firebirdStud

Well, I am looking to find out what the best fuel pressure is for atomization in our cars. I am currently sitting at 37 psi with it running and the vacuum unhooked. We had to lower it on the dyno becuase she was fat. This way the AFR is good. I am looking for a bigger TB and exhaust before I fine tune it from here. Anyway, what is the best fuel pressure to set at? I do have an adjustable one.

Once I find this out, I will set the pressure, and tune the injectors from there.

I have the SVO 42 pounders. There is no way I can run out of injector now!

Real world advise is needed here, aka Experiences. I thought it should be somewhere around 48psi, that is what was floating around at the dyno day last saturday.

Thanks!

Cody

OBE1 95Z28

Best way is to have your PCM tuned to optimize your AFR, not tuning via your fuel pressure. I was previously running 36# injectors with 58 psi of fuel pressure to compensate for the small injectors. The high fuel pressure caused my tuner to have to work hard to solve my driveability issues at part throttle driving. I'm now running 75# low impedance injectors, 43 psi fuel pressure and have great part throttle driveability and WOT AFR. It's all in the tuning...thanks Jeff Creech!

firebirdStud

yeah, im using Jeff Creech too. We stopped tuning right now as I need a bigger throttle body and exhuast. But I want to get the psi set now, then with the datamaster readings he can adjust the tune from there. I have heard 48psi with these injectors is about right, but I want to verify.

firebirdStud

no one knows what their fuel pressure is in their modded cars??? WTF?

James Montigny

Lots of poeple play with it, running 42-47 psi (sometimes higher)
The general consensus seems to be that tuning via PCM is much more efficient.
Use the sensors and computer to your advantage.

5-6 years back , the guy over at ws6.com (I've forgotten his name,
it's been too long) had his at 36psi and picked up like 17rwhp.
http://www.ws6.com/mod-7.htm (page is still up)
The PCM adjusted pulsewidth to compensate and he ended up right back
where he started.

roguedriver

I believe for the SVO's, you need to be at 43.5psi with vac line off. Then adjust your injector constant for the size injector you have and then adjust your tune to get the correct A/F. That would be the best way to do it.

Ken R.