Performance 6.5 Injectors

[gmctd]

Except that the stronger spring delays injection while the pump is still building pressure to 'pop' that spring.

The volume between 1700psi and 2200psi is then lost - PCM doesn't know about that and doesn't compensate with the Fuel Solenoid - it is a fixed beginning\variable ending injection system.

Beginning of injection event, PCM closes FS, rollers are rising on the ramp, plungers are pumping their specific volume against the closed injector, building pressure.

At 1700psi inj pressure, injected volume is from that point on the ramp until PCM opens the FS at some point further up the ramp, ending injection.

At 2200psi, the rollers are further up the ramp when injection begins, but PCM still opens the FS at the same point further up the ramp.

PCM can attempt to correct for that at idle with the Cylinder Balance routines, but that's only at idle, used to maintain idle rpm in Neutral, Drive, A\C on or off or cycling, headlites on or off, anything that varies the load on the engine.

Even at that, hi-pop hi-flow injectors do not idle as smoothly as the standard versions, nor is idle speed stable, and can vary by 100rpm low.

Those Cyl Bal routines are not used off-idle.

The Injection Fuel Rate seen on the scanner is not measured - it is calculated, based on conditions with oem standard lo-pop injectors, spec'ed by engineering to ensure the camring and rollers would survive thru the warranty period, while still giving adequate spray pattern for economy.

'Course - I'm talking EFI DS4, you're talking mechanical injection DB2.....period.......and, as we all know, turning up the fuel on the DB2 effects the fuel rate from idle to full throttle, right?

That's why I would like to see dyno results compared to scanned data.

[Robyn]

I have talked to mark at Diesel fuel injection service in Portland about just such things.
His comments have been that these fancy injectors are real good for making more power in the sellers wallet.

I think its a gimic.
The DB2 Or DS4 was designed to run at a certain pressure and be able to deliver a pre determined amount of fuel as its max capacity and to have nozzles that are designed to work with these pressures and volumes.

I somehow think that maybe there are still folks out there that are trying to relate the nozzles of the 6.2/6.5 to the old "Injectors" of the 2 stroke detroits where they were the nozzle and the pump all wrapped into one.

We were always bumping the injector size on our little 318 Detroits a couple sizes to get a few more ponies, and usually a ton of black smoke in the process.

The little 6V71 I had in my first bus was set up with "city injectors" and IIRC it was rated at 260HPThe thing ran clean and got about 10 MPG on the road at 55mph at max governed speed of 2100 RPM.
Little Detroits were a happy little camper if you let them run at 2100 all day long.

Yup I think these so called performance injectors, at least considering how they are being marketed are just a waste of $$$$.
I will stick with locally rebuilt units that are set up to book spec for the engine.

I always ask Mark to be sure any he does for me are all to the top of the spec for POP pressure and that they dont vary much.
I am a firmy convinced that having the injectors matched closely is a good idea for engine durability.

If one or two are on the low end of the scale and the rest are scattered out with one on the high end it will IMHO make for a rougher running engine especially at idle.

Having the injectors all at the top of there spec does aid in good cold starts.
The spray is finer and easier to ignite.

If you could get some of these 40HP injectors it might be interesting to do some HP and mileage tests for sure..

Sounds like some of the goodies JC Whitney used to sell, maybe they still do.

Robyn

[6.5 Detroit Diesel]

I have the 40 HP Marine Perfomance Injectors from SS. Are you saying that they won't produce any more power than stock even after the pump (DB2) has been turned up? Even if not, buying this set was cheaper than buying stock one's locally.

[gmctd]

Those are marine injectors, designed for the 'marine' DB2 on marine engines - set up to push a big twin-engined cruiser for long hi-speed hauls across the bay.

They're known to make power with the DB2, but what about the DS4 - that is the question the dyno can answer.

[ronniejoe]

The HP claims from SS Diesel are just that...claims. They're bogus straight down the line.

[dieseldummy]

All I can say is that I just built a set of injectors with "marine" nozzels and the do make a difference. I have been running stock 6.2 injectors though... While they may not have netted 40 HP, they have added some more go to my old ride. I set them up with stock pop pressure and the pattern is just fine. I figure no need to add stress to an old injection pump...

[grape]

maybe we could have peninsular dyno a set with their home made fuel flow meter and live and die by their results................yeah i said it

[Kennedy]

Most of these so called 40HP injector claims are from people who have never tested them. This is why they have cheap injectors and claim numbers to sell product. I can say for a fact that the high flow/high pop injectors sold by Kennedy Diesel WILL deliver just shy of 10% increase in fuel delivery and are TRUE high pop. They were tested against a stock injector.

My best guess is 20-25HP max. I believe RJ makes 180RWHP where we typically see a stock 6.5 that is tuned well (exhaust etc) run about 150 RWHP. I have not done a back to back dyno test. I'll also add that in order to make power from this fuel there may be a need to increase boost.



P.S. Some people's ideas of high pop are not the same as others...

[simon]

I posted a question a month ago about pop pressure and got no bite on that one.
Since than I learned from the fellow i got new standard nozzles from that the pop pressure for my 95 6.5 was 2200 psi, so i set them accordingly.
Is this right or wrong??

The truck runs fine at idle as well as full load.

On a couple of 6.2's I have the injectors are set at 1700 psi, wich the manual calls for.

So I will ask again what pressure is hy pop supposed to be ???