Thread: Uncommon common rail

I guess you could adapt the crd sytem from a td5 it could work as it is no different than fitting efi to a carby engine. Lot of work and involves adding electrics to a already uncomplicated engine - i wouldnt bother.

The common rail is usually part of the cylinder head.
Whereas the 300tdi has a pipe to each injector, the common rail design uses the idea of a fuel rail on a multipoint EFI system. Each cylinder has an electronically operated injector to open/close at a precise moment.

The 300tdi has a mechanical fuel pump so unless you had some way of hooking up an electric pump (easy) then controlling the electronic injectors (hard), I'd say it wouldn't be possible.

Besides, that's the beauty of the 300tdi - no electronics .

Yeah i love the simplicity of my Tdi, i was just wondering if you could do it just as another option.Thanks for answering that.

The td5 has a fuel rail in the head, but it is not pressurised to the pressure required for injection.

Each unit injector has a piston to develop the pressure required. This piston is operated by the camshaft via a rocker arm.

The electronics only control a solenoid valve which opens to spill the pressure in order to meter the volume of fuel injected.

you could but youd have to change the injectors to unit injectors, change the cam so its got extra lobes to drive the injectors, re-enforce the cam bearings to deal with the stress of driving the injectors, add rockers to drive the injectors, add a medium pressure fuel pump to prime the injectors, adapt the throttle linkage to drive each individual rack on each injector then replumb the fuel lines.

But your question has remeinded me of one i wanted to ask..

can you fit a dynotard/jake brake to a TD5, Im going to ask it in the tech forum as a new thread.

Why would you want too?
The whole point of a 300tdi (in my view) is that you don't need electrics to run it. If you have a battery or alternator failure when you are out bush a couple of days drive from the nearest repair shop you can remove the fuel cutout solenoid (simple 5 minute job) and push/tow start the vehicle and it will carry on running until the fuel runs out (or you stall it).
I was getting 11km per litre from my 300tdi Disco and am now getting 10km per litre from my Prado which has any number of computers and gizmos and electronic fuel injection. Pity I drowned the Disco!

Originally Posted by loanrangie

I guess you could adapt the crd sytem from a td5 it could work as it is no different than fitting efi to a carby engine. Lot of work and involves adding electrics to a already uncomplicated engine - i wouldnt bother.

i dont think you would have enough cylinders for it work.......

Originally Posted by DEFENDERZOOK

i dont think you would have enough cylinders for it work.......

Tony, it just means you have some spare parts for the future .