turbos10

Guys,

I got a new set of injectors to replace my mismatched set while the engine was appart(not fuel or injector related). Anyhow, it had one injector with a 260bar pressure and the rest 300bar. The new set was 262bar, and I am a little concerned now as to how this is going to work. The old injectors were also 5 port except the one that did not match. The new ones are 4 port. The moral of the story is that the engine just seems a little lazy now. I dont know if it is my imagination or if these new lower pressure injectors could cause issues. This engine is a '93 with P7100 from a Ford truck and is rated at 190HP with CP of 1582. I called cummins on the new injectors and all they could tell me was they were for a 220HP CPL.....which I thought would be a positive.

I dont have a real good handle on the mechanics of injection event related to pop pressure and/or timing. Could the lower pop pressure change engine timing?

Any help is greatly appreciated.

JStull

I've done 24v injectors that were always set to go at 305 bar. When they were old and tired they popped as low as 260 bar on my old 2001 truck.

I'm not exactly sure where the 12 sticks should pop or they may even be 305 bar also????? Sounds like you already knew that though.

And I think my DDP3's are 5 holers. Maybe those sticks are a little smaller than your old ones.

FWIW, my '01 high output rated at 245hp from the factory had smaller injectors than a standard output truck from the same year. It made up the HP with the pump and some other small differences so those sticks may be smaller even with the higher HP engine rating.

Jason

JIT

Should be between 280-310bar

logskidder

290 in the service man.

Big Blue24

lower pop pressure is going to have bigger droplets of fuel/ worse atomization. Poor atomization means the fuel and air don't mix well enough to combust all of the fuel in the combustion chamber, but rather fuel is burning in the exhaust manifold etc. Fuel mileage and power will suffer. Lower pop pressure effectively raises the timing a smidge, but this is negated by the poor atomization.

Don's F1 Mach injectors have slightly lower pop off pressure than stock, so apparently a little lower pressure is not detrimental.

turbos10

I may not have been real clear on these injectors; they are set at 262 bar and are a cummins original part new in the box. I have to think that, 262 bar which is over 3800psi, would still give good atomization....???