Would a delco do di petrol

[barana]

Would It be a simple matter of changing the fuelpump, rails and lines and whatever else is needed...would a '424 upwards(cam angle sensor) be up to the task?
I recon a cheap delco running some direct inject squirters and 11.5:1 like the sidi v6 would be worthwhile to say the least.And fun to implement even if its on something silly-wild like a 202.
Would the '424+ be upto it computationally?

[tjwasiak]

I do not think it would be easy to achieve (if possible at all) as direct injection needs ability to control fuel pressure, it needs different beginning of injection, injection duration (injector pulse width) is different... It might need most of stock injection functions replaced by custom routines if hardware would be able to drive injectors, pressure regulator etc.

[Dylan]

11P has the ability to have the fuel pump on a PWM output. If that's of any help.

[Jayme]

the 424 cant even do sequential as it only has 2 injector drivers, so that pcm is out of the running. the later MAF pcm's which do have separate injector drivers would need lots of code rewrites if it could even do it at all.... you would also need really really big injectors, as with direct injection you only have a quarter of the time to inject your fuel load. maybe a little more than a quarter if you keep injecting into the compression stroke, but even this is really hard to control, as your fuel flow drops as the compression rises... how do you compensate for that to get accurate fuel flow?. but you definitely have less than half the time a normal EFI engine has to inject the fuel, as injection can only happen on 2 out of the 4 strokes.

I put that project squarely in the basket of someone keener and smarter than I

[tjwasiak]

Jayme, you forgot injection pressure is much higher (>=100 bar for high engine load) so you have plenty of time to inject fuel.

[barana]

does tunerpro let you slightly advance/retard injector timing events with a mafbased sequential delco ?
Does it have fine enough resolution?
pwm control for fuel pump.. excellent!

I do not think it would be easy to achieve (if possible at all) as direct injection needs ability to control fuel pressure, it needs different beginning of injection, injection duration (injector pulse width) is different... It might need most of stock injection functions replaced by custom routines if hardware would be able to drive injectors, pressure regulator etc.

good point, higher pressure, different volume and duration parameters.
Next step might be to find out typical durations for DI and see if the vt+ ecu hardware and control program and or rtos is capable of these shorter durations.

[VL400]

The Delco PCM is really missing processing power and triggers (more crank teeth) to be accurate enough, injection timing is critical. Software would need to be changed heaps too, fuel pressure control as mentioned above compared to the constant pressure return style fuel system is just one aspect.

The fuel economy comes from the stratified charge compared to the homogeneous charge we are used to with port injection.

Would also need some hardware to control the injectors, many are powered by over 50 volts.

Certainly a good project but not sure a Delco PCM is the right tool, an FPGA based (or higher end 32bit CPU) aftermarket ECU would be far more suitable (most still require external injector drivers).

[tjwasiak]

IMHO it would only be good idea to run DI on high CR (or even boosted high CR) engine. It seems for lower CR (especially in N/A applications) it is worse than port injection/throttle body injection/carburettor...