Twiss' supercharger+EFI

[twiss]

Right, I've been talking about doing this for ages.
I thought I would post it all for feedback and to get it straight in my head!

Supercharger

I've been looking at supercharging my suzuki with a blow through set up for a while now, since I saw gonzalo bravo's supercharged zook and now know it definitely can be done.

here is a link to gonzalo's build if you want to take a look, it's some top notch stuff!

http://twistedandes.com/foro/showthread ... 72&page=43

I am looking at using a supercharger from a mercedes, as they are quite easy to get hold of and come in a variety of forms... Ive settled for a supercharger from a W203 as they are quite cheap and available with inlet and output on the same side

This should make it easier to make a manifold for it...

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I intend to make a 1 piece manifold that bolts straight onto that surface, but the direction of the pipework will be decided by whatever vitara intake system I end up with

With a standard pulley on them, the supercharger generates about 5.5 psi of boost.

Where mounting to the car is concerned, I am going to try to make a large pivoting bracket, pivoting from the bottom of the engine so the supercharger's weight can keep the belt tight...
I'm going to make it adjustable in a similar fashion to the alternator.
I may have to give up on that idea at a later date, and install a tensioner instead... but I will cross that bridge when I get there!!

What I don't want to have to do:

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Ive found a good website about blow through superchargers and SU carbs, which doesn't sound that difficult, but if I'm going to be getting a supercharger I will need EFI to get the most out of it I think.

http://www.mgexp.com/article/how-to-blo ... an-su.html

EFI

So for that I will be going for a megasquirt 2 controller, as I can make most of it myself! Looking at the calculations I think I can put one together for under £200

Engine Components

I will be using a 16v vit inlet manifold (which should be on my engine in the first place), with high impedance injectors, as it makes things work a bit easier with the ECU!

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Some Injectors and the injector rail missing from the manifold above:

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Im also going to need a high pressure fuel pump to deliver 40-50 psi (maybe more!)

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and a fuel pressure regulator (vacuum adjustable so it will supply more fuel under boost)

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PCBs and Components

I have all the circuit diagrams for the megasquirt 2.2 board

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The reasonably long list of materials is here...

http://www.megamanual.com/v22manual/mass.htm

and the only parts I need to buy already made up are the Megasquirt 2 CPU and a case

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I've costed all the individual components for the board at about £80... but that will leave me with lots of extra components remaining due to minimum order quantities!

I already have a distributor with most of the gubbins removed by tim pink, so it just sends a trigger signal. I am going to probably use a ford coil pack (due to price and availability) and modify the megasquirt to run the ignition timing using this guide. I will be using a 4 cylinder wasted spark setup.

http://www.msextra.com/doc/general/sparkout-v22.html

it all will be wired up like this, except using an additional connector to signal the coil pack:

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Another mod I will probably do it relocating the MAP sensor. As the standard board has the sensor in the ECU box, I will be relocating it via the DB-37 connector so it is part of the relay box in the engine bay. This will save on running a vacuum hose into the glovebox to the ECU!

Then it will just be the matter of programming it and getting it running!!!

Coil on Plug conversion

Scottie mentioned doing away with the distributor completely (yes please!) and its definitely possible! As the ECU can control all of the advance there's not much point in using it except for sensing when to spark!

I would like to use something like this, as its quite a tidy looking option where I wouldn't have to blank off the dizzy hole, but I doubt they make them to fit zooks!

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but I will probably end up with a toothed cam wheel and a hall sensor...

Something like this:

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I will have to slightly rewire the ECU internals, but then will end up with 4 logic signals (low voltage, 1 for each plug) coming out of the additional 15 pin connector along with the coil pack connections. These will then connect into an ignition driver, which will actually power the coils

The two methods share one pin which is the ground return, so it will be able to work in this way

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That provides connectors for each coil... which are wired up as follows
(actually thats for a wasted spark setup, i would do individual firing as in the diagram above)

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If anyone has any comments or anything please go ahead as I'd like to do this one properly

[Edweird]

I'm a dab hand at soldering.

[Jordi]

Get on with it then.

[Rhinoman]

As someone who designs ECUs for OEMS I'll just say that there is is no way I would have an MS on any vehicle of mine.

[twiss]

Howcome? Reliablility issues?

Just seems to me like quite a cost effective way of doing it... especially if I want to add a charger later (ECU remap) and then if I can find one add a GTI head (remap again?)

I know quite a few people with bland rover v8s who use megasquirt quite effectively, and the only person Im aware of putting a supercharger on an SJ (apart from Gonzalo Bravo) also got good results from it...
I'm going to be using the v2.2 board as its the one that I've seen the most people running successfully.

I've heard that most of the issues come with either not assembling the thing correctly, or from setting it up wrong. I know its not the most advanced ECU ever but its got to work better than a carb to charging applications.
I'm pretty good with electronics and its not that complicated a device so the assembly side should be OK, and I know that I shouldn't expect it to dial itself in to my engine immediately!

I can understand why people get it wrong, with guides out there giving stupid ideas like earth high current drivers with the rest of the ECU???!!!

As you are like the only person here who really deals with ECUs on a day to day basis, if you can shed any light on your perspective it would be a help.

[suzukisteve]

fair play to ya mate, the thought of all that wiring makes we shudder

[Rhinoman]

MS is sold as an experimental ECU and they make it quite clear that its probably not road legal - its not legal in the EU and would never pass type approval. If you want to experiment with EFI then its very good but to make it DIY capable they have left out a number of features and compromised on others.
Its well recorded that MS has many issues with noise, this is partly because they don't use an RF ground and partly because of the dreadful PCB layout that you showed above. An RF ground is standard industry practise to present a low impedance, at the pins, to noise signals coming in and out of the ECU. A 2-layer PCB is cheaper to produce but that design doesn't have a working ground plane. They have relatively thin tracking when there is no need, the PCB starts off with copper all over it and a good design removes as little as possible and keeps the tracks widths as wide as possible to reduce impedances.
The 37-way D-type is not at all an automotive standard connector, I don't know why they used that, there are far better connectors about for similar prices, D-types are limited in current capacity and aren't very rugged.
To make it easier to assemble they left out a lot of functionality, count the number of components in a Vit ECU, there is nothing in there that isn't necessary - that would cost. The 16V Vit has an 84-pin processor, the MS has a 44-pin, the Vit connector has 48-pins.
The Megamanual is a little disingenuous in places and doesn't make clear the differences between an OEM ECU and the MS, it just kind of implies that's how an ECU works. I considered an MS years ago for my 8V but ruled it out because I wanted to retain all the stock parts and because it doesn't have a proper low-Z injector driver - the MS manual may have been changed since then but it specifically stated that low-z injector drivers don't work in the way that most do!

MS has the advantage of being easy to tune and its cheap and well supported but with a turbo budget for at least one replacement engine while you're dialling in the tune. Many people do run it but its not plug and play by any means. You'll certainly learn a lot from it.
There was talk of another project that was going to use MS based software which was a 'real' automotive ECU that was produced by Freescale as a demo for the Chinese market, I don't know if it ever took of for not but that used a 'proper' EFI processor.

[Rhinoman]

This is the Freescale ECU:

https://www.freescale.com/files/trainin ... _F0018.pdf

originally it used the Autosar OS but they switched to MS to make it cheaper.

[twiss]

Ahhh excellent, thanks for the info!

I can see why you would run a different ECU that has more features, I had a look at the freescale one and it looks pretty good. My dad actually works at Freescale so I will do some investigation into this!

I was looking at the PCB design and noticed the thin tracking, I was thinking I might adjust the PCB slightly before I make it anyway so could include that...

I've been looking at the noise issues as well, I'm going to try to minimise it by using coil on plug, that way I don't need any drivers for the ignition and will just use logic... why the hell people put them inside the cases I'll never know!!!

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unfortunately theres not much I can do about the ground plane though :(

The connector I have lots of
Commonly found on old medical equipment as it has more pins than a standard PC parallel port!
... but yes I do see your point in this one, they definitely could have picked something more appropriate!
I'm going to run everything from the ECU to a relay board in the engine bay so I won't have to wire that in to anything else at least

In the firmware now I believe there is a decent low impedance injector driver, but I will be using high impedance anyway I think... and I'm not really worried about keeping stock parts

The main reason I was looking at MS was because of the low cost I can put it together for (sub £200 for a MS2 complete and most of an MS1) and because I want to learn about ECUs and tuning with them.
I do understand that it may be a bit of a mission tuning it in, but where would the fun be if it was easy?
The vast knowledge base of people using MS is another appealing point for me

Cheers for the info and I understand the points you've given, but I think unless I can find another ECU that will cost me less I will probably live with its foibles if it runs correctly! Im going to hang on to my carb set up until I've got it right anyway!

I will definitely do some research into the Freescale one though, if I could find something better in budget it's worth a shot

[Anton]

Rhinoman - I've read that many stock ECU's are reflashable - do you know if any of the Vit ones are? If you can, maybe one of the generic ECU's would be suitable for this project? That might make the engine harness simpler, for one thing...

Putting aside the freescale, what ECU would you go for? I'll freely admit that I know *nothing* about ECU's, other than occasionally wondering if a cheap ARM CPU like the one in the Raspberry Pi would make a good CPU for an ECU (at about $5 a pop, a 600mhz 32bit CPU can't really be had any cheaper, now can it?)...