currently got my hand on a 1.9TDI polo 9n 100bhp and wondering what can be done to increase the engine performance, I know that one of the things on the list is a remap but wondering what else i can do

cheers

Not 100% sure, but front mount intercooler? exhaust? decat? air box mods? pd130 injectors pd130 turbo? etc

Most things u can do to a normal turbo petrol engine

Gas flowed cylinder head?

Best things would be, full exaust system with de cat, decent air filter, intercooler and a remap. Also things like new injectors and turbos are good for max power. If its a pd engine you can take a lot stuff off the Ibiza cupra tdi (like injectors and intakes

Diesels work differently to petrol engines.

Petrol engines are power limited by airflow, diesels are power limited by fuel flow (up to a point).

Diesels do not run a throttle plate, so the engine takes in the same amount of air each cycle regardless of if you have your flat on the floor or only have the pedal depressed 10%.

Power is varied by increasing/decreasing the fuel injected.

As diesels always run with an excess of air, you can easily increase power by adding fuel upto the point there is no more air left to react with the extra fuel.

When this point is reached, the exhaust will be full of soot due to incomplete combustion. Known as the smoke point, this is where most power is achieved.

Power can also be increased by increasing the thermal efficiency of the engine.

Thermal efficiency increases with an increase in compression ratio.

Changing the static CR is expensive, but by increasing the air density the effective compression ratio is increased.

Turning the boost up, even without adding extra fuel will increase power.

Putting this into practice would mean to get more power you simply add more boost and more fuel.

Larger injectors, a boost controller and a front mount intercooler should be all you need.

This forum has loads of info:

http://forums.tdiclub.com/

My friend has the same engine in a 2K Caddy.

Thats had a green panel filter, decat and exhaust and a remap. All thats taken it to 142bhp. But, the due to the dual mass flywheel the clutch now vibrates unless you know how to drive it. This can be solved by fitting a single mass from a VR6.

Much over this power and the turbo is starting to struggle. So after that, things start getting expesnive.

The PD100, is a good little engine and responds really well to a remap. As above I managed to get just over 140hp from my mates MK1 Fabia PD100 with pretty much stock hardware, I didn't want to push it much further. Only thing that was done was the CAT and middle silencer removed, and it also has a SMF as standard.

As mentioned above, they run as stock with a fair amount of extra air, so injection can be increased a fair bit before the turbo needs adjusting, but that was my limitation in the end.

In my opinion, the cooler only needs changing if you start changing injectors and turbo, then you can start getting decent power from it, but you'll need to sort out suspension and braking before you head down that road.

Does the flywheel need to be from a VR6? I don't have one kicking about and I'm looking at doing a clutch change, considering a single mass as the mileage suggests the dual one fitted won't last forever, and they're costly new. I don't fancy a used one if Ican't tell how healthy it is.