First let me state, I'm not an expert on injectors. What I know I learned here. I did a search and couldn't find the answer to my next question. Although I know one can run any size injector, the question comes down to best combination.

Based on my intended combination hitting 430-450fwhp, all the online calculators say go with 30lb's/hr. My question is, is there any harm or advantage to going with the 37lb's/hr Siemens injector that Racetronix is currently having a sale on? It's only a few dollars more, and I'd like to go with better technology (if the Siemens in fact are)

Thanks!

 

I'll rephrase slightly. From an engineering perspective, is the Siemens 37lb injector a better manufactured injector than the SVO 30lb?

Thanks!
Merim

 

The 37lb injector is a Delphi/Lucas injector not a Siemens.
The disc injector is considered by most as superior to a pintle injector.

Here is some info from Delphi:

The Top Feed Multi-Port Fuel Injector (MPFI) is a highly precise injector. Disc injectors use a small disc with six holes around its circumference. The disc rests on a short chimney that surrounds a metering hole. As the disc is raised off the chimney by magnetic force, fuel flows through the holes in the disc, over the walls of the chimney, and out the metering hole to form a full, finely atomized cone.

Performance advantages listed by Delphi:
• The flat mating surface ensures that no excess fuel is present to evaporate and therefore, no deposits or clogging can occur.
• Compatible with alternative fuels
• Longer service life
• High-speed disc action allows wider dynamic flow range for
improved idling
• Quieter operation
• Revoltionary disc design resists build up deposits which can
affect fuel flow.
• No Fuel leakage for quicker starts

 

Disc injectors supposedly have a better spray pattern, but pintle injectors typically last longer.

 

The spray pattern is determined by the diffuser or the metering orifice which are independent of the valve (disc) mechanism.

Who says disc injectors don't have the same or better life span than a pintle injector?

 

I thought it was important to use injectors that fell within the proper duty cycle of the PCM, ie. not to small and not to big????

 

Injectors are chosen based on motor HP, BSFC and max DC (RPM).
You can run a large injector on a low HP motor as long as you can get the pulse-width narrow enough at idle / light throttle.

Turbo Buick owners commonly buy 50lb/hr injectors which are good for low 11's (3500lb car) even thought their build of motor only warrants a 37lb injector for a 12s car. They simply calibrate the ECM for the proper fuel delivery based on the build of the motor. This way when they up their HP they don't have to buy injectors again and throw away hard earned money. They simply modify the ECM calibration.

As long as you have a tuner that knows what they are doing running a larger injector is not a problem. Most often we use 37lb or 42lb disc injectors in V8 cars.

Jack
Racetronix