Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) gdi

Good afternoon,

Can you tell me the difference between a Morgan Plus4 and a GDI?
What does GDI mean?
Thanks

Below is quite a good description of the meaning of GDI (gas direct injection - here 'gas' really means fuel, which can be petrol or diesel). Basically, GDI means injecting the fuel directly into the cylinder, whereas other fuel injection systems inject the fuel into the inlet port of the engine. Putting the fuel straight into the cylinder improves efficiency and can offer increased power.

https://www.slashgear.com/1576569/understanding-gasoline-direct-injection-gdi-engines/

It seems that as ever the process of change may not always be 100% positive in it`s outcomes...?

One downside of injecting fuel directly into the combustion chamber may be that the inlet tract may in time become fouled up to some degree with oil related crud which seems likely to reduce volumetric efficiencyof the combustion process by some degree.

The crud being created by manufacturers ever seeking to cut down on emissions..? In this case it seems that the oil mist/pressure created in the crankcase requires to be ingested by the engine via the inlet tract and burned in the combustion chamber..?

All the above worked reasonably well given that pre GDI, fuel washed the inlet tract and the back of the inlet valves on it`s way into the combustion chamber. However there is no such process in most GDI engines.

I think that perhaps Mitsubishi added a supplementary injector on some engines to the inlet manifold in a bid to offset the crud build up....?

More than happy to be corrected if I have got any of this wrong, having been wrong in the past on too many occasions... (-:

Other posts have covered what a GDI engine is but to answer your 1st question.
The Plus 4 has had a number of engines with the 2 litre GDI introduced in 2014 and keeping that engine until the traditional Morgan was replaced by the BMW engined CX Plus Four. Before the GDI the Plus 4 had the 2 litre Duratec engine and others before that.
So a GDI Morgan is a Plus 4.

thank you

thank you

Direct injection is not the be all and end all with petrol engines although it's been the norm for diesel engines since their inception for hopefully obvious reasons. Downside is that petrol doesn't have the opportunity to wash valve stems leading over time to carbon build up.

Interesting that Ford engineers considered direct injection when designing the Cyclone V6 engine in my car, but dropped in favour of port injection.

I had a 2014 GDI, from new built to my own specification and it looked amazing and should have been my lifetime car but replaced it with a 2013 Duratec after 3years. I had so many issues with it, build quality, engine, reliability and just couldn't live with the problems although none related to the well known Direct Injection issues. Possibly due to it being one of the first GDI cars and was definitely not sorted which hopefully the later ones were. Others are very happy with their GDI’s so perhaps I was unfortunate but I would be very wary of taking on an early GDI

Sad to read of your experience Andrew

Sadly don't have a Morgan at the moment but still lurk on here. Bought my 2014 GDI Plus4 new. I feel the earlier non GDI Duratec would have been a better buy because much more tuneable. Eventually I tossed out the n/aGDI engine and inserted a Focus ST turbo motor (loads of torque and 270 bhp so went quite well). On the injection question the answer is easy -- change to VTA (vent to atmosphere). Very easily done. I did this from new with the GDI and the inlet tracts and the inlet valves backs remained clean as a whistle. I do it now with all GDI cars and with my Beemer 340i (same engine as the latest Plus six). The Americans even do a kit for it. Hope this helps.