# Fuel Injector
**URL:** https://forums.speedlife.net/t/fuel-injector/131312
**Category:** SON240sx Automotive
**Created:** [February 6, 2010, 9:08am UTC](https://forums.speedlife.net/t/fuel-injector/131312 "2010-02-06T09:08:33Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@maverick2](https://forums.speedlife.net/u/maverick2)
#### Post date: [February 6, 2010, 9:08am UTC](https://forums.speedlife.net/t/fuel-injector/131312/1 "2010-02-06T09:08:33Z")
Im looking to get injectors that is 500cc+ for my RB20DET …
If somebody can clairify on the whole resistor box use, Im trying to choose between RC Engineering & Deatschwerks.
Peak and Hold-Low resistance & Saturated-High resistance are the options ? Im pretty sure that the oem injectors are peak & hold, so do both resistances require the use of the resistor box ? Or does it depend on the amount of cc’s ?
For example; if I was to go with 550cc Peak & Hold injectors … Will I need a resistor box ?
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### Author:  [@R33](https://forums.speedlife.net/u/R33)
#### Post date: [February 9, 2010, 8:01am UTC](https://forums.speedlife.net/t/fuel-injector/131312/2 "2010-02-09T08:01:59Z")
there are low impedence and high impedence injectors. (top feed /side feed)
low impedence injectors need a resistor pack.
rb20’s come with high impedence injectors.
if you wanna upgrade then either look for 500cc high impediance injectors … or 500cc low impediance injectors with a resistor pack.