Custom Quadzilla Tuning R & D Thread

[kzimmer]

7x.013 VCO nozzles and shim kit are on the way, thanks to @dieselautopower

[dieselautopower]

Kole,  Excited to see your results!

[kzimmer]

The 7x.013's are in. I set the pop pressures around 365 bar. The truck starts, idles, runs, and drives fine. I didn't have time for any tuning tonight since I had to take the family to the rodeo. I've had a couple very minor stalling problems, that were likely partly due to unrelated battery voltage issues. Either way I'm pretty sure I'll need a retune in a big way. My 0 psi level is likely way too low. Hopefully tomorrow... If I finish putting up the Christmas lights before the kids go for a nap...

Edited November 26, 2017 by kzimmer

[dieselautopower]

Glad they are in.  Waiting to see your results.

[kzimmer]

Observations so far for the 7x.013" nozzles:

 

Idle haze is gone, even when cold. My old nozzles had a white haze pretty much all the time, and it was worse when the engine was cold. These idle very clean, even with the 365 bar pop pressure.

 

Cold starts are a tiny bit rough at first, like for a split second. When it's running, it's fine.

 

@Me78569, for some reason I lost high idle. I also flashed 2.7.3 at the same time though. It's actually really strange. I can hear it try to kick in. I have the high idle delay time set for 90 seconds. (side note, before today, the high idle didn't actually ramp up. It just jumps directly from 800 rpm to 1200rpm, which I am totally fine with). Now, after 90 seconds, I can hear the jump like it's going to leap from 800 rpm to high idle, just a quick jump, split second, and then it's back to 800 rpm. And, 90 seconds later, the same quick jump, and back to 800 rpm. It's almost like I tapped the go pedal. But I didn't. I was outside the truck the first time I noticed it.

 

Side note, I just remembered something while I was typing. I was on 2.7.1 when I first started the truck after installing the new nozzles. High idle worked. I flashed 2.7.3 this morning. I guess that's when it stopped working.

 

Had a quick 10 minute cruise on the highway tonight. Just by listening to the truck, it sounds like it could use some more timing. It was at around 19-19.5 degrees at about 107 km/h, probably 1650 rpm or so. Added another degree, but it still has less rattle than before. Interesting.

 

It's definitely louder at idle. More of a pronounced rattle. I don't think it's extreme, or dangeous. Just different.

 

If I put it in drive, and stab the throttle really quick and let off (not normally behavior obviously), there's a chance the truck will stall. When cold, there's a pretty good chance. When the engine is up to operating temperature, it likely won't stall, just stumbles a little. This is the only negative I have seen so far, and if one doesn't do stupid things with the accelerator pedal, it's not a big deal. I need to try it again on lvl 0 and lvl 1, I'm pretty sure I've only done that on level 3. I'm curious if the quad amplifies the problem or relieves the problem.

 

I made a really quick and lazy tune starting at 75% canbus fuel and jumping up by 1% per psi until 10psi and then 2% onward. The old 7x.014" nozzles started at 70%. I'm pretty sure I can still throw some more fuel at these nozzles sub 10 psi and have less smoke. And spoolup is already noticeably better the way it is now. Which is obviously awesome.

[Me78569]

@kzimmer  I dont think I messed with high idle but I will look.

[Me78569]

@kzimmer

 

Try this.  I put the fuel limit back to what it was on 2.7.1 

 

Edited November 27, 2017 by Me78569

[kzimmer]

Thanks Nick, I'll try to give it a go this week, Saturday at the latest.

 

The wife says the truck drives better now. Not sure what that means, but I'll take it.

[Me78569]

meh she shouldn't notice any difference but I wont try and correct her.  

 

 

[kzimmer]

1 hour ago, Me78569 said:

meh she shouldn't notice any difference but I wont try and correct her.  

 

 

 

With the new injectors I mean.

[Me78569]

ooo   yea,  

 

Hows power compard ot the 7 x .014?  did you run the 13's at normal bar or just jack them up and run them like a boss?

[kzimmer]

46 minutes ago, Me78569 said:

ooo   yea,  

 

Hows power compard ot the 7 x .014?  did you run the 13's at normal bar or just jack them up and run them like a boss?

 

I installed the 14's at normal pop pressure. A shop in town set them up for me. When I removed them (maybe 20,000 kms or so) I measured the pop pressures anywhere from 280 to 315. They did a crappy job. Cold starts weren't great, they smoked white at idle pretty much at all times, worse when cold. Idle was getting a little unbalanced if that makes any sense. A month or two ago I bumped them up to 340 bar. Helped cold starts, cut down on smoke when the engine started to warm up. Seemed to build boost faster. A little bit of driveability improvement.

 

I set the pop pressure of the 13's at 365. Might be a little high, stumbles a little when it's put in gear, and when it's cold, as mentioned above, a stab of the throttle in gear has a 50/50 chance of stalling while the motor is cold. Not as bad when it's warm, but still noticable. I haven't driven a ton yet but drivability seems awesome. I haven't finalized my tune yet, but I'm starting 5% higher at 0psi, and smoke significantly less. 

 

Spoolup is even better. I think I'll gain a little more yet when I fine tune timing.

Idle smoke is virtually gone, which is nice. I haven't let it boost higher than 42 psi yet because of my trans, but I'm fairly certain these will flow at least as much fuel as the 7x.014's did, if not more. 14's were rated at 250 HP, and these 13's are rated at 275 HP. They're honed to flow more I guess. So I retained the volume of fuel with the added benefit of slightly smaller holes in the nozzle.

 

I'm not sure at what point increasing pop pressure stops helping atomization, intensity, etc.. Logic tells me the more fuel you can jam in less time with a constant injector size, the better. 340 bar had zero negative affect. 365 has no negative affect while driving along, just the couple unlikely scenarios listed above.

Edited November 29, 2017 by kzimmer

[Me78569]

From your testing and my testing I think 340-350 is about the max "recommended"

[kzimmer]

2 hours ago, Me78569 said:

From your testing and my testing I think 340-350 is about the max "recommended"

 

That's what it seems like. I can't dedicate the time for a while to reduce pop, but when I do I think that's the exact range I'd use. But here's what's bugging me. Ignoring the stab-and-release issue, which again isn't normal operation, it runs great. I wonder at what point it becomes a hindrance as far as efficiency goes, on the highway for example. I don't do enough steady consistent driving to get concrete data.

 

Do you think it can be generally accepted that increasing pop pressure on a vp44 injector is equivalent to a common rail increasing rail pressure? I'm thinking both wouldn't effectively inject x amount of fuel in less time.

[Me78569]

well my theory

 

1. is as we increase pop pressure we are making the total injection event shorter.  

2. the better atomized fuel likely ignites faster ( maybe counter act the delay i the pop event??)

3. I think it makes the timing tuning less forgiving as the detonation event is closer to start of injection event( just theory) 

 

I believe that if you are able to flow the desired amount of fuel then I see no "limit" to the efficency gain.   as we increase pop pressure we are shortening the total duration, this is not the same as cr truck as they control open and close event, but just increase the "static" rail pressure.  The vp is taking pressure from nearly 0 bar to 1700 bar every stroke.  

 

 

question is does pressure in the stroke event ramp up semi linearly?  How much duration are we cutting off per bar of increased pop pressure?  is that extra 30 bar of pop pressure actually creating a noticable difference in the overall length of the injection event?  

 

 

 

Another Big question I have is why has no one done this until now?  Was it just wasted effort because they couldn't control fueling so smoke issues were unavoidable with big boy injectors?   That Comp D thread I started made it seem like I was ignorant for wanting to try because it was "well known" to cause issues.  

[kzimmer]

38 minutes ago, Me78569 said:

Another Big question I have is why has no one done this until now?  Was it just wasted effort because they couldn't control fueling so smoke issues were unavoidable with big boy injectors?   That Comp D thread I started made it seem like I was ignorant for wanting to try because it was "well known" to cause issues.  

 

This bugs me as well. I mean we can't be pioneers here... The pros have done this. But they never had quad v2 tuning either. There has got to be more positive than negative here. My 7x.014's were a night and day difference. So much better with higher pop. I never ran these 13's at stock pop pressure but I'm pretty confident there's some benefit to the higher pop. I just wish I knew more about diesel theory and could prove it.

 

That comp d thread was full of people who basically said "no you can't" without any educated explanation or any reasons that derived from experience. Almost like one of those general consensus things that nobody questions because.... just because? 

 

Similarly, it wasn't long ago that you'd be called an idiot for running 7x.14's and a small single turbo. Everything I read talked about how important it was to match injector size with turbo size. Go too big and you will over fuel the turbo. Now it's moot. Injectors too big? Dial back the fuel. Done.

 

 

[Me78569]

I wish I knew more about the fluid dynamics involved to understand as well.  If we could only figure out how to make money off of spending time figuring it out hahaha.

 

I think it is old dog new trick syndrome.  Its too late in the game to change things now for the masses but maybe some will gain insight, or at the very least my curiousity will be filled.

[Me78569]

@kzimmer @jlbayes @trreed

 

 

Another thing I have been thinking about.  

 

 

the vp has 30* of possible timing ring travel.   Our trucks idle at ~12* of timing and I have seen as low as 10* on stock tuning.  I have pulled it lower than that, down to 3* but anything lower than 8* just results in white smoke.  so the usual timing range we have is ~10*- 30*  leaving that 0 - 10* of ring travel unused.  I see no real need to run less than 10* of timing

 

 

it would be REALLY easy to write in a 10* retard offset for the timing commands, then change the timing gear by 2 teeth resulting in 10* of advanced timing.    the result would be a useable timing range of 10*- 40*    

 

do you think there is any point?  would more timing help given that the vp44 stops making power above 3k?

[Mopar1973Man]

Interesting theory... Now will the PSG and  VP44 tone wheel be considered?

[Me78569]

When CPP did this back in the day ( without the code changes to make it streetable)  he did not say anything about a mismatch code.  It should set a cel though...  thinking our loud.