Megasquirt on a Diesel?

[Bush65]

Some of the euro 4 diesels have up to 5 burns per cycle.

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The reason engines have EMS rather than clockwork is that, for a given engine, you get better power, economy, driveability, reliability etc. from electronics than you do from clockwork.

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The multiple fuel injection events are not what gives them more power. Multiple injection events will never be able to produce as much power as a single injection providing the timing and quantity of fuel is sufficient.

In the USA where diesel racing is taken to extremes, none of the common rails systems can get near the modified mechanical pumps for performance.

The extreme common rail engines are running multiple units to try and inject enough fuel.

The modified mechanical fuel injection pumps are based upon inline pumps (not VE) they have larger plungers and fast rise cams to inject more fuel as fast as possible at the top of the stroke - this is what multiple events can't match.

Leaving that USA scene now: The main feature of common rail systems that improves performance over older mechanical injection systems is higher injection pressure coupled with more smaller nozzle holes in the injectors. This provides better fuel atomisation, resulting in better combustion.

Multiple injection events is more to due with reducing diesel knock, engine smoothness, and meeting emission regs. The 2 stage injectors in 300Tdi engines was an early approach in this direction for the same reasons - obviously computers do this job much better.

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I looked seriously & even went to the US to see the Duramax twin turbo diesels & came back blown away by the power etc but scared ****less by the wiring & computers ...

Fitting a Duramax into another vehicle doesn't seem to be particularly difficult from the few I have seen done where I am - I'm sure if the engines were more available here I would see a lot more conversions using the Duramax.

EFIlive supports the Duramax and makes it simple to tune it for an extra 200+ horses. It is easy to bolt on after market parts, turbos etc. for a lot more.

Sorry none of this has much to do with MS on a 300Tdi, which IMHO is not worth considering for more than 2 seconds, although the discussion makes interesting reading.

IMHO the 300Tdi is not robust enough to push the performance too far. The money to fit a decent turbo, intercooler (been there ), mods (not talking adjusting settings here) to the injection pump and injectors will probably cost much more than the vehicle is worth and then the bottom end probably wont like you.

[TheRecklessEngineer]

Just thought I'd stick in my thoughts on diesel tuning:

A diesel engine behaves like a petrol engine at WOT. However, at maximum fuelling (i.e. foot to floor) on a diesel, you rarely get beyond about lambda=2 (in an old style diesel). So in theory there is still enough air in the cylinder for the same amount of fuel again.

Diesels don't run at stoich at max fuel for emissions. Soot is really the limiting factor here - once stoich is approached the levels of soot produced rises exponentially with fuelling. Ask anyone with a tweaked TDi...

The soot production can be reduced with better swirl design, better injectors and higher injection pressures. More modern diesels incorporating these are able to produce more power. The tendency for the engine to produce soot is decreased, more fuel can be injected without compromising emissions. More modern diesels are still running with around 25% excess air.

So - if you are tuning an engine for power where emissions aren't a problem you can simply turn up the fuel. Your tweaked engine will produce clouds of black smoke, but it will go like stink. If the bottom end can stand this however, is a different matter. Increased fuelling leads to increased peak combustion pressures and temperatures which will result in much larger loads on engine mechanicals.

Back to the point of this thread though - I love having a fully electronic engine in the front of my series. The electronics is able to produce more power and better economy than the clockwork equivalent. Reliability is also better. I can quite see the attraction of fitting an electronic diesel. Persuading a mechanical injection pump to run a modern diesel engine is outside the realm of most homebrew mechanics - in much the same way as designing a carburettor. However, programming an ECU is quite straightforward in comparison. So getting a common rail diesel to run on a simple ECU which can be made in a shed opens up huge possibilities of fitting modern diesels to older vehicles.

I understand the argument that the manufacturer ECU is likely to be better than anything that can be nailed together in a shed - but as FF has already pointed out, you can make your ECU do anything that you want!