I've heard adding an adjustable fuel pressure regulator and cranking up fuel pressure in larger engines can add a lot of cheap horsepower easily... So my question is, will increasing fuel pressure a little in our cars add power? If so, what is our stock fuel pressure # and what would you recommend running? Thanks

 

Never heard that about cranking it up.

These cars run between 41-47 PSI

 

It was in an issue of Hot Rod..they raised fuel pressure on what I think was a 350...I think they raised it from 45 to like 50, and 55, and 60, and gave the dyno numbers.. Power curves were modified slightly, but at the peak it gained like OVER 20 hp just from bringing the fuel pressure up. Not sure which number that was for but I want to say 60. It just robbed a tad of low end power but added a LOT of top end.

 

Ive always been told 35-42psi ?

 

Key On, Engine Off: 40-47 psi for 2 seconds

Key On, Engine Running: 3-10 psi lower than KOEO reading

 

My repair book says same thing as cali just posted.

Plus I tested it once when having probs with the car. Tested at 45 with key on, dropped 4 when started.

 

Also CaliCamaroRS is right, but the fuel gauge has to hold the pressure when the key is off, if it drops quickly it means a return leak somewhere. And that will cause your car to run like crap and that's a hard one to find.

 

without a large amount of engine modifications (read: hard parts, heads, manifold) an AFPR is un-needed

 

I agree with Teal... if you did a ton of head porting and lost performance, you'd probably need to increase the fuel pressure. You might just want to send your injectors (or a junkyard set) out to http://www.cruzinperformance.com and have Rich clean & flow-test them. It made a big improvement in the way my car felt!

 

Yeah? That could be my problem. I've been replacing things one by one and I'm pretty much at the end of my list but the car still has a rapid vibration/shimmy to it. It's got new plugs, wires, cap, and rotor...and the vacuum lines all check out.