Ducati Dual Injector TBs

[pormgb]

I have a 1965 Corvair Turbo that used two large injectors (500lb), one injector fed 3 cylinders and MS was to set to 6 squirts.

This setup was impossible to tune for idle so I have moved to Ducati 996 dual injector TBs and added one additional injectors per side spraying above the throttle plate.

I am trying to determine the best MS setup for this configuration, the Ducati TBs have two 300cc injectors and I have another two 300cc injectors in the intake tube.

Will running two 300cc (per TB) vs 1 500cc (per TB) allow me to get a better idle PW or do I stage the second 300cc with the intake pipe 300cc to come on under load?



How will the number of squirts change with dual injectors per TB?

I am also moving to a MS2 V3 I had laying around, I am not sure if this will help.

Old thread;

http://www.msextra.com/forums/viewtopic ... 01&t=53446

[billr]

I browsed through the old thread, but don't know all the details, I admit.

Have you considered modifying the heads to provide real (and balanced) intake runners? Not ITB, but just decent runners fed from a common plenum. Those old Corvairs had the most primitive of intake "manifolding" and I suspect any improvement there will help.

[pormgb]

I browsed through the old thread, but don't know all the details, I admit.

Have you considered modifying the heads to provide real (and balanced) intake runners? Not ITB, but just decent runners fed from a common plenum. Those old Corvairs had the most primitive of intake "manifolding" and I suspect any improvement there will help.

I have thought about modifying the heads but I don't want tear the motor apart again.

[pormgb]

Anyone?

I am trying to determine the best MS setup for this configuration, the Ducati TBs have two 300cc injectors and I have another two 300cc injectors in the intake tube.

Will running two 300cc (per TB) vs 1 500cc (per TB) allow me to get a better idle PW or do I stage the second 300cc with the intake pipe 300cc to come on under load?

[dontz125]

If by "running two 300cc (per TB) vs 1 500cc (per TB)" you mean running the pair simultaneous in parallel, then you will effectively be running a single 600cc injector, with a reduced PW at idle. If the 300cc injectors have markedly better small-opening performance vs the 500, this MAY improve your situation, otherwise you are likely to be worse off.

You might try operating the 4 300cc injectors as 1x in-TB as a single 300cc primary, then 1x in-TB + 1x in-pipe as an effective combined 600cc secondary.

[billr]

It looks to me like an MSQ file has never been posted, either here or in the old thread. Do that now, maybe we will see some clues.

[pormgb]

If by "running two 300cc (per TB) vs 1 500cc (per TB)" you mean running the pair simultaneous in parallel, then you will effectively be running a single 600cc injector, with a reduced PW at idle. If the 300cc injectors have markedly better small-opening performance vs the 500, this MAY improve your situation, otherwise you are likely to be worse off.

You might try operating the 4 300cc injectors as 1x in-TB as a single 300cc primary, then 1x in-TB + 1x in-pipe as an effective combined 600cc secondary.

OK, I will try both scenarios and see how the car idles.

With regards to (You might try operating the 4 300cc injectors as 1x in-TB as a single 300cc primary), would I configure the injectors as 4 x 150lb?

[dontz125]

No - 1x 300cc primary, 1x 600cc secondary.

[pormgb]

Got the motor up an running, I am now trying to figure out how many squirts would satisfy this configuration. I am seeing around 4ms n the mid 12s AFR with 3 squirts, It seems that I have enough room to get a decent idle.

Prior to the dual injector TB I used 3 squirts and that seem to work quite well. Now, it seems like there is allot of fuel being dumped into the motor that makes is smoke.

What would be the best number of squirts for this configuration?

Also, what would be the best way to stage the secondary injectors? RPM, Table, E.T.C.