Im going to be running a 383 stroker with a sts at 10 lbs. My engine has been completely rebuilt with 8.2:1 and fully forged internals, my only delima is what size injectors do i need to be running, can i get away with 42# or do i need to go bigger?

 

I think you can use the SVO 42# injectors.

You may have to raise your fuel pressure a bit, to 50 - 52 psi, that would be only if you are leaning out on top.

My set up uses those SVO 42# injectors at 51 psi FP. I run 9 psi of boost and run to 6,100 rpms.

559 at the wheels, but that is at 3,200 feet of altitude, so there is less air up here than in most places.

That would be my .02 werth.

And by the way, I called my injectors 48#ers in LT1 editor.

No issues with the SVO injectors, others in the area have tried larger injectors, but had low speed drivablilty and idle issues ...

Hope this helps

LWM

 

Ok, how exactly would i go about upping my fuel pressure, do i add an inline pump or do i need to replace the intank pump again, oh and im in colorado, so our elevation is a bit more around 5 thousand feet.

 

I'll assume you have a 255 liter/hour fuel pump as your intank pump. That is big enough.

You don't need an external in-line pump.

Install an adjustable fuel pressure regulator, a fuel pressure guage and go from there. As always, measure fuel pressure with out any vacuum lines attached to the fuel pressure circuit/regulator (there is one attached on stock cars).

I believe the fuel pressure of the stock 93 Camaro is around 43 psi. There may be a required adjustment based on displacement alone, the 383 is 9% larger in displacement. The SVO injectors are rated at 39 psi, you may be required to adjust the fuel pressure just to keep the computer thinking it still has a 350 cu inch motor to feed. I'm not sure how you tell your computer that it has 42# injectors, but it must be aware of that fact as well or else it will just run pig rich at an idle and die.

Does LT-1 editor work on the 93s??

When you get to tuning, use a dyno that has a wide band 02 sensor. If you notice the Air/Fuel ratio on the top end getting lean, that is less than 12.5 to 1, then I would recommend you bump up the fuel pressure 3 - 4 psi and try again.

You may be able to get a boost a pump also, a way of supplying more voltage to the fuel pump when at WOT. I have never tried one, but RS Krause has and reported satisfactory results.

As a last resort you could go with an inline pump and an FMU from Vortech or the like. They work, but the inline pump is a bit noisy.

And FWIW, the stock fuel map in my case was good for my 383 running a 224/236 cam.

At 5,000 feet you should be good to go with just a bit more fuel pressure.

Hope this helps

LWM

 

I believe you're going to be close to maxed out with 42# injectors, certainly no room for future HP. Talk with a tuner like Jeff Creech.

 

LWM,

Just curious. Why did you calibrate the EFI for 48# injectors. That would lean it. Was it too rich?

Roger

 

I'm running 42lb Racetronics on a mostly stock LT1 in a heavy car.
(I wanted the headroom for a dry shot.)

You sure you don't want to go to a Versafueler and >50# injectors...?

 

Go mototron 60lbs if you dont want to go with the impedance converter.
Have tried 42, 60, 85 and gues what, they are always to small after the winter/garage season
So my advice is, go bigger than you need now, the mototron idels fine so they should work fine for you...

 

Thats what I would do...

 

Hey thanks everyone, i think im going to go with the 60lb mototrons.

 

The SVO injectors are rated at 39 psi, GM injectors are rated at 43 or 43.5 psi.

43 divide by 39 = 1.10

42# SVO injectors should be equivalent to about 42 times 1.1 = 46.3 in GM terms.

Then, seeing as how my fuel pressure was up around 51 psi ... the increased fuel pressure would make the injectors appear even larger than that.

Ran around with a data logger for an afternoon and the fuel trims liked the 48# setting best, had the least movement off of 128.


I haven't any experience with those mototron injectors, but a couple of guys around here have tried the MSD 50# injectors, and eventually went with SVO 42# injectors, just because of idle and low speed drivabiliy issues.

As usuall, your vehicle may vary.

Hope this helps

LWM