Thread: Td5 is it common rail ??

Originally Posted by Defender=1st

hey everyone
I was reading a 4wd mag and it said the Td5 defender was common rail injection is this true ?? i always thought it was electronic injection

Common rail - yes.
The injectors are electronically controlled too.

Common rail just means that one fuel line supplies all the injectors. There's no black magic involved. It can be in the head like the Td5 or it could be outside.

Originally Posted by Scouse

There's no black magic involved.

You sure, it is a Landrover. I reckon a few hundred years ago a few engineers would have been burnt at the stake. In fact I know of a few in my industry over the last few days that should be burnt at the stake, but thats a whole different story.

I don't think the TD5 is a common rail engine (but I'm probably wrong!) - CR means does mean one fuel line supply but that's not all there is to it - the fuel is injected at very high pressure (1600bar or greater) which atomises the fuel to a fine vapour for efficient fuel burn.

I'm pretty sure the first LR to be common rail will be the new Defender Ford sourced engine.

Having said the above - researching the web gives conflicting views - some say the TD5 is CR - others say it isn't a true CR engine - so I'll change my position to - I don't know!

I am not an expert but I believe The TD5 is called Unitary Injection. That is why the injectors are $1700 each.
Common rail is like petrol injection, where the pressure is in the rail.
Unitary injection has injectors that increase the pressure substantially within the injector..
Both these have now been superseded by Piezo injectors, which react much faster and so can have several squirts for each event., eg Merc V6
Regards Philip A

PhilipA is spot on.
TD5 is not CR.
They are 'Electronic Unit Injectors' (EUI). They develop similar pressure to CR so the fuel will be atomizing and they can do multiple 'squirts' for each event. CR requires the high pressure pump to feed the rail where EUI develops the pressure in the unit injector.

Down side over CR - since the pressure within the injector is ‘cam driven’ (so to say - timing and delivery is electronic) the hugely high pressure builds and drops on each cycle, so super retunes (like we read about here) are not quite as good as CR could be;- the multiple squirts or the injector nozzle being opened for longer will see the pressure slightly reduced towards the end of event - but I’m sure there are plenty people here will agree it doesn’t seem to hold anyone back. Injectors ARE expensive but there are Diesel specialists that can recondition EUI now.
And as a late thought check the price of Piezo injectors and the Pump they require (might get a shock - they are no where near as cheap as most Ni**an & To**ta owners may think).

Not really any worse just a different architecture
EUIs are still used in VWs V10tdi.

The first LR to be common rail is not the new Defender- check;
Range Rover TD6 (BMW) 2002
Disco 3 (& RRS) TDV6 (PSA aka Peugeot-Citroen)
RRS & Range Rover TDV8
But I think the prize might go to (correct me if I’m wrong – it happens a lot)
Freelander TD4 (BMW sourced engine)