Graham regarding that Gen III motor - ZR-1 Net Registry Forums

XfireZ51 · 10-26-2019

Graham,

Just curious that the Gen III motor u built uses 8 injectors rather than the 16 the production LT-5s use. I get that part of the reason for using 16 injectors was so u could achieve emissions and idle qualities while still retaining performance in WOT conditions. Small pulse width is easier to control w a smaller injector, at least w a constant fuel pressure.
Using BSFC and a 20% headroom for the injector, u would be using ~ 42#injectors, correct?

When I bumped the power on my 84 Xfire to 280rwhp, I obviously needed more injector, but idle suffered. Used a VAFPR to vary fuel pressure from 10# at idle to 20# for WOT. The ECM I used supported that by calc’ing a new BPW for the differing kPa levels.

What strategy was implemented in order for the Gen III to use one larger injector and still be able to control PW for idle etc?

10-26-2019	#1
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,686	Graham regarding that Gen III motor Graham, Just curious that the Gen III motor u built uses 8 injectors rather than the 16 the production LT-5s use. I get that part of the reason for using 16 injectors was so u could achieve emissions and idle qualities while still retaining performance in WOT conditions. Small pulse width is easier to control w a smaller injector, at least w a constant fuel pressure. Using BSFC and a 20% headroom for the injector, u would be using ~ 42#injectors, correct? When I bumped the power on my 84 Xfire to 280rwhp, I obviously needed more injector, but idle suffered. Used a VAFPR to vary fuel pressure from 10# at idle to 20# for WOT. The ECM I used supported that by calc’ing a new BPW for the differing kPa levels. What strategy was implemented in order for the Gen III to use one larger injector and still be able to control PW for idle etc?