TPI 5.7L and SVO injectors

[timsiford at hushmail.com]

>Are you saying that Ford rates their injectors at a different pressure 
>and you have to re-rate the 24 lb. injectors to 26.7? Can you elaborate 
>here?

Exactly.  Ford rates thier SVO injectors at a lower pressure as compared 
to the stock L98 injectors.  Thus, you have to rerate their injectors using 
the appropriate formula in order to determine what the flow is at the GM 
PSI of 43.5.  When I installed my SVO 30lb/hr injectors I used an injector 
constant of 33lb/hr.

>have been running Ford  19 lb injectors in my TPI with no chip changes 
>and I am seeing BLMs in the 150-160 range and integrators as high as 
>180. 

That's actually BACKWARDS from what you would expect.  Installing SVO injectors 
and using an injector constant equivalent to the advertised SVO flow should 
theoretically result in LOWER BLMs (showing a rich condition).  If you raise 
the injector constant to the appropriate GM expected flow rating then the 
pulse width will decrease and the BLMs will rise.

>Also, I've been thinking of how changing the injector constant effects
>tuning. Seems to me that raising the injector constant in order to match
>newly installed larger injectors should decrease the injector pulsewidth 
>for a given VE since the larger injectors spray more fuel for a given 
>pulsewidth.

Absolutely.

Tim