Confused about Nozzle Sizes, Take Two

Previous thread on subject: http://forums.tdiclub.com/showthread.php?t=406347

Recap: 2002 Jetta ALH, automatic. Never tuned, ECU is 100% stock.

OEM injectors were found to be in need of refresh. Was persuaded to go with Titan-branded .205s, mileage dropped from 43-44 avg (41, if I really flogged it) to 37 avg with babying and much smoke. Swapped two years ago to a set of Bosio DLC520s from KermaTDI when the Titans were found to be not holding up well.

Since at the time the 520s were noted as "great for stock/fuel efficiency", I thought I'd be in good shape, but I was never able to consistently get back above 38MPG (and smoke was still heavier than I wanted).

Back in the spring, my fuel pump started leaking. Got a rebuilt 11mm pump and took the car and pump to my mechanic to fix (and also to deal with a spinning glow plug).

That turned into a bit of an adventure (though he eventually got the plug out and replaced), which involved pulling the head and coincidentally finding the turbo bearings pretty much shot (car was at about 320,000 miles at that point, I'm sitting at 333,000 now).

So, new turbo, freshly-rebuilt pump, and I'm smoking worse than before and struggling to hang onto 36MPG now (and I have a thick soot coating on the back of the car). Per my mechanic (a VW specialist in general and an ALH fan in particular), the car runs great other than really overfueling. I tend to agree with this - it starts with virtually no cranking and drivability is excellent.

I should also note that the MAF is no more than 2 years old, the N75 I replaced just recently because it was "singing" to me when I turned off the engine, the vacuum pump nipple isn't leaking, and the fuel filter was replaced when the new pump went in. I haven't checked the snowscreen or air filter recently, but the low mileage and smoke have persisted across at least two filters and one screen cleaning, so I don't currently consider them major contributors (though I will probably check the snowscreen over the weekend).

I figured at first it was me, so for the past two years I've been futzing with the IQ adaptation value in the computer, hoping to find the "magic number" and not succeeding. Finally, I reached back out to the Kerma folks for help.
After some dialog with the Kerma folks over this, and running them some data logs with my VCDS, it seems that DLC520 + 11mm pump is "not recommended for untuned cars". I was actually emailing direct with Charlie, and he said since my goal was to restore my MPG and get rid of the smoke I should go back down to OEM-sized nozzles.

Ok, so it seems like I blew it going with the DLC520s - I suppose I should have expected this given the size change to them from my originals. I've seen quite a few posts here about folks running that exact nozzle on untuned ALH automatics and supposedly getting OEM or better MPG and no smoke. Beats me how they're do it, but bully for them I suppose. Just shows how unique each of these cars can be.

I plan to reach back out to the Kerma folks in the next day or two to see what options they can offer me (work got busy again, haven't had the chance yet), but one thing I wanted to bounce off the collective minds here is the following:
I know the automatic-equipped ALHs got the smaller nozzles and the manuals got the bigger ones (see linked thread above). The Bosio "357" nozzles are reported to be equivalent to the manual ones, based on a rather thorough article I found online on injector sizes/upgrades/etc. (http://www.myturbodiesel.com/wiki/tdi-nozzle-upgrade-fuel-injector-faq/)

From searching around here, it seems as if the "manual" nozzles (or the 357s) are generally dismissed as a "waste of money" and that there's no real power difference between those and the original smaller ones on an automatic car. What wasn't as clear was whether upgrading a fully stock automatic ALH car to the manual nozzles (or the PP357s, equivalently) would be as indistinguishable in terms of MPG from the OEM automatic nozzles when paired with the OEM 11mm pump.

So, power isn't my aim. What I really want is to get my MPGs back up to the 43-45 I was getting on the original injectors.

So, should I be targeting only OEM Automatic-sized nozzles?
Will OEM Manual-sized nozzles/PP357 perform equivalently for me?

Thanks,

Rob

44mpg with an auto ALH is pretty astounding. Not sure if anyone has ever topped that... Adjusting your IQ or 'hammer mod' should fix the smoke. A tune that's meant for larger injectors will do wonders for your fuel economy (and smoke). Stage 1.5 is what I'd do for that car if you go with Malone. Not sure what other tuners (RC, Kerma, TDT) would call it by name, but basically it's a tune for cars with bigger injectors and a stock clutch (or in your case a weak automatic). No need to put stock nozzles in, just tune it right.

I have to agree with Kevin. Mid 40s for an auto is excellent. I don't even get mid 40s in my manual. I usually get around 37-38ish.

Also, about the smoke. I'd get the fueling turned down via your tune and hammer mod from there. Make sure timing is steadily at the green line(top) also. Advanced timing should help with smoke as well.

Rob Mayercik said:

From searching around here, it seems as if the "manual" nozzles (or the 357s) are generally dismissed as a "waste of money" and that there's no real power difference between those and the original smaller ones on an automatic car. What wasn't as clear was whether upgrading a fully stock automatic ALH car to the manual nozzles (or the PP357s, equivalently) would be as indistinguishable in terms of MPG from the OEM automatic nozzles when paired with the OEM 11mm pump.

So, power isn't my aim. What I really want is to get my MPGs back up to the 43-45 I was getting on the original injectors.

So, should I be targeting only OEM Automatic-sized nozzles?
Will OEM Manual-sized nozzles/PP357 perform equivalently for me?

Thanks,

Rob

Click to expand...

44 mpg in an auto, Damn!!!!!!!!!!


Anyhow, I've put manual nozzles in auto's and its a nice noticeable bump in power with no MPG hit.

I too have read time and time again about running 520's etc without a tune but I"ve done it on a few cars and every car smoked and the MPG dropped, even after playing with the IQ.

Smoke is probably partly due to the 11mm pump, a tune to help up the boost a bit should clear the smoke up and give better mpg as a side effect.
It's just getting the fuel to burn more efficiently.
I ran the PP764'S with no mpg issues or excess smoke but it was a manual so has the 10mm pump. From what I've read the max for those nozzles with 10mm pump is around 170bhp or so but that figure jumps to about 200bhp with the 11mm pump


Quite a difference due to the pump size

Appreciate the input so far, guys.

Just for fun, here's plots of groups 3 and 11 from one of the data runs I did for the Kerma folks:





I think I'm still going to downsize the nozzles though - I just can't see a fueling adjustment being the sole cause for a 25% drop in average MPG, I think that the 520s are just too large for this particular car. I am encouraged by Turbovan+TDI's experience that the manual nozzles didn't hit his MPG (though I wonder what he was averaging before/after), which makes me a little more comfortable considering that size.

Also, I'm surprised you guys think my MPG with the original injector nozzles was surprisingly high for an auto - the window sticker did say 45 highway when I bought it, and I do about 80-85% highway (and I'd hardly call my driving style "hypermiling"). I loaded all the fuel receipts I could find into Excel a while back (missing most of the 2002-2006 data, I think I may no longer have those receipts to find any more) , and I've been keeping it up since. Here's the plot of the MPG values (using tripodometer reading at fillup divided by fully-vented gallons number on the receipt), just so you don't think I'm "blowing smoke" :


The drop-off back in late 2010 was when I started having limp mode issues, I eventually tracked it down to a failed turbo actuator; the Titan nozzles went in during that job, and it's been downhill ever since, which is why I'm so focused on recovering the MPG first.

NOTE: plots are in my album over on the pics side of this site, if they're too small to read the labeling: http://pics.tdiclub.com/showgallery.php?cat=6699

I'm continually surprised at advice people get here to buy big nozzles. And this thread demonstrates that they aren't always the best solution. If I was getting the FE some of you mention here I'd be discouraged, too.

I've had lots of different nozzles in my wagon over the years, from stock to PP764s, most with an 11mm pump. My favorite (and what I have now) is PP357s with RC3+. Based on a previous dyno I'm making about 140/260, the car is responsive and nearly smoke-free, and I'm seeing close to 50 MPG in daily driving, 52-53 on trips. IQ is at 3.0.

Most people would say that PP357s are a waste of money. I'd respectfully disagree.

Rob Mayercik said:

I think I'm still going to downsize the nozzles though - I just can't see a fueling adjustment being the sole cause for a 25% drop in average MPG, I think that the 520s are just too large for this particular car. I am encouraged by Turbovan+TDI's experience that the manual nozzles didn't hit his MPG (though I wonder what he was averaging before/after), which makes me a little more comfortable considering that size.

Also, I'm surprised you guys think my MPG with the original injector nozzles was surprisingly high for an auto - the window sticker did say 45 highway when I bought it, and I do about 80-85% highway (and I'd hardly call my driving style "hypermiling"). I loaded all the fuel receipts I could find into Excel a while back (missing most of the 2002-2006 data, I think I may no longer have those receipts to find any more) , and I've been keeping it up since. Here's the plot of the MPG values (using tripodometer reading at fillup divided by fully-vented gallons number on the receipt), just so you don't think I'm "blowing smoke" :

Click to expand...

I didn't lose any mpg putting the manual nozzles in. I keep records too.

I bet if I kept my highway speeds around 60 mpg, it would do fairly well but I have a lead foot and my best ever was 44 on a long trip, usually I hovered around the 40 mpg mark with a lot of city driving, which I was very happy about-the car had a stage 1.5 tune, stage 2 cam, free exhaust, 205 nozzles.

If anything you should have seen an increase with the nozzles, although 40s for an auto is great. We sell a lot of these tunes and certainly wouldn't if mileage was dropping. How's your timing? IQ?
http://www.ross-tech.com/vag-scope/TDIGraph.html
http://www.myturbodiesel.com/wiki/injection-quantity-adjustment-fuel-pump-hammer-mod/

Sounds like it's probably a tune issue if you're smoking and the timing is correct. 11mm pumps do flow considerably more than 10mms, but we have no problem working with them on near stock setups.

still getting 48 with .360s and a 12mm pump, two tanks averaged so far

fix your ECU maps first
then look for stuff like dragging brakes, improper timing (cam timing, injection timing will throw codes), tstat, what have you

Owain@malonetuning said:

If anything you should have seen an increase with the nozzles, although 40s for an auto is great. We sell a lot of these tunes and certainly wouldn't if mileage was dropping. How's your timing? IQ?
http://www.ross-tech.com/vag-scope/TDIGraph.html
http://www.myturbodiesel.com/wiki/injection-quantity-adjustment-fuel-pump-hammer-mod/

Sounds like it's probably a tune issue if you're smoking and the timing is correct. 11mm pumps do flow considerably more than 10mms, but we have no problem working with them on near stock setups.

Click to expand...

I agree but we are talking bone stock engines with no tune and just swapping to a slightly larger nozzle.

My mistake, read just about everything and missed the second line Just assumed with all the tune talk.

These nozzles with the 11mm are definitely overkill on the stock tune, need another 3 PSI to make good use of them. Stock manual nozzles will be a little smokey but are more manageable. You'll need tuning to get it running right, but bumping you IQ up to ~8 might help a bit for the time being.

My mechanic said he set the timing at "70" when he did fuel pump back in the spring (I was only about 45-50K into a 100K timing belt, but at the mechanic's recommendation I had him do a full belt job done again as part of putting the pump back in and the head back on*, so the whole timing belt path including the water pump has only about 10-11K on it as of today).

IQ currently is at the "bottom" of the SW adjustment - I pushed it as low (numerically high) as it would go, trying to reduce the smoke. When I had it at a sw adj value of 5.5 (one of the Kerma troubleshooting recommendations) it smoked/consumed the same. The old pump was hammer-modded during the "Titan" era to around 6, and once the 520s went in I ended up pushing it out to 8.5 in SW as part of my search for the magic number; that's where it was when the pump seals gave out.

Right now the best I can do in SW is between 7.0-7.5, since I've not "hammered" the new pump yet - I have a socket for the security bolt, bought it at the same time as the 520s, but (a) I can't find it right now and (b) I think the stupid thing may have stripped itself when I tried it on the old pump.

Don't recall when the tstat was last replaced, but I want to say in the last 2 or 3 years.

No codes from the engine - the only faults I have are the passenger rear crash sensor failure and some "implausible signal" sort of thing with the power window switches on the driver's door, neither of which should be contributors here.
Turbovan+TDI, good to hear you have the data to confirm your results - I wasn't trying to cast doubt, I was just hoping you'd have actual data (I'm an engineer, that kind of thing is important to me )

IBW: Sounds like PP357 are a real sweet spot for you for balancing smoke, power, and MPG. I'm going to have to give that option a good hard look over the weekend.

Owain: I know judging smoke is somewhat subjective, but is there any chance you could elaborate a little more on what you consider to be "a little smokey"? Right now I'm leaving a thin cloud of smoke just climbing out of my driveway in the morning, and almost any time I'm applying power I'm leaving some sort of smoke trail behind me.

*head came off to extract a snapped glow plug on the #1 cylinder

I want to weigh in that I'm running DLC520's in the '02 w/01m and a TDTune.
I like the nozzles just fine. They are set at DBW's Stage 1 and only smoke wide open.
My 11mm IP was recently rebuilt by DFIS.
This particular tune was written for the factory auto nozzles, so a little smoke is likely.
I'd keep 'em and check and refine your timing, IQ, etc. They're good nozzles.

Check hard plastic vacuum line that goes to power brake booster along the inside of the bend, all 3 of mine where cracked and caused boost control issues/smoke/poor mpg and weak brakes.

Rob Mayercik said:

Owain: I know judging smoke is somewhat subjective, but is there any chance you could elaborate a little more on what you consider to be "a little smokey"? Right now I'm leaving a thin cloud of smoke just climbing out of my driveway in the morning, and almost any time I'm applying power I'm leaving some sort of smoke trail behind me.

*head came off to extract a snapped glow plug on the #1 cylinder

Click to expand...

You should have no smoke below about 90% throttle, simple as that. IQ in the 7-7.5 range is good, little higher than optimal but no big deal as it can be changed with tuning. Should check the pump timing as well with VCDS, but if it starts and runs normally then it's probably within spec. On the upper end of advanced is ideal.

For optimal power you want a good amount of smoke to spool the turbo, and a haze throughout the whole powerband at wide open throttle. Below 90-95% throttle it should run clean, but you will probably have a bit of diesel smell on startup. Not much can be done about that in the tune. You've gone from a ~0.158 to a 0.205 nozzle, so that's a 30% hole size increase. You can still make 80+% of that optimal power on a relatively smoke free tune, might get a little puff at ~1800 if you stomp on it but nothing serious.

It's going to need tuning, there's no way around it other than swapping nozzles. The stock manual nozzles will be about half the increase you currently saw and still make decent power stock.

(Been away from boards for a few days, just found this)
Owain,
Thanks for the info. I think it sounds like the only way I'm going to get my MPG back to the mid-40s where it was with the original nozzles is to go all the way back to that size. It sounds like, based on my own experiences, I may see an unacceptable MPG hit even with the manual nozzles.
Increasing power has never been my goal - honestly, I thought the car had plenty of power before any of this injector nightmare started and it was totally stock from nose to tail. All I wanted back then was to replace my worn-out, imbalanced OEM injectors with something fresh, and I had it in mind to maybe go to manual nozzles under the assumption that I might find losing 1-2 MPG "livable". Unfortunately, the injector vendor I dealt with talked me into the Titan .205s, and it's been nothing but smoke and crappy mileage since.
Now I just have to steal some time to actually make the call to get the smaller nozzles (at this point, most likely the OEM auto ones), and then install them once they're in-hand.
Hopefully that will get my MPGs back to where they "should" be, based on my fueling history. If it does, maybe then I'll consider a tune.

Slight update, bit of a story:

My next-door neighbor has a set of DLC520s in his car, so he offered to loan them to me back in November to try as a comparison. He and my mechanic put them in and went for a spin - reportedly MUCH better.

Then the fuel pump grenaded during the test drive. Defective pump, replaced promptly under warranty (after UPS spent a week and a half losing, searching down, and finding it when I sent it back for warranty).

Got that sorted, drove the car with my injectors back in (neighbor needed his car back together). Back to heavy black smoke, 35-36MPG at best. Finally ran intake pressure test - pumped the plumbing up to 14-15psi, heard no hissing. No boost leaks, far as I can tell.

With this assembled data, I and the Kerma folks have concluded that something's just not right with the injectors I have, and a fresh set of DLC520s are on their way out for me to swap in.

Keeping my fingers crossed that these work better...

I have the same nozzles in the Jetta and they are a good blend of milage and power.
You should be happy especially if Kerma had Drivbiwire set them up!

They did the setup on the ones I have now - all I can conclude from my experience is that the first set had some sort of problem that they didn't detect.

I'm just hoping that the replacement set works for me the way they claim they are supposed to...

Thanks for the updates on this and sorry to hear about the issues you are having with the nozzles. I am following with great interest as I am trying to decide on a nozzle upgrade as well.
I imagine the most frustrating part is all the troubleshooting to trace it back to the injectors/nozzles. After all, one of the reasons to have nozzles set up properly is to eliminate them when something isn't right.

Granted my car was already tuned, but when I went from .205's to PP764's (.230) without changing the tune my mileage went from 44 MPG in town to 35 MPG in town. I figured there was too much fuel due to the increase in size of the nozzles. I got a new tune that is conservatively fueled, and my mileage was still bad. After chasing my tail for months and after doing a LOT of reading, I decided to use Adaptation to change the SOI timing; technically speaking it shouldn't have made as much difference as it did, but it actually made over 20% increase in FE and she starts a lot easier than she used to. Unless you understand all the ins and outs and potential damage you can do to your engine, don't mess with the SOI timing settings. My tuner isn't sure why I had such a jump in FE, and neither do I, but now I don't hate my nozzle selection anymore. There is a bit more noise at idle than before, but not a great amount.

Rob Mayercik said:

Slight update, bit of a story:

My next-door neighbor has a set of DLC520s in his car, so he offered to loan them to me back in November to try as a comparison. He and my mechanic put them in and went for a spin - reportedly MUCH better.

Then the fuel pump grenaded during the test drive. Defective pump, replaced promptly under warranty (after UPS spent a week and a half losing, searching down, and finding it when I sent it back for warranty).

Got that sorted, drove the car with my injectors back in (neighbor needed his car back together). Back to heavy black smoke, 35-36MPG at best. Finally ran intake pressure test - pumped the plumbing up to 14-15psi, heard no hissing. No boost leaks, far as I can tell.

With this assembled data, I and the Kerma folks have concluded that something's just not right with the injectors I have, and a fresh set of DLC520s are on their way out for me to swap in.

Keeping my fingers crossed that these work better...

Click to expand...

I've had two sets of titan 520s where one set was 30% more flow than the other set. Certainly no consistency between sets of titan 520s. Both sets within the 4 nozzles had flow variances of 28% from one nozzle to another. I had nothing but problems with these sets from hesitations to lots of smoke and crappy econ. Dumped both sets and went with DLC-520s setup by DBW. No more hesitations, nor smoke and FE is in the upper 40s and low 50s again.

I can hear one of my cylinders is running a lot harder than the others
on dss-r .360s now, still getting the same 48 mpg that the pp764s (and the stock m/t ones) got

might try and see what they're flowing, might not

Nevada_TDI said:

Granted my car was already tuned, but when I went from .205's to PP764's (.230) without changing the tune my mileage went from 44 MPG in town to 35 MPG in town. I figured there was too much fuel due to the increase in size of the nozzles. I got a new tune that is conservatively fueled, and my mileage was still bad. After chasing my tail for months and after doing a LOT of reading, I decided to use Adaptation to change the SOI timing; technically speaking it shouldn't have made as much difference as it did, but it actually made over 20% increase in FE and she starts a lot easier than she used to. Unless you understand all the ins and outs and potential damage you can do to your engine, don't mess with the SOI timing settings. My tuner isn't sure why I had such a jump in FE, and neither do I, but now I don't hate my nozzle selection anymore. There is a bit more noise at idle than before, but not a great amount.

Click to expand...

Your tuner could take that info and adjust the tune. Adapting the timing like that adds/subtracts a lot more time in microseconds from lower rpm than it does from higher rpm, since adaptation changes the "degrees" the same across the board at all rpm and all loads. It's important to remember that the factory maps more timing at higher rpm to account for the ignition delay which remains relatively constant in time (microseconds) even as rpm increases (more degrees or crank angle pass tdc per microsecond as rpm increases, requires more advance in the start of injection to achieve the same start of combustion degrees relative to TDC.) That's why it's not necessarily a good idea to change timing in adaptation as a permanent solution. But, you can use it as input to your tuner just like some of them do with logs when they are trying to learn how the boost control works.

kinda curious which way you changed it.

5.5 degrees advanced.

Been meaning to post an update to my little saga:
Got the "fresh set" (new DLC-520 nozzles, freshly-rebuilt/calibrated injector bodies) in, had them installed.

Without checking or adjusting either timing or IQ, the reduction in smoke was astonishing - I was still getting some smoke when I got on it hard, but almost nothing under "normal" driving or hill climbs (climbing hills always threw black smoke on the first set of DLC520s). Car started and idled beautifully.

Drove it for a tank, got 40MPG (a 4-5MPG increase with nothing but the swap of injectors). Then I decided it was time to check the timing/IQ:

Before injector swap: timing at ~55 (mid of graph), IQ at 5.8 with adaptation
After injector swap: timing now at ~64-65 (bumping top of graph), IQ at 4.0 (using adaptation value from prior to swap).

I tweaked the IQ adaptation until I was at about 5.6, that got rid of almost all the smoke I had left (still get a little grey stuff when I get on moderate-hard, I may tweak the IQ up to 5.8 or 6.0). Drove two more tanks, got 42 and 41mpg.

That's the first time I've been able to get multiple consecutive tanks over 40 in several years (between the Titans and the first set of DLC520s, any tank over 37mpg was an anomaly and not consistently reproducible).

Will continue to monitor, but this is very encouraging.

I am glad to hear you have found a solution to your problem. After reading Charlie's comment I put the timing back to where it was and had my tuner change the advance "curve." My FE did increase and the off-idle drivability also improved. My nozzles are set at Stage 2 by DBW, and what really turned out to be the problem with my nozzles was LACK of fuel, that was what was causing my poor fuel economy. Apparently PP764's are kind of an odd-ball nozzle in the sense that they are really designed to flow lots of fuel above 4k RPM, but below that they are really stingy without the right tune. So I got a newly modified tune with more fuel down low to go along with my additional timing and the difference was really night-and-day in FE and "fun factor" for driving. I don't know if I will ever get 52 mpg @75 mph ever again, but I can live with 45 mpg or a little better as D2 is no longer $4.75 a gallon like it was when I had my original Stage 3 tune from TDTuning using .205 nozzles.