pissedoffsol

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

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Saturated:

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.

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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 =)

pissedoffsol

UPDATE:

RC now makes Saturated injectors in 650cc and 750cc varieties.

pissedoffsol

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:

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

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.