What is stock fuel pressure and what is good for max HP??

[Kdubslugga]

I just got a Fuel Pressure guage and it reads about 33 psi warmed up. Im assuming this is rather low??? What should my pressure be?? This winter im installing a Fuel Pressure Regulator and a new 155 lph fuel pump. I want to get max HP out of it so whats the best PSI to set it at???

 

[Daggar]

It's not a question of what is the optimum fuel pressure but rather what fuel pressure is required for optimum Air fuel Ratio on your particular combination. Normally aspirated with stock compression, a good AFR window would be somewhere between 13 to 14:1 at WOT. Blown apps will be richer (about 12.5:1). Put it on a dyno with a sniffer up the pipe and tune your fuel pressure for whatever your car likes best to make power.

Edit: And Welcome back Kdub... haven't seen you in a while.

 

[HISSIN50]

If you read 33 PSI wiht the vac line attached the to reg, that is just right. This should correlate to around 38-39 PSI with the line off and capped.

Remember, as long as you dont run out of pressure at WOT, the puter can adapt a bit around the pressure you set, by increasing or decreasing the injector pulsewidth.

Good luck.

 

[Kdubslugga]

Thanks Daggar, ive been around, ive mainly been posting on Talk though!

 

[mustangGT85]

so stock PSI should be around 40psi?

 

[HISSIN50]

so stock PSI should be around 40psi?

Stock spec is 38-39 PSI with the vac line off and capped. With the line on (as it is normally), anything over 30 PSI is ok, but most see 32-33 PSI.