limit to stock fuel system

[Boogieman142]

i may have just found it. I installed a heavily ported plenum and semi-ported lower runners and after i put this in in a couple days i pulled all the plugs out and they showed all the cyls are running lean. i think i am going to turn up the pressure a bit. this is with all the basic boltons and exhaust and stuff.

[Ondonti]

dont a bunch of people have those mods though?

Any pictures of the plugs?

There is a limit to the fuel system above 5000 rpms just because of our crappy computers VE curve so if you were running @ 6000 rpms and shut down Im pretty sure the plugs will look leaner then normal.

Just trying to say that since your car runs 14.7:1 a/f most of the time when cruising the plugs are going to look "light" or "lean" and thats just normal.

You really have to shut down the motor during your pull to get a good plug read.

[Boogieman142]

it was at highway. i will try to find my camera and take some pics.

[Boogieman142]

can't find it, but they were showing lean

[Ondonti]

I guess I dont really understand what you mean by highway.
You have to turn the engine off under load to really make a good plug read....otherwise any normal cruising will change what the plugs look like.

[DustyR/T]

What color are they? How old, what type, modified heat range?

[Tim_K]

How do you turn up the pressure on a stock fuel system anyhow? You'd have to add in an adjustable regulator and a gauge between the fuel rail and the return line.

And if the stock fuel pressure is 48 psi or whatever, even if it were cranked up to 55 psi, how much extra horsepower would that really allow for?

[Boogieman142]

i just turn the screw, and watch the gauge, white, not sure on age as i change then every few months or so, oem plugs. i was on a highway then pulled in my driveway and changed plugs.