RACE ONLY 

CUMMINS HIGH PERFORMANCE OVERFLOW VALVE

As you know, we have four performance overflow valves for the Bosch P7100 injection pump. Each valve is sized for a fuel pressure range and performance level.

Why another valve? I had the pleasure of meeting Van Haisley of Haisley's Machine at a sled pull in Ohio. This man is a wealth of information when it comes to building ultra high horsepower diesels. I was showing him some of our injector pullers and overflow valves. He asked me if I ever saw a P pump overflow valve for an agricultural application. I said no.... but i would like to see one. His wife gave me one at the Scheid Extravaganza 2010.

I was shocked by the very small orifice in this valve. By any standard, it's micro size. I told Van I was skeptical about using the agricultural version of the Cummins overflow valve. He assured me that they have been used in the Bosch P7100 for years (agricultural applications only).

We tested the valve and it flows less than .28 gallons per minute. Because the orifice is so small, I DO NOT reccomend this valve for street use. I'm concerned about adequate cooling, for the P pump. I suggest that you use the OFV060HP on the street and switch to the OFV070 or 075 at the track.

What fuel pressure should you be running? Here is a general rule to determine the fuel pressure you should be at. Multiply the governor spring rpm (in thousands) times 10. In other words, you want 10 PSI of fuel pressure per 1000 RPM of govenor speed. If you installed a 3K govenor kit, you need a minimum of 30 PSI at full power.  A 4K kit requires 40 PSI at WOT. 5K requires at least 50 PSI. Remember, this is at full power, not idle or cruise.

Here's the advantage to the competition Cummins owner. With that little of fuel being returned back to tank, you can achieve maximum fuel pressure at full power. If you are experiencing low fuel pressure on your competition Cummins, give the OFV075HP a try !

Article number two is ready for your reading. This 6 page article is not white bread fluff! It is a very meaty guide on the importance of the inlet line. Getting the inlet line size right, on your performance engine, is critical in achieving maximum diesel horsepower and torque.