De-tuning Large Injectors....

dirtboy25 · Jan 5, 2012

What are the advantages in de-tuning large injectors?

I understand this much...

larger injectors use less timing and less pulsewidth to deliver the same (comparative) volume of fuel and allows more time for the fuel to burn in the chamber

Since larger injectors (nozzles) empty faster giving the fuel more time to burn, does this result in a cleaner burning truck?

Is there a line when choosing nozzle size? When does the nozzle size become too big for the amount of fuel that you're trying to flow?

IIRC Charles is/was running 300/100's with a 38r. If bigger nozzles are better, why didn't he go with a 200% nozzle? I mean, can you even get all 300cc's through that nozzle at WOT without lots of timing, PW, and EGTs? If that's not a problem then why is there a need to step up to a 200% nozzle on a DD?

Last but far from least.
How does nozzle size affect fuel mileage?

I have more questions but I'll just start off with that. My other questions may get answered with your responses.

Thanks

pontiacross · Jan 5, 2012

I think there is a point where you start loosing tunabilty with nozzles as you go bigger you can turn them way down but they dont atomize the fuel as good so they dont burn as clean

01platinum · Jan 5, 2012

Not to derail but those are some really good questions. I look for to learning from the answers.

Sent from my SPH-D710 using Tapatalk

dirtboy25 · Jan 5, 2012

pontiacross said:
you can turn them way down but they dont atomize the fuel as good so they dont burn as clean

This is one of the bigger questions I was going to ask... I'm more concerned about fuel economy. In my old 01 CCSB 4x4 i had no problem getting 18mpg on the highway and my truck in sig struggles to get 13mpg.

I want a nozzle that flows enough too keep a smile on my face yet I want optimum fuel mileage while I'm at it. I drive like your average grandmother and my truck rarely sees over 2500 rpms. I don't want over sized nozzles to be the reason I can't get good fuel economy.

Am I right in thinking that too large of nozzles can cause a droop in my fuel economy?

Dieselboy. · Jan 5, 2012

Im pretty sure it was a 300/200 that Charles ran. I believe they were laying around and he needed a set for his 450.

He also ran 250/200s in his red truck up to the twins producing a clean 600RWHP.

In my truck if I drive it like a proper law abiding citizen Ive seen just over 700km a tank. Im not sure how to do the math for MPG, but I think my dad said thats around 18-19mpg.

What are your future goals HP wise ?

If you just only want to upgrade the sticks a set of stage ones would be more then sufficient and get you good mpg. If you do plan on more power (under 475) a 238/80 would be nice and can be detuned.

SDS97_7.3 · Jan 5, 2012

Dieselboy. said:
Im pretty sure it was a 300/200 that Charles ran. I believe they were laying around and he needed a set for his 450.

He also ran 250/200s in his red truck up to the twins producing a clean 600RWHP.

In my truck if I drive it like a proper law abiding citizen Ive seen just over 700km a tank. Im not sure how to do the math for MPG, but I think my dad said thats around 18-19mpg.

I thought he had the 100's cause thats all Swamps had in stock at the time.

CurtisF · Jan 5, 2012

It's all in the tuning.

Check out this thread... 400% nozzles, and those opacity results are better than a bone stock 7.3L. http://powerstrokearmy.com/forums/showthread.php?t=10298

That right there should put to rest any and all reservations for how clean larger nozzles can run.

That's Blowby's truck of course.... I wish it was mine, and I wish I could tune as good as he does.

Anyway, I have some results of my own running 250/200's on my truck. My daily driver tune dyno'ed at 310hp at the rear wheels. That's pretty close to many stock trucks running a race tune. Now, how many stock trucks can throw on a race tune, and tow a trailer up a mountain pass without EGT's cracking over 1100 degrees? Anyone?

My truck can put down that power, and tow uphill without reaching 1100 degrees. That just can't be accomplished with a smaller nozzle that drags out a longer pulsewidth in order to achieve that same power level.

Dieselboy. · Jan 5, 2012

You could be right. I cant remember. Matter a fact I think you are right.

Gearhead · Jan 5, 2012

There are tradeoffs with the 200% nozzles at light loads and when cold and the 100% aren't always clean because of the process used. I have pleaded with the industry to produce a .009" EDM with a very light cleanup with extrude hone just like the 80% is a .0075" EDM with very light cleanup with extrude hone. The 100% starts life as the same nozzle size as the 80% but just gets more extrude hone work and the holes start losing their sharp edge, the holes get some other shape than round, and the pintle seats start to erode....

In the old days when the Mini-me was the injector of choice, the factory nozzle was taken to about 30% over stock with extrude hone work.... anything beyond that made for a drippy, crappy, smokey nozzle that ran worse in most cases. Same thing today, but we have a choice in EDM hole sizes so we should be ditching the 100% nozzles and getting something like a 120% (or whatever the flow rate equates to) with a .009" EDM with a light polish with EH..... This new nozzle would make more power than the current 100% and be cleaner.

Worstenemy453 · Jan 5, 2012

Full Force said they would sell me 160/600's...

Im going to get them and make Matt earn his keep

oke: LOL

Chvyrkr · Jan 5, 2012

Jeebus...

DZL JIM · Jan 5, 2012

Worstenemy453 said:
Full Force said they would sell me 160/600's...

Im going to get them and make Matt earn his keep oke: LOL

They will flow as poorly as 400% nozzles.
The internal passages can't pass enough fuel for there to be a difference between 400% and 800% nozzles.

Fordcowboy · Jan 5, 2012

dirtboy25 said:
This is one of the bigger questions I was going to ask... I'm more concerned about fuel economy. In my old 01 CCSB 4x4 i had no problem getting 18mpg on the highway and my truck in sig struggles to get 13mpg.

I want a nozzle that flows enough too keep a smile on my face yet I want optimum fuel mileage while I'm at it. I drive like your average grandmother and my truck rarely sees over 2500 rpms. I don't want over sized nozzles to be the reason I can't get good fuel economy.

Am I right in thinking that too large of nozzles can cause a droop in my fuel economy?

With my 250/200's I did not see a negative effect on my fuel mileage. I am right about the exact same as stock, if not a tiny increase.

I consistently got 18-20 MPG on my trips from Denver to Vail and back. I did this about once a week for a year or more with very consistent, hand calculated results. The trip is over two good sized passes, and my speeds were between 70-80 MPH pretty much the whole way.

Around town I am down in the 15-16 MPG range, but I have a heavy foot, and my tuning still needs a lot of fuel taken out.

Normal driving, you shouldn't see a decrease in mileage unless you want to. Full throttle all the time, I'm sure I could drag my numbers down to 10 MPG or less.

Worstenemy453 · Jan 5, 2012

DZL JIM said:
They will flow as poorly as 400% nozzles.
The internal passages can't pass enough fuel for there to be a difference between 400% and 800% nozzles.

I was playing

I didnt know there was 800% nozzles though. :axe:

907DAVE · Jan 6, 2012

I regularly get 20mpg if cruising unloaded with my 300/200% during the summer months, a bit better than I could with stock injectors.

dietoremain · Jan 6, 2012

Man this is good info, makes me want to get some good hybrids.. I can dream.

dirtboy25 · Jan 6, 2012

Pocket said:
It's all in the tuning.

Check out this thread... 400% nozzles, and those opacity results are better than a bone stock 7.3L. http://powerstrokearmy.com/forums/showthread.php?t=10298

That right there should put to rest any and all reservations for how clean larger nozzles can run.

That's Blowby's truck of course.... I wish it was mine, and I wish I could tune as good as he does.

I understand tuning has a lot to do with it but, how much of a difference would a single turbo make? A single turbo that's sized for 400/400's wouldn't clean up all that fuel when smashing the throttle at 60mph. :shrug:

Am I wrong in thinking this? If so that goes to show my lack of "tuning" knowledge.

And most of us, definitely not me, don't have the knowledge to tweak our own tuning.

Gearhead · Jan 6, 2012

dirtboy25 said:
I understand tuning has a lot to do with it but, how much of a difference would a single turbo make? A single turbo that's sized for 400/400's wouldn't clean up all that fuel when smashing the throttle at 60mph. :shrug:

Am I wrong in thinking this? If so that goes to show my lack of "tuning" knowledge.

And most of us, definitely not me, don't have the knowledge to tweak our own tuning.

Quick easy airflow makes up for a quick injection process..... big singles light better at lower rpms with smaller nozzles because the injection event is a little longer and keeps more heat when the exhaust valve opens compared to a colder injection event. You can drop ICP to lengthen the injection event and now you are battling poor atomization...... I've been an advocate of only running enough nozzle as you have air for. if you make 500 HP with a 200% nozzle or 500 HP with a 80% nozzle, the 80% will be more responsive in the lower rpms.