injector pressure question

[ChevelleFan]

I have a Chevy 383 that I want to put my Megasquirt setup onto. It's a zz383 crate motor, rated at 425hp/450lb-ft. If I plug in 425-450 hp in the RC Fuel Injector web calc, I get that I need 33-35 lb/hr injectors. I can achieve this by running some 30 lb/hr injectors that I already own at 55-60psi instead of 43.5.

Does this reduce the lifespan/reliability of the injector? Is there any reason I shouldn't do this? My other injectors are 42 lb/hr, which I think are probably a bit big for the application.

http://www.rceng.com/technical.aspx

Thanks,

-Dave

[racingmini_mtl]

You need to make sure your fuel pump can provide the needed volume at that pressure. Also, you will need to adjust the dead time; it might be significantly different from what it is at 43.5 psi.

Jean

[ChevelleFan]

Thanks Jean, I hadnt thought about the dead-time needing adjustment.

Refresh my memory, isnt there a way to determine dead time by
1) Setting 2 squirts per cycle, noting AFR at some RPM (say 3000rpm.)
2) Change to 4 squirts per cycle, noting AFR at same 3000 RPM -- if richer, dead time needs to go shorter, if lean, dead time needs to go longer
3) rinse & repeat till the AFR is the same

Or is there some better way?

Thanks,

-Dave