX's H8 version) use spare inputs to get the LPG/petrol switch state - exactly which input depends on the ECU hardware and the mod's code.

See also this thread for some more info which might help.
discostu wrote:
15 Oct 2019, 22:11
I am wondering if its just easier running the plug in module available from the UK. Price wasn't that high for at least one brand, but I think they just advance it by a certain amount, rather than run an actual map
Don't bother with adjusting the advance by a fixed amount would be my advice - yes you'll get a bit of improvement but you'll miss a lot of optimal improvement.

BCX has offered to mod your ROM - I'd accept his offer. If you're not happy with the results, you'll only need to flash back your original ROM.

Any commercial interceptor ECU which can support at least 2 sets of maps with a wiring input to switch between them would also do - you leave the fuel mapping alone and only adjust the ignition mapping.

discostu
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Re: H8 NL Pajero tuning - Findings . likely matches with 3.5 Magna ecu

Post by discostu »

Thank you. That link for signal inputting was really helpful.

I just checked out the aeb timing advance processor, it does appear to just advance by a specific amount rather than have a full map.

I don't currently have tactrix cable, but I'm thinking it will be helpful in the longer term. Until then I won't be able to upload new rom. I need to get the car running properly and registered first.

I've seen similar details for advance curves for lpg in other places, probably same sources as there isn't much info out there. Any idea why it is retarded at high loads/revs? I'm trying to get my head around the requirement for that in comparison to petrol

WytWun
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Re: H8 NL Pajero tuning - Findings . likely matches with 3.5 Magna ecu

Post by WytWun »

discostu wrote:
18 Oct 2019, 10:29
I've seen similar details for advance curves for lpg in other places, probably same sources as there isn't much info out there. Any idea why it is retarded at high loads/revs? I'm trying to get my head around the requirement for that in comparison to petrol
There's not a lot of public info :-( but from what I can gather it's a tale of 2 fuels with different combustion properties and behaviour: the ignition retarding at high loads and/or revs for LPG compared to petrol comes from the fact that LPG will burn faster than petrol at full charge densities (high loads) and also at high rates of compression (not the amount of compression). Rate of compression of course directly derives from piston velocity and thus revs. Because of this faster burn, the optimum advance to achieve maximum power from the burn under these conditions is slightly less with LPG than petrol under these conditions - if you advance the ignition too far, with any fuel, you get less power than with the optimum advance (ignoring other effects like knock etc).

The converse is true with low rates of compression (i.e. low revs) and very light cylinder charge density (low loads), where LPG burns much slower than petrol. It is this slow burn rate under these circumstances which needs lots of extra ignition advance (over what is required for petrol) to ensure that combustion is complete by the time the cylinder intake valve(s) open.

I'm also told that spark quality is very important for getting consistent ignition of LPG as it is a "dry" fuel and so can be harder to ignite, particularly at low charge densities and compression rates, so the various guidelines on maximising LPG performance with careful maintenance of the ignition system still have a place even with fuel specific ignition mapping.

discostu
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Re: H8 NL Pajero tuning - Findings . likely matches with 3.5 Magna ecu

Post by discostu »

Sorry, slow reply again.

Its just funny, you would think at those higher revs on cars running standard ignition timing that you would see a lot more knock etc, but it doesn't seem to be there. Its not like I'm always pushing my cars in those higher rev/load areas, but it doesn't seem to be much of an issue in my experience. Be nice to play around with it though and see how it behaves

WytWun
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Re: H8 NL Pajero tuning - Findings . likely matches with 3.5 Magna ecu

Post by WytWun »

I'm told that LPG, provided it's at least of reasonable quality which most Australian vehicle LPG appears to be, rarely results in any of the combustion behaviours characterised by "knock" (there are several) - regardless of ignition timing abuse. Either you can't get ignition or it ignites and burns well. This may well be a consequence of being a "dry" fuel; petrol and ethanol - both "wet" fuels in this context - just aren't as forgiving in this respect.

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