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Sequential Staged Injection

Beams AE82

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Hi all.

I am currently running  my 2L N/A Toyota 3SGE Gen 4 engine on 95 Octane pump fuel, controlled by a V88 ECU. It's running the stock 315cc injectors at 3.5bar fuel pressure, in sequential mode and peaking at 83% duty cycle so nearing my safe 85% limit.

I am wanting to install a second set of the same injectors, upstream, possibly outside of the ram tubes to facilitate the optional use of E85, permit future engine modifications which will increase the fuel requirement and find gains due to expected improved fuel atomization. Injection mode will then be staged sequential.

The existing 4 injectors are +-13 Ohm high impedance units. Battery voltage is 14.5V so each Injector driver currently draws a peak current of 1.1A. Will I be able to install the second set of 4 injectors to drivers 5, 6, 7 and 8 without any driver overloading issues? Maybe I should rather ask, what is the safe current limit on each Injector driver and is there an overall limit for all the drivers added together?





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Hello Simon.

Our next drag event is in 5 weeks from now so I have a little time to setup staged injection - if this is the way to go.

I am very likely going to utilise a set of secondary injectors mounted at the ram tube entries that are the same flowrate as the primaries which will simplify matters somewhat. I would like to be able to phase them in from about 6500rpm upward with the option to progressively shift  the fueling demand between the primaries and secondaries and not just transfer all the demand to the secondaries. In effect, have the primaries supplying all of the requirement up to 6500rpm and then, progressively bring in the secondaries to carry say 70% of the total fuel demand by 8500rpm.

Would this be possible to set up?

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Sorry I forgot about this one.

In the V series we cant use RPM as the main staging table axis so I suggest TPS, this along with the RPM lockout should give you something similar to what you requested.

In the example below, I have set my lockout to 6000RPM, so over 6000RPM and 70% throttle the secondaries will start to work.  At WOT and any RPM above 6000, 70% of the fuel will be going through the secondary injectors.

Also note since your injectors are going to be different distances from the intake valve you will likely need to use the "accel fuel" and "accel time"  to dial out the lean spot when secondaries turn on.



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  • 3 weeks later...

Hello Adam.

As promised, some feedback on the above. I am staging in the secondary injectors from 4000rpm and 40% Throttle position to carry a total load of 70% at full throttle. I am extremely happy with the functionality and there is definitely an increase in performance. I have mounted the seconndaries just outside the entry to the velocity stacks.

Is there a way in which I can set injector timing differently between the primary and secondary injectors?

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