Quad v2 and injector question

[gipperkid]

Ok, so like this. Using 100% of a 7x.010 to get that 500hp, or using (just guessing here) 70% of a 7x.012 to still get the same 500hp, but have more room to grow.

[dirty830]

3 minutes ago, gipperkid said:

Ok, so like this. Using 100% of a 7x.010 to get that 500hp, or using (just guessing here) 70% of a 7x.012 to still get the same 500hp, but have more room to grow.

This is kinda what i was thinking but trying a 7x13 or 7x14.

[jlbayes]

Correct. It will also produce less heat and smoke. Reduces duration required to get your desired hp.

[dirty830]

7 minutes ago, jlbayes said:

To add to this. Injector size matters when looking for power. Larger size means faster rate of injection.

 

For 500hp nothing more than a 7x.010 is needed. The caveat there is you are at the top end of the duration scale to get it. A larger injector can support it more easily.

 

Sac vs. vco. Cost. That is it until you get into the larger nozzle sizes. They trade back and forth but vco starts to out perform sac. 

Is there any detriment to performance or efficiency to having the a shorter injection cycle with a larger injector?

[jlbayes]

2 minutes ago, dirty830 said:

Is there any detriment to performance or efficiency to having the a shorter injection cycle with a larger injector?

 

None at all pending you have a tuning platform to tune it. Like the quad.

[Me78569]

Exactly I am maxing the fueling duration via canbus commands at peak torque and peak boost ~2000 rpm, but I only using ~400 us of wiretap on my  "hot tune" as that is all my turbo can flow.    this 400 us helps keep power through 3500 rpm.    

 

 

My tune is NOT maxing and holding fueling at %100 duration across a large area of the pull.  

 

 

Here's my datalogs showing fueling of 7 x .009's and 7 x .012's.  Note the difference in how fueling commands are.  This is a poor example, but you can see that with t he 7 x .009's ( blue column) peak and hold MUCH sooner, vs's the .012 commands peaking later.  The truck makes 

 

 

Keep in mind that I am using %100 of what the injecot can do on canbus tuning.  We have to ensure we keep canbus tuning and wiretap tuning seperated in our minds   

 

if you were to ask Bosch and Cummins  I am using the 7 x .012's to their full potential, if you ask Edge or Quadzilla I am not.  Make sense?

[Carbur8tr]

Just a side note on this topic, I think Nick mentioned earlier that 7x.013s are plenty to max out the VP and I would agree with this statement.  Where some might disagree with is "when" this occurs. 

 

[dirty830]

I guess the "when" is when in the rpm range the vp will be tapped out?

[kzimmer]

For what it's worth, my 7x.014's got me 50-55 psi boost worth of WOT fuel, canbus only. I checked yesterday, and my new 7x.013's max out around 52psi. Basically the same amount of fuel up top, which was the goal. Could be because they're honed to flow more. Or maybe that's pretty much all the VP will flow at full canbus demand?

[Carbur8tr]

More or less.  I'll give you an example, I ran a set of DAP's injectors a while back (7x.012 SAC @ 305Bar) and If I stayed in it in 5th and 6th you would have to be careful when you let off because the pump would not be able to keep the truck running.  From my understanding if you get to this point you have drained all the fuel out of the rotor and it does not have enough time to fill back up before the next 3 cylinders need fuel.  Bumping the throttle a little when the RPMs come down seems to help and my theory here is that you're asking the pumping to hold the solenoid closed longer so it has just a little bit more time to fill prior to trying to fire the cylinder.  

 

Either way, one could argue that there is a line somewhere in that area (7x.012 or 6x.013 and above) with some obvious exceptions. To add to that argument, I've seen close to 700 out of both 7x.012s and 6x.013s.  I've also seen similar results from larger injectors as well so in my opinion there is a blurry line of best atomization for most hp.

 

We all know that the SO VP will support close to 700 if everything comes together, HO less obviously.  Regardless, my thought is that if you know that a 7x.014 makes close to the same peak hp as a 7x.012 then what are you trading off to get to that number?  The power band might be a little better in the mid range but beyond that for a daily driver I just can't see the point in going larger than 7x.012.  

 

 

 

 

@kzimmer did you notice a difference in the power band between the two injectors?  Any difference in smoke?  Any pros or cons with either?

[jlbayes]

55 minutes ago, Carbur8tr said:

We all know that the SO VP will support close to 700 if everything comes together, HO less obviously.  Regardless, my thought is that if you know that a 7x.014 makes close to the same peak hp as a 7x.012 then what are you trading off to get to that number?  The power band might be a little better in the mid range but beyond that for a daily driver I just can't see the point in going larger than 7x.012.

 

More has been done with both pumps but requires injectors and turbos very very few would put up with. As well as a better cylinder head (ported).

[Me78569]

The sledge hammer method to making power on a so vp44 truck starts to tap out at 650-700 hp.  Beyond that you are starting to dig for ever HP.  

to me that means at that hp the VP stops being able to cram fuel in.  

[jlbayes]

I know of a mid 700hp truck with nothing special. Just a secondary most will not run as a single.

[Carbur8tr]

1 hour ago, jlbayes said:

I know of a mid 700hp truck with nothing special. Just a secondary most will not run as a single.

 

Hence why I said there will be some obvious exceptions.  Point stands.

[jlbayes]

8 minutes ago, Carbur8tr said:

 

Hence why I said there will be some obvious exceptions.  Point stands.

 

I know. My point is most stop before they are actually limited. Myself included in that.

Edited December 18, 2017 by jlbayes

[kzimmer]

11 hours ago, Carbur8tr said:

 

@kzimmer did you notice a difference in the power band between the two injectors?  Any difference in smoke?  Any pros or cons with either?

 

I've noticed it pulls harder between about 2000-2600 rpm, even at part throttle. Smoke is significantly less with the 7x.013's. Spoolup his improved drastically. With the 7x.014's I started my tune from about 67% fuel ramping up to somewhere over 130. Pretty steep curve, a little doggish down low, pretty smokey when the boost first starts to come on. Now I'm at 79%, ramping to 146 ish, just a nice little haze that doesn't hang around long. I had to squeeze to get 20mpg highway out of the 14's, haven't had a good highway trip yet with the 13's.

 

Just for reference, the 14's started at stock (ish) pop. Upped to 340 bar and started to see and feel some difference. Put the 13's in at 365 bar and that's where we are for now. I need more data before I repop. I really need to get my logs exporting on my Android head unit. I can use my phone too I suppose in a pinch. Just not as convenient.

[Carbur8tr]

On 12/18/2017 at 6:34 PM, kzimmer said:

 

I've noticed it pulls harder between about 2000-2600 rpm, even at part throttle. Smoke is significantly less with the 7x.013's. Spoolup his improved drastically. With the 7x.014's I started my tune from about 67% fuel ramping up to somewhere over 130. Pretty steep curve, a little doggish down low, pretty smokey when the boost first starts to come on. Now I'm at 79%, ramping to 146 ish, just a nice little haze that doesn't hang around long. I had to squeeze to get 20mpg highway out of the 14's, haven't had a good highway trip yet with the 13's.

 

Just for reference, the 14's started at stock (ish) pop. Upped to 340 bar and started to see and feel some difference. Put the 13's in at 365 bar and that's where we are for now. I need more data before I repop. I really need to get my logs exporting on my Android head unit. I can use my phone too I suppose in a pinch. Just not as convenient.

 

Face value, I would say that due to a little better atomization and dropping to something that the pump can better handle might have helped you out overall.  In cases like this it's hard to justify a reason due to the lack of data we have to support our current theories.  Either way it loops back to what we are playing with right now and that is where is the line for too much?

 

Btw, I'm not hinting that you're .013s are over sized for your truck.  I would be curious to see how a set of .012s would perform compared to where you're at right now.

[kzimmer]

2 hours ago, Carbur8tr said:

I would be curious to see how a set of .012s would perform compared to where you're at right now.

 

Ugh... Me too... I want to try, but spending is on hold for a while. The goal is to hit 50psi canbus only, no wiretap. The .013's can, and I'm very curious to know how the .012's would do.