injector size

[Robin Lawrence]

Originally Posted by ss3011

Robin , Do you see a gain by running the injectors at 50 or 55 psi instead of oem 42 psi ?

As in may scenarios my answer is "It Depends". Only testing at the different pressures will tell you if there is any value.
Typically I try to run injectors at their design fuel pressure. As you get away from the design pressure some injectors characteristics can change. An injectors opening and closing can be effected by a couple of things, fuel pressure and voltage. changes in these areas effect the way the injector reacts and can alter flow.
Most modern ECU have voltage compensations tables. Getting the correct "dead times" for a specific injector offset any voltage fluctuations and deliver what you have programmed in your base table.
As for pressure changes only flow testing at the various pressures can tell you what that injector will to a setting different than what it was designed for.
And only track testing can tell you if there is a benefit. (notice I didn't say dyno)

As drag racers we affected less by these variables. A race car that is driven at part throttle or through a wide rpm range will see a benefit. A street car will have better drivability with good injector setup data.

In my opinion you will see the most benefit in a drag race scenario by tuning the individual cylinders at wide open throttle through the RPM band of your combination.

I would used the injector timing tables to help mitigate the effects of a huge cam at idle. If an auto car this can also help when loading the converter.

Sorry if I got long winded

Robin

[Todd Gross]

.

Sorry if I got long winded

Robin[/QUOTE]

No....keep talking. What you have to say is always interesting and helpful.