Race Engine Forum UK

Hi

I have got a 2.0 131 block which I have combined with the head from a Lancia Delta 16v Integrale. The head has been modified with slightly warmer cam shafts and larger valves. I have put on a Megasquirt and Mega Jolt injection system and it has a race exhaust manifold. The block has been re-bored with forged pistons.

The problem is I don’t know what Injectors to use. I currently have Weber/Marelli IW-053's. It has been suggested I use IW-031's or Bosch 803's. The engine is in a Chaterham style kit car so very light, but I am after the ones that will allow the most power I can reasonably afford.

I have not yet tried the engine as it is still in the process of being re-built. I am expecting/hoping for 350bhp+ Can anyone give me any advice on what injectors to use or where I can find out?

Many thanks

Mick

Sorry, don't know.

I don't have any records on injector sizing over 300bhp and with turbochargers.

Can any other reader with direct exp help please?

GC

Once I worked in a Lancia specialist workshop in London and they claimed that standard injectors with fuel pressure at 3,2bar are good for 330HP (384ccm injectors). So you will need something bigger for 350HP. Probably safe will be around 450ccm.
I had 384ccm injectors and got 296HP from my Delta Integrale 16v

Bosch "green" 42lb/440cc injectors will do the job, but maybe only just. Very common and low cost.

Common rule of thumb is 5cc/min per horsepower.

thanks folks, much appreciated.
mick.T

Regarding the bosch "greens", I have seen some footage of them in action - an interesting spray pattern, almost like a spray out of a hosepipe. I have no evidence to suggest that these do not produce good power, however, the fuel does not look particularly well atomised. If you would like to see some footage of this, send me a PM and I will forward the link.

Since you have MS you can easily record the behaviour of your injectors by looking at the duty cycle. Big injectors might give you bad idle (=too low duty cycle) but they will give you potential for more power, and most important you´ll have some safety margins at high loads / boost.

I agree with the other guys, 450ccm injectors should be enough. Don´t forget that you might need larger fuelpump, or maybe two pumps in parallell...

// Peter