Testing Injector Pop Pressure in the real world

[Me78569]

This thread is for the results of the testing of the differnece pop pressure at the same size.   

 

ANY REPLIES NOT ON TOPIC AND OR WITHOUT DATA WILL BE DELETED.  

 

I will be running 3 sets of DAP injectors first set at 305 bar, next at 330 and the last at 350 bar.  We are going to compare real world situtations and what the pros and cons are of increasing pop pressure.   All tests will be datalogged and video taped if applicable.   

 

The tune will be EXACTLY the same for all injectors.  al runs done on Lvl 3, so no wiretap being used

 

Quote

Timing Parameters
Fuel Load Timing	3
Low PSI Timing Reduct	5
Timing Reduct Scaling	50
LightThrottle Timing Adv	1.5
Light Throttle Limit	30
Timing Equilzer
1500RPM	17
2000RPM	20
2500RPM	23
3000RPM	28
MAX	30
Boost Level Fueling - CAN Bus
0 PSI	66
1 PSI	66
2 PSI	67
3 PSI	68
4 PSI	70
5 PSI	71
6 PSI	72
7 PSI	74
8 PSI	76
9 PSI	78
10 PSI	80
11 PSI	82
12 PSI	84
13 PSI	86
14 PSI	90
15 PSI	94
16 PSI	98
18 PSI	102
20 PSI	106
22 PSI	110
24 PSI	114
26 PSI	118
28 PSI	120
30+ PSI	120

 

 

Test conditions. 

 

Quote

 

 

1. 0-60 WOT take off, same stretch of road

2. 55 mph egt on same stretch of road showing egt

3. Lugged 45 mph locked od pull to compare spool.  

 

 

 

 

305 BAR

Test 1 0-60 WOT take off, same stretch of road

 

 

 

 

Test 2 55 mph egt on same stretch of road showing egt

 

 

Test 3 Lugged 45 mph locked od pull to compare spool.  

 

 

 

 

 

330 BAR

Test 1 0-60 WOT take off, same stretch of road

 

 

Test 2 55 mph egt on same stretch of road showing egt

 

Canbus fueling is ~1125 and egt right around 710-725*f  ( road is slightly uphill

 

 

Test 3 Lugged 45 mph locked od pull to compare spool.  

 

 

350 BAR

 

Test 1 0-60 WOT take off, same stretch of road

 

 

 

 

Test 2 55 mph egt on same stretch of road showing egt

 

 

Test 3 Lugged 45 mph locked od pull to compare spool.  

Edited February 12, 2018 by Me78569

[Me78569]

330 vs 305 bar 0-60

So results between the tests,  Both tests were WOT snap from a standstill, same stretch of road, and ambient temps within ~5*f of each other.   

 

Note the area RIGHT offidle where the Quadzilla has not taken over yet,  pretty significant pull in fuel.  

 

It looks like the 330 bar injectors got the truck moving a little faster off the line,  then nearly identical the rest of the run.  The logs are a little delayed ( as you can see by the steps in mph) but when we look at the 59 - 60 mph that I marked, the 330 bar got to that point ~.5 seconds faster.  

 

I am not going to say that the truck actually did a faster 0-60 with the 330 bar vs the 305 bar, but I will say I dont see a noticeable difference.   When I look at where the log jumps for MPH in each case I see VERY similar results at nearly the same point across a wide area of the log.   The lines seem to chase each other and over take at various points suggesting that the runs were very similar.

 

One thing I do find interesting is the EGT's are higher for nearly the entire run with the 330 bar suggesting that timing may be a touch retarded, causing more heat to hit the turbine.  Most notiable is the EGT's right off idle.    That might be why the butt dyno tells me that the turbo lights faster with the 330 bar injectors when in passing situtations.

 

 

More to come

 

 

[Me78569]

330 vs 305 luggd 40 mph pull.

I went out again and ran another lugged test because I was not happy with the differences in conditions, the one from this morning I started at 37 mph vs the 330 bar I started at 41 mph.  

 

so I redid it.  

 

 

Now this log is VERY telling.  My butt dyno told me the 330 bar injectors resulted in significantly more under the curve power, but I thought it might have been in my mind.  Now I am sure of it.   Look at the Boost lines you can see the 330 bar injectors seem to build boost better.  Even at the start you can see boost is building faster.  

 

[jlbayes]

I assume the tps drop along with can fueling drop is due to the 330bar getting to desired speed quicker?

Edited January 8, 2018 by jlbayes

[Me78569]

Yes,  I let off earlier on the 330 bar run because I was already ~30 mph over the posted speed and boost was at ~30,  I held longer on the 305 run because boost was still struggling.

[Carbur8tr]

Man this is juicy.

 

So just playing around with the graphs and it looks like the rate at which canbus was climbing towards the end of the graph was similar for both of the data logs.  This really only tells me one thing; the power towards the end of RPM range is probably very similar (this will be dependent on setup and mainly just at the point where boost builds comes in).  Comparing canbus as well I would go so far as to say that peak power is within 5% on both injectors.

 

I know this is not perfect world data and I know we will never obtain that but I am curious if you could redo this graph with the TPS stabs lined up what it would look like.  The curve below in yellow is duplicated. 

 

 

 

Some thoughts:

EGTs in the 40 pull are virtually the same with a few minor differences which supports:

   - The amount of fuel injected by the 330bar injector was minutely less when using the canbus curve as a reference, but with that in mind the event would need to be more efficient to allow for the response seen in boost, speed, and RPM climb. I would go so far as to say that the previous statements regarding less fuel from a higher pop are almost negated with this data.  Still needs more proof but overall less fuel could have told a different story here but I don't believe that's the case.

 

In fact after digging a little more I would say we have yet another contradiction to previous statements regarding fuel.

Same Rpm, same speed, take a look at the canbus (Green is 305).  This is seen with 70% of the data.

 

 

Still digesting this but this extremely contradicting to previous statements regarding pop pressures. 

[Me78569]

@Carbur8tr  the graph is actually aligned to when I seen the Canbus signal go from cruise to fueling.    If you want to match where tps spikes then move the 305bar lines back by 2 columns, but canbus fueling is updated 2x more often than tps.  

Either way in the lugged pull situtation the 330 bar injectors kill the 305 bar in terms of under the curve power.  

[Me78569]

Alright @Carbur8tr @kzimmer @Mopar1973Man @jlbayes you are going to find this VERY curious. 

55 mph 305 vs 330 bar



It looks like the 305 bar injectors require a smaller fueling command compared to the 330 to move down the road at ~55 mph.  approx %2 less if you average.  I think conditions were the same but I may have had a wind with the 330 bar or something like that.  Even a touch of wind results in a pretty big jump in the fueling commands.    not an excuse, just saying that the canbus fueling command is very dynamic based on conditions I think a dyno would be needed to recreate exact load to truly compare fueling.    

HOWEVER what I find very curious is the EGT's between the 2 runs.  The 330 bar run, even though the fueling command was %2 higher, resulted in a 50*f drop in EGT's at cruise state.  I would be willing to bet that the 330 bar injectors get better MPG.   

 

[kzimmer]

THIS POST IS A WORK IN PROGRESS, AND MAY CHANGE.

 

I'm going to start adding data from my testing. Please be patient while I get everything together in one post. This may take a couple days.

 

365bar vs 330bar rev4.xlsx

 

Above is the raw data and charts in Excel. I will likely revise this a couple more times,especially since I may redo my 330 bar 30 mph 3rd gear locked test to match up closer to the speed of the 365 bar test. The data might be a little skewed.

 

All tests were done on the same road, same stretch, same direction, same time of day. 1 day apart. Ambient temperature within 3°C. Wind unknown, and very well could have played a factor. All results are subject to external variables out of my control.

 

Notes for the Charts: I tried to get a lot of data in the charts, and I tried to get all of the data to look different enough to be legible. If something is too hard to read, please refer to the Excel spreadsheet attached to view the raw data. I will also post a couple "Summary" spreadsheets. The time unit for most of the charts is in 0.25 second intervals to match the Quadzilla logs. Example: Time units 0 through 10 would be 2.5 seconds.

 

WOT From a Stop

365bar 0-80mph Take 1 20180105 101212-4.m4v

 

 

365bar 0-80mph Take 2 20180105 101442-5.m4v

 

 

330 Bar 0-80mph Take 1 20180106 111803-1.m4v

 

 

330 Bar 0-80mph Take 2 20180106 112000-2.m4v

 

 

 

 

 

 

As you can see, the WOT from a stop is almost a complete wash. The data shows the 330 Bar being extremely marginally quicker, with EGT's very slightly higher. This is consistent with both logs.

 

Question for discussion:

Assume for a moment the information above has no error from extraneous variables. Could this small but measurable increase in acceleration, and a minor increase in average EGT's (especially in the low end, not shown in the summary charts) be a result of the lower pop pressure, allowing just a little bit more fuel to be injected? I think so. The theory makes sense.

 

 

3rd Gear Spoolup

The following 3rd Gear Spoolup test data might be a little less reliable because of the difference in speed. 3 MPH faster start on 330 Bar, translates to about 70 rpm according to the logs.

 

365bar 30mph-80mph Locked 3rd 20180105 102428-6.m4v

 

 

330 Bar 30-80 Mph Locked 3rd 20180106 112241-3.m4v

 

 

Regardless of starting point, you can clearly see faster spoolup with the 330 Bar, with higher EGT's. Not a ton higher, but higher. This follows the data from the 0-xx MPH WOT tests.

 

Here's some charts comparing one parameter at a time between 365 bar and 330 bar:

 

Again, higher EGT with the 330 bar. From more fuel?

 

And finally, here is the results from cruise control set at 64 MPH, in 3rd gear and OD.

 

 

This one really caught me by surprise. Same road, same direction, same time of day (24 hours apart). I believe wind conditions were similar, but I don't have that data. I think the data speaks for itself here.

 

Or does it?

 

 

Edited January 12, 2018 by kzimmer
Work in Progress

[Carbur8tr]

@Me78569 This falls right in line with what we are seeing on your 40 lug data and again disproves the theory that the higher pop results in significantly less fuel being injected.  Between comparing overall amount of fuel being injected and atomization efficiency, I really don't buy that the higher pop are having a large effect if any on volume of fuel being moved. I think we would see the opposite here if that were true and we simply don't.   

 

This is starting to become very contradictory to previous schools of thought. 

 

[Me78569]

So if we take that 2.5% difference at cruise state, we are looking at 490hp - 500 hp if it is 330 bar vs 305 bar on the 7 x .012. 

 

 

very fuzzy math, but it gives us an idea of how much difference there is if that was the only change made.  

Edited January 11, 2018 by Me78569

[Carbur8tr]

Very small difference that really would have to be tested on a dyno.

After all 2.5% could really just be a change in temperature, ambient pressure, or really anything.

[Me78569]

nominal by all methods of testing and conditions in my mind

[Mopar1973Man]

In my mind the high pop pressure is affecting the starting point of injection. This can be corrected by adding maybe an extra degree of timing.

[Me78569]

the start of the injection event does happen later with higher pop, but the peak of injection event pressure is unchanged, and hte end of injection is sooner.  there is no drivablity reason to add more timing with 330 bar vs stock bar.

 

Edited January 16, 2018 by Me78569

[kzimmer]

I think it's likely more effected with less commanded fuel, less effected with more commanded fuel.

Edited January 12, 2018 by kzimmer

[Me78569]

I would think %95 of people wouldn't really notice a difference if you just threw them the keys.    however I miss the 330 bar injectors

[kzimmer]

I should also mention that the truck is almost impossible to stall now. I tried my best. I was only able to stall it once, below operating temperature, by putting it in reverse, holding the brake, and stabbing the throttle from 0 to 100 to 0 as fast as possible. And even that took a lot of effort.

[Me78569]

I dunno why I didnt think of this before, but @Carbur8tr asked if I had idle state data logs to compare.  That gets rid of nearly all variables.  

 

Each log is pulled from 0% tps, 0 mph, same IAT , trans temp warm , warmed up engine, and in gear after ~20 seconds of sitting in that condition.  EGTS are stablized in both IE: we are not seeing an idle from right after a hard pull or coasting to a stop.  These are true idle state in gear.  

 

First the graph

 

Again most noticable is the diffence in EGT temps, the 330 bar are noticable cooler. also note how stable the 330 bar load line is compared to the jumpiness of the 305 bar load line.  This suggests the ecm doesn't have to work as hard to keep rpms at 750.

 

Here's the data showing averages from the idle. 305 bar is highlighted in grey

 

First thing I see again is the difference in EGT temp. a full 52* cooler at idle for 330 bar.  Dunno why seems like a lot.  

 

Next is the difference in fueling duration at idle ~%2.05 higher with 330 bar.  this means that in theory the 330 bar inject ~%2 less fuel per the same duration command under the same conditions.  

 

the next thing I notice is in the data itself, the 330 bar injectors seem to idle smoother, the ecm does not have to adjust fueling as much, note the fueling spikes in the 305 bar idle from 800 up to 1100 and back down.  I feel this and hear this as well with the 305 bar, they dont idle as smooth.  

you can see idle is more steady with 330 bar if you look at the min = 1000 and max = 1098.  

 

 

I think it is fair to say a little extra pop pressure results in a smoother idle with the 7 x .012's I have.  I also think it is fair to say that the actual fueling difference between 330 and 305 bar is negligible.  If we compare 0-60 times, idle duration, cruising duration we keep seeing the same thing.  

 

So the real question is, given the negligible difference in fueling reduction going from 305 to 330 bar, is there a perk to upping pop pressure?  I am still not really sure.  If I watch the videos over and over for the 0-60 I see less smoke in the 330 bar, but that is my eyes. 

i am getting excited to test the 350 bar. 

 

 

Pop Vs Timing 

 

Talking with @Carbur8tr  I dont even know if the overall time of combustion is changed by increasing pop.  We know the start of injection is later, but the end of injection is also sooner as a result of the injector shutting sooner.  So the overall time is shortened for the fuel being injected, but the vp44 is still injecting peak pressure at the same point as it was before ( due to the cam ring design). So what about the point of combustion, does that actually change as a result of higher pop pressure moving the injection event a meaningful amount?    Or does the fact that the peak pressure point of the injection cycle is the same mean that the combustion point is steady regardless of pop pressure and we are simply injecting less fuel?

 

What say you @AH64ID you have a mind for this type of stuff.  Does increased pop actually change the point of combustion IE does timing actually change due to a mechanical difference in the injector pop? 

Edited January 16, 2018 by Me78569

[AH64ID]

8 hours ago, Me78569 said:

 

 

What say you @AH64ID you have a mind for this type of stuff.  Does increased pop actually change the point of combustion IE does timing actually change due to a mechanical difference in the injector pop? 

 

It's hard to say for certain, but it should have a slight effect. The delay in start of injection may be overcome by the reduced ignition delay from higher pressure and better atomization. My guess is that ignition will be slightly delayed at lower rpms and fuel loads, and the impact will be negligible at higher rpms and fuel loads. 

 

I do think that the shorter duration for the same fuel is a good thing thou. With CR's I really like overiszed injectors with less that stock duration as it doesn't require huge timing at rpms and all the fuel can still be injected. I have found lower EGT's for the same total fuel this way, all with less timing.