Montreal V8 – SPICA or MS EFI ?

I posted this on the AlfaBB in response to a question about updating an Alfa Montreal with an 8 cylinder SPICA mechanical injection pump with an after market EMS system like the megasquirt, but thought I’d repost here as it had a few arguments for and against after market EFI in a classic car.

I’ve used the megasquirt in both it’s early iteration a good few years ago, and recently the latest version with good effect.

One in a GTV6 to replace the l-jet: I squeezed it into an l-jet box as others had done so it was plug and play with the original loom. All you had to do was add a MAP line and remove the AFM. Massive difference in the ability to tune the car to suit your environment (fuel, age of engine, engine tune etc.) It also laid bare all the functions of the engine to easy tuning, provided the ability to ‘auto-tune’ with an O2 sensor – and added some nice more modern EMS features (3D ignition mapping for example) to make the car more fun, and more economical for commuting. The L-Jet was an ageing analogue system, had the restrictive AFM flap, and annoying issues that niggled me to death and resisted the attempts of myself and other l-jet savants to resolve. The MS unlocked it and turned it into such a pleasure to work on.

I’ve done TwinSpark into 105 conversions using MS instead of motronic. – easy on the engine side because you already have the delivery system plumbed in – a bit fiddly on the 105 chassis side (extra fuel lines, returns to the tank, pumps, swirl pots etc.) but it’s not insurmountable with a little mechanical aptitude – and all easily reversible. Also using the cheaper MS spark unit to provide 3D mapped wasted spark ignition while still running with webers to preserve that period sound and look in the engine bay.

I went the other way as with my Super – with individual throttle bodies, CoilOnPlug wasted spark ignition and 3D mapped VVT control to preserve that function.

On a completely stock TS with original intake and single throttle body – the biggest benefit is the ability to tune more for power over emissions (the motronic has quite a bit of emission tuning ) and also using a Wideband O2 sensor to really get the tune perfect for your particular environment. I’d gently suggest it has similar benefits over the venerable SPICA pump.

Once you start tinkering a little – changing your exhaust, intake (ITBs!) , mild engine porting – the value of the MS system really shines as you can basically let it dial itself back in to take advantage of the changes you’ve made. Taking that a step further – you can rip your engine open, get creative with your cams, pistons etc. – fire it back up and the system will re-adapt to suit what you’ve done where possible – and tell you if you’ve outstripped your injectors / fuel capacity and need to make changes to suit.

A perfectly stock Montreal in great running trim is a beautiful thing – and a 4 cylinder SPICA pump is an amazing piece of engineering – an 8 cyl. unit mind-blowing !

8 cylinder Alfa Romeo Montreal SPICA Mechanical fuel injection pump

But – being able to retrofit something like the megasquirt to allow the average wrencher to plug in their laptop and really dial that engine in to the application / environment – and take full advantage of simple modifications like exhaust / intake and fuel octane… it’s worth gold. It really gives you access to the black arts of the dyno tuner and SPICA pump whisperer. For a little extra dough you can incorporate knock sensing, exhaust gas temp and full monitoring of all the engine sensors. The system can tell you if something is awry and help prevent melted pistons and other nasties. A nice bit of extra insurance in my book.

Whilst not everyone’s cup of tea – but perhaps of interest when competing with the cars – you get complete and granular logging off all the running information for each session – I link this data with the GPS and Accelerometer data from an iPhone / Android track timer app – then you can overlay your gopro video with the data and really dial into what was happening with driver inputs and engine performance during session.

The pricing point of the MS units, particularly if you’re a dab hand with the soldering iron, is pretty spectacular. Additionally – just like the alfabb – there is a vibrant and informative internet community at that is really worth a read. The gear can be purchased in assembled or kit form from MegaSquirt | Engine Management System | Electronic Fuel Injection – Remembering that the design and code base is open source, they’re just charging for the kits and/or assembly.

Not to mislead on the cost of one either – the little things can add up very quickly – fuel fittings, electrical connectors, pressure regulators, later bosch style fuel pumps and filters…. A little creative scavenging from a wrecker / breakers yard saves some pennies here.

Still, from a fiscal point of view – you’re likely still under the cost of an 8Cyl SPICA rebuild (not including your own time of course), and probably well under the cost of 4 freshly rebuilt DCOE or IDF Webers.

Not for the faint of heart where significant changes have to be made, and certainly not as simple as changing a filter but – depending on your point of view – quite a few advantages to utilising the system over the venerable SPICA even perhaps on an otherwise stock engine. You’re in for quite an investment of time working with the system to get a good basic tune to start with too (unless someone who’s done one already can give you some starting configuration..)

If you find yourself in the garage on a Saturday night checking the valve clearances again even though you know they’re fine – it might just be for you. The Montreal is such a jewel of innovation and complexity – with solid engine design links to the mighty Tipo 33 – I think it deserves it !


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