[Max]

Hello,
i´m confused what injectors to run. 24lbs or 30lbs?
I have no idea, what power level my new engine
will have. Please look my setup and give me an opinion.

331 stroker, 10.5 : 1 cr, AFR185, FTI cam (224/228 in/ex,
more lift on intake than exhaust for more low end torque),
comp cam pro magnum roller rockers, hooker long tubes, off road h-pipe, 2.5 inch dual exhaust with flowmaster 2 chamber, 73mm C&L MAF, 65mm TB, GT40 upper/lower,
255l/h fuel pump, FPR, K&N open air cleaner with cold air
induction, Mallory hifire ignition, stock A9L ECU, centerforce D/F and a tremec TKO, no AC, no PS, no EGR, no smog pump.
I have wideband from innovate with data log function but
i have the engine not installed yet and no injectors or sampling tube. I don´t want to buy the injectors twice.
My car i a 100 percent street car, no strip or race.

WHAT WILL THIS DING DO???
Thank you all for reading this!

Markus

 

[Motorhead]

~425hp at 6200 says I. I don't know too much about EFI, but I believe that might put you right on the fence between 24 or 30lb injectors. I'd fudge more on the larger side if it's close... more safe that way, it's easier to put up with a little worse low-end driveability than a high-end lean condition that you can't get rid of.

 

[Is1BadFord]

Larger injectors, if properly calibrated to the Mass Air, will not cause any drivability problems. It's not like a carb at all...what happens, is that the injectors fire at a smaller pulse width/duty cycle (about 80% duty cycle being optimum from my understanding), which in fact is somewhat preferable. If you're on the fence with injectors, ALWAYS err on the side of the larger. From my understanding, it's possible to be two sizes larger, or mre, without any problems. This also gives you room for other upgrades and more power. Sometimes even enough for forced induction.

Smaller injectors however, can be a nasty issue.

Cris

 

[Freddie]

As a general rule use the expected rear wheel horse power divided by ten to get the best injector size. Most injector calculators will use the max an injector can handle to size them. For best performance you never want to run injectors at more then 80% capacity or duty cycle. If you look at all the top drag racers specs you will find them most running at rear wheel power divided by 10. if your engine is good for 425 at the wheels you should use a minimum of 42lb but would be beter at 50lb.JMHO