Thunder G4+. Multi fuel. Injector flow@rated pressure. Limited to 3000cc max.

[bsh]

Hi,

Seems this is limited to 3000cc max. Is it possible to increase this limit? Can I apply a 4D table and just increase whole secondary fuel table like 30% as a band aid, or do it with the sec/pri ratio? My secondarys are 3900cc. 

Btw G4X are 5000cc max.

Details about engine. 4 cyl dual fuel with 2 separate fuel systems. Primary running petrol ID2000 and secondary 100% methanol Fueltech 520lb. Will keep it simple and switch between fuels with a simple switch. Either 100% petrol or 100% Methanol. No blend of fuels.

Thanks

[koracing]

Not sure this is the best method: Lie to the ecu and tell it the injectors are half the size, and the motor is half the size.

2000cc injector on 2.0L motor -> 1000cc injector on 1.0L motor - should give correct pulse width if my thinking is correct.

[Adamw]

Yes I agree with Kris' suggestion as probably the best workaround, choose some nominal ratio to reduce the Inj flow rate by and adjust the engine capacity by the same ratio.  As far as I can think most of the fuel calculation and compensations would still work correctly, there would only be a couple of metrics like instantaneous fuel consumption and estimated air mass that wont report correct values.  

[bsh]

Ok thanks, will do that.

Believe the sec/pri ratio should still be the same like before? Like 3900/2000. 1.77.

[Adamw]

2 hours ago, bsh said:

Believe the sec/pri ratio should still be the same like before? Like 3900/2000. 1.77.

yes.  I always like to do this to get it more accurate though:

1. Initially set to calculated ratio.
2. Set staged injection table to 0 (all fuel through primary).
3. On the dyno hold the engine at a medium RPM, medium load so you are up around 50% DC on the primary injectors (say 3000RPM & 30%TP for example), adjust fuel table so that the measured lambda is close to target lambda.
4. While still holding at same RPM/Load, change staging table to 100% (all fuel now through secondary), you will get a little lean blip as it swaps over but if the ratio is correct your measured lambda should settle on the same value it was at before.  
5. If lambda did change significantly then adjust Sec/Pri ratio and switch back and forwards between 0 & 100% staging until lambda is the same regardless of which injectors are being used.