Club G40 Forum

Technical => Electrical => Topic started by: z3i on February 02, 2014, 04:27:53 pm

Title: Megasquirt/emerald ecu
Post by: z3i on February 02, 2014, 04:27:53 pm
Well just come back from brighton after fitting a megasquirt 2 ecu to a mates mk1 mx5, wasnt expecting much from it, how i was wrong!
for £500 he got a fully customizable ecu, air temp sensor and it pre built by a specialist in greece (also bought a wideband from aem for £150 also an awesome bit of kit)

so anyway, took around 5 hours to properly install, was near enough plug and play as the guy from greece had built all the pin locations in for an mx5

well we got it running and my god! i could not believe the custom capabilitys!!! from setting the the % of fuel enrichment at different engine temp values (all of which can be changed) ie at 10degrees the engine runs 180% richer and theres about 15 boxes to change the enrichment gradually so basicly you can make your car start 10 times nicer and better. then you can set rpm limiter for when the engine is cold
literally EVERYTHING can be adjusted! everything you could possibly imagine your ecu does with fueling and timing, even say fuel advance and fuel enrichment for various throttle loads

has anyone got anything like this on their polo? the one my mate has was built for his mx as a straight swap, does anyone do this for a g40 ecu?
its also a billion times easier for diagnosing your car or sorting smooth running as you can get all the readouts from all the sensors on your screen and if your not happy with something then just change it!
for £500 i think this is the best mod for any car! especially out of date ecu's not only does it maximise performance but you can make maps for the best fuel consumption and switch between them
i want one so bad! amazing bit of kit
what the difference between emerald and megasquirt? any and all advice would be very much appreciated as im still pretty novice with all this and theres probably a shit load more to the ecu i dont know about
thanks all Taylor
Title: Re: Megasquirt/emerald ecu
Post by: Alexiskayak_7 on February 02, 2014, 06:59:43 pm
There is no difference between these two ecus.... The only different thing is that the megasqurt is a DIY ecu.

There is no such a direct fit ecu/loom. You have to build one by yourself.
You will discover lots of things from mapping/changing data really
Title: Re: Megasquirt/emerald ecu
Post by: z3i on February 02, 2014, 07:12:30 pm
Ok thanks mate :)
Yeah my mate bought the ecu and it was just a circuit board etc, so he had it all built by a specialist, is there someone who can build it with the g40 pin layout etc
If that makes sense?
Title: Re: Megasquirt/emerald ecu
Post by: Andy on February 02, 2014, 07:23:55 pm
Being able to buy an off-the-shelf loom for your application saves a lot of arseache. I took a lot of time to plan out my Emerald wiring (matching ECU I/O up to sensors and actuators, as well as calculating wire sizes, fusing strategy etc.) because I wanted it done properly - if someone else has done that, and they've done it well, then it's a boon.

Most of what you can do with Megasquirt or Emerald you can do in Digifant. It's only 'newer' features like closed-loop boost control, switchable maps, wasted spark ignition, drive-by-wire throttle etc. that Digifant lacks in comparison, and there are solutions to some of those. (e.g. boost control you add a standalone boost controller, switchable maps I can add a bit of hardware to do in Digi etc.) Obviously ALL of these ECUs lack the detailed diagnostic features, emissions controls, safety features and limp home strategy of a truly modern production ECU, so I'd not go buying an aftermarket system thinking it'll bring a G40 bang up to date.

The biggest difference, is with Digifant you're limited to who can map it for you, whereas with Megasquirt/Emerald you've got a lot more choice and DIY is more accessible. But on the flip-side VW have spent an awful amount of time optimising all the various parameters In Digifant, so there's less to change when you 'remap'. My Emerald maps have in excess of 80 hours in them (starting from a 'base map' I paid for from Dave Walker which was shite), and only now does the car run as nicely as a Digifant G40 turbo that I can map in <6 hours.

That's mainly because with an aftermarket system you start with nothing in the calibration, e.g. no coolant or inlet temp corrections for fuel and spark, which at least in Digifant VW have already done for you. VW have also optimised the software (e.g. for closed-loop fuelling, idle stabilisation etc.) for the PY engine, which whilst most aftermarket ECUs are very configurable and calibratable to deal with most things - you can't change the code easily. E.g. I find the idle control loop on my Emerald slightly unstable, and whilst I can alter some parameters to influence its behaviour, I can't fully tune the control loop.

You're never going to do a perfect job of all this quickly on Emerald/Megasquirt - unless you've got climate cells and engine dynos at your disposal. Hence why I've spent 80 hours on Emerald doing what'd take me <6 in Digi. On the flip side, you can learn an awful lot, and for some people that's where the fun is! It's certainly why I did it.

It's a long time since I've used Megasquirt, but it seems to have come a long way and has a huge amount of support. Emerald was more 'fit for purpose' when I bought it 7 or 8 years ago, Megasquirt used to use non-automotive connectors and components and the software was very unstable and badly documented. By all accounts that seems to have changed if a colleague's Microsquirt setup is anything to go by, so I think there's less difference these days - and the Megasquirt family's open-source nature has worked in its favour. I bought Emerald assuming it'd be massively professional, but there are a lot of areas that've left me hugely disappointed. The main one being closed-loop electronic boost control, which AFAIK they never got the full PID control implemented in their software for the K3 ECU - and it was one of its main selling points!
Title: Re: Megasquirt/emerald ecu
Post by: z3i on February 02, 2014, 09:14:26 pm
Thanks for taking the time to do that write up mate :)
I wasn't aware the digifant system was so tuneable! I thought it was quite limited to what can and cannot be changed

I didn't know you did all the wiring! Like you say, took you hours!! To be honest I wouldn't want to do that as I would worry about wiring it wrong :( but I guess my mate managed to get it built as megasquirt ecus are quite a common mod for mx5's

Yeah! It was great fun messing around with stuff, seeing how it changed how the car behaved, could spent hours messing around with it :)
Again my mate was lucky enough to be able to download a basic base map for his mx, so had a good starting point to work from

You say digifant is quite customizable, but you need all the gear to do so, whereas just plugging your laptop into megasquirt to see how things are doing. He has version 2 and it was so easy to wire in, sounds like it's come a very long way from what you experienced

You say about the idle control loop, does the digifant ecu have larger parameters to work with then?

I think the main thing I got excited about was instantly smoother his car ran after a few hours play, cold start, warm start, throttle sensitivity from having more resolution for ignition advance (smaller increments of advance under more throttle load situations compared to stock ecu
No leaning out at high rpm, all those sorts of things, non of which power related, his car just ran a thousand times better in everyway, and that's with two noobs at the end of the keyboard

I can't imagine how much better mine would run after a tweak, runs like such a bag of shit with the mods

What do you think mate? I'm a bit put off about wiring it in myself to be honest. And your well clued up on this, think it would be much harder for me to suss it?
Whats this about switchable maps on the g40?
Thanks again
Title: Re: Megasquirt/emerald ecu
Post by: on April 03, 2014, 11:30:17 am
There is a plug and play prorgammable ECU for G40:
Title: Re: Megasquirt/emerald ecu
Post by: z3i on April 03, 2014, 11:37:44 am
Don't really understand that.. A normal g40 ecu is remapable, this has the same amount of mapping points as a normal ecu. It says it eliminates the air flow sensor, but a g40 doesn't have one anyway it also says it has electronic boost control? Not sure how that would work/ be governed?

It's pretty cool you can do it from your laptop and use individual coil packs, for £500 you can just get a megasquirt?
Title: Re: Megasquirt/emerald ecu
Post by: Andy on April 03, 2014, 07:42:13 pm
Isn't that just a Megasquirt variant in a Digifant ECU case? Nice neat solution though.
Title: Re: Megasquirt/emerald ecu
Post by: Alexiskayak_7 on April 03, 2014, 08:03:23 pm
Isn't that just a Megasquirt variant in a Digifant ECU case? Nice neat solution though.

Yes it is
Title: Re: Megasquirt/emerald ecu
Post by: z3i on April 03, 2014, 08:40:34 pm
Isn't that just a Megasquirt variant in a Digifant ECU case? Nice neat solution though.

But it says it only has 16 by 16 mapping points? Thought megasquirt had something like 3000?
Title: Re: Megasquirt/emerald ecu
Post by: Jezza-7 on July 29, 2017, 02:43:35 pm
With regards to the K data ecu, does anyone know anyone that has bought/running one?