Diesel modernisation

[Jakeymd]

The mark 4 Astra 2.0L turbo dielsel engine produced 98bhp (dti), the latest astra dielsel also with a 2.0 turbo engine produces 160bhp (cdti). What differences are there in the engines that means a 60% increase in power and is there anything you can do to get these older diesel engines upto more modern figures and still have room for a performance map afterwards?

[HDi fun]

Jarrus is the expert on old school diesels.

The biggest difference is common rail injection with outrageous fuel pressures.

2000 bar is quite usual in 4th generation common rail diesel engines.

Multiple injection phases are used to smooth the power delivery - this is impossible with traditional diesel engines, whether or not the fuel is injected directly into the combustion chamber.


I don't think you'll ever get an old school 2.0 diesel to deliver 160bhp unless you want to fill the place with smoke and soot and end up averaging about 20mpg

[jarrus]

Actually, it is quite possible without being smokey, but it will be pushing the limits of the injection pump which is notoriously weak on the 2.0 and 2.2 DTI's but the engine itself is strong and will cope with the punishment.

It uses and ECU controlled rotary pump. So modification of said pump is possible with the right parts.

160 hp is easy to get out of and engine like that but it will require more than just a map.

[HDi fun]

Originally Posted by jarrus

Actually, it is quite possible without being smokey, but it will be pushing the limits of the injection pump which is notoriously weak on the 2.0 and 2.2 DTI's but the engine itself is strong and will cope with the punishment.

It uses and ECU controlled rotary pump. So modification of said pump is possible with the right parts.

160 hp is easy to get out of and engine like that but it will require more than just a map.

Exactly.. Old school diesels can be forced to deliver but it's not a simple job.

Common rail injection is the single biggest contributor to modern diesel performance.

[jarrus]

Indeed they are. but they are incredibly complex, at least with a petrol engine you can buy after market ecus which can make things a lot easier for the consumer.

[HDi fun]

That, I'm afraid, is the price of progress. Diesel cars have shed their slow and noisy images. They've also shed their long term reliability and cost effective images.

[Yugguy]

They'll still do mega mileage with regular servicing. But then so I guess will a good modern petrol. V8s last forever. Just ask mad max

[HDi fun]

I agree completely. But diesel servicing generally costs more than petrol servicing over, let's say, ten years, despite the makers fixed price menu servicing during the first three years.