Just wanted to get a general idea of what you guys are running in the way of rail pressure.
I have seen a TON of injector failures in the last few months and can't help but notice it is usually on trucks running an MP8 or something of the sort that gets the pressure up.
I know that high pressure tends to go hand and hand with more power, better fuel economy, but are these injectors really made for this kind of abuse? I just can't see anything holding up to 20k-22k psi for cruising. Sure a short burst of 26k psi down the track or at the pull isn't going to hurt, but for the long haul, high pressure is concerning.

My ideal thought of rail pressure was:
Idle- 5k or 7k (pending on 555 or 600 motor)
60 or 70mph- 15k to 17k
WOT- 24k

So what is the word? High pressure is harmless or harmful? Just looking for what you guys think is right.

JD

 

I havent had any trouble yet. I had an mp8 and now a x2 pressure only.

Idle 5-6k
65-75 mph 9-12k
WOT 26k

If i would have had time today I would have ordered some fluxs. Hopefully tomorrow. So I should have some feedback about how mine look once Don get a hold of them.

 

I run the MP-8 and always have it set on 50-65%


My rail pressure is:
Idle - ~7550 (600 motor)
60 or 70MPH - 19K to 21K (before the SMARTY)
60 or 70MPH - 20K to ~23K (w/ SMARTY REVO non R tune SW8)
WOT- 26k (from stop to 80 MPH)



I have found the the higher the RP the better performance and response of the truck. No injector problems so far!!! I have owned the truck since new and have had the MP-8 at the same setting's for the last 48K miles.

 

My rp dips when I hammer it. If it says 19 or 20k at 65 cruising, it'll dip into the low to mid teens if I floor it, then recover after I let up. This is with the quad xzt.

 

We have seen a massive number of cracked injector bodies lately. I am talking about cracks that leak fuel back into the crankcase. Cracks above the o-ring directly in the holder itself.

Another nasty problem is the injectors are blowing the steel ***** Bosch uses to block a drilled passage after manufacturing. Just below the solenoid cap. This will also cause a direct fuel leak back into the crankcase. Holder cracks are a direct result of the so called water hammer effect. The steel ***** being blown out are from high return rates.

Also, scuffed control plungers and scuffed armatures. Both of these cause a poor running engine. A few scuffed nozzle needles/pintles have been showing up lately. That was a very rare thing in the past.

Lastly, but not leastly....the nozzle pintles are getting pounded so hard they are actually getting deformed in the ZTI region. This can get you a direct leak of fuel constantly dripping into the combustion chamber. I suspect that more than one engine we are all hearing about that melted a slug or scuffed a cylinder wall, has had a dripping nozzle from this damage. This is not all caused by the pressure waves themselves. Some blame is on Bosch, but they did correct the pintle design in late 04 and have had several pintle revisons since then. The latest nozzle used in the late 06 and early 07 5.9 is very refined.

Low engine speeds use little fuel from the rail. The injection duration is very low. This combined with pressure elevation can decrease injector life.

Pressure is best used at the track or dyno. While cruising the freeway....no one should be running high pressure.

Cruise is best under 17K. Idle is best at 5500-7000. WOT if used sparingly, can go to 26-27 and never have a problem. Dont cruise the freeway at 20K plus ever.

 

That is what I thought, but it seems alot of guys like running the high pressure all the time. I just didn't know all the terms used to describe the effects.

So. Let everyone hear the warning....Higher pressure for everyday use DOES kill injectors!

Thanks Don

JD

 

THANKS, GREAT POST DON!!!!!



Thank you for the info. Im a huge fan of high RP and clearly there is no longevity to running it.


What would you suggest for a person that likes everything about higher RP, like myself to keep the truck streetable and reliable for the long run??????

 

Good question PEAKESTRYDE! I'd like to know the same thing. Bout to put the MP_8 on and need to know what to set it to in daily driving conditions. I run sw9 moderate tq.

 

Will aftermarket injectors stand up alot better or same precautions apply?

 

Great post Don......can the 03 injectors be "upgraded" by you to the newer injector standards? Will your nozzles fix all of the issues?

 

Remember guys good filtration is one of the key things to keep up on debris will kill an injector. just don't run the high pressure for prolong times.

 

I recently bought an MP-8 that I replaced my puck with, I can notice more injector noise while running it but I dont like how touchy my truck feels with it. I can tell I have picked up some mpg but I usually dont use it unless I am in short WOT bursts that I have the Mp-8 all the way up. How about the 03 injectors as stated in an earlier post don?

 

With 3.3's I dont need the added preassure. I'll be keepin mine just for the track.

I never new my injectors were leaking until I took them out to send them to don. Found out they were only 80%.

I think there is alot more damage that is being done than just what you can feel.

Thanks for the heads up JD.

 

Don, these have been my thoughts about my truck. Do you think it could have any bearing on the issue we talked about ?

mine aren't anymore

 

When you say 80%, what do you mean?????