EFI / Megasquirt

[Mick Cliff]

OK - hi-jacked from 'Future Events'

Let us know what's going on - Ian and Tim - I'm interested in this.

Can't recollect all the details from Allan Staniforth at Harewood Hill Climb last Saturday (it's an age thing!) except that it was not Megasquirt that he was using. Was developed by a fairly local friend of Allan's initially for car engine/s. Allan's was then first bike engine (Kawasaki) that had been done so lots of 'development' was needed.
Allan gave me and my mate so much information in our 20 minute conversation that we were reeling for hours afterwards (bit like taking on board the 'bits' of information that Phil tosses into conversations!).
Shouldn't be too difficult to track Allan down if you want to, he lives in Harrogate.
The system was something akin to Megasquirt but had 3 initials PTA? PTY? or something like that, Jenvey throttle bodies, 36-1 trigger wheel, sensors on front and rear wheels to differentiate speeds, blah, blah (that's the age thing again!).
Piece de resistance - Woolworth's tea strainers beautifully mounted on the ends of the intake trumpets!

[Ian Donkin]

Mick

It could be DTA that he was talking about? I'm sure James knows about this one as I think his cab had an engine with this system fitted?

I'm very early on in my learning curve and researching Megasquirt is like peeling the layers of the biggest onion you could ever imagine. Tim's already been there with his Bi-Turbo and is ahead of me with his 911.

Although Megasquirt was primarily developed for electronic fuel injection, through subsequent development it's also gained the capability for spark control. One of the easiest ways is to implement this is to utilise the Ford EDIS (electronic distributorless ignition system) in combination with revised code that is available for Meagsquirt.

There seems to be a HUGE community supporting the development of Megasquirt and everything is in the public domain. Some may say that due to the way it has come to be, it will never be as good as the commercial systems (e.g. Motec, Electromotive, etc.), but it seems to me there are some very, very bright people out there (and sadly I certainly don't come into this group in any way, shape or form) supporting it. Just think of it as the Linux of EFI systems.

And then there is the price. I picked up all the EDIS-6 stuff on ebay for $88.50 (less than £50) and sourcing all the components for the ECU will cost another £165. Add in your method of injectors (ITB's or use any of the Porsche common plenum intakes dependant on your age of motor), a willingness to learn and Tim's phone number and you are away!

I want to use this on the engine I'm currently building (well, still pulling apart actually) so in the interim will get a base configuration working on my old 2.4T. That way at least I should be able to do the initial engine break-in without too much difficulty. That's the theory anyway.

Want to know more? Here's the link http://www.bgsoflex.com/megasquirt.html, but don't say I didn't warn you.

[impmad2000]

What is it?
Megasquirt is DIY assembled EFI ECU. It has been designed by two engineers, Bruce Bowling and Al Grippo and is the resulting spin off of an internet based project EFI332. What they have designed is a nice simple, easy to build, easy to install, easy to wire and easy to tune EFI ECU that can be installed to any petrol engine.
how does it work?
Well, since we know that (roughly) 14:1 air:fuel is required for combustion, if we know the basic configuration of an engine (say 6 cylinders, 2400cc) and we know the volume of the air going into the engine, we know how much fuel to inject for correct combustion. Using the ideal gas laws, Volume=Pressure/Temperature, and by measuring the temperature of the air going into the engine(Inlet air temperature, IAT), and the pressure of that air (Manifold pressure, MAP) we know exactly how long to open the injectors for (Given that we know the parameters of the injectors, Injector flow rate, fuel pressure etc..) Crank rotation, throttle position, water temperature and Lambda are other inputs that help to give "corrections" to the basic rule, that will result in a smooth, driveable engine.
What about tuning ?
The basic system requires a series of corrections that allow the theoretical fueling to produce a driveable engine. Most of this is contained in the fueling map. This is a series of settings or bins, often in a grid array, that resolve RPM against mainfold pressure(Speed density) (or alternately RPM vs Throttle position(Alpha N)) This is the basic map that you tune. Software is available off the net to allow you to change this from a laptop as you drive.
But what makes Megasquirt different?
The real clever part is what happened once the ECU had been produced. Instead of selling the product as that, Bowling and Grippo opened up the design, hardware, firmware and Tuning software under an Open source license. This means that anyone can contribute to and change the project to suit their own needs. As a result the contributors, be they documentors, hardware designers, firmware programmers, software programmershave produced a well tested, very well documented, excellently supported ECU that you can build and install yourself. From humble beginnings, the tuning software has grown into one comparable to the best commercial software. The firmware now includes options for spark control aswell as everything else from boost control, water injection and even NOS. The hardware has developed too, with a new version just out, using a better, faster processor and offering even more configuration options.
Want to find out more ?
Check out www.msefi.com for the forum and http://www.megasquirt.info/ for the manual and FAQ.
What do I know
I am an electronics engineer, this project is just my kind of thing. Hey, I built one, installed it on a Maserati Biturbo, ran it and tuned it ! To be honest, this is a vast subject and I do know very little but there are people out there with far less knowledge than me who have installed this system on there own car and use it daily.
Details will follow.....

[Mick Cliff]

Ian - yeah, DTA! Age is a bit like a bad hangover, bits and pieces come back once someone mentions a key word.

11.30 pm is NOT the time to start looking at the Megasquirt info. I might look tomorrow as I still have 1 days 'holiday' left. Hopefully my employer will not have barred Megasquirt access, but the name is a bit dubious!

Tim - you make it sound so simple. No doubt Ian's attempts could prove interesting (I like his approach - glean everything off the Internet, but have your number to hand!).

Good luck guys, keep us informed please.

[davidppp]

Morning all.

MS is in many ways the answer to our prayers.

It enables turbos and superchargers, twin-plugging, radical cam overlap, Coil -on-Plug, dual injectors per cylinder, crankfire with or without dizzy, use of almost any sensors, manifold pressure blended with throttle position, load sites can be placed anywhere in the rev/load map..( enabling many to be concentrated on those small inflections in the torque curve caused by harmonics etc).

It will be almost certain to save a considerable amount of fuel while still allowing top-end high-load enrichment for cylinder cooling.

All for considerably less than a properly reconned and tuned set of Webers..

But it does require some fabrication, and fiddling...

I have the MS built and working, the twin EDIS set up, and am looking for an early twin-plug head to copy...

If no-one has one, I'll copy one of the 3.6 heads lying around here..I would be prepared to do some twin-plugs heads for folk round here if they want them..

Kind regards
David

Kind regards

[impmad2000]

After writing all this, I thought there was one or two more question I should answer at the start....
Why should I do this ?
Well, you dont have to ! But it is an option that is there for the few who like a challenge, don't care about originality, Dont want to invest money into replacement worn out carbs, want to tune their car. Me, well my throttle spindles are so worn I can hear the air sucked up the throttle spindle when on tick over and I don't want to buy more old Zeniths that I haven't a clue how to tune. EFI work for me. I need to nail down the fuelling before playing with the engine. Secretly, the desire to put a low pressure turbo on the car fascinates me ! Water injection and Knock detection are all available.
How do I implement EFI?
Well this is the tricky one. www.jenvey.co.uk do a kit of manifold and throttle bodies (tb's) or http://www.bitzracing.com/ do a kit that adapts the CIS injectors to EFI injectors, dumps the metering plate and replaces it with the electronics. I wander if the same approach can be made with the MFI tb's ? You can even take a set of old Zeniths, gut them, plug all the jets and mount some sort of injector boss in them and use them as a real home made throttle bodies. It all depends how inventive you are. Me, I intend to use motorbike throttle bodies and adapt them onto the standard zenith manifold.

Cheers
Tim[/img]

[hot66]

I was using the DTA box on my cabrio along with jenvey throttle bodies. We custom machined the fan pulley for the crank pick up. The rest of the sensors etc were off the shelf stuff. Never got the chance to run it because I sold the ar but I know plenty of people using the DTA & getting very good results.

Wether you use DTA, Megasquirt or any of the many other ECU's on the market, it seems to be a very personnal choice.

[davidppp]

Well Done, Tim!

What bike are those from please?

Unfortunately the problem with MFI TB's is they are almost always worn out..the spindles need rebushing etc, and very often the butterfly has caused severe electrolytic corrosion in the mag TB..you can see and feel a ditch..so they will never close properly...
About 120 gbp each to redo..!!

Same of course with old carbs..

So your bike ITB solution looks good to me..and in fact, I'd take the opportunity to fab some very simple straight taller manifolds..the old Zenith ones are offset of course..and do crack distressingly often..

Kind regards
David

Kind regards
David

[Ian Donkin]

I've done a fair amount of research on throttle body setups and find myself torn between going down this route or a single common plenum.. Well when I say torn, I actually mean how much I am prepared to spend.

Without doubt in my mind the Jenvey setup is the best, but is it perhaps overkill for a normal road engine? Also, whilst the quality is undoubtedly good they cost in excess of £1,400.

You can ship sufficient air using an old CIS intake setup with the metering plate removed (as Tim suggests in an earlier post) and easily get a MAP reading from this. What you can't do with this however is get too radical with the cam profile.

There are other routes for the ITB's - I've seen it suggested that PMO manifolds and linkages, with TWM throttle bodies can be acquired for $1770 retail; I'm also fairly sure that zenith / weber intake manifolds can be used in conjunction with the bike throttle bodies for significantly less - maybe £150 - £200 for two sets of bike throttle bodies, plus the cost of the inlet manifolds and linkages.

Then there's the airflow - if the throttle bodies are too big, you'll lose intake velocity and therefore bottom end cylinder filling (and resultant torque) could be poor; how long should the intake tract be and where should the injectors be relevant to the valves - close for bottom end power, further away for better high rev performance?

I guess it's all about balancing everything up and coming to a reasonable compromise - at least the good thing with a 'home brew' solution is that it should be fairly easy to experiment with and find a solution that works best for your own application.

Here's a couple of Pelican posts on the approach others have taken:

http://forums.pelicanparts.com/showthre ... genumber=2

http://forums.pelicanparts.com/showthre ... did=225593

Happy reading - let me know what you think works best. As Tim says, not one for the purist.

[hot66]

have a look at the throttle body & plenum chambers on subarus @ a breaker. I was going to use one from an imprezza turbo for my vw. The 3.0 leagcy's are flat 6

[Dyno Soar]

Awesome thread..

[impmad2000]

I was offered a complete Porsche EFI manifold complete with single TB, common plenum, injectors and fuel rail at Husbourne Crawley . I'd have needed to built a taper between the manifold and head, as the port size on my 2.4 was smaller, but it is another option.

[impmad2000]

Just some pictures of where I'm at with this little project
The trigger wheel mounted

The Sensor

As it sits in the car

And the waveform I get on the oscilloscope with the engine running. The big saw tooth is the effect of the missing tooth (60 Deg BTDC)

...It's a start
Tim

[Mick Cliff]

Getting there, Tim.
Presumably you're doing this as a rolling conversion?

This is all fascinating stuff. I'm amazed at what goes on in people's 'sheds'.

[impmad2000]

a rolling conversion?

Very definately a rolling conversion...