2000 Dodge Stratus stock injector size

Tiny
JORDAN721
  • MEMBER
  • 2000 DODGE STRATUS
  • 2.4L
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 130 MILES
I have a 2000 dodge stratus se with a 2.4 liter in it. I cant figure out the size of the stock injectors. Ive looked all over the internet and nothing can give me a straight answer. I need the size in CC
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Monday, February 10th, 2014 AT 1:01 PM

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Tiny
CARADIODOC
  • EXPERT
That isn't how they're rated because they don't flow continuously. They are pulsed on and off with "pulse-width modulation" meaning they're on or off, like a light switch. The Engine Computer varies the on to off times to vary the average mixture.

The closest you're going to get to your answer is to do a search for Jim Linder in Indianapolis. He puts on very high-level classes around the country on fuel systems, and even he never talks about volume except that his company specializes in matching the flow rates of injectors. GM has a big problem with mismatched injectors. Chrysler has no problem because they buy theirs in flow-matched sets from Bosch.

If you were able to find injectors with different flow rates than what your engine calls for, you'll simply get too much or too little fuel at first, but once the engine reaches around 160 degrees the oxygen sensor readings are added to the fuel metering calculations, and the computer will just change how long it holds the injectors open. It will see that it has to keep on making the same "short-term fuel trim" (STFT) corrections each drive cycle so it will move those numbers to the "long-term fuel trim" (LTFT) memory and use those for fuel metering in the future. That ability to adapt is why we never need to worry about getting the right injectors to get the right fuel / air mixture. All we care about is that they all flow the same rate at the same fuel pressure and intake vacuum.
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Monday, February 10th, 2014 AT 1:19 PM
Tiny
JORDAN721
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Okay. The reason I'm asking what the stock sizes are is because I'm upgrading them. The 420a eclipse engine has parts that bolt up to the stratus and will work. I'm getting 550 injectors off of an eclipse and wanted to know how big of a step up that is from the size of my injectors. I know going to big could hurt my car.
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Monday, February 10th, 2014 AT 1:45 PM
Tiny
JORDAN721
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And that if It is to big, then I'm going to need to upgrade a few other thing to make them compatible.
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Monday, February 10th, 2014 AT 1:48 PM
Tiny
CARADIODOC
  • EXPERT
What are you trying to accomplish? Installing injectors with a higher flow rate doesn't mean more fuel will go into the engine. Your fuel pump pumps a couple of gallons per minute but that doesn't mean it all goes into the engine either. You are limited by the volume of the cylinders. Adding more fuel than what is needed to achieve the correct mixture will just increase emissions and waste fuel. You can't get any power from fuel that doesn't have oxygen to go with it.

The Engine Computer pulses the injectors on for a very specific period of time, then it turns them back off. It pulses them once for each intake stroke. The length of that pulse is so short that they have time to turn off even at the highest engine speeds. The only time the length of that pulse width changes is when a richer mixture is desired for heavy acceleration or when the computer makes adjustments as necessary to maintain the proper mixture. Just because you have injectors that are capable of flowing more fuel, doesn't mean you will get more fuel. The computer will see the rich condition and just pulse the injectors on for a shorter period of time.

There is a limit too to how quickly the injectors can be cycled. It takes a lot of electrical energy to unseat the valves against the strong fuel pressure that is holding them closed. It takes time to move that mass and to move it back to its seated position. If a real lot of fuel sprays in and the computer is unable to cycle it fast enough, it will lose control of fuel metering. Too much raw fuel in the exhaust system will overheat the catalytic converters and melt the catalyst. That will result in a blocked exhaust system. You'll also get diagnostic fault codes for "running too rich too long". The Check Engine light will turn on so you'll never know if a totally different problem is detected. Many of those are very minor but can turn into serious problems very quickly if they're ignored.

There is also a limit to how much control the computer has when pulsing the injectors. The minimum length of the injector pulse width is designed in to cover any possible condition, but based on the injectors that were designed for that engine.

Even in NASCAR where they're running fuel injection now, they know that bigger is not better when it comes to injectors. Their injectors are very similar to what is already in your engine. Of course they want more power, but again, there is nothing they can do with more fuel if there isn't more air in the cylinders.
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Monday, February 10th, 2014 AT 3:02 PM

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