i just put a after market fuel pressure reg on my turbo whats a good psi to run stock turbo on it

 

For the stock turbo on the stock pump or other? For an otherwise stock car, use stock fuel pressure: ~30 psi idle, 40 psi @ 0 manifold pressure, 1 psi per lb. of boost. You can run more pressure under boost, if your pump can handle it, and your mixtures are a little lean.

 

hey RR88,i have a air fuel guage and a fuel pressure guage.
my car runs rich(according to the guage) and fuel pressure is ~40psi
can i somehow turn the fuel psi down to retard the mixture a little?

i am very new to this stuff but learning every little thing i can.
o ya and i did get a TPS but havent got it in the mail yet.

 

Yes, but it is probably not such a great idea to attempt to tune your car if you are not very sure about what you are doing. Turning down the fuel pressure will affect the entire fuel map, which may help some areas but may hurt others. It is better to use an aftermarket fuel computer to better target certain areas, and you need to understand where "rich" is warranted and where it isn't. If you want to learn about engine tuning, I recommend taking a cheapie class at your local tech school or junior college, or checking your regional subforum to see if anybody is willing to let you look over their shoulder while they tune their engine. Even learning about piston engines will help.

Also, the term "retard" is used for ignition timing rather than the fuel mixture.
- Ignition Timing: Advance vs. Retard
- Fuel Mixture: Rich (Richen, Enrich) vs. Lean (Enlean), or Stoichiometric (Stoich) for a chemically balanced ratio which is neither rich nor lean.

 

If the air/fuel gauge is just a simple narrow-band, showing "rich" is what you want under boost and at idle. But you can't really tune anything with those, given how inaccurate they are. A true wideband 02 sensor/gauge is needed for that. Generally, with a lightly modified stock turbo car, making the mixture richer under boost is a good idea. Leaning things out semi-blindly is not going to end well.

 

thanx guys, i am learning SO MUCH on here.

and ive been trying to get into some automotive classes cause i am really interested in how and why stuff works and the way it is, but i havent been able to yet due to work, rent, money, ect. but im tryin asap

 

Enlean? Hmmm, I'll have to look that one up.

 

See Enleanment paragraph on page 10:
http://www.state.mn.us/mn/externalDo..._E20Report.pdf

Research paper on modeling enleanment emissions:
http://www.cert.ucr.edu/cmem/docs/TR...Enleanment.pdf

 

how do you change the fuel pressure? is it done on an aftermarket FPR or is it done by the ecu?

 

hey thanks guy but yea i called atkins rotory for my help about 30 to 35 psi with stock turbo even if i have a walbro fuel pump thanks guys for helping

 

It is changed with an aftermarket FPR. Aeromotive and SX are good brands if you are considering buying one. Make sure you get one that is intended for EFI pressures.