Optimal Fuel Pressue for Best Performance
Q: What fuel pressure setting will give me the best performance?
A: The stock setting is 42 PSI. Much track testing has showed that any type of increase will greatly benefit both horse power and torque. Here’s some dyno testing on a stock 350 motor which substantiates those claims:
42 PSI (stock) 46 PSI 50 PSI RPM Torq HP Torq/diff HP/diff Torq/diff HP/diff ———————————————————————— 2250 237.7 101.8 254.9/17.2 109.2/ 7.4 275.0/37.3 117.8/16.0 2500 241.7 115.1 262.1/20.4 124.8/ 9.7 283.3/41.6 134.9/19.8 2750 241.5 126.5 275.2/33.7 144.1/17.6 297.0/55.5 155.5/29.0 3000 237.1 135.4 278.2/41.1 158.9/23.5 305.5/68.4 174.5/39.1 3250 233.8 144.7 278.9/45.1 172.6/27.9 311.3/77.5 192.6/47.9 3500 241.0 160.6 278.2/37.2 185.4/24.8 309.5/68.5 206.3/45.7 3750 246.6 176.1 283.4/36.8 202.4/26.8 303.3/56.7 216.6/40.5 4000 250.4 190.7 278.3/27.9 212.0/21.3 298.0/47.6 227.0/36.3 4250 251.6 203.6 272.5/20.9 220.5/16.9 289.1/37.5 233.9/30.3 4500 253.5 217.2 257.3/ 4.2 220.5/ 3.3 277.0/23.5 237.3/20.1 4750 245.0 221.6 242.1/-2.9 219.0/-2.6 266.4/21.4 240.9/19.3 5000 227.6 216.7 225.0/-1.4 214.2/-2.5 237.8/10.2 226.4/ 9.7
It shows that by increasing the fuel pressure to 50 PSI, results in maximum torque increase of 58 ft-lbs (along with a much flatter torque curve) and a maximum horse power increase of 19 HP over stock. 46 PSI also provides a noticable increase which should work well for day-to-day street driving. An adjustable fuel pressure regulator (see Chap 5.2) is required to increase the fuel pressure.