i am currently running the stock fuel pump and regulator with 32lb injectors and that gives me 38psi. what fuel system is everyone running for there 383's? Be sure to include injector size, fuel pump, fuel regulator, and fuel pressure with that setup. Thanks in advance!

-Steve

 

I have searched high and low. I need expert advice.

 

im running stock fuel system on my 383 except for 36# injectors, seems to be running good, not sure on fuel pressure

 

Rough guideline for sizing injectors (NA applications only).... multiply your FLYWHEEL HP by 0.07..... example:

500 flywheel HP x 0.07 = 35 #/HR

That assumes a decent tune (0.476 BSFC) and no more than 85% duty cycle.

You can go to 42 #/HR injectors with no problems.

Run the stock pressure - 43.5psi, measured with the vacuum compensation line disconnected.

For a fuel pump, a 205 LPH pump will comfortably support a 500 flywheel HP NA engine. No problem if you go up to the more popular 255 LPH pump.

Stock fuel pressure regulator will be fine. There is no need for a larger one, nor for an adjustable FPR.

 

Right now I'm running 30lb injectors with a proper tune by pcm for less. I pulled the number one spark plug and found that it was black indicating a rich condition i believe. It also reeks of gas. Also the car coughs out black smoke and stumbles when the throttle is opened up. I'm thinking its choking on fuel. How would i go about leaning out the fuel mixture? or would i just have to drive it so the computer learns how much fuel is required per rpm?

 

anyone?

 

Run a data log, and look over the long term fuel corrections. If the PCM was tuned correctly, with the correct injector constants, and you are running the fuel pressure you told the tuner you were going to run, excess fuel may be resulting from a "false" lean condition. The long term fuel corrections may be elevated, confirming this possibility.

 

Racetronix PnP kit, 42# SVO's, Accel AFPR @45#'s, but soon to change back to factory unit.

 

why are you changing back if you don't mind me asking?

Also i got my car to idle smooth but it seems to choke under light throttle and still caughs out black smoke. how do adjust how rich or lean the car runs with the stock fuel system. do i have to drive the car and let the computer learn how much fuel is required?

 

Due to the age of the regulator, its coming off, and its not needed.

Who did your tune?

 

Im thinking you have another problem, not fuel related. Im thinking your rich issue is an effect of something not working right.

 

You can't adjust rich or lean conditions without changing things in the PCM as it controls the injector duration and size. Do what injuneer said and get a datalog of your car running (with TTS - Datamaster software) - idling, normal driving and WOT. This log will tell you and most of the guys here alot about your settings and what the car is doing in the LTerm and STerm as well as what trim cells you are in. FYI - The stock setup will be just fine for you unless you want to spray or boost as under these conditions it will be a good idea to increse your fuel flow with the Racetronix kit. I am running SVO 30# on my 383 setup and 44PSI with the stock fuel system with no drop in pressure or any problems.

 

Walbro 255 (on the car now), Lucas 42#s, aeromotive FPR that will go on with my single plane setup. I will have a small stage on a dry system so I went a little overkill on the injectors.

Yeah sounds like you are dumping too much fuel in the cylinders. Changed my plugs last weekend, nice tan color to them. However Im running stock injectors at the moment. Contact whoever did your tune to be sure inj size etc was accounted for correctly. Might be good to check for codes and such if you havent already.