Is it worth me changing my injectors?

[Shaun_E]

For the last 10 years I've had the Siemans 630cc/min injectors on my 260bhp Duratec 2.0L. They were chosen mainly because they physically fitted and were available! Every time it's been mapped, the mapper has complained that the engine is fiddly to map in that it doesn't respond nicely to injection map changes. I always put this down to the injectors being massively oversized (which technically they are). It was never a huge issue and the maps I ended up with were good (both Steve Greenald and Troy at Northampton motorsport have mapped the car at different times).

The engine is out for a rebuild and I've been toying with the idea of getting some more appropriately sized injectors. A slightly lower capacity injector is now available: Siemans 440cc/min so what I'd like to know is if it is worth making the change?

The usual fitment for similar engines is the Bosch "green" 412cc/min but these don't physically fit due to the backplate/air filter set-up I have. The existing injectors have been cleaned and checked recently and are well matched and working well.

Thoughts please 😊

[7 wonders of the world]

At that power you could use the Boash Greens in the OE position in the head, using the OE high volume dead end fuel rail.

 

[Colin_T]

What about IWP162 ? 377cc

at your current power output these should see you around 80% duty cycle.

smaller cc injector will give you much finer control of the injector at lower resolutions. So much better control over the injector at idle and light throttle conditions. 

working with a big injector you always end up having to make compromises in the low end mapping as you simply don’t have fine enough control. 

 

colin