Due to recent problems, I wanted to make a "go to" thread for Fuel injectors for us single slammer guys..
I want to know:
Your experiences with Fuel injector Brands. Who's good, whos not?
Your preferred lph/cc ratings for certain tunes or cams
What your using to tune/modulate fuel pressure and how you like it
Some Injector Info for Newbs
Impedance
Injector impedance describes the electrical resistance of the solenoid windings. These are usually grouped in two categories:
Low Impedance/Peak and Hold- 1.7 to 3.0 ohms
High Impedance/Saturated- 10 to 16 ohms
There are some exceptions to this, notably the Bosch 803 injector used on the Porsche 944 turbo which is 4.7 ohms. Most manufacturers have used both types at one time or another. The trend lately is to use high impedance types in most production cars. The best way to determine impedance is to put a digital ohmmeter across the two electrical connections and see what it reads. The primary advantage of low impedance injectors is a shorter triggering time. When large injectors are fitted to high output engines, low impedance injectors will often give a better idle quality because of this fact. The primary advantage of high impedance injectors is the fact that less heat is generated in the drive circuit and often no external resistors are used.
Nozzle Types
There are essentially 3 different types of nozzles: Pintle
This is the most common type and still the best. A tapered needle sits on a tapered seat. When the solenoid is energized, the core and needle is pulled back, allowing the fuel to discharge. This design has been well proven for over 30 years. Disc Bosch disc type Lucas disc type
The Bosch disc type uses the same type of actuation mechanism as the pintle type but replaces the pintle with a flat disc and a plate with tiny holes. These work fine with a good spray pattern but are slightly more prone to deposits plugging the holes. The Lucas type buries the disc up inside the body to reduce the mass of the assembly for quicker response. The Lucas types typically have a very narrow spray pattern which can affect idle and throttle response in some cases. Ball
The Rochester division of GM makes the ball type injector for OE applications as well as the larger flow race types for MSD. These use a ball and socket arrangement. These have excellent atomization and a wide spray pattern but are also prone to partial plugging by varnish deposits.
Electrical Connections
L-jet connector left, D-Jet right
For the majority of injectors, there are two types of electrical connections. The D-Jetronic type used from 1967 to 1973 or so on Bosch injectors in which the plug fits internally into the injector and the L-Jetronic type in which the plug fits over the injector offreing a waterproof seal. Most injectors of all brands built after 1974 use the later type. Unfortunately, several Japanese manufactuers, notably Subaru and Toyota decided to make their own style connectors in the late '80s. These use an oval shaped plug. The D-Jet type will fit most types but is not waterproof.
D-Jet left, L-Jet middle/right, Barb left, small O-ring middle, 14mm Domestic O-ring right
Fuel Transfer and Sealing
Fuel transfer from the fuel rails was done with barb fittings and hose on early injectors as shown on the left above or small or large O-rings as shown above on the right. The later type uses a rigid fuel rail to hold the injectors down to the manifold as well as seal to the O-rings.
Sealing injectors to the intake manifold usually involves one of two methods. Older type injectors used a square section O-ring slid over the pintle cap to sit against the steel injector body. Newer injectors use a 14mm round section O-ring sitting in an isolated groove. Some new engines use side inlet injectors, notably Subaru, Nissan and some Ford/Mazda engines. These are not compatible with other types.
Manifold end 14mm round O-rings left and middle, older square section right
Flow Rates/ Pressure
Most OE injectors are quite small because stock power outputs are usually quite low on production engines and metering is more precise with small injectors for better idle and emissions. Very few production engines use an injector flowing more than 500cc/minute or 50lbs./hr. For performance applications, engines often require much larger injectors to satisfy the increase in fuel flow. Often larger OE injectors can be fitted from a different engine. Sometimes aftermarket ones must be used. MSD makes 50, 72 and 96 lb./hr. types for racing which are popular. It is essential that you have injectors large enough to feed your engine at maximum power. Most OE systems maintain a fuel pressure of between 36 and 43.5 psi over the intake manifold pressure. Fuel pressure can be raised to increase the rate of fuel flow but this should not exceed 60 psi in most cases. It takes 4 times the fuel pressure to double fuel flow. Raising the pressure to extreme levels is very hard on the pump and can lead to leaks or failures in the plumbing and injectors themselves. Use the proper flow rate for the intended application. If you plan to fit used injectors to a performance engine, always have them flow and leak tested first. If they are not in proper condition, the engine will never run well.
Choosing the correct fuel injector
First you have to know your engines "efficiency number" known as BSFC.
Here is some target BSFC numbers.
Professional racing engine 0.40
High compression engine 0.50
Low compression engine 0.60
Turbo/Super charged engine 0.65
If you know your engines Hp use this formula to determine your injector size Injector Size=Engine Hp x BSFC ___________# of cylinders x 0.8
To convert from lbs/hr to metric cc/min use this formula
What im looking for are some good, budget ~300cc injectors, the stockers are 260cc if you weren't sure..
But more importantly, i want to be able to run the motor at 50% duty cycle at ~180whp so i have play room w/o getting MORE injectors, And i plan on ROM tunning this, unless i can get away with some kind of FPR with a wideband or maybe a used SAFC a buddy might sell me. (dont get me wring, i'd love to rom tune it, but its pretty intimidating)
Im currently looking for some affordable yet reliable 370 CC injectors for my SOHC. After I boosted it it hits fuel cut WAY to fast. The Turbo doesnt even get to spool really so i dont actually know what it feels like for full boost. You can start to here it wine and then starts to instantly miss out. So i found some 370 cc injectors on ebay but im wondering if i should get a diff CC ?? like higher or lower than 370. I dont wanna be risking the engine every time i drive, so i just want somthing that lets me spool abit and have some fun.
well like the above stuff says, you'll be good as long as you dont go over 80% duty cycle. In that equation, where you multiply the # of cylinders, instead of multiplying it by .8, multiply it by .65 or .7. That gives you more play room, so if oyu want to up your boost later, you'll still be okay.
I really want to know what companies are good, and what are bad. A buddy of mine had Venoms, and they crapped on him, and wont run them again.
Im using SARD 550cc's on my 240sx. I havent driven it yet due to it not being done yet. But ive heard lots of good about them. My NCO here is going to put SARD 840cc's on his 240. Soon as i have them sent here.
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"He who wishes to be obeyed must know how to command" -Niccolo Machiavelli
De injectors, and e injectors are diff, DE are side feed where E are topfeed, But you are right about the venoms, they are junk, not really worth it if u ask me, Well hold on let me say this about the venoms, there are alot of fakes on ebay but i got mine from a good distributer and they still dont flow evenly, Derschwek, or however you spell it are good, they flow match each injector withint a certain %, and if u have problems with them, they will help you out alot.
Advanced Fuel Injection is the company i just got my 96lb (1000cc) injectors from. Just order them to fit a 1G talon/eclipse and they will fit the sohc. Great price and just to make sure i had them flow tested today and they are within the 1% of each other like they said they would be. Just wanted to let other sohc ka guys know where to get a good set of injectors. You can find them on Ebay (cheaper) or at advancedfuelinjection.com
I measured the height of each injector with the rubber insulators on them and they are both the same. So they will fit with no problems in that department. The rubber insulator that is included with the injector also fits in place of the stock one so you get new isulators with them too ..However you can see i circled the lower end of the delphi injector, this piece is to big to fit into the intake manifold. When i say its to big its just barely to big. So you have two options. The first option is to Drill the holes slightly bigger (one drill bit size bigger would be enough) but, unless you have you intake manifold already off it would be a big P.I.T.A to pull it just to get the metal savings out. Your second option would be to take a dremel to that part and just take a little bit off to make them fit, which is what i plan to do. So they are not completely plug and play but, they are close.
p.s.
You would run into these problems with any delphi / rochester style injector. You also have to dremel / shave off the little tabs in the connector (like the rx7 injectors) if you plan on using your stock clips, like i plan to do.
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KA24E-T boosted for one year now.
RC makes injectors that fit perfectly fine, i wouldnt go through that trouble. plus they REALLY dont look like they're the same height. at all. and you need to make sure those arent peak&hold injectors, because i think the DSM's use that. in which case you'll need a resistor box before you use them
I am running 50# MSD injectors. I got them from JWT. The guy told me they had to be machined to fit the SOHC fuel rail. They haven't given me any problems as of yet and they use the stock bottom insulators. The top two o-rings are easily found at any auto parts store so replacing them if need be isn't a pain.
Im running a GT30 and its maxing the injectors out at 12psi toward redline so my only regret is that I didn't go bigger.
I'm using Deatschwerks 440cc injectors. I think there great for $240, I'm running 11 psi walbro 255 with a neo safc to control them. No problems at all direct fit =]
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Fuel Injector Thread
Bosch disc type 
Lucas disc type 
..However you can see i circled the lower end of the delphi injector, this piece is to big to fit into the intake manifold. When i say its to big its just barely to big. So you have two options. The first option is to Drill the holes slightly bigger (one drill bit size bigger would be enough) but, unless you have you intake manifold already off it would be a big P.I.T.A to pull it just to get the metal savings out. Your second option would be to take a dremel to that part and just take a little bit off to make them fit, which is what i plan to do. So they are not completely plug and play but, they are close. 
