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  #21  
Old 08-24-2014, 10:40 AM
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Having run 30, 80, 100, and 200% nozzles on various sized hybrids over the past 8 yrs, the 200's are the coolest and cleanest by far. On the downside, going from 100 to 200's I have lost some mpg's but I wouldn't trade the extra 75ish hp back.

On edit; as much as Curtis drives me nuts with politics, the guy knows PMR tuning and he's been very gracious in many threads sharing that knowledge.
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  #22  
Old 08-24-2014, 10:52 AM
CurtisF CurtisF is offline
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Quote:
Originally Posted by Tim @ P.I.S. View Post
You are correct with a tow tune 350 is where you would be. BUT how much fuel do you think you are really injecting in your scenario? No where near the. 250cc. Promise. The difference is with the 175's you still mostly get the. 175 even while towing. It's all in how it comes in. The 250's prolly less than. 200cc. And depending on the brand way under 200. I have seen 250's that under normal conditions seen in everyday driving a bench flow test reveled any where from. 125-195 max output. Yet they are sold and marketed as. 250.
Quote:
Originally Posted by Tim @ P.I.S. View Post
Start with this statement right here.


Simplified version, at 1 rpm you have a huge window to inject fuel. At say 3000 rpm a much, much smaller window to inject fuel.

This is how you spec an injector. Find what you want to do with your truck. Example #1 - Heavy Tow. Spend majority of your time at lower RPM band? select a 30% nozzle because it CAN move a good amount of fuel, yet make for a nice clean burn. 160cc of fuel can easily make in the mid-high 300HP. Perfect for towing and maintaining nice cool EGT's.

Example #2 - sled pulling. Spend majority of your time at higher RPM band? select 400% nozzle because it WILL move a lot of fuel, nothing else matters. 300cc of fuel can easily make in anywhere from 650-850HP depending upon the setup. Anything more that much over 300cc will not inject within the RPM band a lot of pullers are trying to be in. That takes you back to the whole theory of why have 1000cc injector if you can only inject 100cc.

Now you have to also throw into this equation that you really have a set of injectors that REALLY do inject what they claim in a realistic usable time frame.

And then you have to have a tune that is capable of making use of the fuel that is available.
We're on the same page with injection window. And yes on a PMR motor you aren't using all that much fuel, especially on a bigger injector (i.e. 250cc's, 300cc's, 400cc's, etc). But forget what the injector CC's are claimed to be, and I'm not even starting a pissing contest with vendors about who can more accurately pinpoint their specs. None of that matters unless you are really and truly trying to squeeze out every drop of fuel that they are capable of trying to win a drag race or sled pull. This thread isn't about that. It's about making as much useable power as you can without windowing the block. That won't happen until you focus specifically on what I've already said: amount of fuel injected at a specific time and specific duration.

The amount of fuel available and amount of fuel injected are two completely different things. The point when the amount of fuel available becomes a problem is when you don't have enough available to begin with, and you try to get the tuning to squeeze out every last drop to reach your power goal. So if you want 450hp on a PMR motor and you want to achieve it with a 160cc injector, you'd better rethink your build here, because you aren't reaching that 450hp mark. If you come close to 400hp on a 160cc injector, you aren't doing it efficiently enough to make that power useable in the first place.

So you go with an injector that is capable of more in order make that power possible, and to make it useable. Time and time again on this forum people say they want "X" horsepower, and time and time again the response is to suggest an injector that will juuuuuuuuuuust baaaaaarely get you there. Ok fine, but can you actually use that peak HP reliably? The answer is no.

The other part of the equation is the nozzle size. Again, don't pick nozzles that will juuuuuuuuuuust baaaaaarely get you there. Pick nozzles that will make it easy to reach the power goal. That way you or your tuner have more flexibility in that injection window. But it has to be a careful decision, because like I mentioned already, larger nozzles can be more of a bear to get dialed in. But if you have teeny weenie nozzles to begin with, you've already choked yourself down to a lower useable power limit, and immediately limited what can be accomplished. A longer duration as that injection window shrinks will always equal higher EGT's and more smoke. There's no way around it, and suddenly you reach the tipping point where you no longer have useable and reliable power. That's when you see people reach for band-aids. For example, when I see someone running 160cc injectors and water injection, I immediately see they chose the wrong injector and nozzle size in the first place.

In short, get an injector that can easily reach your goal, and one that you can live with as a daily driver. The rest is entirely up to the tuning to achieve it..... and keep the motor alive and happy.
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  #23  
Old 08-24-2014, 11:08 AM
CurtisF CurtisF is offline
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Quote:
Originally Posted by David N View Post
Myself, including a few friends all ran 38r's on our PMR setups with 250/100's. And with that said we also all broke rods eventually. Mine ran for 40k miles before it let go. Others weren't so lucky.
And that's all in the tuning.

For perspective, 250/100's can be tuned to run less fuel than a stock injector. If you have less fuel and have the timing pulled back, you aren't introducing any more stress to the rods, so you aren't going to break them.

In other words, it's not the injector. It goes back to how much fuel injected at what time and duration. Those rods broke because it was too much at the wrong time.

Now before this turns south....... do you go and blame the tuner? Not exactly. There are customers who do ask to push to the limit, and when you do that the result is you will find said limit from time to time.

But at other times there are tunes out there that really do have the wrong amount of fuel at the wrong time. A good conversation with your tuner of choice is key before they ever start touching the keyboard and build your tunes.

Quote:
Originally Posted by David N View Post
If I could do it all over again, I'd go with a 200% nozzle. The way I understand it is a 200% nozzle empties faster thus making the injection event faster and thus lowering cylinder pressure.
Not exactly. I'll clarify so you can see what's going on.

Larger nozzles empty faster, giving you or your tuner more flexibility over the injection duration. This is important as RPM's climb and your injection window gets smaller and smaller.

It doesn't lower your cylinder pressure. It just gives you flexibility to keep it a bit lower as your power demands increase. Because you have more fuel available at higher RPM's, you can shift your power band up in the RPM spectrum. As I mentioned before, torque can be a good indicator of your cylinder pressures. You absolutely must have higher cylinder pressures in order to achieve higher torque numbers at lower RPM's.

So, limit the fuel at lower RPM's. You have now lowered your torque number and cylinder pressures. On the flip side, with a larger nozzle you can now add fuel at higher RPM's. This increases your horsepower number.

My best example I saw in person was when I strapped my truck on the dyno at an event a few years ago. Another guy there had a truck with 238/100's. He made 1hp more than I did, but well over 100 lb/ft of torque than my truck put down. Our trucks were nearly identical except for the injectors. So in the end I essentially made the same horsepower, but with lower cylinder pressures and a shifted power curve that brought in more fuel at higher RPM's.

Does that make sense? I tend to get a bit wordy but hopefully clear enough.
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2015 F-250 4x4 CC/SB 6.7L Lariat
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  #24  
Old 08-24-2014, 11:23 AM
CurtisF CurtisF is offline
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Originally Posted by psduser1 View Post
Maybe you would be willing to post a couple off video again, curtis, of your idle?
Here's some old videos, and I've been too lazy to take new ones. Plus I was playing around with some timing stuff on my tunes, pulled timing waaaaaaaaaaaay back, slapped the tunes on my chip, and then my burner broke. So I've been stuck with these hazing tunes for the last 6 months and I'm a cheapskate who hasn't bought another burner yet. I might just cut my losses and go with a Hydra. That will make things more convenient for tuning.

Ok enough of the side track....

Old idle video Not quite dialed in, but then again I've never had it perfect.

http://youtu.be/eNnIzdOYUSs




0-60 something acceleration test.

http://youtu.be/nNFFSyyTReI
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  #25  
Old 08-24-2014, 12:10 PM
HVFC6040 HVFC6040 is offline
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Curtis, whats the max hp you would expect out of your setup, if you werent holding back?
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  #26  
Old 08-24-2014, 12:18 PM
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David N David N is offline
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You're a smart man Curtis, no doubt in my mind.

And there was no bashing of who tuned my truck. Matt tuned it from day 1, and I always pushed my truck. It never came off the hottest tune and the one time it did, it blew up literally 200 miles later. Coincidence? I'll never know.


Matt can tune anyone's truck to safe levels with pmr's. I just wouldn't expect anywhere close to 500hp though. I was one who didn't care if it blew, so I wanted all the power I could get. And I was 100% satisfied. I still recommend Matt.
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  #27  
Old 08-24-2014, 01:01 PM
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ja_cain ja_cain is offline
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*Stupid Question Alert*

When you guys refer to more timing do you mean when precisely the injection event is initiated relative to tdc?
  #28  
Old 08-24-2014, 01:53 PM
CurtisF CurtisF is offline
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Quote:
Originally Posted by HVFC6040 View Post
Curtis, whats the max hp you would expect out of your setup, if you werent holding back?
Probably a little under 600hp if the 38R could hold together and give it enough air.
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2015 F-250 4x4 CC/SB 6.7L Lariat
Bolt-ons to make it look nice, otherwise bone stock
  #29  
Old 08-24-2014, 02:01 PM
CurtisF CurtisF is offline
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Quote:
Originally Posted by ja_cain View Post
*Stupid Question Alert*

When you guys refer to more timing do you mean when precisely the injection event is initiated relative to tdc?
Yes.

In the simplest of terms, Start of Injection (SOI) is when the injector opens up and sprays fuel.

Now there is a lag time between when the event is "initiated" and when it actually does spray the fuel. That is accounted for in the tuning. There is also another lag time between when the fuel is sprayed and when combustion actually takes place. That varies based on different parameters. For instance, higher injection pressure causes greater atomization of the fuel, and it ignites quicker than fuel injected at lower pressures.

It's a fun game.
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2002 F-250 4x4 CC/SB 7.3L Lariat
478hp/851tq on Haller's dyno - 7/28/12

2015 F-250 4x4 CC/SB 6.7L Lariat
Bolt-ons to make it look nice, otherwise bone stock
  #30  
Old 08-24-2014, 10:27 PM
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Quote:
Originally Posted by jeremiahmercier View Post
238/100s should put you in the 500+ hp range, Jonathon (currently Dyno-proven who wrote and am asumming beans still sells his tunes) got 490 something HP just out of 175/80s
dyno or track hp numbers?
Quote:
Originally Posted by Arisley View Post
Not going to quote Curtis' long post. But you better listen to him.


Sent from my truck while eating, adjusting the radio and passing a Mustang sideways.
what he said^^^

live life full throttle
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