i was thinking about replacing my injectors. i have a 93 z28 383 stroker 6speed. i live in california and theres the strict smog laws and all. i see injectors with 26,30,32,40,44,46, and 48 pounds. which would be ideal for my car. I'm not sure if it'll effect my emissions and cause me to fail a smog check. thank you

 

How much HP (at the flywheel) does your engine make? That is what determines injector size.

Since it appears you already have the 383 stroker, what size injectors do you have now? You must have something larger than stock already. Have you ever encountered problems with running out of fuel?

As long as the ECM is correctly tuned for the injector size you run, it will not affect emissions.

Putting a larger injector than you need in the engine will not increase performance.

 

from what i remember i put 24lbs. what does going any higher do? I'm running close to 410 at the flywheel.

 

Theoretically, you can't make that much HP with 24 #/HR injectors, unless you have an extremely efficient tune (0.44 #/HR/HP), and are operating above 90% duty cycle.

GM supplies 24 #/HR injectors (programmed at 24.9 #/HR) for the stock 285 HP LT1.

But if you are not running out of fuel at the top end, you don't need to change them.

My recommendation is to multiply the flywheel HP by 0.07 to get the minimum acceptable injector size. That figures a brake specific fuel consumption (BSFC) of 0.476 #/HR/HP, and a duty cycle of 85%.

Example:

410 x 0.070 = 28.7 #/HR

Have you ever had the engine on a dyno, with a wide band O2 sensor?

 

no i haven't actually. i called several places and they told me they can't dyne it because only cars from 96 and up can be dyno'd. i want to put some type of performance chip on it as well.

 

That's the most ridiculous thing I have ever heard. I guess my 94 has never been on an engine dyno or a chassis dyno..... just figments of my imagination. What they may have told you is that they can only tune 96 and up, and that would only be true if they only had software for the OBD-2 96 and up cars. For your 93, you can't tune real time on a dyno, because your ECM requires a programmed chip, where 94 and up uses flash programming of a fixed chip. OR maybe it's some sort of weird "California" rule......

So.... if they can't dyno it, how did you determine it's making 410HP at the flywheel?

So you are saying that your 383 ci stroker, possibly with a non-stock cam, and 24 #/HR injectors has never been tuned, and is still running on the stock tune/chip?

I would strongly recommend you get a new chip, even if it's based on a "mail order" tune. Here's a reliable source:

1986-1993 Camaro/Firebird V8 Mail Order Tuning