Peak / Hold VS Saturated Injectors

There are two basic types of injectors that work on Honda and acura cars. How they operate are totally different. Let's take a look.

Peak and Hold:

Peak/hold injectors are low impedence, usually in the 1-4 ohm range. When the ecu calls for fuel to be injected, it sends out voltage via the wire clips until a certain current level is reached (the peak part) (varies by injector size, company). For the duration of 1 pulse width, that current is slightly reduced and held (the hold part).

Advantages of this design:
  • minimizes the injectors "on" time, resulting in faster response
Disadvantages of this design:
  • increases coil heat, which can lead to failure over time


Saturated injectors are generally higher impedence than peak and hold, running in about the 10-15 ohms range. Unlike peak/hold, a saturated injector remains "on" for the entire pulse width.

Advantages of this design:
  • reduces heat
Disadvantages of this design:
  • slower response time
  • can't handel large CC or lb/hr styles due to limitations in its speed.

So, which should I choose?

There are a ton of factors involved in this.
  • First, power level. If you're going big, there simply won't be a saturated injector that will support your power level. The largest common saturated injecotrs on the market are 550cc, with 440cc being a common "cap" in saturated size. Most boosted people run peak/hold setups for not only their availibilty, but also their ease of upgrading later on if so desired. simply swap the injectors. no need to re-wire again.
  • How is your car wired? most obd0 civics and some preludes are wired for peak/hold and have a resisitor box already. No point in changing to a saturated. Obd1+2 civics, and most other honda/acura cars after 1992 are all saturated and are not wired with resisitor boxes. Again, if there is an injector availble in your power range for flow of your car's design type, there's little sense to change.
  • Price. DSM eclipse/talon 450cc peak and hold injectors fit honda rails and with just a minor modification plug right in. best of all, these can be had for about $50-75 a set of 4 instead of $350+ for a set of aftermarket injectors. Add a $25 resistor box from an obd0 civic/crx, wire it up, and you're good to go in you're saturated car.
in a later article, we will cover the injector resistor box install procedure.

any questions, please use the proper forum =)

RC now makes Saturated injectors in 650cc and 750cc and 850cc varieties. More may be available in the future as well, thus taking the saturated injector market up to support larger power numbers.
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Just ran into this site... lots of great info about injectors:

Fuel Injector information & Specifications specs

In case the link dies, here's the page info:

<table border="1" cellpadding="2" cellspacing="4"><tbody><tr><td>Vehicle</td><td>Injector Types</td><td>Factory Flow Rating</td><td>Notes</td></tr><tr><td>1990-'93 Geo Storm GSi</td><td>Peak and Hold </td><td>222cc</td><td></td></tr><tr><td>1990-'93 Geo Storm 2+2 & Stylus S</td><td>Saturated</td><td>222cc</td><td></td></tr><tr><td>1990-'93 Isuzu Impulse & Stylus XS</td><td>Peak and Hold </td><td>222cc</td><td></td></tr><tr><td>1991-'92 Isuzu Impulse RS AWD</td><td>Peak and Hold </td><td>322cc</td><td></td></tr><tr><td>1988-'91 Civic Si/CRX Si</td><td>Peak and Hold </td><td>240cc</td><td></td></tr><tr><td>1992-'95 Civic</td><td>Saturated</td><td>240cc</td><td></td></tr><tr><td>1996-'00 Civic dx cx and lx</td><td>Saturated</td><td>190cc</td><td></td></tr><tr><td>1996-'00 Civic ex/si</td><td>Saturated</td><td>240cc</td><td></td></tr><tr><td>1990-'91 Integra RS/LS/GS</td><td>Peak and Hold</td><td>240cc</td><td></td></tr><tr><td>1992-'00 Integra LS/GS</td><td>Saturated</td><td>240cc</td><td></td></tr><tr><td>1992-'96 Prelude Non-VTEC</td><td>Peak and Hold</td><td>240cc</td><td></td></tr><tr><td>1992-'96 Prelude VTEC </td><td>Peak and Hold</td><td>345cc</td><td></td></tr> <tr><td>1997-up Prelude VTEC H22</td><td>Saturated</td><td>280cc</td><td></td></tr><tr><td>1991-up Sentra SE-R/200SX SE-R</td><td>Saturated</td><td>265cc</td><td></td></tr><tr><td>1991-up MR2 Turbo </td><td>Peak and Hold</td><td>440cc</td><td></td></tr><tr><td>1987-'92 Supra Turbo </td><td>Peak and Hold</td><td>440cc</td><td></td></tr><tr><td>1993-up Supra non-Turbo </td><td>Saturated</td><td>315cc</td><td></td></tr><tr><td>1993-up Supra Twin-Turbo </td><td>Peak and Hold</td><td>550cc</td><td></td></tr><tr><td>2000-up Celica GT-S </td><td>Saturated</td><td>310cc</td><td></td></tr><tr><td>1990-up Miata 1.6-liter </td><td>Saturated</td><td>215cc</td><td></td></tr><tr><td>1993-up Miata 1.8-liter </td><td>Saturated</td><td>240cc</td><td></td></tr><tr><td>1984-85 RX-7 195500-0900</td><td>Peak and Hold</td><td>680cc</td><td>Orange Top</td></tr><tr><td>1986-87 RX-7 195500-1350</td><td>Peak and Hold</td><td>460cc </td><td>Red Top</td></tr><tr><td>1986-87 RX-7 195500-1370</td><td>Peak and Hold</td><td>550cc</td><td>Tan Top</td></tr><tr><td>1988 RX-7 195500-1350</td><td>Saturated</td><td>460cc</td><td>Purple Top</td></tr><tr><td>1988 RX-7 195500-1370</td><td>Saturated</td><td>550cc</td><td>Purple Top</td></tr><tr><td>1989-91 RX-7 195500-2010</td><td>Saturated</td><td>460cc</td><td>Red Top</td></tr><tr><td>1989-91 RX-7 195500-2020</td><td>Saturated</td><td>550cc</td><td>Purple Top</td></tr><tr><td>1993-up RX-7 Twin-Turbo </td><td>Saturated</td><td>Primary 550cc</td><td>Secondary 850cc</td></tr><tr><td>1990-'96 300ZX Twin-Turbo </td><td>Saturated</td><td>370cc</td><td></td></tr><tr><td>1991-up 3000GT/Dodge Stealth non-turbo</td><td>Saturated</td><td>210cc</td><td></td></tr><tr><td>1991-up 3000GT VR-4/ Dodge Stealth R/T TT</td><td>Peak and Hold</td><td>360cc</td><td></td></tr><tr><td>1989-up Eclipse/Laser/Talon Turbo/non-turbo</td><td>Peak and Hold</td><td>450cc Blue Top(95+ Black top)
390cc Tan top
240cc Orange/pink Top
210cc Light Tan Top </td><td></td></tr><tr><td>Mitsubishi EVO</td><td>Peak and Hold</td><td>510cc Yellow Top (1-3)
560cc Red top (4+)</td><td></td></tr><tr><td>1986-89 Ford turboCoupe</td><td>Peak and Hold</td><td>35lb/hr Brown Top
30lb/hr Green Top</td><td></td></tr></tbody></table>

There's a ton more pics and info available at the link. please visit, as i don't want to steal their pics, but i hate how links just end up breaking eventualyl on the net.
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