I was thinkin about getting new injectors, just for the fact that the ones i have are original and 19 years has to affect their performance. Wondering if anyone knew the injector size for 3.8L's. Also would it be best to just get the same size or increase it slightly(lookin for more power). Ive been looking into Delphi and Accel for injectors. Anybody replaced their injectors?

Hi speedy266, hello AllIf it aint broke, don't fix it.
Regards, Norm

KISS


TOC Admin
Brando

Hi speedy266, hello all
bigger nozzles will not increase power without a bigger air intake and mods to your fuel management system.
Delphi or Accel will offer no advantage over OEM replacements.
Regards, Norm

I second that one

yep. Just buy something you add to gas to give em a "clean"

If it aint broke dont fix it,

i also heard another saying fix it till its broke haha

anyways thanks for ur input guys.

That used to be in my signature... "If it aint broke... Fix it till it is!"

lol niceee
Well i was still wondering wat size the original ones are, anyway to find out? Runnin a car a little richer will increase its power output right? I read at a couple places high 12's to 1 air to fuel mixture is optimal for power, while 14.7:1 is optimal for fuel economy because its the right amount of fuel to burn every oxygen molecule in the mix making it the most efficient. Is this why most muscle car owners have the richest mixtures ever? lol u can smell them coming.

Hi speedy266, hello all
The guy at your local parts counter should be able to tell you.
They are sized to meet any requirements that the engine will ever need.
No, Your computer already keeps your mixture and timing at its optimum settings at all times.
They came from the factory in with correct mixtures and the carbs are not properly tuned to compensate for mods made afterward.
Regards. Norm

Hey 88 Coupe

For the computer thing, I would think that the values are programmed in the computer. For example (totally not correct values) The 02 sensor is getting a reading that tells the computer the air fuel mixture is around 14:1. At 14:1 the computer is told to hold the injectors open for 0.5 seconds. As things lets say get richer maybe 10:1 the computer would than send a pulse to open the injectors for only 0.25 seconds. And the other way if there is a lean condition maybe 17:1 the computer would send a pulse to open the injectors for 0.75 seconds.

Now putting on bigger injectors, doesnt change those programmed time values. So now you got the bigger injectors on and the computer is reading a 10:1 mixture so it goes to opens them for 0.25 seconds but it only brings the mixture to 13:1. The computer would probably display a check engine light because the mixture isnt where it should be.

I was thinking this because websites for companies that sell injectors all clearly state on chosing the right sized injectors for your car. Giving a formula to calculate the size depending on the # of cylinders, HP, and different values depending on if its NA, super/turbo, nitrious, alcohal etc.

Hi speedy, hello all

I think I've already covered it.


Please check your favorite dictionary for the definition of optimum and then reread this thread.

If you find anything I posted that is incomplete or inaccurate I will elaboborate or correct it, but, rephrasing the question will not change the answer.

Regards, Norm

hey speedy,
you have to remember that the manufacturer programed the ECM to deliver the most power while still compromizing for emissions and drivability with an aftermarket chip you can eek out a little more power but not much. a new cam/intake-exhaust porting mods and etc are needed to boost power and at that time you will need a PROM optimized for the engine combination.
and remember that at WOT the ECM goes into open loop control which essentially means it doesnt even look at the O2 sensor (narrow band sensors dont give that great of info anyway) but instead rely's on it's programmed in fuel/spark tables and curves this is where an aftermarket chip will eek out a little more for you but not much.
hope i could clarify the way it works fer you schlim

I have played with an aftermarket DIY fuel inj system MegaSquirt and am planning on using it for the rear 3800 engine in a twin engine 94 442 (cutlass) when i get back to IL to start the turbo fabrication. Bowling and Grippo are the main guys behind this system but it a a totaly shareware setup (some with windows based tuning programs) using assembler language to tune it to what you need. the next generation boards will have the ignition system included with adjustable spark curves for DIS systems where the current 2.0 doesnt have ignition capabilities. search for MegaSquirt DIY EFI to learn more, it really is a cheaper way for tech savy people to get into a simple DIY EFI system.