OK, been doing research on the hybrids, and understand the difference in cc delivery, difference between the size of barrels and intensifier pistons more fuel delivery with less oil, but still don't quite grasp the 30% 80% 100% 200% ect, concept. Read someplace that say a 238/80% means that the nozzle size is 80% bigger, but wouldn't that effect the spray pattern, and cc fuel delivery? Someone have a better explanation of the % concept? Thanks
explain hybrid injectors
- Thread starter oldschool
- Start date
dentexpowerstroke
Active member
The bigger the nozzle the less time it will take to empty out the injectors. 400cc of fuel won't want to flow through a stock sized nozzle in a useable pw, so you make the nozzle bigger so the injector can empty in a usable pulse width and still be able to make power. Is this the answer you are looking for? That is what I took from your question.
psduser1
Active member
Didn't check your math,lol, but that's the idea. The tuner compensates for the additional flow by tweaking your injection pressure, I.e. higher icp, and other tables. The pw is also decreased, so the injector is "on" for a smaller window. That's pretty basic, and there are more parameters, but it gives you the idea.
ok, thanks, that makes a lot more sense, with higher injection pressure!. still keeping the proper mist. next thing, how do you figure out what percentage nozzle, and size for different applications? Thanks for the help.
Absolutely it does.
For a quick visual, take a water hose and put one of those adjustable nozzles on it. Turn the nozzle for a different sized opening. As you make the opening smaller you get a finer mist, but less water. As you make the opening larger you get more water, but bigger droplets of water. Similar concept with injector nozzles.
Now it's already been explained that you can move more fuel in less time with larger nozzles. This has several advantages as well as some disadvantages.
The advantages are you get more fuel out quicker. Period. Hence you get more power in the upper RPM range where your injection window rapidly shrinks, and of course you have the ability to more readily "empty" larger CC injectors. So in essence you are capable of a much larger power increase.
This shorter injection window also can be beneficial for daily driving and/or towing. The ability to get the same amount of fuel out in say half the time than much much smaller nozzles allows you to have more "useable" power. For instance, my truck ran stock injectors for years, but towing over a mountain pass in a race tune that made over 300 hp was virtually impossible. The injection window needed was just too long to move enough fuel through tiny nozzles. However with the 250/200's I'm running now, I can tow in tunes well north of 350 hp over those same mountain passes, and my EGT's barely crack 1100 degrees.
Those are advantages.
Now the disadvantages are that a bit of idle quality will be sacrificed, tuning adjustments get more complicated, and fuel economy can become a factor with tuning (along with smoke control, etc). There's a lot more fuel that can be moved in a much shorter amount of time, so getting the tuning right can be trickier for some trucks. This can have a big effect on how the truck idles, the fuel economy you will see, and even how much smoke you'll roll.
On my truck the fuel economy remained almost unchanged. Smoke is very little (passes emissions tests with flying colors). However there is a distinct idle difference than stock split shots, or even smaller singles. That's something I've never been able to tune completely out. Probably my own fault.
So take into consideration what you get as advantages vs. disadvantages.
And of course the obvious is that there is a greater risk of losing it all with larger sticks/nozzles. Tuning will have a lot to say about that, and a small adjustment can make a huge difference.
That depends on you and your tuner. What you plan to use your truck for and what your tuner is comfortable dialing in quickly will overall lead to your happiness..... or unhappiness with the setup.
Most would consider my setup to be completely unfit.... 250/200's on a daily driven (and daily towing) PMR motor. Well, it's been nearly 3 years exactly, and I still think it's the best setup out there. Will everyone think the same if they duplicated what I did? Probably not.
Smaller nozzles are generally easier to tune, so most likely with smaller nozzles you'll have a great running truck on the first one or two tries. Start going with bigger nozzles, and you might need 5, 10, 20 or so tuning reburns to get everything dialed in to where you are happy.
In the end, and with enough patience, you can have just about any nozzle size "work" just fine. Personally I think that 200% is on the edge for reliable streetability. Some have gone bigger with great success. Pick your poison.
m j
Active member
200% and gearhead tunes.
this stuff is old hat now
this stuff is old hat now
DZL JIM
Member
The nozzles are rated in "% increase of flow over stock."
They are NOT "% larger."
An injector with a 80% over nozzle means that nozzle flows 80% over what a stock nozzle flows.
Remember, a small gain in the diameter jumps the area by the radius squared.
Your math is not correct with respect to the actual larger nozzles.
ok, that's what I was wanting to know, cause if you double the size of the hole in the nozzle, it would have to effect the spray pattern. I'm trying to get it in my head how increasing flow by oversizing the holes in the nozzles won't effect the spray pattern or atomization. So then the size increase of the nozzle along with injection pressure increase, maintains the proper spray pattern, Right? So the larger the nozzle is, you have to increase injection pressure, flow and, or increase pulse width. That's the reason of changing intensifier piston diameter to keep injection pressure up, with relativity the same amount of flow. Then with the bigger flow injectors, the pulse width is longer, so the need for dual HPOP, to keep up with the flow, at increased pressure and pulse width. Also with tunes then' is the injection timing advanced a little to help get the fuel in at the proper time? Is that just about right? Just trying to get this clear in my head.
dentexpowerstroke
Active member
No larger nozzle doesn't need pw increase. Larger nozzle lowers the pw needed. Big injector need more oil volume to flow more fuel, it's not because they call for longer pw.
Highrider02
New member
Nice Thread. Very interesting. I'm trying learn this too. I've been sold on hybrids since I read about them a couple years ago. Just got to get the truck to that stage and my wallet to that stage.
