[Dougal]

Aftermarket injector builders do alot of R&D with alot of dyno time. They get a better spray pattern from stagering spray angles and adding more holes to the tip.

I highly doubt aftermarket injector builders can do a better job than the factory suppliers.

There's no comparing the R&D budget of a small aftermarket company with engine manufacturers and their OEM supplier.
Engine makers compete on BSFC. If there was a fuel consumption improvement to have then they would have it.

 

[Dougal]

If you cannot get enough fuel for a given power out in time, you will still be injecting fuel late in the stroke and just basically putting fuel into the exhaust manifold. This is one area where nearly any injector nozzle work can beat the OEM design. They actually have to be less efficient at flame front propogation in some instances in order to meet certain emissions requirements. I don't.

That is not true at all.

Fuel and the fuel lines don't have an appreciable amount of compressibility in them, when the pump (or unit injector or commonrail injector) stops applying pressure the fuel flow stops.

You do not get fuel injected later into the exhaust manifold.

Talk of MPG isn't proof of any upgrade. Get some BSFC numbers if you need to back up fuel economy claims.

 

[Dougal]

428rwhp 180mm^3 per shot of number 2 diesel fuel. That's pretty clear to me. I have NEVER seen a stock injector make more than 300rwhp in person, and only ever heard of 340rwhp. (This is a 7.3L powerstroke)

The title of the thread isn't "will aftermarket injectors make more power".

And it is 100% correct that time to empty is paramount. And yes, the OEM nozzles WILL be spraying late on the stroke attempting to accomplish the same task as the Extrude Honed ones I run, 100% chance.

For a stock nozzle to empty my injector it takes over 5ms, and they still aren't empty. In 4ms they will clear 180mm^3. Whereas my nozzles will 100% empty 250mm^3 in LESS than 4ms. So if you plan to empty my injectors (250mm^3) you'd better have something other than a stock nozzle on it (considering 4ms at 3k rpm is getting pretty dang late in the stroke)

Again, I call BS. If your injectors are emptying sooner, then the injection pressure is much less, the droplet size is bigger and the burn is slower. None of these things are good for EGT's or fuel consumption.

If you have evidence, post it. Another two pages of dribble won't convince me.

I can produce 140% OEM output with no smoke and lower exhaust gas temperature than the OEM injector is producing at the lower power output.

Doesn't prove your point, I can lower my EGT's simply by pushing up boost. It doesn't mean my injectors have improved.

 

[Dougal]

First of all, how does 428hp on 180mm^3 of fuel not mean better BSFC? I have never seen stock injectors make more than 300 in person and 340 I have only heard about The truck that made the 340 is running my exact same turbo, and more timing than me. Stock injectors inject ~150-155mm^3 of fuel per shot at full stroke.

428rwhp divided by 180mm^3 yields 2.37hp per cubic millimeter injected.
340rwhp divided by 150mm^3 yields 2.26hp per cubic millimeter injected.


Droplet size is bigger.......from and orifice of .006" to something LESS than .007" I don't think you can tell me that will effect droplet size, or more correctly, the surface area to volume ratio of the droplets a discernable amount. Injection pressure remains the same, it is not a fixed flow through the nozzle, it is a fixed pressure (assuming flow rates through other parts of the injector are not exceeded).

These are unit injectors. HEUI. Hydraulic Electronic Unit Injection. As long as flow is maintained throughout the hydraulic circuits within the injector, nozzle enlargements do not drop injection pressure. And I will assure you, that a change of less than 1 thousandth of an inch does not drop IP.

BSFC is calculated from measured values. Not by basing assumptions off what your injectors are theoretically supposed to do.

Stock 4BT gets close to 200 g/kwH, similar BSFC to the current crop of hi-tech diesels from mercedes and VW.
Come back when you've got some real data.

 

[Dougal]

I also assumed that the horsepower output from a Dynojet 248 could be used. This is from having made pulls on it with periods exceeding 3 months at a time and the output from one such series of pulls was 402.4, 402.1 and 402.3...... with nearly a month between each pull.

You'll have to excuse me for assuming that to be an accurate device.

Does the dyno have the ability to measure fuel consumption at steady load?
If not then you're not going to get any measurement worth a damn for BSFC.

Min BSFC is never found at full power. You would never want it to be as automotive engines never run continuously at full power.


I could have sworn this was a cummins 4BT forum.