Well, I'm obviously no injector tech, but I've been told quite a few times that there's no reason to run over 3000. Maybe 3200 max. The reason I've been given for this is the injector popets open/ are forced open at 3500ish, and as a result they're then bypassing alot of ICP instead of making all that ICP hit the intensifier piston... So it gets counter productive...

After seein your gauge there though, either you're pushin such high volume that it don't matter.

Or aftermarket injectors have better popets that hold high ICP.

Or several people that are right about other things, are full of crap on this one.

Without derailin the thread to bad, somebody please school me on that one.

Stock AD's in Boggerrs truck, for now.

So what's the deal with popets? Can they hold a sustained 4000?

4000 ICP would have him about 28000 nozzle pressure right?

NO and NO.

If you feel like doing an experiment. Pull a valve cover, remove the HPOP line, and get a -05 ORB fitting and a high pressure pump. Hook it up to where you removed the HPOP line, and start pressuring it up. When you get to around ~3500 psi the poppets will start seaping by. As you go higher, the poppets will lift and piss oil out of the injector spill, the pressure will go down, they will reseat then lift again. This happens over and over. Now imagine this at 3000 RPM.

The only thing that holds the poppet down is a spring, as soon as you overcome the spring seat pressure, the poppet lifts, no if ands or buts about it. Some will have you belive that you need HIGH pressure. Belive what you want but physics say otherwise.

Mods feel free to move this if you feel we need ANOTHER thread about how the injector works.

Your wrong Marc. Feel free to come by my shop and I'll prove it. I went way past 3500.

I can vouch for this I have seen it myself as well.....WELL past 3500

Actually to the point where your scared if the head is gonna pop

You guys have seen this with stock ADs I hear all the time...... Even if it holds 3500 stationary, under rpm you will have poppet bounce just like valve bounce and lowers the effective pressure that can be run. Are you sure you guys aren't running specially modified injectors that have higher spring pressures?

NO they are mostly alll stock ad's, or stage 2's, Joey would probably know better if any b code trucks are running it I believe there are 1 or 2....


I find it funny that most everybody talks about this magic 3500 number.........does anyone know what the blowoffs are set at in a stock oil pump

I have however wondered about the rpm thing.....however has this been tested on a flow bench? running 4000 psi and seeing a change in how much fuel is delivered? or how is this know for certainty....just because at the "3500" number the truck falls on its face and pops a bit? Serious questions.

Because we have had so many running higher pressures that "butt dyno" better driveability.....

Yes, static pissing of oil verified. Reduced injector capacity because of reduced refil of injector also verified.
You might be able to get away with it at less than WOT because you don't need the full injector capacity, but the oil pissing across the poppet would IMO accelerate wear, although the poppet and seat is some really hard stuff.

New thread created to avoid a total derale of the Adrenaline thread.