Setup:
84mm gsr
9.0:1 c/r
pt67 turbo pushing up to 30psi+ at the track
primary injectors being used are 1000cc
walbro 255

secondary injectors will be used to supplement the 100shot of nitrous and I was wondering people's opinion on what size I should get. I'm thinking it shouldn't be much extra, maybe 250's or 310's?

what do you guys think?

 

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why dont you just run a single set of 1600cc injectors and be done with it.

 

Because I would like the ability to have the secondary injectors to come on only when needed. This way I won't have as much of an idle problem with excessive fuel and it will make it easier to tune

 

if you running a good standalone it can do all the features you needdone.

The speedpro,motec and autronic have ability to control nitrous as well as even hondata at certain point. I wuold just run one set of injector rather than making it more complicated than it is

 

This should be an easy calculation. Size the primary injectors to add enough fuel at 80% duty for the motor, then size the secondaries to add enough fuel at 80% cycle to match the spray.

So for example:

Primaries:

450 hp
.45 brake specific fuel consumption
4 injectors
80% duty:

(450 * .45)/(.8 * 4) = 63.28 lbs-hr * 10.5 = 665 cc/min

Secondaries:

200 hp shot
.55 BSFC (nitrous should be burned rich)
4 injectors
80% duty:

(200 * .55)/(.8 * 4) = 34.38 lbs-hr * 10.5 = 360 cc/min

 

I would just run bigger primaries. You can set up a AEM and most other systems to have a triggered input so that when you do push the nitrous it will add x amount of more fuel.